What is Air conditioner: Definition and 61 Discussions

Air conditioning (also A/C, air conditioner) is the process of removing heat and controlling the humidity of air in an enclosed space to achieve a more comfortable interior environment by use of powered 'air conditioners' or a variety of other methods including passive cooling and ventilative cooling. Air conditioning is a member of a family of systems and techniques that provide 'heating, ventilation, and air conditioning' (HVAC).
Air conditioners, which typically use vapor-compression refrigeration, range in size from small units used within vehicles or single rooms to massive units that can cool large building. Air source heat pumps, which can be used for heating as well as cooling are becoming increasingly common in cooler climates.
According to the IEA, as of 2018, 1.6 billion air conditioning units were installed which accounted for an estimated 20% of energy usage in buildings globally with the number expected to grow to 5.6 billion by 2050. The United Nations called for the technology to be made more sustainable to mitigate climate change using techniques including passive cooling, evaporative cooling, selective shading, windcatchers and better thermal insulation. Refrigerants used within air conditioners have caused damage to the ozone layer and are also exacerbating climate change.

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  1. S

    HVAC The technician installed a new AC split without a vacuum pump

    Hello, The technician installed a new AC split without a vacuum pump. (Gree 24000 BTU Inverter) Should we drain the refrigerant, do vacuum, and refill the refrigerant? It is written in the AC manual that we should vacuum during installation. I read that air and humidity are harmful for the...
  2. S

    HVAC Why is my air conditioner making sounds?

    Hello, I bought an air conditioner 24000 btu Inverter. ( for home). The indoor unit makes strange noises/sounds at night. The pattern is as follows: First, wind blowing and cooling are reduced to 80%. (Similar to fan mode) After some minutes(About 3-4 minutes), Then the sound (sound in the...
  3. D

    I Just for fun: treadmill air conditioner efficiency calculation

    What approximate portion of generated heat from being active on the treadmill, both the person on it as well as the machines themselves would be compensated/cooled if the treadmill resistances would be disabled/removed and instead 1/2 end cylinders would be connected to an air conditioner...
  4. S

    Why does decreasing evaporator airflow impact an air conditioner's performance?

    The other day I read on a website that a lower evaporator airflow causes lower low pressure side saturation temperatures and higher delta T on an air-conditioner. Now I think I know why a lower evaporator airflow would cause a high delta T. If there is less air moving over the evaporator, the...
  5. S

    Does a "heat pump" not spew HFCs like an "air conditioner"?

    https://slate.com/technology/2022/07/inflation-reduction-act-climate-bill-manchin-heat-pump-solar-panels-electric-cars.html First, this text makes no sense as it seems to say that the problem with A/C can be solved by "shift[ing] hot air in". But then it also seems to say that a "heat pump" -...
  6. David Lewis

    A solar powered air conditioner

    1. In this system the sun boils Freon in a solar panel. 2. Freon vapor is sent to a turbine or piston motor. 3. Freon discharge from the motor is sent to condenser coils submerged underwater. 4. The cooled, low-pressure Freon is sent back to the solar panel inlet. 5. The Freon-powered motor...
  7. C

    Will an Air Conditioner made in Korea work where I live?

    Hi, A Korean friend owns me money and plans to pay partial with his airconditioner. But the aircon model came from Korea. I just want to know if an air conditioner like Carrier of a specific model made in different countries have the same design, or do they have separate say Korean design, or...
  8. Delta2

    I Cycle of an air conditioner and power consumed

    I have an air condition that is 9.000 BTU and it states at the external unit that its Power is 1.2KW. However because I know that an air condition has inductive loads (motors) its power factor is not 1 so I am not sure 1.2KW is the real power consumed. I am thinking to calculate the power...
  9. C

    Air conditioner dust getting into lungs?

    Hi, If you have dirty window type airconditioner in a room and it hasn't been washed or cleaned for say 3 years since installed, can the dusts, molds, etc. inside the airconditioner got into your lungs and become sort of like streaky infiltrates? Or does it simply circulate the existing dusts...
  10. jaumzaum

    Air conditioner without heat output - Is it possible?

