How does running the A/C affect gas consumption by a car?

Living in AZ I need to run the A/C almost all the time. I am wondering how the AC works. In my Honda I can circulate the air or not, and se;ect fan speed. Does any of that change the rate of gas consumption? ie. if the AC is on is it running always at full capacity?How does running the A/C affect gas consumption by a car?
It is because the air conditioning system has a motor/compressor of it's own.



The best way for you to see the difference yourself is to put your car in park and look at the rev meter....when you turn on the AC your rev meter will increase RPMS (for example it will go from 1 to between 1 and 2)



its not a big difference but it does increase the amount of energy (gas) required by the engine to produce the power which operates the air conditioning.



All cars vary, for instance i have a 2003 accord, but it is the same in all cars.How does running the A/C affect gas consumption by a car?
It takes more h/p to turn the compressor when the a/c is on fan speed and circulation dont. the compressor is easier to turn when the air is off you might say it free wheels untill the a/c is turned on. listen to your engine speed or watch your tach when you turn on your a/c you can actually feel the engine labor as it starts out turning the compressor.How does running the A/C affect gas consumption by a car?
Changing fan speed or recirculating will not change anything. The a/c compressor adds the same parasitic load to the engine when engaged regardless of fan speed. There will be little difference in fuel mileage windows up ac on or windows down ac off. You will add more wind drag by rolling the windows down.How does running the A/C affect gas consumption by a car?
In the refrigeration cycle, a heat pump transfers heat from a lower temperature heat source into a higher temperature heat sink. Heat would naturally flow in the opposite direction. This is the most common type of air conditioning. A refrigerator works in much the same way, as it pumps the heat out of the interior into the room in which it stands.



This cycle takes advantage of the universal gas law PV = nRT, where P is pressure, V is volume, R is the universal gas constant, T is temperature, and n is the number of moles of gas (1 mole = 6.022脳1023 molecules).



The most common refrigeration cycle uses an electric motor to drive a compressor. In an automobile, the compressor is driven by a belt over a pulley, the belt being driven by the engine's crankshaft (similar to the driving of the pulleys for the alternator, power steering, etc.). Whether in a car or the house, both use electric fan motors for air circulation. Since evaporation occurs when heat is absorbed, and condensation occurs when heat is released, air conditioners are designed to use a compressor to cause pressure changes between two compartments, and actively condense and pump a refrigerant around. A refrigerant is pumped into the cooled compartment (the evaporator coil), where the low pressure and low temperature cause the refrigerant to evaporate into a vapor, taking heat with it. In the other compartment (the condenser), the refrigerant vapor is compressed and forced through another heat exchange coil, condensing into a liquid, rejecting the heat previously absorbed from the cooled space.



Humidity



Refrigeration air conditioning equipment usually reduces the humidity of the air processed by the system. The relatively cold (below the dewpoint) evaporator coil condenses water vapor from the processed air, (much like an ice cold drink will condense water on the outside of a glass), sending the water to a drain and removing water vapor from the cooled space and lowering the relative humidity. Since humans perspire to provide natural cooling by the evaporation of perspiration from the skin, drier air (up to a point) improves the comfort provided. The comfort air conditioner is designed to create a 40% to 60% relative humidity in the occupied space. In food retailing establishments large open chiller cabinets act as highly effective air dehumidifying units.



Some air conditioning units dry the air without cooling it. They work like a normal air conditioner, except that a heat exchanger is placed between the intake and exhaust. In combination with convection fans they achieve a similar level of comfort as an air cooler in humid tropical climates, but only consume about 1/3 of the electricity. They are also preferred by those who find the draft created by air coolers uncomfortable.





Refrigerants



%26quot;Freon%26quot; is a trade name for a family of haloalkane refrigerants manufactured by DuPont and other companies. These refrigerants were commonly used due to their superior stability and safety properties. Unfortunately, evidence has accumulated that these chlorine bearing refrigerants reach the upper atmosphere when they escape. The chemistry is poorly understood but general consensus seems to be that CFCs break up in the stratosphere due to UV-radiation, releasing their chlorine atoms. These chlorine atoms act as catalysts in the breakdown of ozone, which does severe damage to the ozone layer that shields the Earth's surface from the strong UV radiation. The chlorine will remain active as a catalyst until and unless it binds with another particle forming a stable molecule. CFC refrigerants in common but receding usage include R-11 and R-12. Newer and more environmentally-safe refrigerants include HCFCs (R-22, used in most homes today) and HFCs (R-134a, used in most cars) have replaced most CFC use. HCFCs in turn are being phased out under the Montreal Protocol and replaced by hydrofluorocarbons (HFCs), such as R-410A, which lack chlorine.



Hope I helped. :)