Talk:Ground source heat pump

Heating

I was reading an article on another site about ground source heating and it made a point that I think is missing from this article.

A typical power plant will achieve an efficiency of about 33% turning gas or coal into electricity, to power the heat pump. Whereas a condensing boiler will turn 90 -> 98% of the gas into heat. Meaning your heat pump will need to have a CoP of at least 2.7 to match the normal gas boiler in terms of efficiency; when considering the entire system from fuel to heat.

I found this interesting as heat pumps are often touted as being an environmentally better options. But, unless the entire heat pumping system can achieve a CoP above 2.7, it's essentially the same as burning gas at the house. This seems similar to battery and fuel cell powered cars, which claim zero emissions. However, there are of coarse emissions; at the power plant generating the electricity to charge them or produce and bottle the fuels.

In terms of operating cost, gas in the UK is around 4 times cheaper than electricity per kWh. Meaning you'd need a CoP of 3-4 for it to compete in terms of operating cost alone.

I understand heat pumps can be useful, but it seems like there is a high potential for ending up with something that a.) is the same as burning fossil fuel on site in terms of emissions and b.) paying more for each unit of heat. —Preceding unsigned comment added by 86.180.249.56 (talk) 22:35, 8 April 2011 (UTC)

All true for many current installations, especially the smaller and older ones. The good news is that ground source heat pumps currently in shop, often really have COP's above 4. (Which will only materialize if you also spend enough money on the ground source itself, and on low temp heating system.) They outperform gas and oil in most new large buildings, otherwise they wouldn't be installed that much. Measured full season COP's for large buildings are often above 5, up to 6.5.

And the theoretical maximum COP is even much higher (12 when you use ground water of 10 Celcius). Current trend is that every ten years, in shop COP's for small heat pumps increase by a full point, and this trend is likely to continue for a few decades. So the better ones already outperform gas and oil heaters, and they will get even a lot better in the near future.Pieter Felix Smit (talk) 08:49, 1 November 2011 (UTC)

Rewrite all this material

This material on geothermal energy and heat-pumps is great example of the overweaning arrogance of 'science experts', and the self-referential antics of 'quasi-professional WikiP editors'. How about this: that the foundational difference, from the crucial perspective of basic energy engineering (esp. sustainable versions thereof), between geothermal energy and heat-pumps is that in the former case, the energy comes from 'below' (i.e. nuclear reactions, mostly, at earth's core or friction at tectonic edge), and in the latter, the energy comes from 'above' (i.e. solar radiation). Go ahead. Make it more complicated. But in doing so, you will neither be more scientific, nor will you be more useful to readers.

What exactly are you trying to achieve with these preposterous complications? This article gets worse every time I need to refer to it for education and professional purposes. I would start to re-edit it, but I know I will be edited away by you guys. Hopeless.

Don't remove this comment. Jmanooch (talk) 18:09, 28 April 2010 (UTC)

I have always thought of these systems as, "Passive" or not! I am no expert but any passive system would be one that only ( pick your method)........................  :) ( cools and heats) and any geothermal power system does just that use mechanical systems that transfer steam( earths core) to power and in some cases space heating(Iceland). so what are your thoughts? passive solar is.............

passive geothermal is................ so my take,heat from earths core and solar energy to electricity are not "passive" systems, all others are some form of thermal differences passive systems. --Infocat13 (talk) 00:50, 12 June 2010 (UTC)

Merge

First, it is clear that these are all (Geo-exchange, Geothermal Exchange Heat Pump, and Geothermal Heat Pump) about the same subject, so they clearly need to be integrated. Secondly, the best article is Geothermal Heat Pump. Geo-exchange article is minimal, each section is only one or two sentences. Plus the name is a sort of weird marketing term not universally used. Geothermal Exchange Heat Pump, well, for one thing, that term is not used by anyone, as confirmed by a google search. And for another, the article talks more about heat pumps in general, which is covered in the Heat Pump article. So that leaves Geothermal Heat Pump, which is the most common name as well as the best article.

