A/C Condenser Evaporative Cooling Assist

dclark1946 wrote:
I am wondering if any company offers an evaporative cooler designed to reduce RV A/C condenser inlet air temp to assist in 95+ deg temps? I designed such a system (inspired by some mechanical engineers I worked with) for our residential central A/C back in the late 70's when the condensing units had coils only on one side making the design much simpler. I had the system in place during the torrid 1980 TX heat wave when peak temps reached 113 deg. The system functioned as a nearly constant condenser inlet temperature regulator. As the temperature increased during the day the relative humidity decreased and the evaporative cooling delta t increased so for outside ambient air temp of 113 deg the condenser inlet air temp was 85. This reduced compressor hgh side pressure and consequently lowered current draw. Our unit cycled nicely even in those extreme temps.

The main complication for RV A/C applications to me is the condensing air inlet being on both sides of the unit requiring some ducting of the evaporative cooler's output air or maybe an enclosure over the whole unit except for the back for the condenser's air exhaust with a single duct feeding the cooled air to the enclosure. Maybe just block off the side inlets and feed the cooled air into the units cover.

Based on Coleman's Evaluating RV A/C performance document, you would expect compressor current draw to increase 1A over LRA for every 5 deg above 95 and also decrease the same amount for every 5 deg below 95 so there would be benefits for reducing power consumption.

I would welcome any thoughts/feedback.

3 years ago at a Jayco Factory training session, the RVP rep brought up that 5 degree figure. Well for the previous 41 years as a TRAINED RV Technician from both Dometic and RVP and the correct figure is 10 degrees. While the rep and I argued the 5 degree in class, I had my smart phone under the table and connected to RVP Technical. THEY confirmed the 10 degree is the correct figure, which made the RVP rep extremely angry. I would bet RVP has not changed to the correct figure for their on line troubleshooting. So, use the 10 degree figure. As I pointed out to that rep, IF I use the 5 degree temp differential when doing a check out under warranty, I could condemn every RVP AC and get RVP to send a new one. BTW, I use the 10 degree figure as of today and the amp draws ARE CORRECT for temp compensated Amp draw. Doug