Air conditioning systems have become indispensable in our daily lives, providing us with comfort and a reprieve from the sweltering heat of summer. However, like any mechanical system, air conditioners are prone to wear and tear over time. Understanding common air conditioning issues and their repairs is crucial for maintaining an efficient and effective HVAC (heating, ventilation, and air conditioning) system. A well-maintained air conditioning system ensures Air conditioning troubleshooting it’s important to schedule repairs as soon as possible.. This understanding further underscores the importance of scheduling annual HVAC maintenance.
One of the most prevalent issues faced by homeowners is inadequate cooling or uneven temperature distribution within a space. This can often be traced back to dirty or clogged filters, which restrict airflow and reduce the system's efficiency.
Another frequent problem is when an air conditioner cycles on and off too frequently-known as short cycling. This issue may arise due to thermostat malfunctions or improper sizing of the air conditioning unit relative to the space it serves. Short cycling not only increases energy consumption but also accelerates wear on the compressor and other components, leading to potential breakdowns if not addressed promptly.
Electrical issues within an AC unit are also common culprits behind operational failures. Faulty wiring or corroded connections can lead to power losses or even pose safety hazards such as electrical fires. Regular inspection by qualified technicians ensures that all electrical components are functioning safely and efficiently.
The condenser coils in outdoor units often accumulate dirt and debris over time, especially if located in dusty environments or areas with high vegetation growth. Dirty coils impede heat exchange processes, forcing the system to work harder than necessary and ultimately resulting in higher energy bills. Routine cleaning of condenser coils during annual maintenance helps prevent this inefficiency.
Understanding these common issues highlights why scheduling annual HVAC maintenance is vital for both homeowners and businesses alike. Regular maintenance allows for early detection of potential problems before they escalate into costly repairs or full system replacements. During these check-ups, HVAC professionals thoroughly inspect all components-from filters to fans-and ensure everything operates at peak efficiency.
Moreover, maintaining your HVAC system annually extends its lifespan while improving indoor air quality-a significant benefit given how much time we spend indoors today compared to previous generations who spent more time outdoors naturally ventilated spaces! Clean systems mean cleaner air free from allergens like dust mites mold spores pet dander etc., contributing positively towards healthier living environments overall well-being occupants therein including those suffering respiratory conditions allergies asthma among others sensitive individuals susceptible adverse effects poor indoor quality pollutants present unchecked neglected systems long periods without proper care attention required maintaining them optimal performance levels expected modern-day standards comfort convenience synonymous contemporary living experiences!
In conclusion investing regular upkeep pays dividends terms reliability cost-effectiveness peace mind knowing equipment dependable operating smoothly consistently year-round regardless weather extremes external conditions might face periodically encounter seasonally variable climate patterns globally experienced increasingly unpredictable recent times climate change-related factors influencing environmental dynamics worldwide affecting regions differently specific ways localized contexts requiring tailored approaches addressing unique challenges posed each situation respectively comprehensively effectively sustainable manner possible future generations enjoy benefits technology afford today responsibly harnessed managed wisely collectively society whole betterment planet inhabitants shared home Earth!
In today's fast-paced world, where technology and machinery are integral to our daily lives, the significance of regular maintenance cannot be overstated. This is especially true for systems that we rely on for comfort and safety, such as HVAC (Heating, Ventilation, and Air Conditioning) units. Scheduling annual HVAC maintenance is not merely a recommendation but a necessity to ensure system longevity and optimal performance.
Firstly, let's consider the primary function of an HVAC system: it regulates indoor climate, providing warmth in winter and coolness during summer while ensuring adequate ventilation throughout the year. Given its continuous operation and crucial role in maintaining a comfortable living environment, the system endures significant wear and tear over time. Just like any other mechanical equipment, neglecting its upkeep can lead to unexpected breakdowns at the most inconvenient times.
Regular maintenance ensures that your HVAC system operates efficiently. An efficiently running system uses less energy, leading to lower utility bills-a benefit that resonates with both environmentally conscious homeowners and those mindful of their budget. During a scheduled maintenance visit, technicians typically clean coils, replace filters, check refrigerant levels, and ensure all components are functioning correctly. These actions prevent minor issues from escalating into major repairs or even complete system failures.
Moreover, annual maintenance extends the lifespan of your HVAC unit. Most systems are designed to last 15-20 years; however, without proper care, this lifespan can be significantly reduced. Regular check-ups help identify potential problems early on-issues that could otherwise shorten your system's operational life or reduce its efficiency if left unaddressed.
Additionally, there are health benefits associated with regular HVAC maintenance. A well-maintained system improves indoor air quality by effectively filtering out dust particles, allergens, and pollutants-factors that contribute to respiratory problems or allergies if neglected. Ensuring your HVAC unit is clean and functioning optimally provides peace of mind knowing you're breathing cleaner air indoors.
