Re: Loss of engine power to air conditioning?

Jul 09, 2004 65 Replies

7 amps at 45 volts is 315 watts - ie about 1/2hp. A compressor that only took this amount would have little effect on cooling a car.

First rule of physics - you don't get owt for nowt.

Raising the voltage of a car electrical system will only really help in making the cables required smaller - as the current goes down. Makes no difference to the energy needed, though.

What does this mean?

The message from "Dave Plowman (News)" contains these words:

My domestic fridge uses more than this and that can barely keep a well insulated box cold, and that ain't parked in the sun with big windows in the side.

The efficiency of the compressors has been proven:

Toyota's compressor is so far advanced, there is a market for it in refrigerated truck trailers already.

Raising the voltage standard is not only for lowering the cable size, do some research on hybrid vehicles and see what the main function of a higher voltage electrical system would be.

The message from "Refinish King" contains these words:

The efficiency isn't what's at issue. A car absorbs a considerable amount of solar energy - and picks up a fair bit from hot air passing underneath from the engine bay - and even if the compressor were 100% efficient and the cooling cycle 100% efficient, a few hundred watts of cooling is never going to shift a kilowatt or so of solar gain.

No - you do some research on basic physics if you think a 315 watt motor can provide adequate air conditioning in an average vehicle.

And raising the standard voltage is nothing to do with hybrid vehicles - it will be used on conventional ones shortly.

Where did a solar vehicle enter this discussion?

Thank you,

Refinish King

Guess what?

The larger capacity of the vehicle's refrigerant content, versus the refrigerator's 12 Oz. capacity would increase the efficiency.

The standard will be raised on both conventionals and hybrids, because of the many benefits to both. Due to the electric power steering, electric power braking systems now ready to be used. Soon water pumps will be electric also.

I suggest you take some basic courses on advanced automotive diagnostics, and pick up the literature at the end of the courses. You will find what's in store for the "Professional" technician in a few short years.

Refinish King

PS Do you even know the concept of temperature transfer?

Time for a new fridge then :-)

Why on earth will increasing your cooling capacity improve the effeciency, more the oppsoite in most systems.

Dear boy, I'd suggest you work out the amount of heat that has to be removed to cool down the average car from about 30+ degrees to under 20, and tell me just how you're going to do this in a reasonable time with only 1/2 of a horsepower available?

Of course, you could prevent the car from getting so hot in the first place by insulation, etc, but that's not the point in question.

I sincerely hope you're not one of those 'technicians' given your total lack of knowledge of basics...

I get the impression the 'king' has got hold of someone's study notes...

1/2 a horsepower would take forever and a day to do the job using almost 30 hp means that the frige in the van needs to be running ro about 40 minutes to get it down to -19, and after that, no matter how long you run it for, it never get's any lower than that even if you set it to -29, there just isn't the power in the motor to cool the refrigerant down any lower and, on a hot day at least, 30 seconds worth of door open means that the whole thing has shot up to past the 22C mark and you have to start all over again never mind the efficency, the feul comsuption is at least another 1/3 with the fridge running

The A/C capacity!

Refinish King

diagnostics,

I think you belong on a farm!

Refinish King

I think you belong on a farm!

Refinish King

D'oh!

Re-read the last post...

/This whole thread would be a whole lot easier to follow if you didn't top post./

Unfortunately for you, Refinish King, you are either not reading the posts, or are incapable of understanding what is being said. That's fine. Admittedly, repeating what has been said, like a battery powered toy, is rather entertaining, but it's not moving the discussion forward.

The point we're making is that you can have as efficient a system as you like, but if you're only able to extract, at most, 300 odd watts of heat from the interior of the car, it's not going to matter.

The message from "Refinish King" contains these words:

Every time you park it in the sun. I'm beginning to think you don't really know a lot about this.

The message from "Refinish King" contains these words:

Back to school and when you know what you're on about you can get out of my killfile. I really don't have time to read twaddle like this.

Oh, and start snipping and stop top-posting.

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