Navigating the world of mobile home HVAC systems can seem daunting, especially when considering the intricacies involved in obtaining an EPA 608 certification. Understanding the key components and common challenges associated with these systems is crucial for anyone aiming to master this field.
Mobile home HVAC systems are designed uniquely to cater to the specific needs of mobile homes, which often have different thermal dynamics compared to traditional houses. The key components of these systems typically include the furnace or heat pump, air conditioning unit, ductwork, and ventilation system. Each component plays a vital role in maintaining a comfortable indoor environment. The furnace or heat pump provides heating during cold months, while the air conditioning unit ensures cooling in warmer seasons. Ductwork is essential for distributing conditioned air throughout the home efficiently.
One of the primary challenges faced by technicians working on mobile home HVAC systems is space constraints. Mobile homes generally have limited space for ductwork and equipment installation, which requires creative solutions and precise work to ensure optimal performance without compromising on energy efficiency or safety standards. Additionally, mobile homes are often relocated, which means their HVAC systems must be robust enough to withstand transportation stresses.
Another challenge is dealing with older units that may not meet current energy efficiency standards or regulatory requirements. Retrofitting such units to improve efficiency or replace outdated components can be complex and costly but necessary for compliance and environmental considerations.
This is where EPA 608 certification comes into play. As per U.S. regulations, any technician who handles refrigerants must be certified under Section 608 of the Clean Air Act. This certification ensures that technicians are knowledgeable about safe handling practices for refrigerants that deplete ozone layers if released improperly into the atmosphere.
The path to obtaining an EPA 608 certification involves understanding various types of certifications available: Type I (for small appliances), Type II (for high-pressure appliances), Type III (for low-pressure appliances), and Universal Certification (covering all types). Candidates must pass a test covering topics like ozone depletion theory, regulations related to refrigerant management, recovery techniques, safety standards, and proper disposal methods.
Preparing for this test requires thorough study and understanding of both theoretical concepts and practical applications in real-world scenarios involving HVAC systems. Many resources are available online or through training programs offered by community colleges or technical schools that focus specifically on preparing candidates for this examination.
In conclusion, mastering mobile home HVAC systems involves comprehending their unique challenges alongside acquiring essential certifications like EPA 608. By focusing on these areas from understanding system components to meeting regulatory requirements technicians can effectively navigate this specialized field while contributing positively towards environmental sustainability through responsible refrigerant management practices.
Navigating the path to EPA 608 certification is a crucial step for individuals seeking to work with refrigerants and air conditioning systems in the United States. The Environmental Protection Agency (EPA) established this certification under Section 608 of the Clean Air Act, aiming to reduce ozone depletion by regulating the handling and disposal of refrigerants. Understanding who can apply for this certification is essential for anyone aspiring to enter this field.
First and foremost, eligibility for EPA 608 certification does not demand formal education prerequisites such as a degree or specific coursework. This accessibility allows a broad spectrum of applicants, from seasoned technicians seeking to formalize their skills to newcomers eager to establish themselves in the HVAC industry. However, it's important that applicants possess a fundamental understanding of refrigeration principles and safety protocols, as these are central components of the certification exams.
The application process begins with selecting the appropriate type of certification needed based on your professional goals. There are four types: Type I covers small appliances; Type II is for high-pressure appliances; Type III pertains to low-pressure appliances; and Universal Certification encompasses all three categories. Each type requires passing a specific exam that tests knowledge pertinent to its category. Thus, determining which type aligns with your career aspirations is vital before applying.
Moreover, while there are no legal age restrictions imposed by the EPA itself, individual test providers may have their own requirements regarding minimum age or identification documentation. Therefore, prospective applicants should verify these details with their chosen testing center prior to scheduling an exam.
Preparing for the exam involves diligent study and comprehension of various topics including environmental impact regulations, leak detection methods, recovery techniques, and safe handling practices for different refrigerant types. Numerous resources-ranging from online courses and practice exams to workshops hosted by industry professionals-are available to assist candidates in mastering these subjects.
Once you feel adequately prepared, registering through an approved testing organization is the next step. These organizations administer proctored exams either online or at designated locations nationwide. Successfully passing any level's exam certifies your ability to responsibly manage refrigerants according to federal standards-a credential highly regarded by employers within HVAC industries.
In conclusion, EPA 608 certification serves as both a regulatory requirement and a testament to one's competence in managing substances critical to environmental protection efforts. While open broadly in terms of educational background requirements, success hinges on comprehensive preparation tailored towards understanding complex technical content related directly to real-world applications within HVAC spheres. For those committed enough-to not only meet but exceed regulatory expectations-the journey toward achieving this certification offers both professional credibility and personal fulfillment derived from contributing positively towards sustainable environmental practices.
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Preparing for the EPA 608 Exam: Study Tips and Resources Specific to Mobile Home HVAC Systems
Navigating the steps toward obtaining your EPA 608 Certification can seem daunting, especially if you're focusing on mobile home HVAC systems. This certification is crucial for anyone who wants to work with refrigerants in the United States, as it ensures that technicians are knowledgeable about handling these substances safely and responsibly. Here's a guide to help streamline your preparation process, tailor your study efforts towards mobile home HVAC systems, and ultimately succeed in passing the exam.
Understanding the Importance of EPA 608 Certification
The EPA 608 Certification is divided into three main types - Type I, Type II, and Type III - along with a Universal certification that covers all three types. Each type corresponds to different equipment categories: Type I for small appliances, Type II for high-pressure appliances (including residential air conditioning), and Type III for low-pressure appliances. For those focusing on mobile home HVAC systems, which typically employ high-pressure refrigerants due to their compact size and efficiency requirements, Type II certification is most relevant.
Key Study Tips
Familiarize Yourself with Core Concepts: Before diving into specifics about mobile homes, ensure you have a solid understanding of basic refrigeration principles. This includes knowledge about pressure-temperature relationships, thermodynamics of refrigerant cycles, superheating, subcooling, and system components like compressors and condensers.
Focus on Regulations: The exam will test your understanding of EPA regulations regarding ozone-depleting substances. Pay particular attention to rules related to leak detection and repair, recordkeeping requirements for refrigerant handling, and disposal regulations.
Tailor Your Studies to Mobile Home Systems: While much of the content will be applicable across various settings, focus on aspects unique to mobile homes such as space constraints which affect system design and maintenance practices.
Use Practice Exams: Taking practice exams is one of the most effective ways to prepare. It helps familiarize yourself with the format of questions you'll encounter and identifies areas where further study might be needed.
