Comparing Credit Requirements for Mobile Home HVAC Financing

Comparing Credit Requirements for Mobile Home HVAC Financing

Overview of HVAC needs specific to mobile homes

When it comes to financing HVAC systems for mobile homes, one of the crucial considerations is understanding the various credit requirements associated with different financing options. Mobile home owners often face unique challenges due to the nature of their residence, which can impact the availability and terms of financing solutions for essential upgrades like HVAC systems. Therefore, comparing credit requirements becomes an essential step in choosing the most suitable financing option.


Ductless mini-splits provide flexible options for mobile home climate control hvac mobile home knowledge.

One common avenue for financing mobile home HVAC systems is through personal loans. These loans typically require a fair to good credit score, usually starting from around 600 or higher. Lenders assess creditworthiness based on several factors such as payment history, current debt levels, and income stability. The advantage of personal loans lies in their flexibility; they can be used for a variety of purposes, including home improvements. However, interest rates may vary significantly depending on one's credit profile, with lower scores potentially attracting higher rates.


Another option is manufacturer or dealer financing. This type of financing is often directly offered by HVAC manufacturers or dealers who partner with financial institutions to provide tailored loan products to buyers. Credit requirements here can be more lenient than traditional bank loans because these arrangements are designed to boost sales volume for manufacturers and dealers. Nevertheless, having a decent credit score remains beneficial as it could lead to better interest rates and terms.


Home equity loans or lines of credit (HELOCs) represent another viable option but are generally applicable only if the mobile home owner owns both the home and the land it sits on-often referred to as real property status. These loans are secured against the equity in one's property and typically offer lower interest rates compared to unsecured loans because they pose less risk for lenders. As such, lenders might have stringent credit requirements along with demands for substantial equity in your property.


For those who may have difficulty qualifying through conventional methods due to poor or limited credit history, there are specialized lenders that cater specifically to mobile home improvements. These institutions might consider alternative criteria beyond traditional credit scores when assessing applications-such as steady employment history or proof of ability to repay-providing opportunities even for those with sub-prime scores.


Lastly, government-backed programs like FHA Title I loans could also serve as potential avenues since they do not explicitly require excellent credit scores but do necessitate that borrowers demonstrate financial reliability through other means such as consistent income streams.


In conclusion, while each financing option presents its own set of benefits and constraints concerning credit requirements, understanding them allows homeowners to align their choices with their financial capabilities and needs effectively. By evaluating these options carefully and perhaps seeking professional advice where necessary, mobile home owners can secure optimal solutions that facilitate comfortable living environments without unnecessary financial strain.

When it comes to financing a heating, ventilation, and air conditioning (HVAC) system for a mobile home, understanding the key credit requirements is essential. The need for efficient climate control in mobile homes is undeniable, given their unique construction and insulation characteristics. However, securing financing for an HVAC system can be influenced significantly by one's credit profile. This essay explores the pivotal credit requirements and compares them across different lenders.


First and foremost, a potential borrower's credit score plays a crucial role in determining eligibility for HVAC financing. Typically, lenders look for a minimum credit score that ranges from 620 to 680. A higher score often translates into more favorable terms such as lower interest rates or reduced fees. Conversely, those with lower scores might still find options but should expect less advantageous terms.


In addition to the credit score, lenders also examine the applicant's debt-to-income (DTI) ratio. This ratio measures the applicant's total monthly debt payments against their gross monthly income and provides insight into their ability to manage additional debts responsibly. Ideally, lenders prefer a DTI ratio below 36%, though some may accept up to 43% depending on other factors.


Another critical requirement is the borrower's credit history length. Lenders favor applicants who have established credit over several years as it demonstrates their experience in managing loans effectively over time. Those with shorter histories might face challenges but could leverage other strengths like stable income or collateral.


Moreover, specific types of mobile home HVAC financing options may cater to different credit profiles. For instance, personal loans are generally more flexible with respect to credit requirements compared to specialized home improvement loans that might mandate stricter criteria due to their secured nature.


Comparing these requirements across various lenders reveals both subtle differences and commonalities. Traditional banks often uphold stringent standards given their risk-averse nature whereas online lenders might offer more lenient conditions albeit possibly at higher rates. Credit unions represent another avenue where members might benefit from personalized service and potentially softer requirements.


Ultimately, when navigating mobile home HVAC financing options, prospective borrowers should thoroughly research each lender's criteria while considering their own financial standing comprehensively. Improving one's credit score prior to application or opting for co-signers could enhance approval chances significantly.


In conclusion, understanding key credit requirements is fundamental for individuals seeking mobile home HVAC financing. By comparing these requirements across different lending institutions-taking into account factors like credit scores, DTI ratios, and historical financial behavior-borrowers can better position themselves within this competitive landscape ensuring successful acquisition of necessary funding tailored towards improving comfort in their living spaces efficiently yet affordably.

Flexible Financing Options for Mobile Home HVAC Repairs

Flexible Financing Options for Mobile Home HVAC Repairs

Managing costs effectively when it comes to mobile home HVAC repairs can be a daunting task, especially given the array of financial pressures many homeowners face.. However, flexible financing options can significantly ease this burden and provide peace of mind.

Posted by on 2024-12-30

Affordable Payment Plans for Upgrading Mobile Home AC Systems

Affordable Payment Plans for Upgrading Mobile Home AC Systems

Choosing the right payment plan for upgrading your mobile home AC system is a crucial decision that can significantly impact your financial stability and comfort at home.. With numerous options available, it's essential to consider several factors to ensure you select a plan that aligns with your needs and budget. Firstly, assess your financial situation.

Posted by on 2024-12-30

Exploring Brand-Specific Financing Solutions for Mobile Home Heating Needs

Exploring Brand-Specific Financing Solutions for Mobile Home Heating Needs

Exploring the future trends in financing for mobile home heating systems unveils a fascinating landscape of innovation and adaptation.. As we delve into brand-specific financing solutions tailored to meet the unique needs of mobile home owners, we witness an evolving market that is increasingly responsive to both technological advancements and consumer demands. The mobile home sector has traditionally faced challenges in securing affordable and accessible heating solutions due to the limited structural capabilities and specific spatial requirements of these homes.

Posted by on 2024-12-30

Understanding Financing Options for Mobile Home HVAC

When it comes to financing the installation or replacement of HVAC systems in mobile homes, understanding the differences between traditional and specialized lenders is crucial. Both types of lenders offer distinct advantages and challenges based on their credit criteria, and choosing the right one can significantly affect the financial outcome for homeowners.


Traditional lenders, such as banks and credit unions, typically have stringent credit requirements. These institutions often prioritize borrowers with established credit histories, higher credit scores, stable income sources, and substantial collateral. Their risk-averse nature ensures that they lend to customers who present a lower risk of default. As a result, borrowers who meet these criteria can benefit from lower interest rates and more favorable loan terms. However, this also means that individuals with poor or limited credit histories may find it challenging to secure financing through traditional channels.


On the other hand, specialized lenders cater specifically to niche markets like mobile home HVAC financing. These lenders understand the unique challenges associated with mobile homes and may offer more flexible credit criteria compared to traditional institutions. Specialized lenders are often more willing to work with individuals who have non-traditional income sources or less-than-perfect credit scores. They tend to assess applications on a broader spectrum of factors beyond just conventional metrics-such as employment history or recent financial improvements-which provides an opportunity for those who might not fit into the rigid frameworks of traditional lending.


Despite their flexibility, specialized lenders can come with drawbacks. The increased risk they assume by accepting borrowers with weaker credit profiles is often offset by charging higher interest rates or imposing stricter repayment terms than those offered by traditional lenders. Therefore, while these loans might be more accessible initially, they could potentially lead to higher overall costs for homeowners over time.


In summary, comparing traditional and specialized lenders in terms of their credit criteria reveals a trade-off between accessibility and cost-effectiveness. Traditional lenders offer lower interest rates but maintain high entry barriers due to their strict requirements. Conversely, specialized lenders provide greater accessibility at potentially higher costs due to their willingness to accommodate diverse financial situations. Homeowners seeking HVAC financing for mobile homes should carefully evaluate their own financial circumstances and long-term goals before choosing a lender that best suits their needs.

Understanding Financing Options for Mobile Home HVAC

Explanation of common financing packages available

When considering financing options for a new HVAC system, particularly in mobile homes, understanding the impact of credit scores on loan terms and interest rates is crucial. HVAC systems are essential for maintaining comfort and livability, especially in mobile homes where insulation and temperature control can be more challenging. However, securing financing for such an installation can be significantly influenced by one's credit score.


Credit scores are numerical representations of a person's creditworthiness, reflecting their likelihood of repaying borrowed money. These scores, typically ranging from 300 to 850, are used by lenders to assess risk. Generally, higher credit scores indicate lower risk to lenders and thus result in more favorable loan terms. This principle holds true across most types of lending, including HVAC financing for mobile homes.


For individuals with excellent credit scores (usually above 750), lenders are likely to offer loans with lower interest rates and more flexible repayment terms. This is because these borrowers have demonstrated reliability in managing debt effectively over time. As a result, they may have access to promotional offers or special financing deals that can significantly reduce the cost of borrowing.


Conversely, those with poor credit scores (below 600) might face higher interest rates and less favorable terms due to perceived increased risk by lenders. In some cases, they may also encounter difficulty obtaining any financing without providing additional collateral or having a co-signer. This scenario often leads to increased financial strain as the cost of borrowing becomes substantially higher.


Mobile home residents might face unique challenges when seeking HVAC financing due to the specific nature of their housing situation. Mobile homes sometimes carry stigmas regarding depreciation and stability which might further complicate lending scenarios even if one has a fair or good credit score (ranging from 650-700). As such, it becomes even more important for those living in mobile homes to maintain strong credit profiles to ensure access to competitive loan products.


It's also worth noting that some lenders specialize in serving customers with subprime credit or those who reside in manufactured housing communities. These lenders might offer tailored solutions that consider factors beyond just the traditional credit score model. Exploring these options could provide pathways for securing necessary funding at reasonable costs despite potential obstacles posed by lower scores or non-traditional housing circumstances.


