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AC_Hacker · 03-23-13, 11:21 AM

Drake,

Unless I miss my guess, he has an Etech air-to-water heat pump that was originally sold as a retrofit for an existing water heater, similar (only bigger) to the A7 units that Xringer and others are getting.

Etech was a division of AOSmith. Although they work well, and as advertised, I think they never took off because they're probably a bit over-sized for the average water heater, they were selling for $1600, and the price of energy was still too low.

I actually had one (still do if I want it back) to use as a ASHP in my hybrid heat pump system.

HERE is an article about the little wonder.

In the instructions, it clearly states that the unit is intended to be used indoors. It is evident that this is so as, the compressor has no sump heater to assure startup in winter, and the overall unit is subject to corrosion when left in outdoor conditions.

I decided that for my purposes, getting the outdoor unit of a 12,000 BTU mini-split unit and modifying it, with the addition of a suitable brazed-plate HX to heat water, would be a better alternative for me.

Although my searching was not able to locate an Etech water-to-water heat pump, if michael's unit actually is one, it could have been user-modified from an ASHP Etech unit with the addition of a water-to-refrigerant evaporator HX.

I noticed that my Etech had a tube-in-tube coiled condenser HX, which would be required for an open system water heater (water heaters are, by default, open system). So his would need two of these, or similar... and no air coils and no big fan.

I'm interested in michael's response, to see how close I actually got to the target .

Best,

-AC

03-23-13, 11:21 AM	#6
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	Etech Heat Pump... Drake, Unless I miss my guess, he has an Etech air-to-water heat pump that was originally sold as a retrofit for an existing water heater, similar (only bigger) to the A7 units that Xringer and others are getting. Etech was a division of AOSmith. Although they work well, and as advertised, I think they never took off because they're probably a bit over-sized for the average water heater, they were selling for $1600, and the price of energy was still too low. I actually had one (still do if I want it back) to use as a ASHP in my hybrid heat pump system. HERE is an article about the little wonder. In the instructions, it clearly states that the unit is intended to be used indoors. It is evident that this is so as, the compressor has no sump heater to assure startup in winter, and the overall unit is subject to corrosion when left in outdoor conditions. I decided that for my purposes, getting the outdoor unit of a 12,000 BTU mini-split unit and modifying it, with the addition of a suitable brazed-plate HX to heat water, would be a better alternative for me. Although my searching was not able to locate an Etech water-to-water heat pump, if michael's unit actually is one, it could have been user-modified from an ASHP Etech unit with the addition of a water-to-refrigerant evaporator HX. I noticed that my Etech had a tube-in-tube coiled condenser HX, which would be required for an open system water heater (water heaters are, by default, open system). So his would need two of these, or similar... and no air coils and no big fan. I'm interested in michael's response, to see how close I actually got to the target . Best, -AC __________________ I'm not an HVAC technician. In fact, I'm barely even a hacker... Last edited by AC_Hacker; 03-23-13 at 11:24 AM..