Develop Efficient Test-Taking Strategies: Time management during exams is crucial. Practice answering questions efficiently without sacrificing accuracy by reading each question carefully but swiftly identifying key information needed.
Resources Specific to Mobile Home HVAC Systems
Manufacturer Manuals: Review manuals from manufacturers specific to mobile home HVAC units as they often cover installation considerations unique to these environments.
Online Courses or Workshops: Some organizations offer specialized training sessions or webinars focused specifically on mobile home HVAC systems which can provide valuable insights beyond standard preparatory materials.
Community Forums or Networks: Engage with online communities or forums where professionals discuss challenges faced in maintaining or repairing mobile home units; real-world experiences can be incredibly informative when studying theoretical concepts.
Technical Guides or Textbooks: Look for textbooks that include sections dedicated specifically towards smaller-scale residential systems like those found in mobile homes; they can offer tailored advice on troubleshooting common issues encountered in this niche market segment.
In conclusion, while preparing for the EPA 608 Exam requires dedication and thorough study across several topics pertinent under federal guidelines governing refrigerant use within various sectors - including specific nuances associated uniquely within realm dealing primarily among modular living spaces such as modern manufactured housing solutions - success ultimately hinges upon how well candidates blend foundational knowledge concerning general operational principles alongside deeper comprehension regarding special cases represented therein like optimized spatial efficiency demands necessitated therein throughout every step involved along way towards achieving ultimate goal securing coveted credentials required perform vital services safely competently anytime anywhere industrywide today tomorrow
The process of becoming certified under the EPA 608 Certification is an essential step for technicians working with refrigeration and air conditioning systems in the United States. This certification is mandated by the Environmental Protection Agency (EPA) to ensure that individuals handling refrigerants do so responsibly, minimizing harm to the environment. Navigating the registration process can seem daunting at first glance, but a clear, step-by-step approach can simplify your journey towards achieving this crucial credential.
First and foremost, understanding the different types of EPA 608 certifications is essential. The certification is divided into four types: Type I for servicing small appliances; Type II for servicing high-pressure appliances; Type III for low-pressure appliances; and Universal Certification, which covers all three categories. Determining which certification you need depends on the equipment you plan to work with, so take time to evaluate your career goals and job requirements before proceeding.
Once you've decided on the type of certification you require, the next step involves finding an approved testing organization. The EPA does not administer these exams directly but rather works through various government-approved organizations that offer training and administer tests. Research thoroughly to select a reputable provider that offers both preparation courses and exams either online or in-person, depending on what suits you best.
After selecting a provider, it's advisable to enroll in a preparatory course. These courses are designed to equip candidates with comprehensive knowledge about safe refrigerant handling practices, recovery procedures, leak detection methods, proper disposal techniques, and environmental regulations related to refrigerants. A thorough understanding of these topics is critical not only for passing the exam but also for performing responsibly in your professional role.
With adequate preparation under your belt, you're ready to register for the exam itself. Registration processes vary slightly among providers but generally involve filling out an application form and paying an examination fee. Some providers allow online registration while others may require physical forms or phone calls-be sure to confirm these details well ahead of time.
On exam day, bring any required identification as specified by your testing organization along with confirmation of your registration details. The test format typically includes multiple-choice questions tailored to assess your knowledge across various relevant categories depending on whether you're pursuing Type I, II, III or Universal Certification.
Patience plays a key role after taking your exam as results may take some time due to processing periods involved with certification issuance. Upon passing the exam successfully-and congratulations if you've reached this stage-you'll be granted an EPA 608 Certification card signifying your qualification status within specific categories.
In conclusion, while navigating through EPA 608 Certification steps might initially appear complex given regulatory standards involved plus study commitments required-approaching it methodically makes it manageable plus rewarding professionally afterwards when equipped legally handling refrigerants within industry settings sustainably plus safely following completion overall!
The journey to becoming a proficient Mobile Home HVAC Technician involves mastering various skills and knowledge areas, one of which is navigating the EPA 608 Certification steps. This certification is crucial as it ensures technicians are qualified to handle refrigerants safely and responsibly, a key aspect of their profession. Understanding the exam format and structure can significantly enhance a candidate's confidence and performance on test day.
The EPA 608 Certification exam is structured into four distinct sections: Core, Type I, Type II, and Type III. Each section targets specific competencies that are vital for different aspects of HVAC work. The Core section lays the foundation by testing basic knowledge of ozone depletion, refrigerant properties, recovery techniques, safety protocols, regulations, and more. This part is mandatory for all certification levels.
Type I certification focuses on small appliances that contain five pounds or less of refrigerant. It emphasizes understanding proper handling procedures for small-scale equipment typically found in mobile homes. Type II certification covers high-pressure systems commonly used in commercial settings but also relevant to larger mobile home installations that require robust cooling solutions.
Type III certification pertains to low-pressure systems often employed in chillers found in large residential complexes or industrial environments. While not directly applicable to mobile homes, having this certification can expand a technician's versatility and open doors to broader career opportunities.
On test day, candidates can expect a multiple-choice format with questions designed to assess both theoretical knowledge and practical skills relevant to each section's focus area. It's essential for candidates to manage their time efficiently across these sections while ensuring they comprehend each question thoroughly before responding.
To prepare effectively for the EPA 608 Certification exam, aspiring technicians should engage in comprehensive study sessions using available resources such as textbooks, online courses, practice exams, and workshops offered by training centers or employers. Familiarity with real-world scenarios through hands-on experience can also greatly aid in understanding how theoretical concepts apply practically.
Understanding the structure of the EPA 608 Certification exam helps alleviate some test-day anxiety by providing clarity on what will be assessed. It empowers candidates to tailor their preparation strategies accordingly-focusing on weak areas while reinforcing strengths-and approach the exam with confidence.
In conclusion, mastering the steps required for EPA 608 Certification is an integral part of becoming a competent Mobile Home HVAC Technician. By knowing what to expect regarding the exam format and structure, candidates can streamline their study efforts effectively and maximize their chances of success on test day. With this certification under their belt, technicians demonstrate adherence to industry standards concerning environmental safety-a commitment crucial not only for career advancement but also for contributing positively towards sustainable practices within the field.
Embarking on the journey of obtaining EPA 608 certification is a significant milestone for professionals in the HVACR industry. This credential not only validates one's expertise in handling refrigerants but also underscores a commitment to environmental responsibility and compliance with legal standards. However, achieving certification is just the beginning; maintaining it and staying abreast of industry changes are equally critical steps that ensure continued professional competence and adherence to evolving regulations.
