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Absolutely! I'll try to check this site more often. I'll be happy to help any way I can.
Hey Rumi, I probably should clarify a couple of things. My system is a water cooled chilled water system. Both the condenser (condenses hot gas from compressor to hot liquid refrigerant) and the chiller (chills a glycol/water brine to about 35 deg. F) are tube-in-tube heat exchangers. The outer tube is steel and the inner tube is copper. Refrigerant flow is between the steel and the copper. Water flow is inside the copper. I use one circulating pump for the condenser to carry heat to the river. I use another circulating pump to move brine between the chiller and the fan coil units (closed loop). I have a cap tube metering device at the chiller. There are some other efficiency enhancements that I can get into in greater detail if you like.Using a DX coil in place of a fan coil unit will work with some extensive copper tubing modifications. The metering device must be removed. U-bends will most likely have to be added to get adequate water flow. The airflow will be much greater than the heat transfer rate, which will waste energy. The fan should be slowed as much as possible. I will be happy to view pics of the AHU you intend to use and make suggestions.If you live where the relative humidity is low, you can use a swamp cooler alone to chill the water without a refrigerant system. I designed many systems to do just that under certain conditions. Otherwise, you'll have to rely on an air cooled condenser. If so, the size of the condenser coil will determine efficiency... the bigger, the better. I hope this helps. Good luck!
Regarding efficiency, this is a step in the right direction. One must also determine the flow rate and the specific heat of the medium used to transfer the heat. I do not wish to go off the rails here but ultimately, efficiency is the watts moved versus the watts expended. If we expend 1000 watts to move 3000 watts, then our efficiency coefficient is 3. The higher the coefficient, the greater the efficiency. An analogous situation would be moving freight by truck or by rail. It takes about ten times the energy to move a given mass of anything by truck as it does by rail. Therefore, the efficiency coefficient of rail is ten times that of a truck. Another efficiency consideration is that excess energy in one area (living space) might be moved to an area where it is desirable (hot water for showers, washing dishes, etc.) This can also be accomplished through judicious use of heat exchangers.
A couple of tips from an old thermodynamics geezer. I designed and built chilled water systems for comfort air conditioning and process (chemical industry) systems for many years. I have a chilled water system in my home in south Florida. It works very well. First, it is important to understand that medium temp (regular air conditioning) compressors will move heat (in the range that you are contemplating) much more efficiently than will a low temp compressor. Secondly, moving heat with water is about 4 times as efficient as moving it with air. Therefore, if you can cool the system with water, your efficiency is greatly enhanced. I live next to a vast body of water that I use as a heat sink. Before I get any diatribes about thermal pollution, let me say that my system adds as much heat to the water in one season as does a 200 hp boat motor in 24 hours. Third, air handling units (kinda like automotive radiators) that are actually designed for chilled water are much more efficient/less bulky than discarded A/C evaporators (as suggested by rum100proof below). You can occasionally find them at a bargain on ebay. The A/C evaporators will definitely work, but the fans are not usually part of the package. Fourth, I always utilized propylene glycol in my systems. At a 50% mix, my efficiency loss was 6%, but the brine remained liquid down to -50 degrees F. That's pretty cheap insurance to keep from freeze-damaging your system and the propylene glycol is food safe (as opposed to automotive antifreeze).Making ice with such a system does not improve efficiency. However, if you are producing an abundance of energy, this is a good way to use it. Liquid water absorbs one Btu per pound per degree F. rise in temperature. Ice melting absorbs 144 Btu per pound without a change in temperature. Obviously, the cooling capacity per pound of ice is much greater than that of liquid water.NOTE: I have never posted here before. I am not sure how I might be contacted if any of you might have questions. You can email me at email@example.com.
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