I personally think Ground Source Heat Pump is the better, more precise name, but I will defer to industry lingo, in the name of compromise. Jaywilson —Preceding comment was added at 02:16, 21 February 2008 (UTC)

I completely disagree. But that is because the overall title is misleading and technically incorrect. Ground Source Heat Pumps are NOT GEOTHERMAL. They are solar thermal systems as they utilise energy stored in the soil from the sun. A geothermal system utilises heat that results from friction in the core and mantle layers of the earth. A true geothermal system does not require the use of a heat pump as it will quite happily generate steam. Alankiff (talk) 16:12, 3 January 2008 (UTC)

Alan, your description of geothermal is correct, but it isn't what is being described in this wiki article. It's describing installation of pipes a couple of metres deep (and providing photos) and misleadingly, it's calling them geothermal. Just like you say, the energy is solar, not geothermal. And therefore at the moment, people (like me) are wasting their time by coming to the page to research geothermal energy and finding Ground Source heat energy instead. The title should be changed. 222.230.93.66 (talk) 17:57, 8 February 2009 (UTC)

Geothermal heat is the very high heat used to produce electricity,and is not universally available. Geothermal heat does not come from friction in the core as the person above said, but results from radioactive decay and perhaps some friction in subduction zones. But the tectonic plate motion is driven by radioactivity. Lord Kelvin erroneously concluded that the age of the Earth was something like 30,000 years, because he did not know about radioactive decay. Geothermal sources are found in Iceland, New Zealand, the Salton Sea, and Italy to name a few, and are related to Hot spots, subduction zones, and spreading centers, and occassionaly transverse faults and shear zones. Ground or more precisely ground water resources used to cool and heat houses are not the highly saline, corrosive waters found in geothermal zones. Ground source, or geo-exchange heat can be used in any area. To use the term geothermal for this low temperature source is a total misnomer. I prefer ground source heat pump or geo-exchange heat pump, and just because an article is well written, but uses the incorrect term is no reason to continue using a misleading and incorrect term. Its bad enough that people think the lead in a pencil is the same material that plumbers used to use so frequently. Let's not start using geothermal when we mean a ground source heat pump or geo-exchange heat pump. user: Terry sayer (talk) 00:48, 27 February 2008 (UTC)Terry.Sayer, 26 February 2008

Untrue. If ground heat in the top 100 meter was only from the sun, then temperature would get colder, deeper down. But ground temperature gets warmer with roughly one Celcius every 100 meter deeper (1 Fahrenheit per 130 feet) So most ground heat is in fact geothermal, and it is always a mix with solar. (although below 100 meter the percentage of solar heat gets insignificant)Pieter Felix Smit (talk) 08:58, 1 November 2011 (UTC)

I think that geothermal exchange heat pump should be merged into this article because they are the same thing. I think that the name of the merged article should be "geothermal heat pump" because it is far more commonly used than "geothermal exchange heat pump" and Wikipedia heavily favors the most common usage. In addition, the addition of "exchange" does not make the article's subject clearer or provide any other benefit. -- Kjkolb 10:54, 13 April 2007 (UTC)

However think that iot does somewhat relate to the topic and should be discussed also. I say this because Peyton Manning suggested a theory that linked the two together.

I fully agree that they should be merged with discussion. Also there is an important discussion to be had about the word 'GeoExchange(tm)' which is used in Canada and I think is where the confusion over 'geothermal exchange' comes from. Any revision should include all the terms most commmonly used and synonyms.

I agree they should be merged as they are both explaining the same thing. A common term for geothermal heat pump in europe is Ground Source Heat Pump (GSHP) this should link to it as well (it currently links to geothermal exchange heat pump). Lkleinjans 19:20, 7 May 2007 (UTC)

I also agree that all four pages regarding ground source heat pumps should be 'merged' into one article. This, I would be tempted to suggest, will not require an insignificant amount of editing. Bewp 16:14, 12 June 2007 (UTC)

When you say all four, do you mean including Geothermal heating? If so, I disagree, as in some places, e.g. Iceland, it is possible to get heating from a geothermal source without a heat pump. But I do agree as far as geothermal heat pump, geothermal exchange HP, and geo-exchange. Is there a way we can create a temporary page on which to work on the merged version, before actually getting rid of the others?Ccrrccrr 03:44, 6 August 2007 (UTC)

I also think that a merger with geothermal exchange heat pump would be a good idea, but that Geothermal heating is a quite separate topic. However I am conscious that as with quite a number of other pages relating to domestic heating and cooling, we are suffering from a difference in practice between North America and Europe (or, specifically, the UK as the main English-speaking bit of Europe). UK practice varies somewhat, and almost invariably uses the name Ground Source Heat Pump. Ideally, I would like to see quite distinct pages for the UK and US practice, using quite different names, but with a cross-reference between the two. (I write this in a personal capacity, but as an employee of the body that provides the secretariat to the UK Ground Source Heat Pump Association, the main trade body for GSHPs in the UK.) Petrolmaps (talk) 15:31, 2 January 2008 (UTC)