    Hello everybody! I was wondering today if physically, it'd be possible for the world to develop an air conditioner without an outdoor heat unit? I know this seems to violate the second law of thermodynamics, but the known version of the second law thermodynamics only consider this is impossible...
  11. C

    Can a window-mounted air conditioner suck in air or particulates from outside?

    I read before that room air conditioner is not supposed to suck in air or particulates/dusts from outside but my air quality monitor can detect some increase in pm2.5 particulates when the aircon is opened. Is it because its sucking those particulates from outside or the fan of the air...
  12. Fooality

    Omnidirectional air conditioner allowed by physics?

    I know heat is a form of energy, and that’s conserved, so usually an air conditioner will emit heat on one side, cooling on the other, probably increasing the overall heat in total. What’s not clear to me is if it always must do this, specifically if the air conditioner produces another form...
  13. J

    Appliances Peltier based mini air conditioner not working

    Hi guys I am not certified engineer but I watched many videos to make home based mini air conditioners using Peltier module. So I decided to try this as experiment. My plan is if this small test project works well then I will proper mini a/c (for my small 10x10 feet office or at least for my...
  14. T

    Air conditioner fan not starting

    I have a problem with my air conditioner fan not starting. As seen from the schematic below, when I test for voltage between the brown and black wires, I get 0 V (this is the problem). The indoor unit isn't sending the control signal to turn the fan on. The compressor powers on fine though. When...
  15. M

    When the COP of refrigerator is greater or less than 1?

    I still confuse about COP of refrigerator. When i read some journal, it is said that COP of VCRS can be greater than 1 (usually 2 - 4). But, why the COP other than VCRS usally lower than 1? like vortex tube, vapour absorption refrigeration system, etc. Actually, now i am doing a research about...
  16. Psinter

    Turning on and off the air conditioner consumes more energy?

    The air conditioner is set up to put the temperature at 72F. Which I hate because that's cold, but whatever. The air conditioner turns on and works for about 6 minutes when it automatically turns off because the temperature reached 72F. It stays off for 10 minutes and then it turns on again...
  17. mechlite

    Possible Air Conditioning System?

    Hello everyone! Summer is coming and instead of buying a $200-$400 air conditioner, I'd figure I could try a DIY version. I came up with a schematic (attached below) and how I think it would work. I feel like I'm missing something blatantly obvious that will make it not feasible. Wondering if...
  18. M

    What do you think about conditioning the outdoor air?

    What do you think about conditioning the outdoor air? Is it impossible? Is it useless? Is there any research about it?
  19. T

    AC vs evaporative cooler: ratio of (BTUs/hr)/electric watts

    Hi Air conditioner vs evaporative cooler: ratio of (BTUs/hr) / electrical watts I know evaporative coolers do not state BTUs/hr. I do not know why. Did anyone try them and record time taken to cool. I found this example, but I do not know if it is practically relevant...
  20. T

    Power vs BTU: Is There a Direct Relationship?

    Hi Air conditioners power should vary with thermostat and fan/Airflow rate levels. Is there data on Power vs BTU? Is it directly proportional? Thanks
  21. srinaath

    MATLAB Simulation of air conditioner in openmodelica/matlab?

    am trying to simulate air conditioner in open modelica and matlab.. is there any library like hvac so that i can do the simulation in mush easier way...
  22. srinaath

    Air conditioner compressor capacity control in VRF systems

    hi guys... am working on a variable refrigerant flow (VRF) type air conditioner. my aim is to change the capacity of the compressor based on load change. i can vary compressor capacity by using inverter...now my doubt is on what basis i should change compressor speed for muti evaporator...
  23. Iconoclast

    Function of the air conditioner fan outside?

    Really quick question, what exactly does the fan of the outside part of my split ac do? That fan seems to just make wind for no clear reason. I'm curious to know what it actually does.
  24. V

    Air conditioner Energy consumption for my Scenario

    I am currently doing a research on energy consumption of Room Air conditioners based on BEE rating. Are there any available industry benchmarks for energy consumption of Air conditioners by rating of the AC? For instance, for the given scenario (defined constants) below, any inputs on how to...
  25. R

    Air Conditioner commissioned without a vacuum pump & N2?