Once certified, technicians must focus on maintaining their certification status. The EPA 608 certification does not expire, which provides professionals with a stable foundation for their careers. Nonetheless, this permanence should not be mistaken for complacency. It is paramount that certified individuals continuously hone their skills and knowledge base to remain effective in their roles.
Regularly reviewing core concepts and practices learned during the certification process can help maintain proficiency. Engaging in ongoing education such as workshops, seminars, or online courses can be invaluable. These educational opportunities not only refresh existing knowledge but also introduce new technologies and methodologies emerging within the HVACR field.
Staying updated on industry changes is another crucial aspect of post-certification life. The HVACR landscape is dynamic, with technological advancements and regulatory shifts occurring frequently. For instance, changes in refrigerant types due to environmental regulations necessitate that technicians stay informed about new products and techniques for safe handling and disposal.
Subscribing to industry publications or joining professional associations can provide access to cutting-edge information and trends. Networking with peers through these organizations also offers insights into practical applications of new technologies or regulatory updates that may affect day-to-day operations.
Moreover, participating in manufacturer training sessions can keep technicians up-to-date with specific equipment innovations or modifications-knowledge that is essential as companies strive to improve energy efficiency and reduce environmental impact.
In summary, while obtaining EPA 608 certification marks an important achievement, it represents merely a single step in an ongoing professional journey. Maintaining this credential requires dedication to continuous learning and adaptability amidst change. By actively seeking educational opportunities and keeping abreast of industry developments, certified professionals can ensure they remain competent, compliant, and competitive within the ever-evolving realm of HVACR services.
Navigating the EPA 608 Certification Steps: A Guide for Mobile Home HVAC Technicians
In the realm of mobile home HVAC maintenance and repair, possessing an EPA 608 certification is not just beneficial-it's essential. This certification, mandated by the Environmental Protection Agency (EPA), ensures that technicians are adequately trained to handle refrigerants in a manner that is safe for both people and the environment. As we delve into the practical application of this certification in mobile home settings, it becomes crucial to understand the steps involved in obtaining and utilizing this credential effectively.
The journey toward EPA 608 certification begins with a comprehensive understanding of its purpose. The EPA established this program under the Clean Air Act to reduce ozone-depleting emissions from refrigerants used in air conditioning and refrigeration systems. For technicians working on mobile home HVAC units, which often involve older systems more prone to leaks, having this certification signifies a commitment to environmental responsibility and safety.
The first step in navigating the certification process involves deciding which type of certification best fits your needs. There are four types: Type I for small appliances, Type II for high-pressure appliances, Type III for low-pressure appliances, and Universal Certification, which covers all three categories. Given that mobile homes often use various types of HVAC systems, obtaining Universal Certification might be most advantageous for comprehensive service capabilities.
Preparation is key when approaching the EPA 608 examination. Aspiring technicians should immerse themselves in study materials covering core topics such as ozone depletion, regulations surrounding refrigerants, safe handling practices, leak detection methods, and recovery techniques. Many resources are available online or through vocational training programs that offer practice exams and detailed guides tailored to each certification type.
Once adequately prepared, scheduling and taking the exam is the next critical step. The test can be taken either online or at approved testing centers nationwide. It comprises multiple-choice questions divided into sections corresponding to different appliance types; passing requires both a solid grasp of theoretical knowledge and practical application skills.
After successfully passing the exam and receiving certification, technicians must focus on applying their knowledge in real-world scenarios typical of mobile home environments. This includes routinely inspecting HVAC units for leaks using advanced detection tools -a fundamental responsibility outlined by EPA regulations-and ensuring proper recovery of refrigerants during repair or disposal processes.
Moreover, staying informed about regulatory updates is vital as environmental policies evolve continuously. Certified technicians should engage in ongoing education opportunities to stay abreast of changes that may affect their work scope or introduce new compliance requirements.
In conclusion, navigating the EPA 608 certification steps demands dedication but rewards technicians with enhanced expertise crucial for maintaining efficient and environmentally-friendly HVAC operations within mobile homes. By embracing this structured approach-from selecting appropriate certifications through rigorous preparation to applying learned principles-technicians not only advance their professional competencies but also contribute significantly toward safeguarding our planet's atmosphere against harmful emissions.
Air conditioning, often abbreviated as A/C (US) or air con (UK),[1] is the process of removing heat from an enclosed space to achieve a more comfortable interior temperature (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling the humidity of internal air. Air conditioning can be achieved using a mechanical 'air conditioner' or by other methods, including passive cooling and ventilative cooling.[2][3] Air conditioning is a member of a family of systems and techniques that provide heating, ventilation, and air conditioning (HVAC).[4] Heat pumps are similar in many ways to air conditioners, but use a reversing valve to allow them both to heat and to cool an enclosed space.[5]
Air conditioners, which typically use vapor-compression refrigeration, range in size from small units used in vehicles or single rooms to massive units that can cool large buildings.[6] Air source heat pumps, which can be used for heating as well as cooling, are becoming increasingly common in cooler climates.
Air conditioners can reduce mortality rates due to higher temperature.[7] According to the International Energy Agency (IEA) 1.6 billion air conditioning units were used globally in 2016.[8] The United Nations called for the technology to be made more sustainable to mitigate climate change and for the use of alternatives, like passive cooling, evaporative cooling, selective shading, windcatchers, and better thermal insulation.
