How much is fuel economy effected by aircon useage?

http://greenliving.about.com/od/travelinggreen/a/Air-Conditioning-MPG-Gas-Mileage.htm

there is a study here which compares windows up/down air-con on/off and combinations.

SAE study from 2004

Boris beat me to it, but that report is quite thorough, I can’t add much more other than to say that the faster you go, the better off you are using the air-con.
That’s a generalisation, but a pretty good one.

I got a funny message Boris.
You are the weakest link Boris.

Boris said:

http://greenliving.about.com/od/travelinggreen/a/Air-Conditioning-MPG-Gas-Mileage.htm

there is a study here which compares windows up/down air-con on/off and combinations.

SAE study from 2004

Ta Boris, I think I will continue to use my aircon.

you just want my flambeau pwm.

you could use the heat from the exhaust to heat up the compressant and rob less energy from the engine

hybrid air con systems use this system except they use the sun to heat up the compressant and increase the pressure via the temperature rise and fixed volume

with this idea you use the burning hot exhaust to heat up the compressant and increase the pressure

the pump for the air con could then just be a small electric motor rather than a mechnaically driven unit

or

you could use the heat in the radiator water to heat up the compressant and increase pressure that way

>hybrid air con systems use this system except they use the sun to heat up the compressant and increase the pressure via the temperature rise and fixed volume

Do they? Can you find a link?

Systems that use ammonia’water or other absorption or adsorption use this, but I am not aware of any single fluid phase change systems that do.

morrie said:

>hybrid air con systems use this system except they use the sun to heat up the compressant and increase the pressure via the temperature rise and fixed volume

Do they? Can you find a link?

Systems that use ammonia’water or other absorption or adsorption use this, but I am not aware of any single fluid phase change systems that do.

if you heat a gas, it will want to expand.

All air conditioning systems use a closed loop cycle for the refrigerant (gas). The compressor (within the condenser) is typically used to pressurise the refrigerant to allow the process to take place. Alternatively, an external heat source (such as a flat plate collector) may be used to capture ambient temperature and impart the heat in to the refrigerant, thus creating pressure within a closed loop of refrigerant. The more heat the refrigerant is exposed to, the less work that the compressor must do to allow the process to occur and therefore more energy efficient.

With this in mind, the ICE Solair solar air conditioning system has a flat plate collector installed adjacent to the condenser, which is used to capture heat and impart it in to the refrigerant prior to it passing in to the compressor. To optimise efficiency, the flat plate collector has heat conducting inner coils inside it and a header tank (full of water). Once the refrigerant passes through the flat plate collector, it enters the compressor and the final pressurisation of the system occurs. This process facilitates energy savings of up to 30 – 50%.
http://www.icesolair.com/The-Basics-On-How-Solar-Air-Conditioning-Works/

i doubt that they’d put it into vehicles because it would make them very efficient

with a hybrid approach to air con in cars the windows would remain up all the time and the car would be like an ice box

you could probably use this method for refrigerated trucks – the heat from the engine could be used to make the cold part colder and make the truck more efficient.

maybe in 100 years

wookiemeister said:

morrie said:

>hybrid air con systems use this system except they use the sun to heat up the compressant and increase the pressure via the temperature rise and fixed volume

Do they? Can you find a link?

Systems that use ammonia’water or other absorption or adsorption use this, but I am not aware of any single fluid phase change systems that do.

if you heat a gas, it will want to expand.

All air conditioning systems use a closed loop cycle for the refrigerant (gas). The compressor (within the condenser) is typically used to pressurise the refrigerant to allow the process to take place. Alternatively, an external heat source (such as a flat plate collector) may be used to capture ambient temperature and impart the heat in to the refrigerant, thus creating pressure within a closed loop of refrigerant. The more heat the refrigerant is exposed to, the less work that the compressor must do to allow the process to occur and therefore more energy efficient.

With this in mind, the ICE Solair solar air conditioning system has a flat plate collector installed adjacent to the condenser, which is used to capture heat and impart it in to the refrigerant prior to it passing in to the compressor. To optimise efficiency, the flat plate collector has heat conducting inner coils inside it and a header tank (full of water). Once the refrigerant passes through the flat plate collector, it enters the compressor and the final pressurisation of the system occurs. This process facilitates energy savings of up to 30 – 50%.
http://www.icesolair.com/The-Basics-On-How-Solar-Air-Conditioning-Works/

i doubt that they’d put it into vehicles because it would make them very efficient

with a hybrid approach to air con in cars the windows would remain up all the time and the car would be like an ice box

you could probably use this method for refrigerated trucks – the heat from the engine could be used to make the cold part colder and make the truck more efficient.

maybe in 100 years

It sounds good on the Icesolar site Wookie but unfortunately it doesn’t work:

http://www.choice.com.au/reviews-and-tests/household/heating-and-cooling/home-cooling/first-look-ice-solair-solar-air-conditioner.aspx

http://www.ata.org.au/forums/topic/2513

Fish said:

wookiemeister said:

morrie said:

>hybrid air con systems use this system except they use the sun to heat up the compressant and increase the pressure via the temperature rise and fixed volume

Do they? Can you find a link?

