Hello everyone…I am a first timer here on the forum and I am seriously considering building a home on a lot that I have owned for years now that I have decided that if I am going to do so, I wish to pick a builder, plan and internal systems that are efficient, within a reasonable budget…

 

I have decided (with the prospected builder) that I don’t wish to go with a 3 ton geothermal heat pump system. But the water heating byproduct keeps making me reconsider…

 

My question is this…I assume that (and please correct me if I am wrong) if I go with a conventional air source heat pump system, I can have a desuperheater fitted (depending on the particular model), but are there currently smaller geothermal (ground source heat pump) systems that are designed for domestic water heating alone.

 

The builder has alluded that to his knowledge they don’t exist, but is that the case? And if they do exist…then can anyone point me in the right direction, especially if they have personal or professional experience with a particular model or manufacturer.

 

And I suppose if they do exist, this builder should no longer be a serious prospect...

Any water to water Heat pump can make hot water for domestic use, radiant floor or fan coils. Hydron module makes a 2 ton dual capacity W/W heat pump. Low stage is about 1.5 tons

http://www.hydronmodule.com/hwt

thanks a bunch heat of the earth...I really need to reconsider this builder...so if I unerstand correctly, this 2 ton w/w heat pump is ground source and designed for ground loop installation?

Sorry for the abundance of ignorance, I'm kinda flying solo and attempting to educate myself b/c afterall I can't rely on some of the self proclaimed pros..

Yes it is a ground source HP designed for ground loop installations. Waterfurnace also makes a small W/W unit. I think its single stage and 1.5 tons.

would it make sense to consider uising one of these W/W units just for water heating? Or will this defeat the purpose of having a potentially integratable system? I guess what I am asking is that I was never warm to the idea of using a geothermal system for space heating and cooling, but does it make more sense if I choose to go the ground source heat pump route for water heating?

Abraham,

We have read through your comments regarding the use of a water to water unit to heat your domestic hot water. We have sent you a private message, as we would like to discuss the application you are considering.

WaterFurnace International, Inc.

Posted By Abraham on 26 Mar 2010 03:42 PM
would it make sense to consider uising one of these W/W units just for water heating?

Or will this defeat the purpose of having a potentially integratable system?

Not wise to use just any ol' water-water heat pump for (potable) DHW.
Should have a double-wall isolating heat exchanger on the load side to
prevent contamination of domestic water in the event of HX failure.

BTW, what's a "potentially intergatable system?"  ...integrate with what?

For DHW only, it makes more sense to install Solar Thermal Panels. Cost efficiency vs. output will be better with Solar Thermal rather than a geothermal installation for YOUR APPLICATION. However, it also makes good sense to install a DX geothermal system which will give you heating, cooling and hot water all from the same heat pump.

Paul
Total Green Geothermal

The WF ew020 is as good a candidate as any dedicated ground source domestic water heat pump I've come across. It incorporates a double wall and vented heat exchanger to prevent potable water contamination by refrigerant and oil in the event of heat exchanger failure. This is required by some codes.

That said, deploying a ground source heat pump for domestic water heating alone would likely result in a payback measured somewhere between "decades" and "never"

In mild climates an air source heat pump water heater is worth considering if a 1000 cu ft room or garage is available for it. They can operate at half the cost of a conventional electric resistance heater as well as provide potentially useful cooling and dehumidifcation. Geyser, Rheem, and GE are models to consider.

Geyser works fairly well in a retrofit (I've owned one for almost a year) but GE is my favorite integrated model - higher efficiency and no water pump, though I have no field experience with one.

I can't wrap my head around the choice to use geo for hot water but not space conditioning.
As Curt points out the payback is never.
Further I wouldn't discharge a builder who isn't well researched in a bad idea. It is likely no one else ever asked him about making hot water with geo so he has never inquired how to make that happen.
In a perfect world your builder hires experts to do the heating, electrical and plumbing so that he needn't be an expert in 4 trades.
J