Air conditioning dates back to prehistory.[9] Double-walled living quarters, with a gap between the two walls to encourage air flow, were found in the ancient city of Hamoukar, in modern Syria.[10] Ancient Egyptian buildings also used a wide variety of passive air-conditioning techniques.[11] These became widespread from the Iberian Peninsula through North Africa, the Middle East, and Northern India.[12]
Passive techniques remained widespread until the 20th century when they fell out of fashion and were replaced by powered air conditioning. Using information from engineering studies of traditional buildings, passive techniques are being revived and modified for 21st-century architectural designs.[13][12]
Air conditioners allow the building's indoor environment to remain relatively constant, largely independent of changes in external weather conditions and internal heat loads. They also enable deep plan buildings to be created and have allowed people to live comfortably in hotter parts of the world.[14]
In 1558, Giambattista della Porta described a method of chilling ice to temperatures far below its freezing point by mixing it with potassium nitrate (then called "nitre") in his popular science book Natural Magic.[15][16][17] In 1620, Cornelis Drebbel demonstrated "Turning Summer into Winter" for James I of England, chilling part of the Great Hall of Westminster Abbey with an apparatus of troughs and vats.[18] Drebbel's contemporary Francis Bacon, like della Porta a believer in science communication, may not have been present at the demonstration, but in a book published later the same year, he described it as "experiment of artificial freezing" and said that "Nitre (or rather its spirit) is very cold, and hence nitre or salt when added to snow or ice intensifies the cold of the latter, the nitre by adding to its cold, but the salt by supplying activity to the cold of the snow."[15]
In 1758, Benjamin Franklin and John Hadley, a chemistry professor at the University of Cambridge, conducted experiments applying the principle of evaporation as a means to cool an object rapidly. Franklin and Hadley confirmed that the evaporation of highly volatile liquids (such as alcohol and ether) could be used to drive down the temperature of an object past the freezing point of water. They experimented with the bulb of a mercury-in-glass thermometer as their object. They used a bellows to speed up the evaporation. They lowered the temperature of the thermometer bulb down to −14 °C (7 °F) while the ambient temperature was 18 °C (64 °F). Franklin noted that soon after they passed the freezing point of water 0 °C (32 °F), a thin film of ice formed on the surface of the thermometer's bulb and that the ice mass was about 6 mm (1⁄4 in) thick when they stopped the experiment upon reaching −14 °C (7 °F). Franklin concluded: "From this experiment, one may see the possibility of freezing a man to death on a warm summer's day."[19]
The 19th century included many developments in compression technology. In 1820, English scientist and inventor Michael Faraday discovered that compressing and liquefying ammonia could chill air when the liquefied ammonia was allowed to evaporate.[20] In 1842, Florida physician John Gorrie used compressor technology to create ice, which he used to cool air for his patients in his hospital in Apalachicola, Florida. He hoped to eventually use his ice-making machine to regulate the temperature of buildings.[20][21] He envisioned centralized air conditioning that could cool entire cities. Gorrie was granted a patent in 1851,[22] but following the death of his main backer, he was not able to realize his invention.[23] In 1851, James Harrison created the first mechanical ice-making machine in Geelong, Australia, and was granted a patent for an ether vapor-compression refrigeration system in 1855 that produced three tons of ice per day.[24] In 1860, Harrison established a second ice company. He later entered the debate over competing against the American advantage of ice-refrigerated beef sales to the United Kingdom.[24]
Electricity made the development of effective units possible. In 1901, American inventor Willis H. Carrier built what is considered the first modern electrical air conditioning unit.[25][26][27][28] In 1902, he installed his first air-conditioning system, in the Sackett-Wilhelms Lithographing & Publishing Company in Brooklyn, New York.[29] His invention controlled both the temperature and humidity, which helped maintain consistent paper dimensions and ink alignment at the printing plant. Later, together with six other employees, Carrier formed The Carrier Air Conditioning Company of America, a business that in 2020 employed 53,000 people and was valued at $18.6 billion.[30][31]
In 1906, Stuart W. Cramer of Charlotte, North Carolina, was exploring ways to add moisture to the air in his textile mill. Cramer coined the term "air conditioning" in a patent claim which he filed that year, where he suggested that air conditioning was analogous to "water conditioning", then a well-known process for making textiles easier to process.[32] He combined moisture with ventilation to "condition" and change the air in the factories; thus, controlling the humidity that is necessary in textile plants. Willis Carrier adopted the term and incorporated it into the name of his company.[33]
Domestic air conditioning soon took off. In 1914, the first domestic air conditioning was installed in Minneapolis in the home of Charles Gilbert Gates. It is, however, possible that the considerable device (c. 2.1 m × 1.8 m × 6.1 m; 7 ft × 6 ft × 20 ft) was never used, as the house remained uninhabited[20] (Gates had already died in October 1913.)
In 1931, H.H. Schultz and J.Q. Sherman developed what would become the most common type of individual room air conditioner: one designed to sit on a window ledge. The units went on sale in 1932 at US$10,000 to $50,000 (the equivalent of $200,000 to $1,100,000 in 2023.)[20] A year later, the first air conditioning systems for cars were offered for sale.[34] Chrysler Motors introduced the first practical semi-portable air conditioning unit in 1935,[35] and Packard became the first automobile manufacturer to offer an air conditioning unit in its cars in 1939.[36]
Innovations in the latter half of the 20th century allowed more ubiquitous air conditioner use. In 1945, Robert Sherman of Lynn, Massachusetts, invented a portable, in-window air conditioner that cooled, heated, humidified, dehumidified, and filtered the air.[37] The first inverter air conditioners were released in 1980–1981.[38][39]
In 1954, Ned Cole, a 1939 architecture graduate from the University of Texas at Austin, developed the first experimental "suburb" with inbuilt air conditioning in each house. 22 homes were developed on a flat, treeless track in northwest Austin, Texas, and the community was christened the 'Austin Air-Conditioned Village.' The residents were subjected to a year-long study of the effects of air conditioning led by the nation’s premier air conditioning companies, builders, and social scientists. In addition, researchers from UT’s Health Service and Psychology Department studied the effects on the "artificially cooled humans." One of the more amusing discoveries was that each family reported being troubled with scorpions, the leading theory being that scorpions sought cool, shady places. Other reported changes in lifestyle were that mothers baked more, families ate heavier foods, and they were more apt to choose hot drinks.[40][41]
Air conditioner adoption tends to increase above around $10,000 annual household income in warmer areas.[42] Global GDP growth explains around 85% of increased air condition adoption by 2050, while the remaining 15% can be explained by climate change.[42]
As of 2016 an estimated 1.6 billion air conditioning units were used worldwide, with over half of them in China and USA, and a total cooling capacity of 11,675 gigawatts.[8][43] The International Energy Agency predicted in 2018 that the number of air conditioning units would grow to around 4 billion units by 2050 and that the total cooling capacity would grow to around 23,000 GW, with the biggest increases in India and China.[8] Between 1995 and 2004, the proportion of urban households in China with air conditioners increased from 8% to 70%.[44] As of 2015, nearly 100 million homes, or about 87% of US households, had air conditioning systems.[45] In 2019, it was estimated that 90% of new single-family homes constructed in the US included air conditioning (ranging from 99% in the South to 62% in the West).[46][47]
Cooling in traditional air conditioner systems is accomplished using the vapor-compression cycle, which uses a refrigerant's forced circulation and phase change between gas and liquid to transfer heat.[48][49] The vapor-compression cycle can occur within a unitary, or packaged piece of equipment; or within a chiller that is connected to terminal cooling equipment (such as a fan coil unit in an air handler) on its evaporator side and heat rejection equipment such as a cooling tower on its condenser side. An air source heat pump shares many components with an air conditioning system, but includes a reversing valve, which allows the unit to be used to heat as well as cool a space.[50]
Air conditioning equipment will reduce the absolute humidity of the air processed by the system if the surface of the evaporator coil is significantly cooler than the dew point of the surrounding air. An air conditioner designed for an occupied space will typically achieve a 30% to 60% relative humidity in the occupied space.[51]
Most modern air-conditioning systems feature a dehumidification cycle during which the compressor runs. At the same time, the fan is slowed to reduce the evaporator temperature and condense more water. A dehumidifier uses the same refrigeration cycle but incorporates both the evaporator and the condenser into the same air path; the air first passes over the evaporator coil, where it is cooled[52] and dehumidified before passing over the condenser coil, where it is warmed again before it is released back into the room.[citation needed]
Free cooling can sometimes be selected when the external air is cooler than the internal air. Therefore, the compressor does not need to be used, resulting in high cooling efficiencies for these times. This may also be combined with seasonal thermal energy storage.[53]
Some air conditioning systems can reverse the refrigeration cycle and act as an air source heat pump, thus heating instead of cooling the indoor environment. They are also commonly referred to as "reverse cycle air conditioners". The heat pump is significantly more energy-efficient than electric resistance heating, because it moves energy from air or groundwater to the heated space and the heat from purchased electrical energy. When the heat pump is in heating mode, the indoor evaporator coil switches roles and becomes the condenser coil, producing heat. The outdoor condenser unit also switches roles to serve as the evaporator and discharges cold air (colder than the ambient outdoor air).