Furthermore, considering the financial aspect of homeownership or business operations is essential. Investing in annual maintenance may seem like an added expense initially; however, it pales in comparison to the costs associated with emergency repairs or premature replacement of an entire unit due to neglect.
Finally yet importantly-the importance of professional involvement should not be underestimated when it comes to maintaining complex systems such as HVAC units. Certified technicians have specialized knowledge about these systems' intricacies-they understand what needs attention during inspections better than anyone else possibly could without extensive training themselves!
In conclusion: scheduling annual HVAC maintenance isn't just about keeping things running smoothly today-it's about safeguarding future functionality too! By prioritizing routine checks now - you're investing long-term health & efficiency into perhaps one most vital aspects within household infrastructure itself!
In the modern world, where comfort and efficiency are prized more than ever, the role of a well-functioning HVAC system cannot be overstated. These systems are the unsung heroes that maintain our indoor environments at optimal temperatures throughout the year. However, like any machinery, HVAC systems require regular attention to operate efficiently and effectively. Scheduling annual HVAC maintenance is not just a recommendation-it's a necessity. One of the most compelling reasons for this routine check-up is its profound impact on preventing costly repairs.
Annual HVAC maintenance serves as a preventive measure against potential breakdowns and malfunctions. During these scheduled check-ups, trained technicians thoroughly inspect the entire system. They clean components, replace filters, and identify minor issues before they escalate into significant problems. This preventative care approach is akin to receiving an annual health check-up; it identifies vulnerabilities and addresses them proactively.
One of the primary benefits of such maintenance is cost savings in terms of repair expenses. Without regular upkeep, small issues can quickly snowball into larger, more costly repairs. For instance, a dirty filter or clogged drain line might seem trivial but could lead to overheating or water damage if left unchecked. By catching these problems early during annual inspections, homeowners can avoid the hefty costs associated with emergency repairs or even full system replacements.
Moreover, regular maintenance extends the lifespan of an HVAC system. A well-maintained unit operates under less strain and uses energy more efficiently, reducing wear and tear over time. This longevity translates to fewer replacements and reduced expenditure on new installations-a clear financial advantage for any homeowner.
In addition to direct cost savings from avoiding major repairs or replacements, maintaining an efficient HVAC system also translates into lower utility bills. Systems that operate smoothly consume less energy while providing consistent performance year-round. This efficiency not only reduces environmental impact but also keeps monthly household expenses in check.
Furthermore, annual maintenance enhances safety within homes by ensuring all components function correctly and safely. Faulty wiring or malfunctioning parts can pose severe risks if neglected; thus, regular inspections help mitigate such dangers.
In conclusion, scheduling annual HVAC maintenance goes beyond mere compliance with manufacturer recommendations; it's a strategic decision that safeguards both your comfort and finances. By investing in routine care now, homeowners can prevent unexpected breakdowns later while enjoying enhanced efficiency today-all contributing factors towards long-term savings on costly repairs down the road.
Scheduled maintenance is often viewed as an inconvenient necessity, a box to be checked off in the never-ending list of responsibilities that come with owning or managing a property. However, when it comes to HVAC systems, scheduling annual maintenance is not just about prolonging the life of the equipment; it's also about enhancing energy efficiency and realizing significant cost savings.
HVAC systems are complex machines composed of numerous components that must work harmoniously to heat and cool spaces effectively. Over time, these components can wear down, accumulate dust and debris, or simply fall out of sync due to regular usage. This gradual degradation often leads to decreased efficiency as the system struggles to maintain desired temperatures with compromised functionality. Scheduled maintenance acts as a preventative measure, ensuring that all parts are clean, properly lubricated, and functioning optimally.
One of the most immediate benefits of regular HVAC maintenance is improved energy efficiency. A well-maintained system does not have to work as hard to produce the same results as a neglected one. For example, replacing air filters during routine check-ups allows for unobstructed airflow through the system, which reduces energy consumption significantly. Similarly, cleaning coils and calibrating thermostats ensures that the system operates at peak performance without unnecessary strain on any single component.
This improvement in energy efficiency translates directly into financial savings. According to various studies conducted by energy experts, regularly maintained HVAC systems can reduce energy bills by up to 20%. This is particularly significant in larger commercial settings where HVAC costs constitute a substantial portion of overall operating expenses. By investing in scheduled maintenance, property owners can enjoy lower monthly utility bills while simultaneously reducing their carbon footprint—a win-win scenario for both their wallets and the environment.
Moreover, scheduled maintenance helps prevent costly repairs or replacements down the line. Minor issues detected during routine inspections can be addressed quickly before they escalate into major problems requiring expensive fixes or even complete system overhauls. In this way, regular check-ups serve as an insurance policy against future breakdowns while extending the lifespan of the equipment.