Let's just get this done! Since they would all link to each other, should not be a problem. As for the fact that it is called geothermal and its inaccuracy, this can be explained in the text - if that's what people call it, even if inaccurate, it should be covered.--Gregalton (talk) 07:30, 21 February 2008 (UTC)

Merge is done. The article name is still open to debate. However, I suggest you do your research before weighing in. See, for example the following quote:

Contrary to a common presumption in some reference material, GSHPs do not work by exploiting the ability of the earth to absorb the sun’s energy as heat. This misconception is most likely held because approximately 51% of insolation is absorbed by land and oceans (National Aeronautics and Space Administration 2005). While surficial sediment temperatures more directly affect horizontal ground loop systems, heat pumps in these configurations extract energy from the subsurface despite insolation variations, rather than because of them.

Surficial temperature fluctuations induced by solar radiation are superimposed on a constant and larger scale heat flow that originates inside the earth (this energy source is not susceptible to cloud cover, weather, or climatic influences). The depths at which temperatures stabilize indicate the interface at which seasonal influences are fully overwhelmed by the heat flowing to the surface from inside the earth. The energy generated inside the earth originates from numerous sources such as the decay of radioactive elements (Henning and Limberg 1995) and the release of gravitational potential of descending material (Buffet 2000).

Dowlatabadi, H (9 November 2007), "Strategic GHG reduction through the use of ground source heat pump technology" (PDF), Environmental Research Letters, vol. 2, UK: IOP Publishing, pp. 044001 8pp, doi:10.1088/1748-9326/2/4/044001, ISSN 1748-9326, retrieved 2009-03-22

--Yannick (talk) 04:59, 27 March 2009

English translation, two miles down in the South African gold mines or the ones in South Dakota its hot! This is from radioactive decay but here this heat, not being near a magma chamber is not hot enough to generate steam to power in a generator.15 feet under your building the soil is not much influenced by solar or radioactive heat.The lizards of the Sahara desert know this, as they bury themselves not to deep underground.This difference in temperature is a PASSIVE one that can be transferd by water or some other fluid from one location to another.The lizard knows this, the sun never heats the sub soil by much--Infocat13 (talk) 01:56, 12 June 2010 (UTC)

Geothermal energy reaches the earths surface at 0.1W/m2, solar energy arrives at approximately 1W/m2. The system is therefore primarily a solar one and describing it as geothermal is inaccurate. Hot Dry Rock (HDR) and Enhanced Geothermal Systems (EGS) are geothermal, harvesting heat at over 1km below below the earths surface.

Rewrite

I do not agree with merging the above two b/c these three:

• Geothermal heat pump
• Geothermal exchange heat pump
• Geothermal heating

are all inaccurate and should be used to strengthen Geo-exchange which more precisely explains the topic. ~ bcoste1 3May'07

To follow the Wikipedia policy on most common usage, "geothermal heat pumps" or "ground source heat pumps" are most commonly used to describe devices for the extraction or buriel of heat in the Earth's crust. The introduction to this artile could be entitled "Geothermal exchange" to expalin the basic physics involved. Bewp 16:31, 12 June 2007 (UTC)

I actually think the the present geo-exchange article is the worst of the present articles. In any case, the various names should be discussed in the article. Some argue the ground-source heat pump is the most technically clear and accurate description, although geothermal heat pump is becoming a more common name in the US.Ccrrccrr 03:39, 6 August 2007 (UTC)

Latitude considerations

When I inquired about geothermal HVAC in west central Florida (US) I was told that it was not used in this area because the ground is not as cold as further north. This made little sense to me, despite being uttered by multiple HVAC companies. However, If they are correct, perhaps some mention of latitude considerations should be included in this article. PhiDeck 18:19, 30 June 2007 (UTC)

GSHP's have lower thermal efficiency but better cost efficiency in Northern climates. This is complicated to explain, but I've tried to give the outline in the article.--Yannick (talk) 04:58, 27 March 2009 (UTC)

Lots of Errors

User PhiDeck makes a good point. The article presently states "These systems operate on a very simple premise; the ground, below the frost line, stays at approximately 50 °F (10 °C) year round". First of all, many places don't even have a frost line. For the U.S., see this map: http://www.usace.army.mil/usace-docs/eng-manuals/em1110-1-1905/c-2.pdf#search='frost%20depth' Second, deep earth temperature varies by location. 50 °F places whoever wrote this pretty far north -- Detroit, Michigan, perhaps. But in Atlanta for example the deep earth temperature is more like 65 °F. In South Texas it is around 80 °F. The reason geothermal heat pumps are more efficient than air source heat pumps is because in general, deep earth temperature is warmer than outdoor air when heating is needed, and cooler than outdoor air when cooling is required.