Most air source heat pumps become less efficient in outdoor temperatures lower than 4 °C or 40 °F.[54] This is partly because ice forms on the outdoor unit's heat exchanger coil, which blocks air flow over the coil. To compensate for this, the heat pump system must temporarily switch back into the regular air conditioning mode to switch the outdoor evaporator coil back to the condenser coil, to heat up and defrost. Therefore, some heat pump systems will have electric resistance heating in the indoor air path that is activated only in this mode to compensate for the temporary indoor air cooling, which would otherwise be uncomfortable in the winter.
Newer models have improved cold-weather performance, with efficient heating capacity down to −14 °F (−26 °C).[55][54][56] However, there is always a chance that the humidity that condenses on the heat exchanger of the outdoor unit could freeze, even in models that have improved cold-weather performance, requiring a defrosting cycle to be performed.
The icing problem becomes much more severe with lower outdoor temperatures, so heat pumps are sometimes installed in tandem with a more conventional form of heating, such as an electrical heater, a natural gas, heating oil, or wood-burning fireplace or central heating, which is used instead of or in addition to the heat pump during harsher winter temperatures. In this case, the heat pump is used efficiently during milder temperatures, and the system is switched to the conventional heat source when the outdoor temperature is lower.
The coefficient of performance (COP) of an air conditioning system is a ratio of useful heating or cooling provided to the work required.[57][58] Higher COPs equate to lower operating costs. The COP usually exceeds 1; however, the exact value is highly dependent on operating conditions, especially absolute temperature and relative temperature between sink and system, and is often graphed or averaged against expected conditions.[59] Air conditioner equipment power in the U.S. is often described in terms of "tons of refrigeration", with each approximately equal to the cooling power of one short ton (2,000 pounds (910 kg) of ice melting in a 24-hour period. The value is equal to 12,000 BTUIT per hour, or 3,517 watts.[60] Residential central air systems are usually from 1 to 5 tons (3.5 to 18 kW) in capacity.[citation needed]
The efficiency of air conditioners is often rated by the seasonal energy efficiency ratio (SEER), which is defined by the Air Conditioning, Heating and Refrigeration Institute in its 2008 standard AHRI 210/240, Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment.[61] A similar standard is the European seasonal energy efficiency ratio (ESEER).[citation needed]
Efficiency is strongly affected by the humidity of the air to be cooled. Dehumidifying the air before attempting to cool it can reduce subsequent cooling costs by as much as 90 percent. Thus, reducing dehumidifying costs can materially affect overall air conditioning costs.[62]
This type of controller uses an infrared LED to relay commands from a remote control to the air conditioner. The output of the infrared LED (like that of any infrared remote) is invisible to the human eye because its wavelength is beyond the range of visible light (940 nm). This system is commonly used on mini-split air conditioners because it is simple and portable. Some window and ducted central air conditioners uses it as well.
A wired controller, also called a "wired thermostat," is a device that controls an air conditioner by switching heating or cooling on or off. It uses different sensors to measure temperatures and actuate control operations. Mechanical thermostats commonly use bimetallic strips, converting a temperature change into mechanical displacement, to actuate control of the air conditioner. Electronic thermostats, instead, use a thermistor or other semiconductor sensor, processing temperature change as electronic signals to control the air conditioner.
These controllers are usually used in hotel rooms because they are permanently installed into a wall and hard-wired directly into the air conditioner unit, eliminating the need for batteries.
Types | Typical Capacity* | Air supply | Mounting | Typical application |
---|---|---|---|---|
Mini-split | small – large | Direct | Wall | Residential |
Window | very small – small | Direct | Window | Residential |
Portable | very small – small | Direct / Ducted | Floor | Residential, remote areas |
Ducted (individual) | small – very large | Ducted | Ceiling | Residential, commercial |
Ducted (central) | medium – very large | Ducted | Ceiling | Residential, commercial |
Ceiling suspended | medium – large | Direct | Ceiling | Commercial |
Cassette | medium – large | Direct / Ducted | Ceiling | Commercial |
Floor standing | medium – large | Direct / Ducted | Floor | Commercial |
Packaged | very large | Direct / Ducted | Floor | Commercial |
Packaged RTU (Rooftop Unit) | very large | Ducted | Rooftop | Commercial |
* where the typical capacity is in kilowatt as follows:
Ductless systems (often mini-split, though there are now ducted mini-split) typically supply conditioned and heated air to a single or a few rooms of a building, without ducts and in a decentralized manner.[63] Multi-zone or multi-split systems are a common application of ductless systems and allow up to eight rooms (zones or locations) to be conditioned independently from each other, each with its indoor unit and simultaneously from a single outdoor unit.