In conclusion, while securing HVAC financing for mobile homes largely depends on one's credit score, understanding how different tiers affect loan terms is vital for making informed decisions. Maintaining a healthy credit profile remains crucial not only for accessing affordable finance but also ensuring long-term financial health through reduced interest expenditures and improved repayment conditions. For those struggling with lower scores yet needing urgent improvements like an HVAC system upgrade, seeking specialized financial advice or exploring niche lending markets could prove beneficial paths forward.

Key factors to consider when choosing a financing option

When it comes to financing options for mobile home HVAC systems, understanding credit score requirements can be crucial. Your credit score is a significant factor that lenders consider when determining your eligibility and the terms of financing you might receive. Improving your credit score can open doors to better financing options, making it easier to afford necessary upgrades or installations.


Firstly, it's important to recognize the role of your credit score in securing financing. Lenders typically assess your financial history to gauge how likely you are to repay a loan. A higher credit score often translates into lower interest rates and more favorable terms. For mobile home HVAC systems, where costs can be substantial, qualifying for better financing options can significantly reduce the financial burden.


To improve your credit score, begin by checking your current credit report from major bureaus like Experian, Equifax, and TransUnion. Ensuring that there are no errors or inaccuracies is vital as these could unjustly lower your score. Dispute any discrepancies you find promptly.


Next, focus on paying down existing debts. Credit utilization-the ratio of your current debt to your available credit-plays a critical role in determining your score. Aim to keep this ratio below 30%. If possible, pay off high-interest debts first as this will also save you money in the long run.


Timely bill payments cannot be overstated when it comes to improving credit scores. Late payments negatively impact scores significantly; thus, setting up automatic payments or reminders can help ensure bills are paid on time consistently.


Another strategy involves avoiding opening too many new accounts at once. Each application for new credit results in a hard inquiry on your report, which can temporarily lower your score. Therefore, apply judiciously and only when necessary.


Building a diverse mix of credit types-such as revolving (credit cards) and installment loans (car loans)-can also benefit your score over time if managed responsibly.


For those with limited or poor credit history, becoming an authorized user on someone else's account or applying for a secured credit card could provide opportunities to build positive payment histories without taking on excess risk.


In comparing requirements across different lenders for mobile home HVAC systems specifically, you'll notice that some may have less stringent criteria than others-often catering to borrowers with varying levels of creditworthiness. By improving your own standing before applying for such financing options, you'll not only increase the likelihood of approval but also position yourself for better terms-ultimately leading to cost savings over the life of the loan.


In summary, taking active steps towards improving one's credit score is beneficial not just broadly but particularly so when seeking specific financings like those required for mobile home HVAC systems. With diligent attention to financial habits and strategic planning around debt management and repayment schedules-you'll be well-equipped to secure more attractive financing solutions tailored exactly toward meeting both immediate needs as well as long-term goals efficiently and effectively.

Personal Loans for HVAC Systems

In the realm of mobile home ownership, maintaining a comfortable living environment is paramount, particularly when it comes to heating, ventilation, and air conditioning (HVAC) systems. However, financing these essential upgrades can pose a unique set of challenges. For many homeowners, navigating the credit requirements for HVAC financing becomes an intricate dance between financial capability and lender expectations. By examining real-world case studies of mobile home owners who have successfully secured HVAC financing, we gain valuable insights into the diverse credit landscapes they encountered.


Consider the story of Linda from Ohio, a single mother living in a vibrant community of mobile homes. With her aging HVAC system on the brink of failure during an unusually harsh winter, Linda faced an urgent need for replacement but had limited savings. Her initial search for financing options revealed that credit scores were a significant factor in determining eligibility and interest rates. With a fair credit score hovering around 650, she approached several lenders with varying results.


One lender offered her financing with an interest rate much higher than she anticipated due to her credit score being below their preferred threshold of 700. However, another lender specialized in working with clients who owned mobile homes and understood their unique circumstances. They provided more flexible terms that accommodated her financial situation by considering her steady income and payment history beyond just her credit score alone.


Similarly, John and Mary from Texas found themselves in dire need of upgrading their outdated HVAC system to combat the sweltering summer heat. Their challenge was compounded by having recently refinanced their mobile home mortgage which temporarily affected their overall credit profile. Despite this setback, they were able to secure favorable terms through a local credit union that had specific programs tailored for energy-efficient upgrades.


The key to John and Mary's success lay not only in their diligent research but also in building relationships with local financial institutions familiar with regional housing market conditions. This approach allowed them access to lower interest rates despite having less-than-perfect credit at that moment.


These case studies highlight critical lessons for mobile home owners embarking on similar journeys toward HVAC financing. Firstly, understanding one's own credit profile and how it aligns with lender requirements is crucial; doing so allows homeowners like Linda to strategically target lenders who offer tailored solutions rather than generic high-interest loans based solely on traditional metrics such as FICO scores.


Secondly - as demonstrated by John and Mary - engaging directly with community-based lenders or those specializing in niche markets often yields better outcomes compared to larger national entities whose criteria may not account sufficiently for specific homeowner scenarios involving mobile properties.


Ultimately though challenges remain prevalent when seeking funding pathways within this sector-especially given historical biases against manufactured housing-it is evident through these narratives that persistence coupled with informed decision-making can indeed pave pathways toward successful acquisition without undue strain upon personal finances nor compromise upon desired quality standards expected from modern-day residential climate control systems today's consumers seek eagerly therein!

Tubular heat exchanger
Partial view into inlet plenum of shell and tube heat exchanger of a refrigerant based chiller for providing air-conditioning to a building

A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes.[1] The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact.[2] They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.[3]

Flow arrangement

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Countercurrent (A) and parallel (B) flows

There are three primary classifications of heat exchangers according to their flow arrangement. In parallel-flow heat exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow heat exchangers the fluids enter the exchanger from opposite ends. The counter current design is the most efficient, in that it can transfer the most heat from the heat (transfer) medium per unit mass due to the fact that the average temperature difference along any unit length is higher. See countercurrent exchange. In a cross-flow heat exchanger, the fluids travel roughly perpendicular to one another through the exchanger.

For efficiency, heat exchangers are designed to maximize the surface area of the wall between the two fluids, while minimizing resistance to fluid flow through the exchanger. The exchanger's performance can also be affected by the addition of fins or corrugations in one or both directions, which increase surface area and may channel fluid flow or induce turbulence.

The driving temperature across the heat transfer surface varies with position, but an appropriate mean temperature can be defined. In most simple systems this is the "log mean temperature difference" (LMTD). Sometimes direct knowledge of the LMTD is not available and the NTU method is used.

Types

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Double pipe heat exchangers are the simplest exchangers used in industries. On one hand, these heat exchangers are cheap for both design and maintenance, making them a good choice for small industries. On the other hand, their low efficiency coupled with the high space occupied in large scales, has led modern industries to use more efficient heat exchangers like shell and tube or plate. However, since double pipe heat exchangers are simple, they are used to teach heat exchanger design basics to students as the fundamental rules for all heat exchangers are the same.

1. Double-pipe heat exchanger

When one fluid flows through the smaller pipe, the other flows through the annular gap between the two pipes. These flows may be parallel or counter-flows in a double pipe heat exchanger.

(a) Parallel flow, where both hot and cold liquids enter the heat exchanger from the same side, flow in the same direction and exit at the same end. This configuration is preferable when the two fluids are intended to reach exactly the same temperature, as it reduces thermal stress and produces a more uniform rate of heat transfer.

(b) Counter-flow, where hot and cold fluids enter opposite sides of the heat exchanger, flow in opposite directions, and exit at opposite ends. This configuration is preferable when the objective is to maximize heat transfer between the fluids, as it creates a larger temperature differential when used under otherwise similar conditions.[citation needed]

The figure above illustrates the parallel and counter-flow flow directions of the fluid exchanger.

2. Shell-and-tube heat exchanger

In a shell-and-tube heat exchanger, two fluids at different temperatures flow through the heat exchanger. One of the fluids flows through the tube side and the other fluid flows outside the tubes, but inside the shell (shell side).

Baffles are used to support the tubes, direct the fluid flow to the tubes in an approximately natural manner, and maximize the turbulence of the shell fluid. There are many various kinds of baffles, and the choice of baffle form, spacing, and geometry depends on the allowable flow rate of the drop in shell-side force, the need for tube support, and the flow-induced vibrations. There are several variations of shell-and-tube exchangers available; the differences lie in the arrangement of flow configurations and details of construction.

In application to cool air with shell-and-tube technology (such as intercooler / charge air cooler for combustion engines), fins can be added on the tubes to increase heat transfer area on air side and create a tubes & fins configuration.

3. Plate Heat Exchanger

A plate heat exchanger contains an amount of thin shaped heat transfer plates bundled together. The gasket arrangement of each pair of plates provides two separate channel system. Each pair of plates form a channel where the fluid can flow through. The pairs are attached by welding and bolting methods. The following shows the components in the heat exchanger.

In single channels the configuration of the gaskets enables flow through. Thus, this allows the main and secondary media in counter-current flow. A gasket plate heat exchanger has a heat region from corrugated plates. The gasket function as seal between plates and they are located between frame and pressure plates. Fluid flows in a counter current direction throughout the heat exchanger. An efficient thermal performance is produced. Plates are produced in different depths, sizes and corrugated shapes. There are different types of plates available including plate and frame, plate and shell and spiral plate heat exchangers. The distribution area guarantees the flow of fluid to the whole heat transfer surface. This helps to prevent stagnant area that can cause accumulation of unwanted material on solid surfaces. High flow turbulence between plates results in a greater transfer of heat and a decrease in pressure.

4. Condensers and Boilers Heat exchangers using a two-phase heat transfer system are condensers, boilers and evaporators. Condensers are instruments that take and cool hot gas or vapor to the point of condensation and transform the gas into a liquid form. The point at which liquid transforms to gas is called vaporization and vice versa is called condensation. Surface condenser is the most common type of condenser where it includes a water supply device. Figure 5 below displays a two-pass surface condenser.