Pelkabo 19:12, 12 July 2007 (UTC)

I'm a bit confused about the third paragraph, which reads:
"This article focuses on geothermal heat pumps that use water to exchange heat with the ground, often referred to as "water-source geothermal heat pumps" or "water loop geothermal heat pumps."....
I thought water-source heat pumps use heat from a water source, such as lakes, ponds or underground rivers, rather than using water to circulate the heat, as this implies. See http://www.teainc.org/glossary_wxyz.html. Could this be clarified / corrected? (Shannonagain (talk) 14:11, 3 April 2008 (UTC))

Reference of 11 to 22 cents per meter squared cost is correct, but the original document (by Bloomquist) meant per square foot. Next sentence in original document and the source it cites, an ASHRAE study, state values in square feet. —Preceding unsigned comment added by 24.4.39.169 (talk) 18:21, 7 June 2009 (UTC)

Remove Geothermal exchange heat pump

I think that Geothermal heat pump and Geothermal exchange heat pump are almost exactly the same. I think that we should just remove Geothermal exchange heat pump because it is very inferior compared to Geothermal heat pump.

Drkshadowmaster 04:43, 22 July 2007 (UTC)

I agree. These are redundant and Geothermal heat pump is the best title.

Duncn3 02:44, 1 October 2007 (UTC)

I disagree. Geothermal exchange heat pump is the page that most closely reflects UK (European practice), and although it is shorter with fewer illustrations, this is not necessarily a bad thing! It's not inferior, just different. For example, UK standard practice would not support the closed loop fields as illustrated; guidance here suggests a minimum spacing between collector coils that clearly is at odds with the photographs. Likewise, most of the statistics on Geothermal heat pump relate to the US; again this is not a bad thing per se, but it does underline my comment in the Merge section about needing a clear distinction between the two regions in this case. Does this run against any Wikipedia guidelines? Petrolmaps (talk) 15:45, 2 January 2008 (UTC)

I'm not sure about WP guidelines, but I don't like the idea of separate pages. I think it would be much more useful to readers in both regions to have one article, clearly highlighting the differences in practice in both regions. It may take some work to get to that point.

Let's try to separate two issues: one is what article title(s) we should use. Then the next is what content should go under that title. If nobody is lobbying for as a better title than the others, we should definitely not use that as an article title. But that needn't mean we delete the content--we can more that content to section of this article, titled UK Practice perhaps, or better, merge the content in, and include notes on UK vs. NA practice where needed. Petrolmaps, if we go with your plan of having two articles (which I don't support), I don't think you'd be arguing that Geothermal exchange heat pump is the best name for the UK-oriented article--wouldn't you argue for the title being Ground source heat pump? If we can agree to get rid of the title Geothermal exchange..., then we can proceed to decide what to do with its content.Ccrrccrr (talk) 22:51, 2 January 2008 (UTC)

Personally I don't care about the title, although I tend to think shorter is better; if it were up to me I'd merge them into Geothermal heat pump for that reason alone. I would also prefer to see "Geothermal" stay in the title. What I think is more important is that they be merged into one article. I suspect that lots of the regionally specific information is not necessary, and could be removed (which would be easier to tell if it were all in one place). When that information is encyclopedic, it could be clearly marked by the appropriate region (there are certainly more than two, not just US vs. UK); that's a frequent pattern about Wikipedia that may make sense here. I'd like to see all three articles (Geo-exchange being the third) be merged into one. This one is my preference, but again, it's more important to me to see one article emerge. --Ahc (talk) 23:20, 12 February 2008 (UTC)

One reason geo-exchange heat pumps are more efficient that air exchangers is because of the high heat capacity of water. Ground water temperature remains more uniform seasonally and does not get as cold as the air in northern climes nor as hot as the air in southern climes. Terry sayer (talk) 00:54, 27 February 2008 (UTC)Terry.sayer

Cleanup of references/links

I see some edits that need to be made and don't want to make a mess of it because I'm a n00b. Someone want to show me?