The first mini-split system was sold in 1961 by Toshiba in Japan, and the first wall-mounted mini-split air conditioner was sold in 1968 in Japan by Mitsubishi Electric, where small home sizes motivated their development. The Mitsubishi model was the first air conditioner with a cross-flow fan.[64][65][66] In 1969, the first mini-split air conditioner was sold in the US.[67] Multi-zone ductless systems were invented by Daikin in 1973, and variable refrigerant flow systems (which can be thought of as larger multi-split systems) were also invented by Daikin in 1982. Both were first sold in Japan.[68] Variable refrigerant flow systems when compared with central plant cooling from an air handler, eliminate the need for large cool air ducts, air handlers, and chillers; instead cool refrigerant is transported through much smaller pipes to the indoor units in the spaces to be conditioned, thus allowing for less space above dropped ceilings and a lower structural impact, while also allowing for more individual and independent temperature control of spaces. The outdoor and indoor units can be spread across the building.[69] Variable refrigerant flow indoor units can also be turned off individually in unused spaces.[citation needed] The lower start-up power of VRF's DC inverter compressors and their inherent DC power requirements also allow VRF solar-powered heat pumps to be run using DC-providing solar panels.
Split-system central air conditioners consist of two heat exchangers, an outside unit (the condenser) from which heat is rejected to the environment and an internal heat exchanger (the evaporator, or Fan Coil Unit, FCU) with the piped refrigerant being circulated between the two. The FCU is then connected to the spaces to be cooled by ventilation ducts.[70] Floor standing air conditioners are similar to this type of air conditioner but sit within spaces that need cooling.
Large central cooling plants may use intermediate coolant such as chilled water pumped into air handlers or fan coil units near or in the spaces to be cooled which then duct or deliver cold air into the spaces to be conditioned, rather than ducting cold air directly to these spaces from the plant, which is not done due to the low density and heat capacity of air, which would require impractically large ducts. The chilled water is cooled by chillers in the plant, which uses a refrigeration cycle to cool water, often transferring its heat to the atmosphere even in liquid-cooled chillers through the use of cooling towers. Chillers may be air- or liquid-cooled.[71][72]
A portable system has an indoor unit on wheels connected to an outdoor unit via flexible pipes, similar to a permanently fixed installed unit (such as a ductless split air conditioner).
Hose systems, which can be monoblock or air-to-air, are vented to the outside via air ducts. The monoblock type collects the water in a bucket or tray and stops when full. The air-to-air type re-evaporates the water, discharges it through the ducted hose, and can run continuously. Many but not all portable units draw indoor air and expel it outdoors through a single duct, negatively impacting their overall cooling efficiency.
Many portable air conditioners come with heat as well as a dehumidification function.[73]
The packaged terminal air conditioner (PTAC), through-the-wall, and window air conditioners are similar. These units are installed on a window frame or on a wall opening. The unit usually has an internal partition separating its indoor and outdoor sides, which contain the unit's condenser and evaporator, respectively. PTAC systems may be adapted to provide heating in cold weather, either directly by using an electric strip, gas, or other heaters, or by reversing the refrigerant flow to heat the interior and draw heat from the exterior air, converting the air conditioner into a heat pump. They may be installed in a wall opening with the help of a special sleeve on the wall and a custom grill that is flush with the wall and window air conditioners can also be installed in a window, but without a custom grill.[74]
Packaged air conditioners (also known as self-contained units)[75][76] are central systems that integrate into a single housing all the components of a split central system, and deliver air, possibly through ducts, to the spaces to be cooled. Depending on their construction they may be outdoors or indoors, on roofs (rooftop units),[77][78] draw the air to be conditioned from inside or outside a building and be water or air-cooled. Often, outdoor units are air-cooled while indoor units are liquid-cooled using a cooling tower.[70][79][80][81][82][83]
Compressor types | Common applications | Typical capacity | Efficiency | Durability | Repairability |
---|---|---|---|---|---|
Reciprocating | Refrigerator, Walk-in freezer, portable air conditioners | small – large | very low (small capacity)
medium (large capacity) |
very low | medium |
Rotary vane | Residential mini splits | small | low | low | easy |
Scroll | Commercial and central systems, VRF | medium | medium | medium | easy |
Rotary screw | Commercial chiller | medium – large | medium | medium | hard |
Centrifugal | Commercial chiller | very large | medium | high | hard |
Maglev Centrifugal | Commercial chiller | very large | high | very high | very hard |
This compressor consists of a crankcase, crankshaft, piston rod, piston, piston ring, cylinder head and valves. [citation needed]
This compressor uses two interleaving scrolls to compress the refrigerant.[84] it consists of one fixed and one orbiting scrolls. This type of compressor is more efficient because it has 70 percent less moving parts than a reciprocating compressor. [citation needed]
This compressor use two very closely meshing spiral rotors to compress the gas. The gas enters at the suction side and moves through the threads as the screws rotate. The meshing rotors force the gas through the compressor, and the gas exits at the end of the screws. The working area is the inter-lobe volume between the male and female rotors. It is larger at the intake end, and decreases along the length of the rotors until the exhaust port. This change in volume is the compression. [citation needed]
There are several ways to modulate the cooling capacity in refrigeration or air conditioning and heating systems. The most common in air conditioning are: on-off cycling, hot gas bypass, use or not of liquid injection, manifold configurations of multiple compressors, mechanical modulation (also called digital), and inverter technology. [citation needed]
Hot gas bypass involves injecting a quantity of gas from discharge to the suction side. The compressor will keep operating at the same speed, but due to the bypass, the refrigerant mass flow circulating with the system is reduced, and thus the cooling capacity. This naturally causes the compressor to run uselessly during the periods when the bypass is operating. The turn down capacity varies between 0 and 100%.[85]
Several compressors can be installed in the system to provide the peak cooling capacity. Each compressor can run or not in order to stage the cooling capacity of the unit. The turn down capacity is either 0/33/66 or 100% for a trio configuration and either 0/50 or 100% for a tandem.[citation needed]
This internal mechanical capacity modulation is based on periodic compression process with a control valve, the two scroll set move apart stopping the compression for a given time period. This method varies refrigerant flow by changing the average time of compression, but not the actual speed of the motor. Despite an excellent turndown ratio – from 10 to 100% of the cooling capacity, mechanically modulated scrolls have high energy consumption as the motor continuously runs.[citation needed]
This system uses a variable-frequency drive (also called an Inverter) to control the speed of the compressor. The refrigerant flow rate is changed by the change in the speed of the compressor. The turn down ratio depends on the system configuration and manufacturer. It modulates from 15 or 25% up to 100% at full capacity with a single inverter from 12 to 100% with a hybrid tandem. This method is the most efficient way to modulate an air conditioner's capacity. It is up to 58% more efficient than a fixed speed system.[citation needed]