The pressure of steam at the turbine outlet is low where the steam density is very low where the flow rate is very high. To prevent a decrease in pressure in the movement of steam from the turbine to condenser, the condenser unit is placed underneath and connected to the turbine. Inside the tubes the cooling water runs in a parallel way, while steam moves in a vertical downward position from the wide opening at the top and travel through the tube. Furthermore, boilers are categorized as initial application of heat exchangers. The word steam generator was regularly used to describe a boiler unit where a hot liquid stream is the source of heat rather than the combustion products. Depending on the dimensions and configurations the boilers are manufactured. Several boilers are only able to produce hot fluid while on the other hand the others are manufactured for steam production.

Shell and tube

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A shell and tube heat exchanger
Shell and tube heat exchanger

Shell and tube heat exchangers consist of a series of tubes which contain fluid that must be either heated or cooled. A second fluid runs over the tubes that are being heated or cooled so that it can either provide the heat or absorb the heat required. A set of tubes is called the tube bundle and can be made up of several types of tubes: plain, longitudinally finned, etc. Shell and tube heat exchangers are typically used for high-pressure applications (with pressures greater than 30 bar and temperatures greater than 260 °C).[4] This is because the shell and tube heat exchangers are robust due to their shape.
Several thermal design features must be considered when designing the tubes in the shell and tube heat exchangers: There can be many variations on the shell and tube design. Typically, the ends of each tube are connected to plenums (sometimes called water boxes) through holes in tubesheets. The tubes may be straight or bent in the shape of a U, called U-tubes.

  • Tube diameter: Using a small tube diameter makes the heat exchanger both economical and compact. However, it is more likely for the heat exchanger to foul up faster and the small size makes mechanical cleaning of the fouling difficult. To prevail over the fouling and cleaning problems, larger tube diameters can be used. Thus to determine the tube diameter, the available space, cost and fouling nature of the fluids must be considered.
  • Tube thickness: The thickness of the wall of the tubes is usually determined to ensure:
    • There is enough room for corrosion
    • That flow-induced vibration has resistance
    • Axial strength
    • Availability of spare parts
    • Hoop strength (to withstand internal tube pressure)
    • Buckling strength (to withstand overpressure in the shell)
  • Tube length: heat exchangers are usually cheaper when they have a smaller shell diameter and a long tube length. Thus, typically there is an aim to make the heat exchanger as long as physically possible whilst not exceeding production capabilities. However, there are many limitations for this, including space available at the installation site and the need to ensure tubes are available in lengths that are twice the required length (so they can be withdrawn and replaced). Also, long, thin tubes are difficult to take out and replace.
  • Tube pitch: when designing the tubes, it is practical to ensure that the tube pitch (i.e., the centre-centre distance of adjoining tubes) is not less than 1.25 times the tubes' outside diameter. A larger tube pitch leads to a larger overall shell diameter, which leads to a more expensive heat exchanger.
  • Tube corrugation: this type of tubes, mainly used for the inner tubes, increases the turbulence of the fluids and the effect is very important in the heat transfer giving a better performance.
  • Tube Layout: refers to how tubes are positioned within the shell. There are four main types of tube layout, which are, triangular (30°), rotated triangular (60°), square (90°) and rotated square (45°). The triangular patterns are employed to give greater heat transfer as they force the fluid to flow in a more turbulent fashion around the piping. Square patterns are employed where high fouling is experienced and cleaning is more regular.
  • Baffle Design: baffles are used in shell and tube heat exchangers to direct fluid across the tube bundle. They run perpendicularly to the shell and hold the bundle, preventing the tubes from sagging over a long length. They can also prevent the tubes from vibrating. The most common type of baffle is the segmental baffle. The semicircular segmental baffles are oriented at 180 degrees to the adjacent baffles forcing the fluid to flow upward and downwards between the tube bundle. Baffle spacing is of large thermodynamic concern when designing shell and tube heat exchangers. Baffles must be spaced with consideration for the conversion of pressure drop and heat transfer. For thermo economic optimization it is suggested that the baffles be spaced no closer than 20% of the shell's inner diameter. Having baffles spaced too closely causes a greater pressure drop because of flow redirection. Consequently, having the baffles spaced too far apart means that there may be cooler spots in the corners between baffles. It is also important to ensure the baffles are spaced close enough that the tubes do not sag. The other main type of baffle is the disc and doughnut baffle, which consists of two concentric baffles. An outer, wider baffle looks like a doughnut, whilst the inner baffle is shaped like a disk. This type of baffle forces the fluid to pass around each side of the disk then through the doughnut baffle generating a different type of fluid flow.
  • Tubes & fins Design: in application to cool air with shell-and-tube technology (such as intercooler / charge air cooler for combustion engines), the difference in heat transfer between air and cold fluid can be such that there is a need to increase heat transfer area on air side. For this function fins can be added on the tubes to increase heat transfer area on air side and create a tubes & fins configuration.

Fixed tube liquid-cooled heat exchangers especially suitable for marine and harsh applications can be assembled with brass shells, copper tubes, brass baffles, and forged brass integral end hubs.[citation needed] (See: Copper in heat exchangers).

Plate

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Conceptual diagram of a plate and frame heat exchanger
A single plate heat exchanger
An interchangeable plate heat exchanger directly applied to the system of a swimming pool

Another type of heat exchanger is the plate heat exchanger. These exchangers are composed of many thin, slightly separated plates that have very large surface areas and small fluid flow passages for heat transfer. Advances in gasket and brazing technology have made the plate-type heat exchanger increasingly practical. In HVAC applications, large heat exchangers of this type are called plate-and-frame; when used in open loops, these heat exchangers are normally of the gasket type to allow periodic disassembly, cleaning, and inspection. There are many types of permanently bonded plate heat exchangers, such as dip-brazed, vacuum-brazed, and welded plate varieties, and they are often specified for closed-loop applications such as refrigeration. Plate heat exchangers also differ in the types of plates that are used, and in the configurations of those plates. Some plates may be stamped with "chevron", dimpled, or other patterns, where others may have machined fins and/or grooves.

When compared to shell and tube exchangers, the stacked-plate arrangement typically has lower volume and cost. Another difference between the two is that plate exchangers typically serve low to medium pressure fluids, compared to medium and high pressures of shell and tube. A third and important difference is that plate exchangers employ more countercurrent flow rather than cross current flow, which allows lower approach temperature differences, high temperature changes, and increased efficiencies.

Plate and shell

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A third type of heat exchanger is a plate and shell heat exchanger, which combines plate heat exchanger with shell and tube heat exchanger technologies. The heart of the heat exchanger contains a fully welded circular plate pack made by pressing and cutting round plates and welding them together. Nozzles carry flow in and out of the platepack (the 'Plate side' flowpath). The fully welded platepack is assembled into an outer shell that creates a second flowpath ( the 'Shell side'). Plate and shell technology offers high heat transfer, high pressure, high operating temperature, compact size, low fouling and close approach temperature. In particular, it does completely without gaskets, which provides security against leakage at high pressures and temperatures.

Adiabatic wheel

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A fourth type of heat exchanger uses an intermediate fluid or solid store to hold heat, which is then moved to the other side of the heat exchanger to be released. Two examples of this are adiabatic wheels, which consist of a large wheel with fine threads rotating through the hot and cold fluids, and fluid heat exchangers.

Plate fin

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This type of heat exchanger uses "sandwiched" passages containing fins to increase the effectiveness of the unit. The designs include crossflow and counterflow coupled with various fin configurations such as straight fins, offset fins and wavy fins.

Plate and fin heat exchangers are usually made of aluminum alloys, which provide high heat transfer efficiency. The material enables the system to operate at a lower temperature difference and reduce the weight of the equipment. Plate and fin heat exchangers are mostly used for low temperature services such as natural gas, helium and oxygen liquefaction plants, air separation plants and transport industries such as motor and aircraft engines.

Advantages of plate and fin heat exchangers:

  • High heat transfer efficiency especially in gas treatment
  • Larger heat transfer area
  • Approximately 5 times lighter in weight than that of shell and tube heat exchanger. [citation needed]
  • Able to withstand high pressure

Disadvantages of plate and fin heat exchangers:

  • Might cause clogging as the pathways are very narrow
  • Difficult to clean the pathways
  • Aluminium alloys are susceptible to Mercury Liquid Embrittlement Failure

Finned tube

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The usage of fins in a tube-based heat exchanger is common when one of the working fluids is a low-pressure gas, and is typical for heat exchangers that operate using ambient air, such as automotive radiators and HVAC air condensers. Fins dramatically increase the surface area with which heat can be exchanged, which improves the efficiency of conducting heat to a fluid with very low thermal conductivity, such as air. The fins are typically made from aluminium or copper since they must conduct heat from the tube along the length of the fins, which are usually very thin.

The main construction types of finned tube exchangers are:

  • A stack of evenly-spaced metal plates act as the fins and the tubes are pressed through pre-cut holes in the fins, good thermal contact usually being achieved by deformation of the fins around the tube. This is typical construction for HVAC air coils and large refrigeration condensers.
  • Fins are spiral-wound onto individual tubes as a continuous strip, the tubes can then be assembled in banks, bent in a serpentine pattern, or wound into large spirals.
  • Zig-zag metal strips are sandwiched between flat rectangular tubes, often being soldered or brazed together for good thermal and mechanical strength. This is common in low-pressure heat exchangers such as water-cooling radiators. Regular flat tubes will expand and deform if exposed to high pressures but flat microchannel tubes allow this construction to be used for high pressures.[5]

Stacked-fin or spiral-wound construction can be used for the tubes inside shell-and-tube heat exchangers when high efficiency thermal transfer to a gas is required.

In electronics cooling, heat sinks, particularly those using heat pipes, can have a stacked-fin construction.

Pillow plate

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A pillow plate heat exchanger is commonly used in the dairy industry for cooling milk in large direct-expansion stainless steel bulk tanks. Nearly the entire surface area of a tank can be integrated with this heat exchanger, without gaps that would occur between pipes welded to the exterior of the tank. Pillow plates can also be constructed as flat plates that are stacked inside a tank. The relatively flat surface of the plates allows easy cleaning, especially in sterile applications.

