Just wondering, could the unit from the back of a fridge be used as a phase chager ( ) with a bit of ? it uses the same concept doesn't it? i dont know much about them so i could be totally wrong. Or could the rad be used? Death
it IS possible indeed.. but it is not an easy task, and i guess you will be just as poor afterwards as if you bought a real system. but here goes: first you will have to ensure that the compressor is able to handle enough gas and pressure to ensure the temps you are after. if it is too small you will be able to reach nice temps, but they cant hold it at load. second is all the modding: the only thing you will use is the compressor and eventually the heat exchanger (radiator) when you have got that take it to a HVAC guy.. tihis is necessary as i guess you know nothing about brazing, calculating bap tube length and so on?? then the HVAC guy will braze a system together, usually like this: compressor -> cap tube -> evaporator -> suction line -> heat exchanger -> compressor If you can braze you would be able to do this.. however, we are talking bigger pressures than usually.. and the capillary tube must have a certain length depending on compressor strength, amount of gas and boiling point of gas. the evaporator is just a head like for water.. but it must be virtyally zero restrictive and be able to withstand the pressure. suction line should be som kind of flexible metal hose. such a system could work but it would not be itself worth in cooling power, price or work, imo.. another solution is to tear the freezer apart and put the evaporator, which is usually some kind of plate on freezers, into the water you could cool your system with. this works nice, but takes some time to get cold, and is not as effective as direct cooling.
K Oh ok it's just my mate has a fridge he's gettin rid of and theres a freezer bein thrown out at work as well. If it was a decent fridge it would be better then??? If i was to do it i would like to try and do it all myself, im sure you all could help how much are we talkin here, or is it just totally not worth it? would it be worse than w\c?? Thanx Death
It is not so much a case of needing a HVAC engineer to do the work because it is hard, but more importantly, you NEED a license to carry out ANY HVAC work. Without this, you shouldn't even think about it. As a result, fridges are a little difficult owing to the fact that they almost always need taking apart and new components added and so on. If on the other hand, you can find an old dehumidifier, this can be ripped out of it's casing (if you're careful and don't damage the capillary tube) and used without modification as a waterchiller. In a dehumidifier, there will be two (probably identical) heat exchangers. One is the condenser and the other is the evaporator. The evap gets cold and the condenser coil gets hot. If you can mount the evaporator in an insulated reservoir, then you can chill the coolant to sub ambient temperatures. However, this will require a lot of condensation protection. Alternatively, you could run it with a thermostat to maintain the coolant temps at ambient, providing pretty good cooling with no need for condensation protection. This would also be a rather efficient system, not using too much electricity. The long and the short of it. DON'T mess around with HVAC unless you REALLY know what you are doing. The main reason for this is the use of very high pressure, often highly flammable refridgerants. Equally, the equipment required to do it PROPERLY can be very expensive. Another point which I have tried to get across on MANY occasions, is that fridges are NOT designed for a high heat load, NOR are they designed for continuous use. 8-ball
Hmm, not agreeing with you on this one. You only need a licence if you plan to register your product with a UL rating. Otherwise, you can build anything you want. The fittings are not hard at all. Just get adequate piping, prefferably in stainless. Use care when bending to the shapes you need, use a rod of some sort for >=90 degree curves. Make sure you install a fitting to fill/charge the system. Find where you can get compression fittings. Theres no real need to braze. Granted, I have use of an orbital welder and its very nice, but compression does the job just as well. Compression fittings are rated for over 3000PSI (and Ive tested them to 10,000PSI). But warning should be taken here: normal refridgeration compressors are not intended for quick thermal transfer. A fridge can take its sweet time bringing a cavity to cool temperatures with good insulation. It doesnt do so well if you put a hot-plate inside that cavity. It would be more prudent to augment/replace a watercooling systems radiator with refridgerant cooling instead of directly trying to refridgerate a CPU. If you decided to go hay-wire and get a large capacity compressor to directly cool the CPU, then you run into the problem people have with pletier's: condensation. And since a peltier is much cheaper than a high-load compressor, why do it?
Because they are a lot more efficient than a large compressor. It would take long, particularly if the computer is on a lot of the time, to recoup any difference in initial outlay, due to the monthly savings on the electricity bill. As to the HVAC license, I was under the impression that one was needed in the UK. Not so sure about the states. But having an HVAC license would imply that you actually knew what you were doing, a real bonus. If you are really serious about phase change, I suggest you check out the forums at www.phase-change.com or www.xtremesystems.org as they both have a lot of very alented phase changers. 8-ball
most mini fridges are just 80w pelts. so it migt be possible, but it would be better to cool water in it
A dehumidifier/chiller setup is probably widely regarded as the best step to take if you're considering getting your feet icy (as opposed to wet) on the cheap, rather than a fridge. Check this thread if you're interested in seeing what's involved with the most basic approach. It's not direct phase change per se but it's a good starting point for cluing yourself up.
In the States you can do all the hvac work you want, you just need a license to handle the refigerant. Except R-134a (newer automotive refirgerant) you can pick up a 1lb can of R-134a/oil/leak sealer with a gauge and hose at wallmart.