    I bought a new home AC (split; 1.5 ton) and the tech the company sent to install it didn't seem to have neither a vacuum pump nor a N2 cylinder in his kit. I am leery. Is it really possible to install an AC without these items? Can he do a reasonable job evacuating the lines & leak testing any...
  26. R

    Saw in the Papers: Air Conditioner Ad

    The ad says: "5 Years Warranty on Compressor, 1 Year Warranty on Main Unit" Nice so far. Next the ad says: "Not Covered in Warranty Plastic and Rubber Parts, Lamp, Interconnecting Cable, Rubber Pads for Remote Control, Interconnecting Copper Tube, Aesthetic Parts, Condenser Coil, Evaporator...
  27. M

    Why air conditioner evaporation cools

    Preface- I am anoob scum who doesn't know much How and why does an air conditioner gas cool when it evaporates. Exactly how does the gas's molecular kinetic energy lessen, and more specifically how does the kinetic engery from the room and pipe that holds the gas, get transferred to the...
  28. S

    Using condensed water of Air Conditioner to top up a battery

    Hi; As we know that flooded lead acid battery needs to be top-up (watering) after passage of some time and it is recommended to use distilled water. Many people say that water condensed by Air Conditioner is also very good to top-up the battery. Is it true?
  29. Z

    Buying a perfect air conditioner for my room

    Hey Guys, I'm not a physics student, not a physics lover but so admire those people that know physics! Well that's why i come here for this question: what kind of air conditioner can help my room exchange fresh air? Does the Fan mode in every air conditioner intake fresh air or not? Here is...
  30. C

    Design experiment to test air conditioner performance at different ambient temps

    Homework Statement I have access to a test facility for window type air conditioners that has a small room that is used to simulate the outdoors. I need to use the facility to test the effect of temperature on the performance of one of our window type AC units. The performance must e done as a...
  31. DHF

    Air Conditioner for your tower?

    I am always looking for the right combination of cooling products to keep my system frosty and in my digital travels I have encountered a wide variety of fans, heat sinks and liquid cooling units. Now perhaps I have just overlooked them but why has no manufacturer ever come out with a micro air...
  32. V

    How should I switch an air conditioner off?

    I have heard from not very educated 'technicians' who installed my air conditioner, that I must first switch off the compressor of the AC by switching it to fan mode, and after some time, switch it off, to avoid some kind of collection of cold air inside it. I kind of followed it for the time...
  33. Z

    Manufacturing Process To Made Air Conditioner Evaporator

    Hi! I really want to know how evaporator is made. i mean it is impossible to made by casting process, but i also not sure. anyboby who involve in this industry can please help me
  34. S

    Air conditioner specs: watts vs Btu/hr

    Hello, I am confused about air conditioner Btu specs. When I try to match the power input in watts, to power out in Btu/hr, the numbers don't come out even close. Example: This 6000 Btu window unit has the following specs: Volts 115 Amps 5.4 So the power input in watts is: 115 x 5.4 = 621w...
  35. D

    About home made air conditioner

    I am making homemade ac. I am using an ice box for it. I found the link on the internet http://www.instructables.com/id/Cheap-DIY-Air-Conditioner/ I want to ask is 1. The fan which is used must get heated by the operation 2. This will produce a lot of heat 3. This will melt the ice or take...
  36. T

    Work Air Conditioner Must Do To Keep Room Constant Temperature

    Homework Statement If a room is at 27C and the surroundings at 42C, and the heat into the room is 2,000 Cal s-1. What is the minimum work the air conditioner must do to keep the room at 27C?Homework Equations COP = Tc/(Th-Tc) Win = Qout/(1+COP) The Attempt at a Solution COP =...
  37. M

    Keep Air Conditioner On All Day, or Turn it Off When Not Home? (2-story apt)

    I haven't been able to find a satisfactory answer. What would save the most electricity? One of my roomates and some of the neighbors below us think that it is better to leave the air conditioner on all day. Normally, for just one house with one air conditioner, I would be very skeptical: I...
  38. D

    Should I turn off my upstairs air conditioning during peak hours to save energy?

