Geothermal systems

[Scottpat]

I'm seeing more new homes and new buildings with geothermal systems. I have an office building to inspect at the end of the week that has a geothermal system I think it has three systems in it(well type).

Does anyone have any information on what to look for or "Red Flags" that I should be looking for? In 20 years I think I have only seen 3 geothermal systems during an inspection.

I have already told the client that they would be best served if they can find out who installed the system and have them evaluate the system including the controls.

From what I have been able to gleam, most geothermal systems are custom made for the structure including the controls system.

[kurt]

It's probably a ground source heat pump arrangement; I doubt it's geothermal.

Lottsa stuff to talk about. I'd start by getting the installer and engineering involved.

[Tom Raymond]

Ground source or open source, that type of heat pump arrangement is called geothermal no?

[Scottpat]

They are ground source, the building has 5 wells that were drilled and are used with the system. From what I was told each geothermal heat pump has one well.

[Marc]

I thought 'ground sourced' was just an older name for 'geothermal'.

Marc

[John Kogel]

I would do a heat pump inspection on each heat pump and if you still have that IR camera, I would get some shots of the pipes to show the temp differences.

Then I would get some room temps and check thermostats. Then like you said refer a professional to do a formal inspection of the systems

[Marc]

Why not just turn them on and see if they work? Remove the service covers and do a cursory visual inspection? I don't think they're a big deal.

Marc

[kurt]

I've been corrected by the Green Brigade about geothermal and ground source so much I've gotten skittish.

Geothermal is directly tapping inner Earth heat source, i.e., Icelandic type thermal springs or similar.

Ground source heat pump is the term applied to what we usually see, i.e., "wells" and some form of transfer system.

What's it called everywhere else?

[Jim Katen]

I've been corrected by the Green Brigade about geothermal and ground source so much I've gotten skittish.

Geothermal is directly tapping inner Earth heat source, i.e., Icelandic type thermal springs or similar.

Ground source heat pump is the term applied to what we usually see, i.e., "wells" and some form of transfer system.

What's it called everywhere else?

I was taught the same thing. A ground source heat pump leverages the constant temperatures found underground to produce heating or cooling. A geothermal system moves heat directly from the earth into the house without amplifying it.

I don't know how often the terms are really used this way either.

[Scottpat]

Well the real estate agent is calling it a geothermal heat pump, so they must be right. []

[David Meiland]

You can probably determine if it's sorta working or not, but most of the problems I hear about with ground source are that it's nowhere near as efficient as was claimed when the contractor sold it. Problems with ground loop size, problems with lots of electricity used for pumping, etc. I've seen a few here with whopping electric bills to go with them. If I were buying a building with a ground source system I would want to see a bill history.

[John Kogel]

It seems Geothermal is to ground source as Modular is to mobile home. []

[kurt]

You can probably determine if it's sorta working or not, but most of the problems I hear about with ground source are that it's nowhere near as efficient as was claimed when the contractor sold it. Problems with ground loop size, problems with lots of electricity used for pumping, etc. I've seen a few here with whopping electric bills to go with them. If I were buying a building with a ground source system I would want to see a bill history.

Yes. AFAIC, it's for the ecomansion crowd.

[John Kogel]

Good point, David.

I checked ground source heat pumps out before I filled in a swimming pool on my property. The plan was to line the pool with pipes before filling it in. However, a shallow hole is said to be inefficient. They say you need the loop to go deep to be practical. Does anyone know why that would be?

Frost is not an issue here.

I can see that pumping water through a pipe could cost more than operating a conventional above ground fan. Also in the shoulder heating months, the air temp rises around the outdoor unit where the ground source temp never varies.

[inspector57]

The ground source units were very popular and the gold standard about 25 years ago.

The last house I built my a/c guy told me to save my money since the gains in air source unit efficiencies made payback a loosing proposition.

Double or quadruple the up front cost and calculate the payback from 10 or 25% utility savings and the equipment will be worn out before getting the ROI. Great idea but there is no need for it in my area.

If you are in the extreme northern climates the numbers may work.

Scott, There are a multitude of different variations but generally you have a water pump and water cooled condenser/evaporator that takes the place of the outdoor units coil and fan.

[Tom Raymond]

If you install a ground source heat pump before December 31, 2016 the federal government will give you a 30% tax credit. The systems qualify under the geothermal portion of the renewable energy credits.

Now you know where the RE got it from.

[Scottpat]

Thanks all...