The three bulleted lists under "Characteristics" are tagged "citation needed." They are lifted verbatim from the PDF referenced under "External Links" as "GeoExchange Heating and Cooling Systems: Fascinating Facts." Is this fair use?

Does this call for a single footnote reference or three separate ones? Does the external link stay in "External Links" or does the link become redundant once the PDF is cited in "References"? Does this count as a "verifiable" source, or do you have to actually know anything about the organization making these claims?

Note that a lot of the figures are cited incorrectly, e.g. he uses gigawatt-hours instead of kilowatt-hours! Ha! —Preceding unsigned comment added by Universe Man (talk • contribs) 18:08, 22 September 2007 (UTC)

DNR?

Who's the DNR? A state agency? Ccrrccrr (talk) 02:58, 30 November 2007 (UTC)

Extra part added

This extra part was added:

Geothermal heat pumps in combination with cold/heat storage

is used extensively for applications as the heating of greenhouses. In summer, the greenhouse is cooled with ground water, pumped from a aquifer, which is the cold source. This heats the water. the water is then stored by the system in a warm source. In winter, the relative warm water is again pumped up, which derives heat. The now cooled water is again stored in the cold source. The combination of cold and heat storage with heat pumps can be very intresting for greenhouses as it may be combined with water/humidity application. This obviously is a great advantage for greenhouses. In the (closed circuit) system, the water used as a storage medium for heat is done in a 1st aquifer, while the cold water is held in a 2nd aquifer. The heat and cold stored in the water mass is when needed spread as hot or cold air trough the use of fans. In the described system, everything can be automated (eg with the systems as those from HortiMax or other suppliers

Please do not remove; if need to be altered, do so here and reupload info Thanks.

Note: extra references added for claims not yet fully described in article: KVDP (talk) 15:01, 7 April 2008 (UTC) KVDP (talk) 14:08, 6 April 2008 (UTC)

I removed part of the last sentence and the reference to a nn website not meeting WP:RS. I made the edit before I saw this section, but I'm not sure why you want to make edits here to a section that's already in the mainspace. Flowanda | Talk 21:52, 14 April 2008 (UTC)

Does that greenhouse system actually use a heat pump? Not all geothermal heating requires a heat pump. This sounds a lot like downhole heat exchangers, which are documented on the web, but not yet on Wikipedia.--Yannick (talk) 05:07, 27 March 2009 (UTC)

picture added

One picture was added, hope its not removed:

A heat pump with heat/cold storage

KVDP (talk) 18:43, 7 April 2008 (UTC)

It's really unclear (to me) what the picture is showing. Could you possibly provide a caption explaining what it's showing. At the moment it doesn't seem to add anything to the article and doesn't appear to be of any sort of pump... —Sladen (talk) 20:40, 22 June 2008 (UTC)

Water pumps are implied, but I see no heat pump.--Yannick (talk) 05:07, 27 March 2009 (UTC)

Garden

Can installed the loop under a garden ?. I imagine I would use short root vegetables. —Preceding unsigned comment added by 82.159.136.215 (talk) 15:37, 7 December 2008 (UTC)

No, it needs to be at least a few feet deep below the frost line. See article.--Yannick (talk) 05:09, 27 March 2009 (UTC)

Earth Tubes

"Earth Tubes" are entirely different from "geothermal heat pumps" and require a separate category! Both are ground coupled installations that exchange heat, however "geothermal heat pumps" use a liquid or a refrigerant to achieve the exchange of heat from or to the earth and "earth tubes" rely on the incoming air to pick up or lose heat by the contact of the air with the walls of the earth tubes. My experience with "earth tubes" or "air tunnels" is their use for tempering the outside fresh-air supply using the thermal mass of the surrounding earth to absorb excess heat to cool the incoming air in the summer or to warm incoming air in the winter. This is an alternative to heat recovery ventilators or enthalpy wheels that are more commonly used in applications where a more active (less passive) approach is desired and where the conditions are unfavorable for "earth tubes". The below-grade temperature of the earth varies with the region and with the depth below grade. The depth required to achieve temperatures from 52 to 55 degrees F may be 5 or 6 ft below grade in most parts of the world. It is not necessary to be at that depth to achieve the benefit of earth tubes. The temperature surrounding a below grade "earth tube" or "air tunnel" is always more stable than the outside ambient air temperature. Safety and health factors to consider include: planning for proper drainage, safeguards against pollutants and irritants, safeguards to prevent insect and animal intrusion, and proper sizing for the desired air flow. Donoberlin (talk) 23:45, 10 February 2009 (UTC)