In hot weather, air conditioning can prevent heat stroke, dehydration due to excessive sweating, electrolyte imbalance, kidney failure, and other issues due to hyperthermia.[8][86] Heat waves are the most lethal type of weather phenomenon in the United States.[87][88] A 2020 study found that areas with lower use of air conditioning correlated with higher rates of heat-related mortality and hospitalizations.[89] The August 2003 France heatwave resulted in approximately 15,000 deaths, where 80% of the victims were over 75 years old. In response, the French government required all retirement homes to have at least one air-conditioned room at 25 °C (77 °F) per floor during heatwaves.[8]
Air conditioning (including filtration, humidification, cooling and disinfection) can be used to provide a clean, safe, hypoallergenic atmosphere in hospital operating rooms and other environments where proper atmosphere is critical to patient safety and well-being. It is sometimes recommended for home use by people with allergies, especially mold.[90][91] However, poorly maintained water cooling towers can promote the growth and spread of microorganisms such as Legionella pneumophila, the infectious agent responsible for Legionnaires' disease. As long as the cooling tower is kept clean (usually by means of a chlorine treatment), these health hazards can be avoided or reduced. The state of New York has codified requirements for registration, maintenance, and testing of cooling towers to protect against Legionella.[92]
First designed to benefit targeted industries such as the press as well as large factories, the invention quickly spread to public agencies and administrations with studies with claims of increased productivity close to 24% in places equipped with air conditioning.[93]
Air conditioning caused various shifts in demography, notably that of the United States starting from the 1970s. In the US, the birth rate was lower in the spring than during other seasons until the 1970s but this difference then declined since then.[94] As of 2007, the Sun Belt contained 30% of the total US population while it was inhabited by 24% of Americans at the beginning of the 20th century.[95] Moreover, the summer mortality rate in the US, which had been higher in regions subject to a heat wave during the summer, also evened out.[7]
The spread of the use of air conditioning acts as a main driver for the growth of global demand of electricity.[96] According to a 2018 report from the International Energy Agency (IEA), it was revealed that the energy consumption for cooling in the United States, involving 328 million Americans, surpasses the combined energy consumption of 4.4 billion people in Africa, Latin America, the Middle East, and Asia (excluding China).[8] A 2020 survey found that an estimated 88% of all US households use AC, increasing to 93% when solely looking at homes built between 2010 and 2020.[97]
Space cooling including air conditioning accounted globally for 2021 terawatt-hours of energy usage in 2016 with around 99% in the form of electricity, according to a 2018 report on air-conditioning efficiency by the International Energy Agency.[8] The report predicts an increase of electricity usage due to space cooling to around 6200 TWh by 2050,[8][98] and that with the progress currently seen, greenhouse gas emissions attributable to space cooling will double: 1,135 million tons (2016) to 2,070 million tons.[8] There is some push to increase the energy efficiency of air conditioners. United Nations Environment Programme (UNEP) and the IEA found that if air conditioners could be twice as effective as now, 460 billion tons of GHG could be cut over 40 years.[99] The UNEP and IEA also recommended legislation to decrease the use of hydrofluorocarbons, better building insulation, and more sustainable temperature-controlled food supply chains going forward.[99]
Refrigerants have also caused and continue to cause serious environmental issues, including ozone depletion and climate change, as several countries have not yet ratified the Kigali Amendment to reduce the consumption and production of hydrofluorocarbons.[100] CFCs and HCFCs refrigerants such as R-12 and R-22, respectively, used within air conditioners have caused damage to the ozone layer,[101] and hydrofluorocarbon refrigerants such as R-410A and R-404A, which were designed to replace CFCs and HCFCs, are instead exacerbating climate change.[102] Both issues happen due to the venting of refrigerant to the atmosphere, such as during repairs. HFO refrigerants, used in some if not most new equipment, solve both issues with an ozone damage potential (ODP) of zero and a much lower global warming potential (GWP) in the single or double digits vs. the three or four digits of hydrofluorocarbons.[103]
Hydrofluorocarbons would have raised global temperatures by around 0.3–0.5 °C (0.5–0.9 °F) by 2100 without the Kigali Amendment. With the Kigali Amendment, the increase of global temperatures by 2100 due to hydrofluorocarbons is predicted to be around 0.06 °C (0.1 °F).[104]
Alternatives to continual air conditioning include passive cooling, passive solar cooling, natural ventilation, operating shades to reduce solar gain, using trees, architectural shades, windows (and using window coatings) to reduce solar gain.[citation needed]
Socioeconomic groups with a household income below around $10,000 tend to have a low air conditioning adoption,[42] which worsens heat-related mortality.[7] The lack of cooling can be hazardous, as areas with lower use of air conditioning correlate with higher rates of heat-related mortality and hospitalizations.[89] Premature mortality in NYC is projected to grow between 47% and 95% in 30 years, with lower-income and vulnerable populations most at risk.[89] Studies on the correlation between heat-related mortality and hospitalizations and living in low socioeconomic locations can be traced in Phoenix, Arizona,[105] Hong Kong,[106] China,[106] Japan,[107] and Italy.[108][109] Additionally, costs concerning health care can act as another barrier, as the lack of private health insurance during a 2009 heat wave in Australia, was associated with heat-related hospitalization.[109]
Disparities in socioeconomic status and access to air conditioning are connected by some to institutionalized racism, which leads to the association of specific marginalized communities with lower economic status, poorer health, residing in hotter neighborhoods, engaging in physically demanding labor, and experiencing limited access to cooling technologies such as air conditioning.[109] A study overlooking Chicago, Illinois, Detroit, and Michigan found that black households were half as likely to have central air conditioning units when compared to their white counterparts.[110] Especially in cities, Redlining creates heat islands, increasing temperatures in certain parts of the city.[109] This is due to materials heat-absorbing building materials and pavements and lack of vegetation and shade coverage.[111] There have been initiatives that provide cooling solutions to low-income communities, such as public cooling spaces.[8][111]
Buildings designed with passive air conditioning are generally less expensive to construct and maintain than buildings with conventional HVAC systems with lower energy demands.[112] While tens of air changes per hour, and cooling of tens of degrees, can be achieved with passive methods, site-specific microclimate must be taken into account, complicating building design.[12]
Many techniques can be used to increase comfort and reduce the temperature in buildings. These include evaporative cooling, selective shading, wind, thermal convection, and heat storage.[113]
Passive ventilation is the process of supplying air to and removing air from an indoor space without using mechanical systems. It refers to the flow of external air to an indoor space as a result of pressure differences arising from natural forces.