    I have a 2600 sq' home in Arizona. I have a 13 seer a/c system with two units. I havea second story of my house which is only a loft. Is is more beneficial for me to leave the thermostat off upstairs to conserve energy during the peak hours that my electric provider has from noon-7pm? Or is it...
  39. C

    Air Conditioner Efficiency - Humidity & Precooling

    I have two questions/ideas about the efficiency of A/C's that I'd like to bounce off you guys. I couldn't find anything on Google about either of these items being discussed before. 1) Precooling The first thought I was wondering was whether it was more efficient to pre-cool your house in...
  40. M

    Carnot Air Conditioner Question.

    Q: A Carnot air conditioner operates between an indoor temp of 20C and an outdoor temp of 39C, how much ENERGY does it need to remove 2000 J of heat from the interior of the house? A: 130J i got 121J O.o?
  41. N

    How Efficient is a Carnot Air Conditioner at 76°F Indoors and 96°F Outdoors?

    A Carnot air conditioner takes energy from the thermal energy of a room at 76°F and transfers it as heat to the outdoors, which is at 96°F. For each joule of electric energy required to operate the air conditioner, how many joules are removed from the room? Attempt at problem 76 + 273 = 349 96...
  42. R

    The fan mode of an Air Conditioner?

    Hi friends, My air conditioner is a split one (it has 2 parts: one inside the house and the other outside). It has 4 modes of operation: cool, fan, and 2 other modes. My question is that what does the machine really do in the fan mode? I wonder whether it just serves as a normal fan...
  43. A

    What is the Efficiency of a Carnot Air Conditioner?

    Homework Statement A Carnot air conditioner takes energy from the thermal energy of a room at 70 degrees F and transfers it to the outdoors, which is at 96 degrees F. For each joule of electric energy required to operate the air conditioner, how many joules are removed from the room? Homework...
  44. Andre

    Understanding the Role of Latent Heat Energy Transport in Climate Change

    In some threads in the past I hinted vaguely that one feedback mechanism in climate is not really mentioned extensively, that's the latent heat energy transport, from evaporation at the Earth surface to condensation in the higher levels, forming clouds and altering the dynamic radiation balance...
  45. P

    Does turning off the air conditioner waste money?

    I can't seem to find a straight answer so I thought asking here might come up with a credible response. Everyone I know tells me that it wastes more electricity to turn off your air conditioner because of the amount of energy it takes to cool the house those extra degrees when you turn it on...
  46. L

    Thermal Efficiency of an air conditioner

    Homework Statement The thermal efficiency of a refrigerator is determined by the coefficient of performance , which is defined as the ratio of the amount of heat removed to the input of mechanical work needed for operation, or K=Q_c/W_in An air conditioner operates exactly as a...
  47. W

    Thermodynamics: Room Air Conditioner

    [SOLVED] Thermodynamics: Room Air Conditioner Homework Statement A room air conditioner acts as a Carnot cycle refrigerator between an outside temperature T_h and a room at a lower temperature T_l. The room gains heat from the outdoors at a rate A(T_h - T_l); this heat is removed by the air...
  48. P

    Powering 5K BTU 115V Air Conditioner in Auto

    Folks This is my first post to Physics Forum. I've started a project to put air conditioning into my '86 Westfalia van. The stock AC never worked and was ill-designed with huge long runs of tubing back and forth in the van, so I've removed it. I located the smallest possible 115 V AC window...
  49. M

    How can i do the correct sizing for split air conditioner?

    hello everybody, in fact,im asking for a help in a matter confused me alot,its about how can i select the right (split,mini split,portable,window,etc) air conditioner,which is not central air conditioner. im working now in a company and they size the air conditioner for the customer according...
  50. X

    Air Conditioner: Refrigerator or Heat Pump?

    Homework Statement Air conditioners operate on the same principle as refrigerators. Consider an air conditioner that has 7.00 kg of refrigerant flowing through its circuit each cycle. The refrigerant enters the evaporator coils in phase equilibrium, with 54.0 % of its mass as liquid and the...