Thread: Another Cooling idea from a dreamer...

Originally Posted by Sillydipstixs18

It would be a great source of cooling. basically what i intend to do is from scratch make and entire ac system like you would find in your car, use fans to blow the cold air where you want it and to cool the case. i spend the bulk of my day b4 work looking over how the compressors in cars and such work and i found a diagram online of an automotive ac compressor which i hope to recreate but much much smaller (preferable 3inches long by 1 inch diameter or something like that). and i dont know much about ac systems and the only think i have a clue about it r-134a. so that was automatically my choice.

So the first compressor you purchased will not do the job?

Originally Posted by McGreggor

Sorry, but that inaccurate. Its a common misconception that higher flow rates mean less cooling. Besides, don't thermostats in cars just control the cooling fan to come on/off?
When you have a closed loop watercooling system, car or pc, the water passes heat to the radiator to be disapated. If you double the flow rate, the water only spends half the amount of time in the radiator, but cycles through the rad twice which gives the same cooling performace. Hard to explain, but if you imagine a car on a race track that laps at a steady speed of 1lap per 60secs. It passes down the straight every lap, which takes say 20secs. If the car doubles its speed, it does the straight in 10secs, but for every 60secs its now doing 2 laps so spends the same amount of time on the straight.

Yes, But it takes more energy to go faster so it produces more heat. I am a certified mechanic. The thermastat in a car holds the water in the engine until it reaches a specified temprature. That also allows the water in the radiator time to cool. if it passes through the radiator to quickly not enough heat is disapated so the water doesn't cool enough, then it goes back to the engine being heated more because it wasn't cool enough to cool it down, the longer this cycle continues the hotter the water gets. It needs to spend long enough inb the radiator for the heat exchange to take place.



Yes, this is kind of confusing.

OK, here is a picture of an automotive cooling system. I added a few arrows to show the direction the water flows. As you can see in the picture the thermastat is in the housing where the water exits the engine heading to the radiator.

A thermastat from a car is nothing more then a spring that operates a door. The spring side of the thermastat is in the water on the engine side. when the water heats the spring to a specified temprature it's coils contract and it pulls the door open allowing water to exit the engine. When the cooler water from the radiator runs in, it cools the spring and closes the door. and then the cycle continues.

Without the thermastat the water cycles to quickly for the heat to disipate so each cycle the temp would rise just a bit causeing it to overheat.



Thats my class for the day

One more pic I just threw together in paint...LoL. Don't know if it helps.


the spring at the bottom / engine side of the thermastat heats up and pulls the door (center oval at the top of thermastat) open.

The amount of heat the radiator dissipates is proportional to the difference in temperatures of the water and the ambient air, which is why a water cooling system will reach a stable temperature... it's the equilibrium point, where the amount of heat dissipated by the radiator equals the amount generated by the CPU, and it depends on the amount of heat being produced by the CPU, and the temperature of the outside air. (assuming the fan speed stays the same)

However, the job of a thermostat in a car is to allow the engine to heat up.
http://auto.howstuffworks.com/question248.htm

a car's thermostat stays OPEN above a certain temperature, so it allows constant flow when the temperature is above that level, and allows no flow when the temp is below. if it was intended to cool water to a certain temp before releasing it, then it would have to work the opposite way (open when cooler than that temp, closed when hotter) This differs from a computer water cooling system in that an engine is supposed to be at a certain operating temp, and a computer must just be as cool as possible... but the point is, the coolant should be circulating whenever the engine is too hot, not sitting in the radiator. The hotter the radiator water is, the faster heat is removed, so allowing radiator water to be cooler than engine water would not make things cool faster.

Look at your description; you're contradicting yourself. what happens if the water in the engine AND the water in the radiator are above the thermostat temp? it stays wide open until the temperature falls below its set temp. having the water in continuous flow removes the most heat... the thermostat is making sure the temperature doesn't go BELOW its set temp, not above... when the temp is above, it's the radiator's job to get it back down.

saying that this intermittent flow removes more heat than continuous can't be true. then the engine would overheat if the radiator water and engine water were hotter than the thermostat set temp (it would never close, so you'd have continuous flow)

also:
"Yes, But it takes more energy to go faster so it produces more heat."
I think that's completely irrelevant. The amount of energy it takes to pump coolant through a cooling system is just a drop in a bucket compared to the amount of energy being consumed by the device generating the heat. not to mention, water pumps generally do not produce significant heat. The water pump I had when water cooling my computer was warm to the touch, never hot. even going to a higher-flow pump would still produce an insignificant heat increase compared to the heat of the processor.