The pillow plate can be constructed using either a thin sheet of metal welded to the thicker surface of a tank or vessel, or two thin sheets welded together. The surface of the plate is welded with a regular pattern of dots or a serpentine pattern of weld lines. After welding the enclosed space is pressurised with sufficient force to cause the thin metal to bulge out around the welds, providing a space for heat exchanger liquids to flow, and creating a characteristic appearance of a swelled pillow formed out of metal.

Waste heat recovery units

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A waste heat recovery unit (WHRU) is a heat exchanger that recovers heat from a hot gas stream while transferring it to a working medium, typically water or oils. The hot gas stream can be the exhaust gas from a gas turbine or a diesel engine or a waste gas from industry or refinery.

Large systems with high volume and temperature gas streams, typical in industry, can benefit from steam Rankine cycle (SRC) in a waste heat recovery unit, but these cycles are too expensive for small systems. The recovery of heat from low temperature systems requires different working fluids than steam.

An organic Rankine cycle (ORC) waste heat recovery unit can be more efficient at low temperature range using refrigerants that boil at lower temperatures than water. Typical organic refrigerants are ammonia, pentafluoropropane (R-245fa and R-245ca), and toluene.

The refrigerant is boiled by the heat source in the evaporator to produce super-heated vapor. This fluid is expanded in the turbine to convert thermal energy to kinetic energy, that is converted to electricity in the electrical generator. This energy transfer process decreases the temperature of the refrigerant that, in turn, condenses. The cycle is closed and completed using a pump to send the fluid back to the evaporator.

Dynamic scraped surface

[edit]

Another type of heat exchanger is called "(dynamic) scraped surface heat exchanger". This is mainly used for heating or cooling with high-viscosity products, crystallization processes, evaporation and high-fouling applications. Long running times are achieved due to the continuous scraping of the surface, thus avoiding fouling and achieving a sustainable heat transfer rate during the process.

Phase-change

[edit]
Typical kettle reboiler used for industrial distillation towers
Typical water-cooled surface condenser

In addition to heating up or cooling down fluids in just a single phase, heat exchangers can be used either to heat a liquid to evaporate (or boil) it or used as condensers to cool a vapor and condense it to a liquid. In chemical plants and refineries, reboilers used to heat incoming feed for distillation towers are often heat exchangers.[6][7]

Distillation set-ups typically use condensers to condense distillate vapors back into liquid.

Power plants that use steam-driven turbines commonly use heat exchangers to boil water into steam. Heat exchangers or similar units for producing steam from water are often called boilers or steam generators.

In the nuclear power plants called pressurized water reactors, special large heat exchangers pass heat from the primary (reactor plant) system to the secondary (steam plant) system, producing steam from water in the process. These are called steam generators. All fossil-fueled and nuclear power plants using steam-driven turbines have surface condensers to convert the exhaust steam from the turbines into condensate (water) for re-use.[8][9]

To conserve energy and cooling capacity in chemical and other plants, regenerative heat exchangers can transfer heat from a stream that must be cooled to another stream that must be heated, such as distillate cooling and reboiler feed pre-heating.

This term can also refer to heat exchangers that contain a material within their structure that has a change of phase. This is usually a solid to liquid phase due to the small volume difference between these states. This change of phase effectively acts as a buffer because it occurs at a constant temperature but still allows for the heat exchanger to accept additional heat. One example where this has been investigated is for use in high power aircraft electronics.

Heat exchangers functioning in multiphase flow regimes may be subject to the Ledinegg instability.

Direct contact

[edit]

Direct contact heat exchangers involve heat transfer between hot and cold streams of two phases in the absence of a separating wall.[10] Thus such heat exchangers can be classified as:

  • Gas – liquid
  • Immiscible liquid – liquid
  • Solid-liquid or solid – gas

Most direct contact heat exchangers fall under the Gas – Liquid category, where heat is transferred between a gas and liquid in the form of drops, films or sprays.[4]

Such types of heat exchangers are used predominantly in air conditioning, humidification, industrial hot water heating, water cooling and condensing plants.[11]

Phases[12] Continuous phase Driving force Change of phase Examples
Gas – Liquid Gas Gravity No Spray columns, packed columns
      Yes Cooling towers, falling droplet evaporators
    Forced No Spray coolers/quenchers
    Liquid flow Yes Spray condensers/evaporation, jet condensers
  Liquid Gravity No Bubble columns, perforated tray columns
      Yes Bubble column condensers
    Forced No Gas spargers
    Gas flow Yes Direct contact evaporators, submerged combustion

Microchannel

[edit]

Microchannel heat exchangers are multi-pass parallel flow heat exchangers consisting of three main elements: manifolds (inlet and outlet), multi-port tubes with the hydraulic diameters smaller than 1mm, and fins. All the elements usually brazed together using controllable atmosphere brazing process. Microchannel heat exchangers are characterized by high heat transfer ratio, low refrigerant charges, compact size, and lower airside pressure drops compared to finned tube heat exchangers.[citation needed] Microchannel heat exchangers are widely used in automotive industry as the car radiators, and as condenser, evaporator, and cooling/heating coils in HVAC industry.

Micro heat exchangers, Micro-scale heat exchangers, or microstructured heat exchangers are heat exchangers in which (at least one) fluid flows in lateral confinements with typical dimensions below 1 mm. The most typical such confinement are microchannels, which are channels with a hydraulic diameter below 1 mm. Microchannel heat exchangers can be made from metal or ceramics.[13] Microchannel heat exchangers can be used for many applications including:

  • high-performance aircraft gas turbine engines[14]
  • heat pumps[15]
  • Microprocessor and microchip cooling[16]
  • air conditioning[17]

HVAC and refrigeration air coils

[edit]

One of the widest uses of heat exchangers is for refrigeration and air conditioning. This class of heat exchangers is commonly called air coils, or just coils due to their often-serpentine internal tubing, or condensers in the case of refrigeration, and are typically of the finned tube type. Liquid-to-air, or air-to-liquid HVAC coils are typically of modified crossflow arrangement. In vehicles, heat coils are often called heater cores.

On the liquid side of these heat exchangers, the common fluids are water, a water-glycol solution, steam, or a refrigerant. For heating coils, hot water and steam are the most common, and this heated fluid is supplied by boilers, for example. For cooling coils, chilled water and refrigerant are most common. Chilled water is supplied from a chiller that is potentially located very far away, but refrigerant must come from a nearby condensing unit. When a refrigerant is used, the cooling coil is the evaporator, and the heating coil is the condenser in the vapor-compression refrigeration cycle. HVAC coils that use this direct-expansion of refrigerants are commonly called DX coils. Some DX coils are "microchannel" type.[5]

On the air side of HVAC coils a significant difference exists between those used for heating, and those for cooling. Due to psychrometrics, air that is cooled often has moisture condensing out of it, except with extremely dry air flows. Heating some air increases that airflow's capacity to hold water. So heating coils need not consider moisture condensation on their air-side, but cooling coils must be adequately designed and selected to handle their particular latent (moisture) as well as the sensible (cooling) loads. The water that is removed is called condensate.

For many climates, water or steam HVAC coils can be exposed to freezing conditions. Because water expands upon freezing, these somewhat expensive and difficult to replace thin-walled heat exchangers can easily be damaged or destroyed by just one freeze. As such, freeze protection of coils is a major concern of HVAC designers, installers, and operators.

The introduction of indentations placed within the heat exchange fins controlled condensation, allowing water molecules to remain in the cooled air.[18]

The heat exchangers in direct-combustion furnaces, typical in many residences, are not 'coils'. They are, instead, gas-to-air heat exchangers that are typically made of stamped steel sheet metal. The combustion products pass on one side of these heat exchangers, and air to heat on the other. A cracked heat exchanger is therefore a dangerous situation that requires immediate attention because combustion products may enter living space.

Helical-coil

[edit]
Helical-Coil Heat Exchanger sketch, which consists of a shell, core, and tubes (Scott S. Haraburda design)

Although double-pipe heat exchangers are the simplest to design, the better choice in the following cases would be the helical-coil heat exchanger (HCHE):

  • The main advantage of the HCHE, like that for the Spiral heat exchanger (SHE), is its highly efficient use of space, especially when it's limited and not enough straight pipe can be laid.[19]
  • Under conditions of low flowrates (or laminar flow), such that the typical shell-and-tube exchangers have low heat-transfer coefficients and becoming uneconomical.[19]
  • When there is low pressure in one of the fluids, usually from accumulated pressure drops in other process equipment.[19]
  • When one of the fluids has components in multiple phases (solids, liquids, and gases), which tends to create mechanical problems during operations, such as plugging of small-diameter tubes.[20] Cleaning of helical coils for these multiple-phase fluids can prove to be more difficult than its shell and tube counterpart; however the helical coil unit would require cleaning less often.

These have been used in the nuclear industry as a method for exchanging heat in a sodium system for large liquid metal fast breeder reactors since the early 1970s, using an HCHE device invented by Charles E. Boardman and John H. Germer.[21] There are several simple methods for designing HCHE for all types of manufacturing industries, such as using the Ramachandra K. Patil (et al.) method from India and the Scott S. Haraburda method from the United States.[19][20]

However, these are based upon assumptions of estimating inside heat transfer coefficient, predicting flow around the outside of the coil, and upon constant heat flux.[22]

Spiral

[edit]
Schematic drawing of a spiral heat exchanger

A modification to the perpendicular flow of the typical HCHE involves the replacement of shell with another coiled tube, allowing the two fluids to flow parallel to one another, and which requires the use of different design calculations.[23] These are the Spiral Heat Exchangers (SHE), which may refer to a helical (coiled) tube configuration, more generally, the term refers to a pair of flat surfaces that are coiled to form the two channels in a counter-flow arrangement. Each of the two channels has one long curved path. A pair of fluid ports are connected tangentially to the outer arms of the spiral, and axial ports are common, but optional.[24]

The main advantage of the SHE is its highly efficient use of space. This attribute is often leveraged and partially reallocated to gain other improvements in performance, according to well known tradeoffs in heat exchanger design. (A notable tradeoff is capital cost vs operating cost.) A compact SHE may be used to have a smaller footprint and thus lower all-around capital costs, or an oversized SHE may be used to have less pressure drop, less pumping energy, higher thermal efficiency, and lower energy costs.

