Using portable A/C for DHW Heater

xotet · 03-10-12, 12:34 PM

Hi Folks, first off all I´m apologize for my bad english, I´m writting from Spain. This is the most interesting forum found over the net talking about Heat pumps DIY and A/C hacking.

The goal of my project is to heat more efficiently the 150 liters of the water heater. Currently i´m using AC resistence (2Kw), I think the efficiency is under 1.

I will like to hack a 9000BTU portable A/C, replacing the Air/gas condenser with an water/gas HX, and installing a TXV and a filter before the evoporator.

I spent a lot of hours reading the A/C operation and theorics about TXV operation and selection, but I have a few doubt´s.

What´s the way to determine the Evaporation temperature?
Can I expect the Gas temp on HX Inlet, according refrigerant propierties? (I will like to use R407C or R410A, very difficult to find hardware working with R22 here)

I will like in two stage project first approach with mecanical TXV, and on a second stage control the expansion with an EEV, maybe with arduino acting as a procesor to get the COP as much higher as possible.

Any advice, comments etc... are welcome.

Thanks in Advance

03-10-12, 12:34 PM	#1
xotet Lurking Renovator Join Date: Mar 2012 Location: Spain Posts: 16 Thanks: 0 Thanked 0 Times in 0 Posts	Using portable A/C for DHW Heater Hi Folks, first off all I´m apologize for my bad english, I´m writting from Spain. This is the most interesting forum found over the net talking about Heat pumps DIY and A/C hacking. The goal of my project is to heat more efficiently the 150 liters of the water heater. Currently i´m using AC resistence (2Kw), I think the efficiency is under 1. I will like to hack a 9000BTU portable A/C, replacing the Air/gas condenser with an water/gas HX, and installing a TXV and a filter before the evoporator. I spent a lot of hours reading the A/C operation and theorics about TXV operation and selection, but I have a few doubt´s. What´s the way to determine the Evaporation temperature? Can I expect the Gas temp on HX Inlet, according refrigerant propierties? (I will like to use R407C or R410A, very difficult to find hardware working with R22 here) I will like in two stage project first approach with mecanical TXV, and on a second stage control the expansion with an EEV, maybe with arduino acting as a procesor to get the COP as much higher as possible. Any advice, comments etc... are welcome. Thanks in Advance