See Earth tubes.--Yannick (talk) 05:10, 27 March 2009 (UTC)

Merge

Ground-coupled heat exchanger or earth tubes are completely different to Geothermal Heat Pumps. Firstly these systems use air and not water glycol mix that is used in heat pumps. Secondly heat pumps use large amounts of electrical energy to provide useful heat. Earth tubes are not heating systems but modify the incoming air adding useful energy in winter and cooling the ventilation air in summer. A typical heat pump system will produce 3 or 4 units of heating energy for every unit of electrical energy used in the heat pump. Earth tube require very little electrical energy just a fan to push the air through the tubes and it is possible to get as much as 100 units of energy out for one unit of energy in. The design, construction and operation of earth tubes are covered in a very useful VDI guideline VDI 4640 part 4. I very useful document in both German and English. Mikem001

I think what was needed was a disambiguation hatnote at the top of ground-coupled heat exchanger. Done.--Yannick (talk) 05:12, 27 March 2009 (UTC)

Leaks in Direct Exchange systems

Could we discuss how to present the potential for leaks in direct exchange systems? There seems to be a strong difference of opinioin on this point. I am personally dubious of three claims currently written here:

1. DX is more tolerant of small leaks. The argument given would only make sense if we're talking about a percentage of coolant leaked over time. That is, it's probably true that a DX system can tolerate loses 10% of its refrigerant much better than a closed loop system that loses 10% of its water. But what I was trying to say is that a closed loop system can tolerate a pinhole leak of a given size much better than a DX system would, because gas leaks out much faster than water through the same size hole. Plus, a small leak in a closed loop can be compensated for by simply by topping up the system with water. So when designing installing a DX system, more care must be taken to eliminate defects.
2. Leaked refrigerant evaporates harmlessly. I think this kind of discussion belongs in the environmental impact section, which already notes that leaked refrigerant contributes to ozone depletion. As a result, I object to the word "harmlessly" here. And while it's true that the antifreeze from a closed water loop can leak into the water table, the most commonly used antifreeze is methanol, which is biodegradable and produces very limited environmental damage. For comparison, we have international treaties in place to try to control and reduce the use of refrigerants, whereas no such attention is being given to methanol.
3. Copper loops have a very long lifetime. Closed loop water pipes are usually plastic. I have trouble believing that a metal pipe would last longer than a plastic one when burried in the ground. I understand how sacrificial anodes can eliminate that problem, but that comes with costs in efficiency and environmental impact. I would be much more worried about disolved zinc reaching my water table than methanol. But again, I think that particular aspect belongs in the environmental impact section.

As always, verifiability is key, and I admit I have not yet provided sources. If we cannot come to a consensus on these points, it may be best to remove the whole discussion of leaks from the article until one of us can provide a reliable unbiased source to support our statements.--Yannick (talk) 17:05, 4 April 2009 (UTC)

Seeing no debate, I've gone ahead and rewritten that section. I've tried to keep to a neutral middle ground, but I've got to say I'm uncomfortable with how good it makes direct exchange systems look. If they were so superior, why did water source systems overtake them in the market?--Yannick (talk) 14:06, 10 April 2009 (UTC)

What I hear from copper direct loop systems in Netherlands is that they last for ten or 15 years, and then start leaking. They all do, it seems. From working in ships maintenance, I know that anodes work, but get eaten away by the corrosion, and need to be replaced every two or three years. And you need one every 20 feet, so its not possible.

PE piping has been used for 40 years under ground now, since 30 years also for transporting heating gas, and old ones dug up were tested and still in perfect condition. The COP-loss can be minimised by increasing the size of the condenser. DX systems are no longer allowed in Netherlands and surrounding countries, I have seen no single innovation to answer the corrosion / leaking issues, and I think they are no longer produced anywhere in the rich world, so they can be referred to as an outgoing system.Pieter Felix Smit (talk) 09:14, 1 November 2011 (UTC)

Intro paragraph, source of heat

I don't really like the new sentence order in the first paragraph. Ending the paragraph with the distinction from traditional geothermal power puts too much emphasis on that sentence and gives the impression that deep geothermal sources do not contribute heat to geothermal heat pumps. In fact, this source often dominates, especially for open loop or closed vertical loop systems. I would like to revert to the old sentence order, where the contrast statement was immediately followed by a clarification. But if there's a better way to say it, I'm always open to that.--Yannick (talk) 04:06, 22 July 2009 (UTC)