Construction

[edit]

The distance between the sheets in the spiral channels is maintained by using spacer studs that were welded prior to rolling. Once the main spiral pack has been rolled, alternate top and bottom edges are welded and each end closed by a gasketed flat or conical cover bolted to the body. This ensures no mixing of the two fluids occurs. Any leakage is from the periphery cover to the atmosphere, or to a passage that contains the same fluid.[25]

Self cleaning

[edit]

Spiral heat exchangers are often used in the heating of fluids that contain solids and thus tend to foul the inside of the heat exchanger. The low pressure drop lets the SHE handle fouling more easily. The SHE uses a “self cleaning” mechanism, whereby fouled surfaces cause a localized increase in fluid velocity, thus increasing the drag (or fluid friction) on the fouled surface, thus helping to dislodge the blockage and keep the heat exchanger clean. "The internal walls that make up the heat transfer surface are often rather thick, which makes the SHE very robust, and able to last a long time in demanding environments."[citation needed] They are also easily cleaned, opening out like an oven where any buildup of foulant can be removed by pressure washing.

Self-cleaning water filters are used to keep the system clean and running without the need to shut down or replace cartridges and bags.

Flow arrangements

[edit]
A comparison between the operations and effects of a cocurrent and a countercurrent flow exchange system is depicted by the upper and lower diagrams respectively. In both it is assumed (and indicated) that red has a higher value (e.g. of temperature) than blue and that the property being transported in the channels therefore flows from red to blue. Channels are contiguous if effective exchange is to occur (i.e. there can be no gap between the channels).

There are three main types of flows in a spiral heat exchanger:

  • Counter-current Flow: Fluids flow in opposite directions. These are used for liquid-liquid, condensing and gas cooling applications. Units are usually mounted vertically when condensing vapour and mounted horizontally when handling high concentrations of solids.
  • Spiral Flow/Cross Flow: One fluid is in spiral flow and the other in a cross flow. Spiral flow passages are welded at each side for this type of spiral heat exchanger. This type of flow is suitable for handling low density gas, which passes through the cross flow, avoiding pressure loss. It can be used for liquid-liquid applications if one liquid has a considerably greater flow rate than the other.
  • Distributed Vapour/Spiral flow: This design is that of a condenser, and is usually mounted vertically. It is designed to cater for the sub-cooling of both condensate and non-condensables. The coolant moves in a spiral and leaves via the top. Hot gases that enter leave as condensate via the bottom outlet.

Applications

[edit]

The Spiral heat exchanger is good for applications such as pasteurization, digester heating, heat recovery, pre-heating (see: recuperator), and effluent cooling. For sludge treatment, SHEs are generally smaller than other types of heat exchangers.[citation needed] These are used to transfer the heat.

Selection

[edit]

Due to the many variables involved, selecting optimal heat exchangers is challenging. Hand calculations are possible, but many iterations are typically needed. As such, heat exchangers are most often selected via computer programs, either by system designers, who are typically engineers, or by equipment vendors.

To select an appropriate heat exchanger, the system designers (or equipment vendors) would firstly consider the design limitations for each heat exchanger type. Though cost is often the primary criterion, several other selection criteria are important:

  • High/low pressure limits
  • Thermal performance
  • Temperature ranges
  • Product mix (liquid/liquid, particulates or high-solids liquid)
  • Pressure drops across the exchanger
  • Fluid flow capacity
  • Cleanability, maintenance and repair
  • Materials required for construction
  • Ability and ease of future expansion
  • Material selection, such as copper, aluminium, carbon steel, stainless steel, nickel alloys, ceramic, polymer, and titanium.[26][27]

Small-diameter coil technologies are becoming more popular in modern air conditioning and refrigeration systems because they have better rates of heat transfer than conventional sized condenser and evaporator coils with round copper tubes and aluminum or copper fin that have been the standard in the HVAC industry. Small diameter coils can withstand the higher pressures required by the new generation of environmentally friendlier refrigerants. Two small diameter coil technologies are currently available for air conditioning and refrigeration products: copper microgroove[28] and brazed aluminum microchannel.[citation needed]

Choosing the right heat exchanger (HX) requires some knowledge of the different heat exchanger types, as well as the environment where the unit must operate. Typically in the manufacturing industry, several differing types of heat exchangers are used for just one process or system to derive the final product. For example, a kettle HX for pre-heating, a double pipe HX for the 'carrier' fluid and a plate and frame HX for final cooling. With sufficient knowledge of heat exchanger types and operating requirements, an appropriate selection can be made to optimise the process.[29]

Monitoring and maintenance

[edit]

Online monitoring of commercial heat exchangers is done by tracking the overall heat transfer coefficient. The overall heat transfer coefficient tends to decline over time due to fouling.

By periodically calculating the overall heat transfer coefficient from exchanger flow rates and temperatures, the owner of the heat exchanger can estimate when cleaning the heat exchanger is economically attractive.

Integrity inspection of plate and tubular heat exchanger can be tested in situ by the conductivity or helium gas methods. These methods confirm the integrity of the plates or tubes to prevent any cross contamination and the condition of the gaskets.

Mechanical integrity monitoring of heat exchanger tubes may be conducted through Nondestructive methods such as eddy current testing.

Fouling

[edit]
A heat exchanger in a steam power station contaminated with macrofouling

Fouling occurs when impurities deposit on the heat exchange surface. Deposition of these impurities can decrease heat transfer effectiveness significantly over time and are caused by:

  • Low wall shear stress
  • Low fluid velocities
  • High fluid velocities
  • Reaction product solid precipitation
  • Precipitation of dissolved impurities due to elevated wall temperatures

The rate of heat exchanger fouling is determined by the rate of particle deposition less re-entrainment/suppression. This model was originally proposed in 1959 by Kern and Seaton.

Crude Oil Exchanger Fouling. In commercial crude oil refining, crude oil is heated from 21 °C (70 °F) to 343 °C (649 °F) prior to entering the distillation column. A series of shell and tube heat exchangers typically exchange heat between crude oil and other oil streams to heat the crude to 260 °C (500 °F) prior to heating in a furnace. Fouling occurs on the crude side of these exchangers due to asphaltene insolubility. The nature of asphaltene solubility in crude oil was successfully modeled by Wiehe and Kennedy.[30] The precipitation of insoluble asphaltenes in crude preheat trains has been successfully modeled as a first order reaction by Ebert and Panchal[31] who expanded on the work of Kern and Seaton.

Cooling Water Fouling. Cooling water systems are susceptible to fouling. Cooling water typically has a high total dissolved solids content and suspended colloidal solids. Localized precipitation of dissolved solids occurs at the heat exchange surface due to wall temperatures higher than bulk fluid temperature. Low fluid velocities (less than 3 ft/s) allow suspended solids to settle on the heat exchange surface. Cooling water is typically on the tube side of a shell and tube exchanger because it's easy to clean. To prevent fouling, designers typically ensure that cooling water velocity is greater than 0.9 m/s and bulk fluid temperature is maintained less than 60 °C (140 °F). Other approaches to control fouling control combine the "blind" application of biocides and anti-scale chemicals with periodic lab testing.

Maintenance

[edit]

Plate and frame heat exchangers can be disassembled and cleaned periodically. Tubular heat exchangers can be cleaned by such methods as acid cleaning, sandblasting, high-pressure water jet, bullet cleaning, or drill rods.

In large-scale cooling water systems for heat exchangers, water treatment such as purification, addition of chemicals, and testing, is used to minimize fouling of the heat exchange equipment. Other water treatment is also used in steam systems for power plants, etc. to minimize fouling and corrosion of the heat exchange and other equipment.

A variety of companies have started using water borne oscillations technology to prevent biofouling. Without the use of chemicals, this type of technology has helped in providing a low-pressure drop in heat exchangers.

Design and manufacturing regulations

[edit]

The design and manufacturing of heat exchangers has numerous regulations, which vary according to the region in which they will be used.

Design and manufacturing codes include: ASME Boiler and Pressure Vessel Code (US); PD 5500 (UK); BS 1566 (UK);[32] EN 13445 (EU); CODAP (French); Pressure Equipment Safety Regulations 2016 (PER) (UK); Pressure Equipment Directive (EU); NORSOK (Norwegian); TEMA;[33] API 12; and API 560.[citation needed]

In nature

[edit]

Humans

[edit]

The human nasal passages serve as a heat exchanger, with cool air being inhaled and warm air being exhaled. Its effectiveness can be demonstrated by putting the hand in front of the face and exhaling, first through the nose and then through the mouth. Air exhaled through the nose is substantially cooler.[34][35] This effect can be enhanced with clothing, by, for example, wearing a scarf over the face while breathing in cold weather.

In species that have external testes (such as human), the artery to the testis is surrounded by a mesh of veins called the pampiniform plexus. This cools the blood heading to the testes, while reheating the returning blood.

Birds, fish, marine mammals

[edit]
Counter-current exchange conservation circuit

"Countercurrent" heat exchangers occur naturally in the circulatory systems of fish, whales and other marine mammals. Arteries to the skin carrying warm blood are intertwined with veins from the skin carrying cold blood, causing the warm arterial blood to exchange heat with the cold venous blood. This reduces the overall heat loss in cold water. Heat exchangers are also present in the tongues of baleen whales as large volumes of water flow through their mouths.[36][37] Wading birds use a similar system to limit heat losses from their body through their legs into the water.

Carotid rete

[edit]

Carotid rete is a counter-current heat exchanging organ in some ungulates. The blood ascending the carotid arteries on its way to the brain, flows via a network of vessels where heat is discharged to the veins of cooler blood descending from the nasal passages. The carotid rete allows Thomson's gazelle to maintain its brain almost 3 °C (5.4 °F) cooler than the rest of the body, and therefore aids in tolerating bursts in metabolic heat production such as associated with outrunning cheetahs (during which the body temperature exceeds the maximum temperature at which the brain could function).[38] Humans with other primates lack a carotid rete.[39]

In industry

[edit]

Heat exchangers are widely used in industry both for cooling and heating large scale industrial processes. The type and size of heat exchanger used can be tailored to suit a process depending on the type of fluid, its phase, temperature, density, viscosity, pressures, chemical composition and various other thermodynamic properties.