In conclusion, scheduling annual HVAC maintenance should not be seen merely as an optional task but rather as an essential practice for anyone looking to optimize energy efficiency and achieve cost savings. It ensures that systems run smoothly and efficiently year-round while preventing unexpected failures and reducing environmental impact. By prioritizing regular upkeep now, individuals can reap substantial benefits both immediately and in the long term—making it a smart investment for any responsible property owner or manager.
In today's fast-paced world, where indoor environments often serve as our primary habitats, ensuring the quality of the air we breathe is paramount. One critical but sometimes overlooked aspect of maintaining healthy indoor air is routine HVAC maintenance. By scheduling annual check-ups for your heating, ventilation, and air conditioning (HVAC) system, you can significantly enhance indoor air quality and safeguard the health of all occupants.
The importance of regular HVAC maintenance cannot be overstated. Our homes and offices are enclosed spaces where pollutants such as dust, allergens, and volatile organic compounds can accumulate over time. An efficient HVAC system acts as the lungs of a building, circulating clean air while filtering out impurities. However, without routine checks and maintenance, the efficiency of these systems can decline, leading to poor air circulation and increased levels of contaminants.
Annual HVAC checks are essential for several reasons. Firstly, they ensure that filters are replaced or cleaned regularly. Dirty or clogged filters can obstruct airflow and reduce the system's ability to trap harmful particles effectively. By maintaining clean filters, you allow your HVAC system to function optimally, thereby reducing indoor pollutant levels and promoting better respiratory health.
Secondly, routine maintenance helps in identifying potential issues before they escalate into major problems. Technicians can detect signs of wear and tear on components such as coils, fans, and ductwork during an inspection.
Furthermore, a neglected HVAC system can become a breeding ground for mold and bacteria if moisture accumulates unnoticed within its components. These microorganisms may then circulate through your indoor space each time the system is in use. Routine inspections help prevent such occurrences by ensuring that drainage lines are clear and humidity levels are controlled.
Ultimately, scheduling annual HVAC maintenance emerges as a simple yet effective strategy to enhance indoor air quality significantly. Inhabitants of well-maintained environments report fewer allergy symptoms and enjoy improved overall well-being thanks to cleaner air free from unwanted pollutants.
In conclusion, prioritizing annual HVAC checks is an investment in health-both physical due to improved respiratory conditions-and financial because it enhances efficiency while minimizing repair costs over time. As we continue navigating modern life largely indoors amidst various environmental challenges outside our control; taking charge with proactive measures like routine heating/ventilation/air conditioning upkeep provides peace-of-mind knowing you've created safer spaces filled with fresh breathable atmosphere inside every day!
When it comes to maintaining the comfort and efficiency of our homes, the heating, ventilation, and air conditioning (HVAC) system plays a crucial role. Ensuring that this system functions optimally often hinges on regular maintenance. However, homeowners are frequently faced with a decision: should they rely on professional HVAC services or opt for a do-it-yourself (DIY) approach? Both paths come with their own set of advantages and disadvantages.
Professional HVAC maintenance provides peace of mind through expert service. Technicians are trained to identify potential issues that might not be apparent to the untrained eye. They have access to specialized tools and equipment that can ensure a thorough inspection and servicing of your system. Moreover, professionals stay updated on industry standards and safety protocols, which minimizes the risk of accidents during maintenance.
One significant advantage of professional service is the comprehensive nature of the inspection. Technicians can spot problems early, potentially saving homeowners from costly repairs down the line. They can also provide valuable advice on improving system efficiency, which could lead to reduced energy bills over time. Additionally, many manufacturers require proof of annual maintenance by certified technicians to keep warranties valid.
On the other hand, DIY maintenance offers an attractive alternative for some homeowners due to its cost-effectiveness. By undertaking basic tasks like cleaning or replacing filters themselves, homeowners can save money that would otherwise be spent on professional fees. DIY projects also provide a sense of satisfaction and self-reliance as individuals take control over their home’s upkeep.
However, DIY maintenance is not without its drawbacks. Without proper training or experience, there is a higher risk of overlooking critical issues or causing accidental damage to complex components within the HVAC system. Such mistakes could lead to more expensive repairs in the future or even compromise safety within the home if issues like gas leaks go undetected.
Time is another consideration; while professionals typically complete maintenance efficiently thanks to their expertise and tools, DIY efforts may take significantly longer for those unfamiliar with all aspects of HVAC systems.
In conclusion, scheduling annual HVAC maintenance is undeniably important for ensuring optimal performance and longevity of your heating and cooling systems. Choosing between professional services or a DIY approach depends largely on individual circumstances such as budget constraints and personal comfort levels with technical tasks. While professionals offer thoroughness backed by expertise—which can prevent future headaches—DIY solutions provide affordability at the risk of potential oversights. Carefully weighing these pros and cons will help homeowners make informed decisions best suited for their needs while keeping their homes comfortable year-round.
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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 and in some cases also 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 $1,200,000 in 2024.)[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.
* 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]
medium (large capacity)
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]
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 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€Å
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.
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.
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.