I see your point, I have restored the sentence ordering back. LK (talk) 02:56, 26 July 2009 (UTC)

Suggested merge

It has been suggested that Deep water source cooling should be merged into this article.
— V = I * R (talk) 09:16, 26 August 2009 (UTC)

And I take it deep lake water cooling would be merged as well. I see a couple of possible problems though: first, do these systems always use a heat pump? In theory, they could simply work with a heat exchanger, but I don't know how common that is, if it's done at all. Second problem is that this seems to be a misnomer. "Geothermal" implies taking heat from the ground, whereas deep water cooling only works against geothermal power.--Yannick (talk) 03:10, 29 October 2009 (UTC)

• Oppose. One uses the ground as a heat sink, the other uses cold water in a deep lake as a heat sink. However, the deep water source cooling does not require mechanical "heat pump" operations. Also geothermal systems do both heating and cooling while deep water source cooling can't be used for heating. Racepacket (talk) 03:37, 3 November 2009 (UTC)
• Oppose. Agree with Racepacket. Sunray (talk) 19:37, 16 November 2009 (UTC)
• Hang on. I don't see polling as useful here. Can we do some research and talk about this instead of just voting? Although deep water cooling does not require a heat pump, some systems use them, and I don't know how common one type is over the other. Those that do are not all that different from pond loop or open loop systems that draw water from a lake. Deep water systems with heat pumps could theoretically provide heating, but I don't know if that's actually done in practice. But in any case, many geothermal heat pumps in southern latitudes are used predominantly for cooling, and yet they are still commonly called geothermal heat pumps. It seems clear to me that some deep water systems deserve coverage under the geothermal heat pump article, but other material belongs elsewhere, or may deserve it's own page. If you have knowledge or ideas about this, please share it with us.--Yannick (talk) 12:08, 24 November 2009 (UTC)

• Oppose. Agree with Racepacket. Merging would only confuse technologies that are indeed different. Pointing to like technologies would minimize confusion. —Preceding unsigned comment added by 194.117.24.10 (talk) 13:02, 25 November 2009 (UTC)

This poll is pointless because this is not a black-and-white issue. How would you classify an open loop heat pump that draws water from a small lake? Does it make a difference how deep the lake is? What if it's small enough to call it a pond? What if you use a closed loop at the bottom of one of the great lakes? All of these things are done. There's plenty of overlap between geothermal heat pumps and lake water cooling. What we should be doing is brainstorming ideas about where to draw the line, and comparing those ideas to the way these technology names are used in practice.--Yannick (talk) 14:53, 6 December 2009 (UTC)

The systems we are discussing here are "passive" in that they do not generate electricity,in the case of the ocean thermal energy conversion it does.we could call this, "Passive water thermal cooling and heating" and have that article referenced with any passive geo system.For our readers all of this should be called passive cooling and heating pump and then its source of thermal difference.--Infocat13 (talk) 01:19, 12 June 2010 (UTC)

• Oppose. Agree with Racepacket, plus consider that these are not just theoretical engineering concepts, but geothermal heat pumps at least are a major industry, with millions of installations in commercial, government, and residential properties. (I am a participant in this industry.) Lots of people are specifically looking for info on geothermal heat pumps and this merger would confuse them needlessly. While it is true that there is technological overlap (open and closed water loop geo heat pumps can use a body of water as their heat reservoir), in terms of application and interest, I can see very little overlap. When my potential customers go to wikipedia for a primer on geo heat pumps, they won't be interested in the additional content in these other articles. Yannick has a good point that there is overlap and the line must be drawn somewhere, but I think the line is already drawn in the correct place. I propose this has been an open issue long enough, has become dormant, and should be closed and the tag removed. Jaywilson (talk) 14:34, 10 December 2010 (UTC)

GeoExchange is a trademark

The Geothermal Heat Pump Consortium http://www.geoexchange.org/component/content/article/370-front-page/69-whats-in-a-name.html owns the trademark GeoExchange in the US.

In Canada, at least two organizations, Earth Energy Society of Canada (earthenergy.ca) and Canadian Association for Renewable Energies (renewables.ca), have encountered legal problems for using the trademarked term GeoExchange. —Preceding unsigned comment added by 99.233.85.43 (talk) 20:13, 6 October 2009 (UTC)

I'm not sure how the trademarks work, but the word and logo is used by the Canadian Geoexchange Coalition: http://www.geo-exchange.ca/ This is an industry association that is developing a system of certification for heat pumps that meet their standards.--Yannick (talk) 11:26, 24 November 2009 (UTC)

Move?

