Water cooled condenser coil and compressor (A/C)

[steppinthrax]

Essentially this is the deal. I have a split system at home. Outdoor condensor with fan and indoor furnace (air handler). I have no water bill and it's included in my HOA fee. You guys all know when you turn the A/C on the fan outside turns cooling the condenser coil as well as the compressor.

But I was thinking about something. If you could setup a system by which cool water (from house) is sprayed or submerged on the condenser coil. Instead of using a fan. The entire outdoor A/C system can be water cooled. It would make the operational cost cheaper because I woudln't be running an outdoor fan but rather using my water too cool the system. Is there any advantage of cooling capacity by doing this. In other words will the system cool better considering that water removes more heat then air.

 

[Howard]

It would cool the coils better than air alone, but I don't think you should turn off the fan.

 

[CycloWizard]

You could increase the cooling capacity, sure, but the cost would also increase. That, and you'd flood your yard pretty quickly. 😛

 

[bryanl]

It usually works, but with some installations the water cooling makes the condenser pressure drop excessively and results in decreased performance. However the most common problems with water cooling are, by far, mineral deposit buildup on the condenser fins (if the water is hard) or the fins corrode away (soft water). In other words, don't do it. Instead keep your condenser and evaporator fins clean, and have the system inspected annually for proper amp draws and system pressures.

 

[dkozloski]

I've worked on computer room coolers that have a water cooled condensor and they are a major PIA. Your HOA will start looking for the "big leak" as soon as you implement your idea. The water consumption is staggering. Disposing of the exhaust water is a big problem. Scale buildup on the condensor is very expensive to deal with.

 

[Modelworks]

I have a brother in hvac and he routinely tells people that have a fan go bad on the oustide unit to use the water hose on the unit until he can get out to service the call.

I asked him about using just water all the time and he told me that the problem is that some of those units also use the air to cool the compressor. He said that most of the cooling for the compressor is through the refrigerant but a good percentage also comes from the air blowing over it. So unless you plan to keep the compressor wet I would just leave it alone.

Just for info he pointed me to this link for units that don't use air.
http://prostar-mechanical.com/heatpump/Trane/trane_geo_hp.htm

 

[HVAC]

Proper water cooled condensers are specially designed (tube inside a tube, for example) and typically use a brine loop (water + antifreeze/anticorrosion chemicals). This approach can be used with a geothermal type installation where the brine loop dumps the heat generated by the condenser into the ground (several feet down where the dirt temperatures are stable and lower than most ambients for which you would want air conditioning.)

If you use "city water" as the cooling medium for your condenser, it can be very expensive and corrosive. Also, there are environmental considerations for dumping large quantities of warm or hot water "down the drain".

As bryanl alluded to, using water cooling is not what your normally air cooled system is designed to handle. If you do a conversion, typically you must perform a "charge determination" to figure out how much refrigerant actually belongs in the system for your ambient temperatures and expected usage. (This is an oversimplification, but sufficient to illustrate the design issues inherent in refrigeration systems).