Air Cooled Chillers vs Water cooled Chillers
Air Cooled Chillers vs Water cooled Chillers
(OP)
What are the advantages of Water cooled chillers over air cooled chillers ?
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Air Cooled Chillers vs Water cooled Chillers
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RE: Air Cooled Chillers vs Water cooled Chillers
RE: Air Cooled Chillers vs Water cooled Chillers
Film coefficient controls heat transfer given constant area and delta t.
RE: Air Cooled Chillers vs Water cooled Chillers
The NESLAB specialists in the UK
http://www.weekstechnic.com/index.htm
RE: Air Cooled Chillers vs Water cooled Chillers
RE: Air Cooled Chillers vs Water cooled Chillers
When you compare air and water cooled chilles, an overall system cost (both running and installed) has to be worked out. Also, the type of application, the ambient conditions (wet bulb and dry bulb), number of hours of operation, part load pattern, cost of maintenance, etc., play a role in this decision.
There is no single answer to this question - Water-cooled is better or air-cooled is better. It depends.
HVAC68
RE: Air Cooled Chillers vs Water cooled Chillers
I would disagree with NESLABman that water-cooled units require less maintenance. Maintenance and water treatment costs are the main disadvantage of the cooling towers and/or evaporative condensers.
There are a few locations (usually coastal climates) where the difference between the wet-bulb temperature and the dry-bulb temperature does not offset the required pumping costs for cooling towers.
krb's statement is true in my experience. Small systems are almost always air-cooled since the extra requirements of water treatment and maintenance are capital intensive and will not be offset quickly by the lower operating costs. Larger systems are almost always water-cooled at least in my industrial experience.
RE: Air Cooled Chillers vs Water cooled Chillers
Evapco is pushing a new 'chemical free' maintenance system that looks promising.
http://www.evapco.com/whatsnew.asp?WN_ID=13
RE: Air Cooled Chillers vs Water cooled Chillers
For example - 24 hour application.
The night time dry bulb temperature are generally much lower than the day time dry bulb temperature, as compared to the difference in wet bulb temperature between day and night. This advantge is best capitalised by an air-cooled system.
Other instances could be where the wet bulb temperatures are very high, especially coastal areas.
Water scarcity and hence cost of water is another issue which is a point to be considered while deciding on the system. This happens in many countries - not necessarily in the US or the European countries.
HVAC68
RE: Air Cooled Chillers vs Water cooled Chillers
And the chilled water lines are sealed anyway, you always treat the water on installation, so again, why is the cost /quality of water a problem in less than ideal situation?
Common sense should be the deciding factor on the chiller selection. Air cooled are smaller and noisy, neighbors don't like then on ice make mode. water cooled are quiter and more costly to install maintain.
RE: Air Cooled Chillers vs Water cooled Chillers
The cost/quality of the water is an issue due to the water that is lost in an evaporative cooling tower. The chilled water lines are sealed and treated, condenser water is lost to evaporation and exposed to the outdoors.
RE: Air Cooled Chillers vs Water cooled Chillers
What speed (m/s) and unit pressure drop (Pa/m) are recommended?
Thanks
RE: Air Cooled Chillers vs Water cooled Chillers
I dunno, maybe this one works. I'd let somebody else try it for couple of years first, though.
RE: Air Cooled Chillers vs Water cooled Chillers
RE: Air Cooled Chillers vs Water cooled Chillers
Where do you live (affects WB temperature distribution)? What is the minimum condensing temperature for the water cooled unit? What is the minimum condensing temperature for the DX system? There are BIN analyzers for refrigeration (and A/C) equipment that can tell you what the difference in energy usage will be. Don't forget that you need to take into account water pumping costs and water treatment costs. If it lasted 53 years then I guess the water can't be that bad. There are some fiberglass cooling towers available now that may be better. Yours is the first residence that I have heard of with a cooling tower.
RE: Air Cooled Chillers vs Water cooled Chillers
Not sure of how to figure the minimum condensing temperature. Typically, here Dallas, Texas experiences a great many summer days in the 90-100 degree range, and we keep the thermostat at 78 during the day while we are away, and lower it to 75 in the evenings, and 74 at night. It can get uncomforably cool if we go much lower. The duct outlet temperature when in cooling mode can give be 40 degrees cooler than the outside air.
The cooling tower is located in a shady spot on the North side of the house. It uses a 1/2 hp single phase recirculating pump, and a 1 1/2 hp 3 phase for the squirrel cage blower. I plan to replace it with one of the newer fiberglass cooling toweres you mentioned, so the water and energy costs are reasonable for cooling a 3900 SF residence.
My dilemma is whether or not to replace the water cooled equipment or junk it and put in DX equipmnet taking into consideration operating costs and comfort. Eithr system will be in the $14-16,000 price range, which is why I am so concerned about making the right decision.
Where could I find BIN analyzer information that you mentioned to compare operating costs?
Your comments are appreciated.
RE: Air Cooled Chillers vs Water cooled Chillers
See my post in "residential water-cooled air conditioning", part of which I have copied below.
If you want to actually calculate how much water (evaporative) cooled air conditioners will save you compared to air-cooled systems you can download the Carlyle (a division of Carrier) compressor rating software at http:
In this software there is a BIN analyzer which allows you to specify the degree of approach of the condensing temperature to the heat sink temperature. The heat sink is selectable as either dry-bulb (air) temperature or the wet-bulb temperature. You also put in the minimum condensing temperature (to take care of the problem of the TEV minimum condensing temperature). Select the location (or the location with a similar climate) and the system will go through the weather data hour by hour and calculate the energy used. The compressors that they have are more small commercial compressors but the COP's or EER's are basically the same as residential. After you do this then you need to add the additional water pumping energy, water treatment energy, and water usage energy to the energy used by a water-cooled air conditioner.