Geothermal Energy's Future Couldn't be Greener

I thought that "geothermal energy" referred to such things as geysers and hot springs that could be tapped for steam-powered electrical generators.

The heat pumps described in the article use electricity rather than generate it. They use less electricity than other choices, which is a good idea. But I think it is confusing to use the word "geothermal" for these quite different applications.

In this case, the term "generate" is probably not as appropriate as "extract". Using common geothermal sources (no, not necessarily a hot water spring but as simple as the ground thermal mass, accessible through tubing) along with heat pumps does represent an energy saving opportunity for heating as well as for cooling purposes. May not always make sense economically because of high installation costs and relatively cheap local electricity but extraction of such otherwise free energy does indeed make sense in many places.

In the grand scheme of things, such geothermal sources can be interpreted as an equivalent to production : Those sources do indeed pick-up part of the energy load that would have to be delivered for the work to be performed.

This is marketing hype.

As Tornado pointed out these heat pumps don't produce any energy at all.

They produce revenue for the people who sell them and replacement pumps, but not much else.

As was pointed out - pure marketing hype & BS from some management type that probably knows nothing about the topic.

Unless you are in the frozen north it is really hard to make a case for a ground linked/ground sourced heat pump.

The mention of becoming geothermal certified is a joke to me. For a GSHP the things that are different are:

1) piping - usually HDPE fusion welded

2) Underground analysis for heat transfer characteristics

Neither of which fall in the field of HVAC.

I think everyone is missing the mark on this thread. The OP is referring to "geothermal" but geothermal does not necessarily have to come from real deep wells and can be found in shallower wells. It is in truth solar heated ground water or soils rather than geothermal. I think they use the term geothermal because it is found within the earth. Many companies refer to it as ground source heat pumps. The ground water temperature at about 100 feet deep is generally the ambient annual air temperature as heated by Sol. You can use this stored temperature to then heat or cool a house.

Where I live the ambient air temperature is about 12 degrees C or 53.6 degrees F. Consider that with a heat pump you can extract 80 BTU/gallon of water pumped. I could then use the heat extracted to heat a home with a 20,000 BTU per hour demand at a flow rate of 4.1 gpm. Not bad use of energy even if you include the cost of running the pump to operate. Here is a calculation of savings for my house on Wolfe Island Ontario.

System Comparisons:

1 Geothermal Heating and Cooling with Hot Water Generator

2 Natural Gas Furnace, 80% eff. / 10 SEER Air Conditioner / Natural Gas Water Heater
3 Natural Gas Furnace, 80% eff. / 10 SEER Air Conditioner / Natural Gas Water Heater
Annual heating, Cooling, and Hot Water Costs: 3 year old, 2000 sq. ft. home
Kingston, ON

Electric rate: $0.075/kWh
Propane Rate: $2.75/gallon
Natural Gas Rate: $1.75/ccf

Fuel Oil Rate: $2.60/gallon

Water Furnace is a big supplier of "ground source heat pumps" and I think that is what they should be calling it rather than misusing the term "geothermal". I am thinking to convert to this system as it looks like about an 8 year payout. The banks also like it if you are mortgaging the house.

Put an ASHP (air source heat pump) in the chart and the GSHP loses all attraction in milder climates.

Where I am I would have to live for a 100 years to payback the additional expense of a GSHP system.

Comaprison:

Electric resistance - say 100 USD per month

ASHP with a COP of 3 - say 33 USD per month

GSHP with a COP of 4 - say 25 USD per month

You have the difference of 8 USD per month to payback the many thousands of USD additional cost.

If winter temps are too cold the ASHP has electric resistance for a backup and becomes expensive to operate. That is where the GSHP (ground source or ground linked) comes in.

Google geothermal and you will find that in science it refers to heat deep in the earth or hot water from there - not surface temp as do the GSHP systems.

Great post thanks! I guess the first step is trying to find a mechanical contractor able to install the geothermal heat pumps.

You will find many that are able. Competent is a different thing!

If the wells or ground loops are not done well you end up with an expensive nightmare.

I believe I would turn down any contractor without extensive experience and references you can personally check with GSHP systems and that could explain to me in detail how the ground loops or wells will provide adequate heat exchange.

I really wanted one of these systems for my new house but last winter we had one day below freezing - not the right environment.

Well,

hah

well, "a deep subject for shallow minds" limited to just the earthly platform... hah again!

But to date, as Thermal Energy Transfer late President and Inventor David Hart of TETCO then 1979 demonstrated GEO THERMAL was any thermal exchange. Such are going to always be not isolated to a sole conjecture: opining "produce(ing) energy"...

since the energy was ALREADY produced a while before CR4.

No one PRODUCES energy at all, nor even causes the movement of heat energy that I have seen. I have seen materials and fluids presented to higher temperature locations, and returned as "sources" of heated materials and fluids, but that the heat energy ALREADY available in existing to combusted or other forms, quite capably moves by the physics of its own. I mean accounted for , and noticed , and used, but no one "produces" nor "moves" energy.

Here HEAT-Energy has been put in place in the Earth to here in GEOTHERMAL conversations have of any COLDER substance or material or fluid as a material delivered near by it (wherever found)- usably-enough - is just to continue to be called at any distance below a grade: GeoThemal Heating or Heat transfer-capable.

I believe Subclasses of "production" are still just exchanges as any exchange is.

I agree, an air source heat pump is cheaper, but much of the world, especially Canada, Scandinavia, and Russia experience very cold winter weather where ground source is the only alternative during winter months. Temperatures at night often fall below minus 20 degrees C. in winter. That is when we really need the heat.

Geothermal is not used correctly in the article as stated. It is solar used by these ground source heat pumps. The sun warms the ground water (albeit indirectly) and soils in the horizontal loops.