In many industrial processes there is waste of energy or a heat stream that is being exhausted, heat exchangers can be used to recover this heat and put it to use by heating a different stream in the process. This practice saves a lot of money in industry, as the heat supplied to other streams from the heat exchangers would otherwise come from an external source that is more expensive and more harmful to the environment.

Heat exchangers are used in many industries, including:

  • Waste water treatment
  • Refrigeration
  • Wine and beer making
  • Petroleum refining
  • Nuclear power

In waste water treatment, heat exchangers play a vital role in maintaining optimal temperatures within anaerobic digesters to promote the growth of microbes that remove pollutants. Common types of heat exchangers used in this application are the double pipe heat exchanger as well as the plate and frame heat exchanger.

In aircraft

[edit]

In commercial aircraft heat exchangers are used to take heat from the engine's oil system to heat cold fuel.[40] This improves fuel efficiency, as well as reduces the possibility of water entrapped in the fuel freezing in components.[41]

Current market and forecast

[edit]

Estimated at US$17.5 billion in 2021, the global demand of heat exchangers is expected to experience robust growth of about 5% annually over the next years. The market value is expected to reach US$27 billion by 2030. With an expanding desire for environmentally friendly options and increased development of offices, retail sectors, and public buildings, market expansion is due to grow.[42]

A model of a simple heat exchanger

[edit]

A simple heat exchange [43][44] might be thought of as two straight pipes with fluid flow, which are thermally connected. Let the pipes be of equal length L, carrying fluids with heat capacity (energy per unit mass per unit change in temperature) and let the mass flow rate of the fluids through the pipes, both in the same direction, be (mass per unit time), where the subscript i applies to pipe 1 or pipe 2.

Temperature profiles for the pipes are and where x is the distance along the pipe. Assume a steady state, so that the temperature profiles are not functions of time. Assume also that the only transfer of heat from a small volume of fluid in one pipe is to the fluid element in the other pipe at the same position, i.e., there is no transfer of heat along a pipe due to temperature differences in that pipe. By Newton's law of cooling the rate of change in energy of a small volume of fluid is proportional to the difference in temperatures between it and the corresponding element in the other pipe:

( this is for parallel flow in the same direction and opposite temperature gradients, but for counter-flow heat exchange countercurrent exchange the sign is opposite in the second equation in front of ), where is the thermal energy per unit length and γ is the thermal connection constant per unit length between the two pipes. This change in internal energy results in a change in the temperature of the fluid element. The time rate of change for the fluid element being carried along by the flow is:

where is the "thermal mass flow rate". The differential equations governing the heat exchanger may now be written as:

Since the system is in a steady state, there are no partial derivatives of temperature with respect to time, and since there is no heat transfer along the pipe, there are no second derivatives in x as is found in the heat equation. These two coupled first-order differential equations may be solved to yield:

where , ,

(this is for parallel-flow, but for counter-flow the sign in front of is negative, so that if , for the same "thermal mass flow rate" in both opposite directions, the gradient of temperature is constant and the temperatures linear in position x with a constant difference along the exchanger, explaining why the counter current design countercurrent exchange is the most efficient )

and A and B are two as yet undetermined constants of integration. Let and be the temperatures at x=0 and let and be the temperatures at the end of the pipe at x=L. Define the average temperatures in each pipe as:

Using the solutions above, these temperatures are:

        

Choosing any two of the temperatures above eliminates the constants of integration, letting us find the other four temperatures. We find the total energy transferred by integrating the expressions for the time rate of change of internal energy per unit length:

By the conservation of energy, the sum of the two energies is zero. The quantity is known as the Log mean temperature difference, and is a measure of the effectiveness of the heat exchanger in transferring heat energy.

See also

[edit]
  • Architectural engineering
  • Chemical engineering
  • Cooling tower
  • Copper in heat exchangers
  • Heat pipe
  • Heat pump
  • Heat recovery ventilation
  • Jacketed vessel
  • Log mean temperature difference (LMTD)
  • Marine heat exchangers
  • Mechanical engineering
  • Micro heat exchanger
  • Moving bed heat exchanger
  • Packed bed and in particular Packed columns
  • Pumpable ice technology
  • Reboiler
  • Recuperator, or cross plate heat exchanger
  • Regenerator
  • Run around coil
  • Steam generator (nuclear power)
  • Surface condenser
  • Toroidal expansion joint
  • Thermosiphon
  • Thermal wheel, or rotary heat exchanger (including enthalpy wheel and desiccant wheel)
  • Tube tool
  • Waste heat

References

[edit]
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    • "Process Heating". process-heating.com. BNP Media. Archived from the original on Mar 16, 2008. Last accessed 17/3/08.
  30. ^ Wiehe, Irwin A.; Kennedy, Raymond J. (1 January 2000). "The Oil Compatibility Model and Crude Oil Incompatibility". Energy & Fuels. 14 (1): 56–59. doi:10.1021/ef990133+.
  31. ^ Panchal C;B; and Ebert W., Analysis of Exxon Crude-Oil-Slip-Stream Coking Data, Proc of Fouling Mitigation of Industrial Heat-Exchanger Equipment, San Luis Obispo, California, USA, p 451, June 1995
  32. ^ Domestic heating compliance guide : compliance with approved documents L1A: New dwellings and L1B: Existing dwellings : the Building Regulations 2000 as amended 2006. London: TSO. 2006. ISBN 978-0-11-703645-1. OCLC 500282471.
  33. ^ Epstein, Norman (2014), "Design and construction codes", HEDH Multimedia, Begellhouse, doi:10.1615/hedhme.a.000413, ISBN 978-1-56700-423-6, retrieved 2022-04-12
  34. ^ Heat Loss from the Respiratory Tract in Cold, Defense Technical Information Center, April 1955
  35. ^ Randall, David J.; Warren W. Burggren; Kathleen French; Roger Eckert (2002). Eckert animal physiology: mechanisms and adaptations. Macmillan. p. 587. ISBN 978-0-7167-3863-3.
  36. ^ "Natural History Museum: Research & Collections: History". Archived from the original on 2009-06-14. Retrieved 2019-09-09.
  37. ^ Heyning and Mead; Mead, JG (November 1997). "Thermoregulation in the Mouths of Feeding Gray Whales". Science. 278 (5340): 1138–1140. Bibcode:1997Sci...278.1138H. doi:10.1126/science.278.5340.1138. PMID 9353198.
  38. ^ "Carotid rete cools brain : Thomson's Gazelle".
  39. ^ Bruner, Emiliano; Mantini, Simone; Musso, Fabio; De La Cuétara, José Manuel; Ripani, Maurizio; Sherkat, Shahram (2010-11-30). "The evolution of the meningeal vascular system in the human genus: From brain shape to thermoregulation". American Journal of Human Biology. 23 (1): 35–43. doi:10.1002/ajhb.21123. ISSN 1042-0533. PMID 21120884.
  40. ^ "United States Patent 4498525, Fuel/oil heat exchange system for an engine". United States Patent and Trademark Office. Retrieved 3 February 2009.
  41. ^ Croft, John. "Boeing links Heathrow, Atlanta Trent 895 engine rollbacks". FlightGlobal.com. Retrieved 3 February 2009.
  42. ^ Research, Straits (2022-07-06). "Heat Exchanger Market Size is projected to reach USD 27 Billion by 2030, growing at a CAGR of 5%: Straits Research". GlobeNewswire News Room (Press release). Retrieved 2022-07-15.
  43. ^ Kay J M & Nedderman R M (1985) Fluid Mechanics and Transfer Processes, Cambridge University Press
  44. ^ "MIT web course on Heat Exchangers". [MIT].
  • Coulson, J. and Richardson, J (1999). Chemical Engineering- Fluid Flow. Heat Transfer and Mass Transfer- Volume 1; Reed Educational & Professional Publishing LTD
  • Dogan Eryener (2005), 'Thermoeconomic optimization of baffle spacing for shell and tube heat exchangers', Energy Conservation and Management, Volume 47, Issue 11–12, Pages 1478–1489.
  • G.F.Hewitt, G.L.Shires, T.R.Bott (1994) Process Heat Transfer, CRC Press, Inc, United States Of America.
[edit]
  • Shell and Tube Heat Exchanger Design Software for Educational Applications (PDF)
  • EU Pressure Equipment Guideline
  • A Thermal Management Concept For More Electric Aircraft Power System Application (PDF)

 

Prefabricated house in Valencia, Spain.

A modular building is a prefabricated building that consists of repeated sections called modules.[1] Modularity involves constructing sections away from the building site, then delivering them to the intended site. Installation of the prefabricated sections is completed on site. Prefabricated sections are sometimes placed using a crane. The modules can be placed side-by-side, end-to-end, or stacked, allowing for a variety of configurations and styles. After placement, the modules are joined together using inter-module connections, also known as inter-connections. The inter-connections tie the individual modules together to form the overall building structure.[2]

Uses

[edit]
Modular home prefab sections to be placed on the foundation

Modular buildings may be used for long-term, temporary or permanent facilities, such as construction camps, schools and classrooms, civilian and military housing, and industrial facilities. Modular buildings are used in remote and rural areas where conventional construction may not be reasonable or possible, for example, the Halley VI accommodation pods used for a BAS Antarctic expedition.[3] Other uses have included churches, health care facilities, sales and retail offices, fast food restaurants and cruise ship construction. They can also be used in areas that have weather concerns, such as hurricanes. Modular buildings are often used to provide temporary facilities, including toilets and ablutions at events. The portability of the buildings makes them popular with hire companies and clients alike. The use of modular buildings enables events to be held at locations where existing facilities are unavailable, or unable to support the number of event attendees.

Construction process

[edit]

Construction is offsite, using lean manufacturing techniques to prefabricate single or multi-story buildings in deliverable module sections. Often, modules are based around standard 20 foot containers, using the same dimensions, structures, building and stacking/placing techniques, but with smooth (instead of corrugated) walls, glossy white paint, and provisions for windows, power, potable water, sewage lines, telecommunications and air conditioning. Permanent Modular Construction (PMC) buildings are manufactured in a controlled setting and can be constructed of wood, steel, or concrete. Modular components are typically constructed indoors on assembly lines. Modules' construction may take as little as ten days but more often one to three months. PMC modules can be integrated into site built projects or stand alone and can be delivered with MEP, fixtures and interior finishes.