Systems that use ammonia’water or other absorption or adsorption use this, but I am not aware of any single fluid phase change systems that do.

if you heat a gas, it will want to expand.

All air conditioning systems use a closed loop cycle for the refrigerant (gas). The compressor (within the condenser) is typically used to pressurise the refrigerant to allow the process to take place. Alternatively, an external heat source (such as a flat plate collector) may be used to capture ambient temperature and impart the heat in to the refrigerant, thus creating pressure within a closed loop of refrigerant. The more heat the refrigerant is exposed to, the less work that the compressor must do to allow the process to occur and therefore more energy efficient.

With this in mind, the ICE Solair solar air conditioning system has a flat plate collector installed adjacent to the condenser, which is used to capture heat and impart it in to the refrigerant prior to it passing in to the compressor. To optimise efficiency, the flat plate collector has heat conducting inner coils inside it and a header tank (full of water). Once the refrigerant passes through the flat plate collector, it enters the compressor and the final pressurisation of the system occurs. This process facilitates energy savings of up to 30 – 50%.
http://www.icesolair.com/The-Basics-On-How-Solar-Air-Conditioning-Works/

i doubt that they’d put it into vehicles because it would make them very efficient

with a hybrid approach to air con in cars the windows would remain up all the time and the car would be like an ice box

you could probably use this method for refrigerated trucks – the heat from the engine could be used to make the cold part colder and make the truck more efficient.

maybe in 100 years

It sounds good on the Icesolar site Wookie but unfortunately it doesn’t work:

http://www.choice.com.au/reviews-and-tests/household/heating-and-cooling/home-cooling/first-look-ice-solair-solar-air-conditioner.aspx

http://www.ata.org.au/forums/topic/2513

i think the problem with it so far is that although the pressure is increased there would be a fair amount of energy that would need to be dumped by the heat exchanger after the gas was heated..

i think if the car companies looked into it you’d have more success.

the heat from the engine would be enormous, if you could harness this waste heat to do something like run the air con system you could claw back the efficiency.

if the car was electric you might even use the car body to collect the suns energy to help pressurise the gas

there must be some efficiency benefit otherwise they would be skating on thin ice trades description wise.

bump.

It is OK Boris, The A/C doesn’t work and I can’t be bothered fixing it.

i like to try to back up my statements. more professional.

Boris said:

i like to try to back up my statements. more professional.

I am aware.

I just don’t get paid to sound professional.. but I can carve the earth intuitively enough to have never allowed the stresses to bear down upon me.

Mercedes Benz did quite a lot of work in the 1980’s on the notion that waste heat in the exhaust could be used to run a car air conditioner in the same manner that a gas or kero fridge works. That they don’t use a system based on this principle indicates that their experimental work was unsuccessful.

Michael V said:

Mercedes Benz did quite a lot of work in the 1980’s on the notion that waste heat in the exhaust could be used to run a car air conditioner in the same manner that a gas or kero fridge works. That they don’t use a system based on this principle indicates that their experimental work was unsuccessful.

The difficulties lie inherent in the fact that waste heat from exhaust needs to get out of the engine bay.

mayb e the fluid was the problem. don’t really want ammonia spilled in a crash.

Boris said:

mayb e the fluid was the problem. don’t really want ammonia spilled in a crash.

if that was the case.. petrol should be a bigger problem than it has proven to be.

Michael V said:

Mercedes Benz did quite a lot of work in the 1980’s on the notion that waste heat in the exhaust could be used to run a car air conditioner in the same manner that a gas or kero fridge works. That they don’t use a system based on this principle indicates that their experimental work was unsuccessful.

maybe you could use the heat to pressrise a gas that in turn then pushes past a turbine, the heat in the gas behind the turbine is lost through a large heat exchanger

the turbine is used to turn a generator to provide electrical power

the body work could be the heat exchanger

wookiemeister said:

Michael V said:

Mercedes Benz did quite a lot of work in the 1980’s on the notion that waste heat in the exhaust could be used to run a car air conditioner in the same manner that a gas or kero fridge works. That they don’t use a system based on this principle indicates that their experimental work was unsuccessful.

maybe you could use the heat to pressrise a gas that in turn then pushes past a turbine, the heat in the gas behind the turbine is lost through a large heat exchanger

They are trying to make cars smaller.. The engine bay is packed tight with stuff now..