Outside the box again....
Discussion
During some head scratching regarding heat, insulation, cooling and general layout.. this came to mind.....
An electric aircon pump/compressor unit (Denso type) situated at the front (less plumbing)... condenser rad at the front where the current main rad is situated (more efficient)
Oh and a pair of similar sized but thinner main coolant rads fitted in the sidepod vents, with some minor ducting/ electric fans hence keeping all the hot stuff behind the cabin.... might even help the Can-Am drivers with their dry scalp problems too !!
Was gonna incorporate all this tangenital thinking for my own build but it might be on long term hold or even temporarily shelved quite soon, so maybe useful for others/ new builds.
I like simple stuff..... plumbing back and forth along the car is not simple to me.. get rid of this and the build becomes a cooler, easier task ..
DW
An electric aircon pump/compressor unit (Denso type) situated at the front (less plumbing)... condenser rad at the front where the current main rad is situated (more efficient)
Oh and a pair of similar sized but thinner main coolant rads fitted in the sidepod vents, with some minor ducting/ electric fans hence keeping all the hot stuff behind the cabin.... might even help the Can-Am drivers with their dry scalp problems too !!
Was gonna incorporate all this tangenital thinking for my own build but it might be on long term hold or even temporarily shelved quite soon, so maybe useful for others/ new builds.
I like simple stuff..... plumbing back and forth along the car is not simple to me.. get rid of this and the build becomes a cooler, easier task ..
DW
Edited by 738 driver on Saturday 27th August 12:20
Yep that's the way I was going to go when I looked into fitting the Audi V8, plus it would've saved the fueling headache of twin tanks.
In your senario where would you place the fuel tank assuming you go the LS route, not enough room in the side pods unless the rads are the same size as the current condenser already there?
In your senario where would you place the fuel tank assuming you go the LS route, not enough room in the side pods unless the rads are the same size as the current condenser already there?
i dont think you will get enough airflow to side mounted radiators. a lot of the IMSA and Group C cars with the radiators in the side pods had trouble with cooling, with a variety of engines fited - 1000BHP turbos.
the only other car i can think if would be the Diablo and that has got some serious vents there as well.
the only other car i can think if would be the Diablo and that has got some serious vents there as well.
Wasnt worried about cooling intake area as combined left and right there would be more than the current front intake.. the idea is to create sufficient low pressure extraction to draw air over the rads even at low speeds with good quality, ducted electric fans to assist when stationary.
I'm sure one of my old GT40 mates did the electric motor stile AC Pump... Do you know what these pumps were fitted to would be nice to know how much they weight ??
If you did fit it then at the front of the side pods behind the front wheels would be a great place with a access panel of course, front mounted Condenser is the best place for it but you have to get a good radiator behind it that's not to thick so you don't stop the air flow....
If you did fit it then at the front of the side pods behind the front wheels would be a great place with a access panel of course, front mounted Condenser is the best place for it but you have to get a good radiator behind it that's not to thick so you don't stop the air flow....
The idea is to completely eliminate all front to rear plumbing (no pipes in sidepods) .. Main cooling rads in the rear sidepods only... air con system fully at the front going direct to the cabin.
99% figured out but continuing/executing the build is likely to be considerable time off.. just thought Id share some of it.
99% figured out but continuing/executing the build is likely to be considerable time off.. just thought Id share some of it.
You won't find a 12v electric A/C unit (at least not one that works very well) Typical AC systems requires approx 3kW mechanical work input during "pull down" and even during the "maintain" phase they will still be pulling 1kW odd (actual cooling work is approx double these values due to the ~200% efficiency of the AC cycle).
Now, if you divide 1000W by 12V you get a lot of amps (83.3A - doable) but 3000W / 12v = 250A, which is a massiev number, and normal lead acid batteries cannot supply that kind of power for any period.
Hence, cars like the Prius use a 200V electric AC unit........
Now, if you divide 1000W by 12V you get a lot of amps (83.3A - doable) but 3000W / 12v = 250A, which is a massiev number, and normal lead acid batteries cannot supply that kind of power for any period.