The buildings are 60% to 90% completed offsite in a factory-controlled environment, and transported and assembled at the final building site. This can comprise the entire building or be components or subassemblies of larger structures. In many cases, modular contractors work with traditional general contractors to exploit the resources and advantages of each type of construction. Completed modules are transported to the building site and assembled by a crane.[4] Placement of the modules may take from several hours to several days. Off-site construction running in parallel to site preparation providing a shorter time to project completion is one of the common selling points of modular construction. Modular construction timeline

Permanent modular buildings are built to meet or exceed the same building codes and standards as site-built structures and the same architect-specified materials used in conventionally constructed buildings are used in modular construction projects. PMC can have as many stories as building codes allow. Unlike relocatable buildings, PMC structures are intended to remain in one location for the duration of their useful life.

Manufacturing considerations

[edit]

The entire process of modular construction places significance on the design stage. This is where practices such as Design for Manufacture and Assembly (DfMA) are used to ensure that assembly tolerances are controlled throughout manufacture and assembly on site. It is vital that there is enough allowance in the design to allow the assembly to take up any "slack" or misalignment of components. The use of advanced CAD systems, 3D printing and manufacturing control systems are important for modular construction to be successful. This is quite unlike on-site construction where the tradesman can often make the part to suit any particular installation.

Upfront production investment

[edit]

The development of factory facilities for modular homes requires significant upfront investment. To help address housing shortages in the 2010s, the United Kingdom Government (via Homes England) invested in modular housing initiatives. Several UK companies (for example, Ilke Homes, L&G Modular Homes, House by Urban Splash, Modulous, TopHat and Lighthouse) were established to develop modular homes as an alternative to traditionally-built residences, but failed as they could not book revenues quickly enough to cover the costs of establishing manufacturing facilities.

IIke Homes opened a factory in Knaresborough, Yorkshire in 2018, and Homes England invested £30m in November 2019,[5] and a further £30m in September 2021.[6] Despite a further fund-raising round, raising £100m in December 2022,[7][8] Ilke Homes went into administration on 30 June 2023,[9][10] with most of the company's 1,150 staff made redundant,[11] and debts of £320m,[12] including £68m owed to Homes England.[13]

In 2015 Legal & General launched a modular homes operation, L&G Modular Homes, opening a 550,000 sq ft factory in Sherburn-in-Elmet, near Selby in Yorkshire.[14] The company incurred large losses as it invested in its factory before earning any revenues; by 2019, it had lost over £100m.[15] Sales revenues from a Selby project, plus schemes in Kent and West Sussex, started to flow in 2022, by which time the business's total losses had grown to £174m.[16] Production was halted in May 2023, with L&G blaming local planning delays and the COVID-19 pandemic for its failure to grow its sales pipeline.[17][18] The enterprise incurred total losses over seven years of £295m.[19]

Market acceptance

[edit]
Raines Court is a multi-story modular housing block in Stoke Newington, London, one of the first two residential buildings in Britain of this type. (December 2005)

Some home buyers and some lending institutions resist consideration of modular homes as equivalent in value to site-built homes.[citation needed] While the homes themselves may be of equivalent quality, entrenched zoning regulations and psychological marketplace factors may create hurdles for buyers or builders of modular homes and should be considered as part of the decision-making process when exploring this type of home as a living and/or investment option. In the UK and Australia, modular homes have become accepted in some regional areas; however, they are not commonly built in major cities. Modular homes are becoming increasingly common in Japanese urban areas, due to improvements in design and quality, speed and compactness of onsite assembly, as well as due to lowering costs and ease of repair after earthquakes. Recent innovations allow modular buildings to be indistinguishable from site-built structures.[20] Surveys have shown that individuals can rarely tell the difference between a modular home and a site-built home.[21]

Modular homes vs. mobile homes

[edit]

Differences include the building codes that govern the construction, types of material used and how they are appraised by banks for lending purposes. Modular homes are built to either local or state building codes as opposed to manufactured homes, which are also built in a factory but are governed by a federal building code.[22] The codes that govern the construction of modular homes are exactly the same codes that govern the construction of site-constructed homes.[citation needed] In the United States, all modular homes are constructed according to the International Building Code (IBC), IRC, BOCA or the code that has been adopted by the local jurisdiction.[citation needed] In some states, such as California, mobile homes must still be registered yearly, like vehicles or standard trailers, with the Department of Motor Vehicles or other state agency. This is true even if the owners remove the axles and place it on a permanent foundation.[23]

Recognizing a mobile or manufactured home

[edit]

A mobile home should have a small metal tag on the outside of each section. If a tag cannot be located, details about the home can be found in the electrical panel box. This tag should also reveal a manufacturing date.[citation needed] Modular homes do not have metal tags on the outside but will have a dataplate installed inside the home, usually under the kitchen sink or in a closet. The dataplate will provide information such as the manufacturer, third party inspection agency, appliance information, and manufacture date.

Materials

[edit]

The materials used in modular buildings are of the same quality and durability as those used in traditional construction, preserving characteristics such as acoustic insulation and energy efficiency, as well as allowing for attractive and innovative designs thanks to their versatility.[24] Most commonly used are steel, wood and concrete.[25]

  • Steel: Because it is easily moldable, it allows for innovation in design and aesthetics.
  • Wood: Wood is an essential part of most modular buildings. Thanks to its lightness, it facilitates the work of assembling and moving the prefabricated modules.
  • Concrete: Concrete offers a solid structure that is ideal for the structural reinforcement of permanent modular buildings. It is increasingly being used as a base material in this type of building, thanks to its various characteristics such as fire resistance, energy savings, greater acoustic insulation, and durability.[26]

Wood-frame floors, walls and roof are often utilized. Some modular homes include brick or stone exteriors, granite counters and steeply pitched roofs. Modulars can be designed to sit on a perimeter foundation or basement. In contrast, mobile homes are constructed with a steel chassis that is integral to the integrity of the floor system. Modular buildings can be custom built to a client's specifications. Current designs include multi-story units, multi-family units and entire apartment complexes. The negative stereotype commonly associated with mobile homes has prompted some manufacturers to start using the term "off-site construction."

New modular offerings include other construction methods such as cross-laminated timber frames.[27]

Financing

[edit]

Mobile homes often require special lenders.[28]

Modular homes on the other hand are financed as site built homes with a construction loan

Standards and zoning considerations

[edit]

Typically, modular dwellings are built to local, state or council code, resulting in dwellings from a given manufacturing facility having differing construction standards depending on the final destination of the modules.[29] The most important zones that manufacturers have to take into consideration are local wind, heat, and snow load zones.[citation needed] For example, homes built for final assembly in a hurricane-prone, earthquake or flooding area may include additional bracing to meet local building codes. Steel and/or wood framing are common options for building a modular home.

Some US courts have ruled that zoning restrictions applicable to mobile homes do not apply to modular homes since modular homes are designed to have a permanent foundation.[citation needed] Additionally, in the US, valuation differences between modular homes and site-built homes are often negligible in real estate appraisal practice; modular homes can, in some market areas, (depending on local appraisal practices per Uniform Standards of Professional Appraisal Practice) be evaluated the same way as site-built dwellings of similar quality. In Australia, manufactured home parks are governed by additional legislation that does not apply to permanent modular homes. Possible developments in equivalence between modular and site-built housing types for the purposes of real estate appraisals, financing and zoning may increase the sales of modular homes over time.[30]

CLASP (Consortium of Local Authorities Special Programme)

[edit]

The Consortium of Local Authorities Special Programme (abbreviated and more commonly referred to as CLASP) was formed in England in 1957 to combine the resources of local authorities with the purpose of developing a prefabricated school building programme. Initially developed by Charles Herbert Aslin, the county architect for Hertfordshire, the system was used as a model for several other counties, most notably Nottinghamshire and Derbyshire. CLASP's popularity in these coal mining areas was in part because the system permitted fairly straightforward replacement of subsidence-damaged sections of building.

Building strength

[edit]
Modular Home being built in Vermont photo by Josh Vignona
Modular home in Vermont

Modular homes are designed to be stronger than traditional homes by, for example, replacing nails with screws, adding glue to joints, and using 8–10% more lumber than conventional housing.[31] This is to help the modules maintain their structural integrity as they are transported on trucks to the construction site. However, there are few studies on the response of modular buildings to transport and handling stresses. It is therefore presently difficult to predict transport induced damage.[1]

When FEMA studied the destruction wrought by Hurricane Andrew in Dade County Florida, they concluded that modular and masonry homes fared best compared to other construction.[32]

CE marking

[edit]

The CE mark is a construction norm that guarantees the user of mechanical resistance and strength of the structure. It is a label given by European community empowered authorities for end-to-end process mastering and traceability.[citation needed]

All manufacturing operations are being monitored and recorded:

  • Suppliers have to be known and certified,
  • Raw materials and goods being sourced are to be recorded by batch used,
  • Elementary products are recorded and their quality is monitored,
  • Assembly quality is managed and assessed on a step by step basis,
  • When a modular unit is finished, a whole set of tests are performed and if quality standards are met, a unique number and EC stamp is attached to and on the unit.

This ID and all the details are recorded in a database, At any time, the producer has to be able to answer and provide all the information from each step of the production of a single unit, The EC certification guaranties standards in terms of durability, resistance against wind and earthquakes.[citation needed]

Open modular building

[edit]

The term Modularity can be perceived in different ways. It can even be extended to building P2P (peer-to-peer) applications; where a tailored use of the P2P technology is with the aid of a modular paradigm. Here, well-understood components with clean interfaces can be combined to implement arbitrarily complex functions in the hopes of further proliferating self-organising P2P technology. Open modular buildings are an excellent example of this. Modular building can also be open source and green. Bauwens, Kostakis and Pazaitis[33] elaborate on this kind of modularity. They link modularity to the construction of houses.