There are two types of natural ventilation occurring in buildings: wind driven ventilation and buoyancy-driven ventilation. Wind driven ventilation arises from the different pressures created by wind around a building or structure, and openings being formed on the perimeter which then permit flow through the building. Buoyancy-driven ventilation occurs as a result of the directional buoyancy force that results from temperature differences between the interior and exterior.[114]
Since the internal heat gains which create temperature differences between the interior and exterior are created by natural processes, including the heat from people, and wind effects are variable, naturally ventilated buildings are sometimes called "breathing buildings".Passive cooling is a building design approach that focuses on heat gain control and heat dissipation in a building in order to improve the indoor thermal comfort with low or no energy consumption.[115][116] This approach works either by preventing heat from entering the interior (heat gain prevention) or by removing heat from the building (natural cooling).[117]
Natural cooling utilizes on-site energy, available from the natural environment, combined with the architectural design of building components (e.g. building envelope), rather than mechanical systems to dissipate heat.[118] Therefore, natural cooling depends not only on the architectural design of the building but on how the site's natural resources are used as heat sinks (i.e. everything that absorbs or dissipates heat). Examples of on-site heat sinks are the upper atmosphere (night sky), the outdoor air (wind), and the earth/soil.
Passive cooling is an important tool for design of buildings for climate change adaptation – reducing dependency on energy-intensive air conditioning in warming environments.[119][120]Passive daytime radiative cooling (PDRC) surfaces reflect incoming solar radiation and heat back into outer space through the infrared window for cooling during the daytime. Daytime radiative cooling became possible with the ability to suppress solar heating using photonic structures, which emerged through a study by Raman et al. (2014).[122] PDRCs can come in a variety of forms, including paint coatings and films, that are designed to be high in solar reflectance and thermal emittance.[121][123]
PDRC applications on building roofs and envelopes have demonstrated significant decreases in energy consumption and costs.[123] In suburban single-family residential areas, PDRC application on roofs can potentially lower energy costs by 26% to 46%.[124] PDRCs are predicted to show a market size of ~$27 billion for indoor space cooling by 2025 and have undergone a surge in research and development since the 2010s.[125][126]
Hand fans have existed since prehistory. Large human-powered fans built into buildings include the punkah.
The 2nd-century Chinese inventor Ding Huan of the Han dynasty invented a rotary fan for air conditioning, with seven wheels 3 m (10 ft) in diameter and manually powered by prisoners.[127]: 99, 151, 233 In 747, Emperor Xuanzong (r. 712–762) of the Tang dynasty (618–907) had the Cool Hall (Liang Dian 涼殿) built in the imperial palace, which the Tang Yulin describes as having water-powered fan wheels for air conditioning as well as rising jet streams of water from fountains. During the subsequent Song dynasty (960–1279), written sources mentioned the air conditioning rotary fan as even more widely used.[127]: 134, 151â€ÅÂ
In areas that are cold at night or in winter, heat storage is used. Heat may be stored in earth or masonry; air is drawn past the masonry to heat or cool it.[13]
In areas that are below freezing at night in winter, snow and ice can be collected and stored in ice houses for later use in cooling.[13] This technique is over 3,700 years old in the Middle East.[128] Harvesting outdoor ice during winter and transporting and storing for use in summer was practiced by wealthy Europeans in the early 1600s,[15] and became popular in Europe and the Americas towards the end of the 1600s.[129] This practice was replaced by mechanical compression-cycle icemakers.
In dry, hot climates, the evaporative cooling effect may be used by placing water at the air intake, such that the draft draws air over water and then into the house. For this reason, it is sometimes said that the fountain, in the architecture of hot, arid climates, is like the fireplace in the architecture of cold climates.[11] Evaporative cooling also makes the air more humid, which can be beneficial in a dry desert climate.[130]
Evaporative coolers tend to feel as if they are not working during times of high humidity, when there is not much dry air with which the coolers can work to make the air as cool as possible for dwelling occupants. Unlike other types of air conditioners, evaporative coolers rely on the outside air to be channeled through cooler pads that cool the air before it reaches the inside of a house through its air duct system; this cooled outside air must be allowed to push the warmer air within the house out through an exhaust opening such as an open door or window.[131]
In our method I shall observe what our ancestors have said; then I shall show by my own experience, whether they be true or false
Cornelius Drebbel air conditioning.
cite press release
: CS1 maint: archived copy as title (link)Though he did not actually invent air-conditioning nor did he take the first documented scientific approach to applying it, Willis Carrier is credited with integrating the scientific method, engineering, and business of this developing technology and creating the industry we know today as air-conditioning.
cite web
: CS1 maint: archived copy as title (link) CS1 maint: bot: original URL status unknown (link)cite journal
: Cite journal requires |journal=
(help)Passive daytime radiative cooling (PDRC) dissipates terrestrial heat to the extremely cold outer space without using any energy input or producing pollution. It has the potential to simultaneously alleviate the two major problems of energy crisis and global warming.
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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]
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 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.
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.
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]
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]
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]
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.
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]
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]
Mobile homes often require special lenders.[28]
Modular homes on the other hand are financed as site built homes with a construction loan
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]
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.
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]
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:
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]
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]
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]
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
Very knowledgeable, friendly, helpful and don't make you feel like you're inconveniencing them. They seem willing to take all the time you need. As if you're the only thing they have to do that day. The store is clean, organized and not cluttered, symmetrical at that. Cuz I'm even and symmetricals biggest fan. It was a pleasure doing business with them and their prices are definitely reasonable. So, I'll be doing business with them in the future no doubt.
This is another amazing place where we will do much more business. They are not tyrannical about the totally useless face diapers, they have a great selection of stock, they have very knowledgeable staff, very friendly staff. We got the plumbing items we really needed and will be getting more plumbing items. They also have central units, thermostats, caulking, sealants, doors, seems everything you need for a mobile home. We've found a local treasure and will be bringing much more business. Their store is clean and tidy as well!
Royal installed a new furnace and air conditioner just before we got our used mobile home. Recently, the furnace stopped lighting. Jared (sp?) made THREE trips to get it back to good. He was so gracious and kind. Fortunately for us it was still under warranty. BTW, those three trips were from Fenton, Missouri to Belleville, Illinois! Thanks again, Jared!
Horrible workmanship, horrible customer service, don't show up when they say they are. Ghosted. Was supposed to come back on Monday, no call no show. Called Tuesday and Wednesday, left messages both days. Nothing. Kinked my line, crooked to the pad and house, didn't put disconnect back on, left the trash.....
Went to get a deadbolt what they had was one I was told I'd have take it apart to lengthen and I said I wasn't buying something new and have to work on it. Thing of it is I didn't know if it was so that it could be lengthened said I didn't wanna buy something new I had to work on just to fit my door. He got all mad and slung the whole box with part across the room. A real business man. I guess the owner approves of his employees doing as such.