Hence, cars like the Prius use a 200V electric AC unit........
Max_Torque said:
You won't find a 12v electric A/C unit (at least not one that works very well) Typical AC systems requires approx 3kW mechanical work input during "pull down" and even during the "maintain" phase they will still be pulling 1kW odd (actual cooling work is approx double these values due to the ~200% efficiency of the AC cycle).
Now, if you divide 1000W by 12V you get a lot of amps (83.3A - doable) but 3000W / 12v = 250A, which is a massiev number, and normal lead acid batteries cannot supply that kind of power for any period.
Hence, cars like the Prius use a 200V electric AC unit........
Little off topic here, but Max you say that a AC cycle is 200% efficent? How is that possiable? Dose that mean that for every 1Kw of energy you put in you can remvoe 2Kw of heat energy?.....Now, if you divide 1000W by 12V you get a lot of amps (83.3A - doable) but 3000W / 12v = 250A, which is a massiev number, and normal lead acid batteries cannot supply that kind of power for any period.
Hence, cars like the Prius use a 200V electric AC unit........
ah, the clever laws of thermodynamics! Of course, technically the actual "cycle" is not over 100% efficient, but i couldn't think of a short simple way to explain the fact that you can move more heat than the "input power" you use to move said heat!
(i.e. you apply say 1kW of mechanical work to a compressor, that changes the state of a working fluid. During this phase change the working fluid can absorb or reject MORE heat than the work you are applying. This heat can then be moved around the system (from cold end to hot end or vise-versa) and then another phase change in the working fluid transfers said heat once again to another medium. The laws of thermodynamics are NOT broken of course because the "other" 1kW (in this case) is removed (and replaced) from/to the atmosphere surrounding the system (so the total power is balanced) That work is done by the A/C condensor and evaporator. So for the system described, applying 1kW of mechanical work "moves" 2kW of heat from A to B. (this is of course the beauty of phase change systems and why they are used so much across all industries etc)
For a typical automotive HVAC system, the peak cooling work will be in the region of 7kW (for a typical large family car with a significant glass house area) and in places like Arizona etc, even the maintain cycle will be over 3kW due to the high solar load. In more temperate places (like the UK) the system will be using approximately 0.8 to 1kW to hold the cabin at a sensible temperature during our "summer".
The limiting factor is usually (assuming the vehicle is moving) the minimum temperature in the evaporator core before icing occurs. Most systems will target an evaporator temperature of approx 3degC (just above icing). The only way to increase heat transfer is then to increase the system mass flow, but huge powerful cabin fans become noisy and distracting to the occupants, to this also limits the systems maximum performance.
(i.e. you apply say 1kW of mechanical work to a compressor, that changes the state of a working fluid. During this phase change the working fluid can absorb or reject MORE heat than the work you are applying. This heat can then be moved around the system (from cold end to hot end or vise-versa) and then another phase change in the working fluid transfers said heat once again to another medium. The laws of thermodynamics are NOT broken of course because the "other" 1kW (in this case) is removed (and replaced) from/to the atmosphere surrounding the system (so the total power is balanced) That work is done by the A/C condensor and evaporator. So for the system described, applying 1kW of mechanical work "moves" 2kW of heat from A to B. (this is of course the beauty of phase change systems and why they are used so much across all industries etc)
For a typical automotive HVAC system, the peak cooling work will be in the region of 7kW (for a typical large family car with a significant glass house area) and in places like Arizona etc, even the maintain cycle will be over 3kW due to the high solar load. In more temperate places (like the UK) the system will be using approximately 0.8 to 1kW to hold the cabin at a sensible temperature during our "summer".
The limiting factor is usually (assuming the vehicle is moving) the minimum temperature in the evaporator core before icing occurs. Most systems will target an evaporator temperature of approx 3degC (just above icing). The only way to increase heat transfer is then to increase the system mass flow, but huge powerful cabin fans become noisy and distracting to the occupants, to this also limits the systems maximum performance.
Edited by anonymous-user on Sunday 28th August 14:14
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