This commons-based activity is geared towards modularity. The construction of modular buildings enables a community to share designs and tools related to all the different parts of house construction. A socially-oriented endeavour that deals with the external architecture of buildings and the internal dynamics of open source commons. People are thus provided with the tools to reconfigure the public sphere in the area where they live, especially in urban environments. There is a robust socializing element that is reminiscent of pre-industrial vernacular architecture and community-based building.[34]

Some organisations already provide modular housing. Such organisations are relevant as they allow for the online sharing of construction plans and tools. These plans can be then assembled, through either digital fabrication like 3D printing or even sourcing low-cost materials from local communities. It has been noticed that given how easy it is to use these low-cost materials are (for example: plywood), it can help increase the permeation of these open buildings to areas or communities that lack the know-how or abilities of conventional architectural or construction firms. Ergo, it allows for a fundamentally more standardised way of constructing houses and buildings. The overarching idea behind it remains key - to allow for easy access to user-friendly layouts which anyone can use to build in a more sustainable and affordable way.

Modularity in this sense is building a house from different standardised parts, like solving a jigsaw puzzle.

3D printing can be used to build the house.

The main standard is OpenStructures and its derivative Autarkytecture.[35]

Research and development

[edit]

Modular construction is the subject of continued research and development worldwide as the technology is applied to taller and taller buildings. Research and development is carried out by modular building companies and also research institutes such as the Modular Building Institute[36] and the Steel Construction Institute.[37]

See also

[edit]
  • Affordable housing
  • Alternative housing
  • Commercial modular construction
  • Construction 3D printing
  • Container home
  • Kit house
  • MAN steel house
  • Manufactured housing
  • Modern methods of construction
  • Modular design
  • Portable building
  • Prefabrication
  • Open-source architecture
  • Open source hardware
  • OpenStructures
  • Prefabricated home
  • Relocatable buildings
  • Recreational vehicles
  • Shipping container architecture
  • Stick-built home
  • Tiny house movement
  • Toter

References

[edit]
  1. ^ a b Lacey, Andrew William; Chen, Wensu; Hao, Hong; Bi, Kaiming (2018). "Structural Response of Modular Buildings – An Overview". Journal of Building Engineering. 16: 45–56. doi:10.1016/j.jobe.2017.12.008. hdl:20.500.11937/60087.
  2. ^ Lacey, Andrew William; Chen, Wensu; Hao, Hong; Bi, Kaiming (2019). "Review of bolted inter-module connections in modular steel buildings". Journal of Building Engineering. 23: 207–219. doi:10.1016/j.jobe.2019.01.035. S2CID 86540434.
  3. ^ "Halley VI Research Station – British Antarctic Survey". Bas.ac.uk. Retrieved 2016-05-03.
  4. ^ "Why Build Modular?". Modular.org. Retrieved 2016-05-03.
  5. ^ Morby, Aaron (4 November 2019). "Government pumps £30m into modular house builder". Construction Enquirer. Retrieved 14 March 2024.
  6. ^ Morby, Aaron (27 September 2021). "Ilke Homes raises £60m for top 10 house builder plan". Construction Enquirer. Retrieved 14 March 2024.
  7. ^ Morby, Aaron (6 December 2022). "Ilke Homes pulls off £100m record-breaking fund raise". Construction Enquirer. Retrieved 14 March 2024.
  8. ^ O'Connor, Rob (6 December 2022). "ilke Homes announces new £100m investment". Infrastructure Intelligence. Retrieved 14 March 2024.
  9. ^ Gardiner, Joey (30 June 2023). "Ilke Homes sinks into administration with most of firm's 1,100 staff set to lose their jobs". Building. Retrieved 14 March 2024.
  10. ^ Riding, James (30 June 2023). "Modular house builder Ilke Homes enters administration with majority of staff to be made redundant". Inside Housing. Retrieved 14 March 2024.
  11. ^ Morby, Aaron (30 June 2023). "Ilke Homes falls into administration". Construction Enquirer. Retrieved 14 March 2024.
  12. ^ Prior, Grant (25 August 2023). "Ilke Homes went under owing £320m". Construction Enquirer. Retrieved 14 March 2024.
  13. ^ Willmore, James (14 February 2024). "Homes England to lose most of £68.8m it is owed from Ilke Homes following collapse". Inside Housing. Retrieved 14 March 2024.
  14. ^ Dale, Sharon (11 May 2020). "Head of Legal & General modular homes factory reveals plans for its future". Yorkshire Post. Retrieved 20 March 2024.
  15. ^ Morby, Aaron (30 November 2020). "L&G modular homes losses exceed £100m". Construction Enquirer. Retrieved 20 March 2024.
  16. ^ Morby, Aaron (3 October 2022). "L&G modular homes amassed loss deepens to £174m". Construction Enquirer. Retrieved 20 March 2024.
  17. ^ Prior, Grant (4 May 2023). "L&G halts production at modular homes factory". Construction Enquirer. Retrieved 20 March 2024.
  18. ^ Kollewe, Julia (4 May 2023). "Legal & General halts new production at modular homes factory near Leeds". The Guardian.
  19. ^ Morby, Aaron (6 November 2023). "L&G modular homes foray amassed £295m of losses". Construction Enquirer. Retrieved 20 March 2024.
  20. ^ fab, ukporta (19 August 2020). "prefabricated structures". ukportaprefab. Retrieved 4 September 2020.
  21. ^ "Factory-Built Construction and the American Homebuyer: Perceptions and Opportunities" (PDF). Huduser.gov. p. 9. Retrieved 2017-09-10.
  22. ^ Solutions, Dryside Property – Jennifer Mitchell and Magic Web. "Mobile homes vs Manufactured homes vs Modular homes". Drysideproperty.com. Retrieved 2018-03-09.
  23. ^ "HCD Manufactured and Mobile Homes". Hcd.ca.gov.
  24. ^ Métodos modernos de construcción (MMC): Fabricación modular. Upv.es. 2020-10-02 Retrieved 2022-09-08
  25. ^ A guide to the latest modular building construction materials. Hydrodiseno.com. 2021-12-14 Retrieved 2022-09-05
  26. ^ Construcción modular en hormigón: una tendencia al alza (PDF). Andece.org. p. 53. Retrieved 2022-07-06
  27. ^ "Prefabricated Housing Module Advances Wood Research at the University of British Columbia | 2017-05-15T00:00:00 | Perkins + Will News". Archived from the original on 2019-03-31. Retrieved 2019-03-31.
  28. ^ "HUD Financing Manufactured (Mobile) Homes". Portal.hud.gov. Archived from the original on 2016-05-03. Retrieved 2016-05-03.
  29. ^ "Australian Government modular home regulations". Austlii.edu.au. Retrieved 2007-10-21.
  30. ^ "Building Codes for Modular Homes". Modularhomesnetwork.com. Retrieved 2010-08-06.
  31. ^ "Disruptive Development: Modular Manufacturing In Multifamily Housing" (PDF). p. 35. Retrieved 10 September 2017.
  32. ^ "FIA 22, Mitigation Assessment Team Report: Hurricane Andrew in Florida (1993)". Fema.gov.
  33. ^ Bouwens, M., Kostakis, V., & Pazaitis, A. 2019. The Commons Manifesto. University of Westminster Press, London, pg. 24
  34. ^ Bouwens, M., Kostakis, V., & Pazaitis, A. 2019. The Commons Manifesto. University of Westminster Press, London, pg. 25
  35. ^ "Thomas Lommée & Christiane Hoegner - Autarkytecture | z33". Archived from the original on 2014-12-31. Retrieved 2015-01-01.
  36. ^ "Modular Building Institute". Modular.org.
  37. ^ "The Steel Construction Institute (SCI) UK Global Steel Expertise". Steel-sci.com.

34 - "Volumetric modular construction trend gaining groun d". https://www.aa.com.tr/en/corporate-news/volumetric-modular-construction-trend-gaining-ground/2357158 06.09.2021

 

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Driving Directions in Tulsa County


Driving Directions From OYO Hotel Tulsa International Airport to Durham Supply Inc
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Reviews for Durham Supply Inc


Durham Supply Inc

Ty Spears

(5)

Bought a door/storm door combo. Turns out it was the wrong size. They swapped it out, quick and easy no problems. Very helpful in explaining the size differences from standard door sizes.

Durham Supply Inc

Gerald Clifford Brewster

(5)

We will see, the storm door I bought says on the tag it's 36x80, but it's 34x80. If they return it.......they had no problems returning it. And it was no fault of there's, you measure a mobile home door different than a standard door!

Durham Supply Inc

Dennis Champion

(5)

Durham supply and Royal supply seems to find the most helpful and friendly people to work in their stores, we are based out of Kansas City out here for a few remodels and these guys treated us like we've gone there for years.

Durham Supply Inc

Ethel Schiller

(5)

This place is really neat, if they don't have it they can order it from another of their stores and have it there overnight in most cases. Even hard to find items for a trailer! I definitely recommend this place to everyone! O and the prices is awesome too!

Durham Supply Inc

B Mann

(5)

I was in need of some items for a double wide that I am remodeling and this place is the only place in town that had what I needed ( I didn't even try the other rude place )while I was there I learned the other place that was in Tulsa that also sold mobile home supplies went out of business (no wonder the last time I was in there they were VERY RUDE and high priced) I like the way Dunham does business they answered all my questions and got me the supplies I needed, very friendly, I will be back to purchase the rest of my items when the time comes.

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Frequently Asked Questions

The typical credit score requirement for financing a mobile home HVAC system varies by lender, but generally ranges from 580 to 650. Some lenders may offer options for those with lower scores.
Yes, certain financial institutions and specialized lending companies focus on manufactured or mobile home improvements, including HVAC systems. Its important to research and compare their terms.
A higher credit score typically results in lower interest rates, making monthly payments more affordable over time. Conversely, lower scores might lead to higher rates.
Some government programs or grants may be available to assist low-income individuals or those with poor credit in upgrading their homes energy efficiency, including HVAC systems. Checking local resources is advisable.
Yes, alternatives such as personal loans from online lenders, secured loans using collateral, or retailer-specific payment plans can be considered if traditional financing isnt accessible due to high credit score demands.