The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the proposal was consensus against move per our policy on using the common name of a subject.--Fuhghettaboutit (talk) 02:26, 5 November 2009 (UTC)

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Geothermal heat pump → Geothermal heat and cool pump — User:Nopetro 12:58, 28 October 2009 (UTC)

• Question - Why should the name be changed? There is no "and cool" in the common name. The lede of the article until a little while didn't have "and cool" either. ~~ GB fan ~~ ^talk 18:39, 28 October 2009 (UTC)
• Oppose - "Geothermal heat pump" is the most commonly used name by non-technical readers, and is widely used (though disputed) in technical communities. The words "and cool" do not add any accuracy, since it is still a heat pump when used for space cooling.--Yannick (talk) 02:59, 29 October 2009 (UTC)
• Oppose per Yannick. Beagel (talk) 08:02, 1 November 2009 (UTC)
• Oppose per Yannick. Racepacket (talk) 03:40, 3 November 2009 (UTC)

The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Poorly written, inaccurate, repetitive intro

The intro repeats things and contains boring and obvious statements. This is possibly caused by its length - someone adding a sentence to the 2nd paragraph may not have read the 5th paragraph. I hope to come back and normalise that text some day, but wanted to note this problem in case someone else with writing skills has some time for it. 109.128.216.198 (talk) 06:59, 11 November 2010 (UTC)

The intro also is wrong in stating that ground temp within 3 m of the surface is constant and between 10 and 16 deg centigrade. In fact, ground temp varies seasonally, the more so the nearer one gets to the surface. Below 2 m it is stable enough for geothermal heat pumps. But the temp range, depending on latitude, is more like 0-30 centigrade. I'll fix this if there is a consensus (or no response). Jaywilson (talk) 15:01, 10 December 2010 (UTC)

Section titled Differing terms and definitions needs rewrite, shortening

This section is far too long and wordy. It gets in the way of the reader's interest in and ability to comprehend the actual subject at hand. Some of it could be moved to or merged with geothermal (disambiguation) which actually needs more explanatory text. I don't object to it remaining in a much much shorter form that would list the various names ground source heat pump, geoexchange, etc. as well as have a quick list of what it isn't (geothermal power, etc.). It should be no more than a paragraph, maybe two. By the time the reader reaches the end of this (first) section, they have been told three times that geo heat pumps are not the same as geothermal power, and the reader is probably ready to know what geo heat pumps actually are. Jaywilson (talk) 15:26, 10 December 2010 (UTC)

Error in claim of heat pump efficiency vs. electric heater.

The article states that “ a heat pump is always more efficient than an electric heater” but this is not true. A heat pump becomes less efficient as the outside air becomes cooler. In fact this is the main reason why it is becoming popular to use below ground loops these days. I can’t remember at what point its efficiency drops below that of an electric resistance type heater but I believe its somewhere between ten degrees and zero degrees Fahrenheit. This is also why some houses in very cold climates, but where gas is very expensive, use a heat pump for heating when the outside air is above a certain temperature (about 40 degrees) and a furnace kicks in only when the air temperature drops below this point. Anyway the point is that the colder the outside air is the less heat there is to extract from that air so the heat pump must work that much harder and is therefore less efficient. It is only reasonable to assume that there is a point at which it will be less efficient than an electric heater. — Preceding unsigned comment added by Slobeachboy (talk • contribs) 08:06, 6 August 2011 (UTC)

You're mixing up two things. A heat pump working on outside air becomes less efficient then a gas or oil heater when it gets freezing hard. But both the heat pump in freezing weather, and the oil and gas heaters are still at least double as energy efficient as an electric heater.

(Electric heater is a very simple metal box with inside only a hot electric coil, and sometimes a fan behind it, working exactly like the old fashion light bulb, but being bigger, less hot and exposed to air.)Pieter Felix Smit (talk) 09:30, 1 November 2011 (UTC)

Actually I’m not mixing them up at all. You just don’t understand how a heat pump works. A gas furnace and an electric heater both “produce” heat by converting either gas or electricity into heat. A heat pump on the other hand does not produce anything it simply moves heat from one location to another. Also the loss in efficiency I spoke of has nothing to do with the heat exchanger icing up, although that would indeed affect efficiency. Anyway as a heat pump extracts heat from the outside air, and there is less and less heat to extract from the air as it get colder, then it has to work harder and harder to get the same amount of heat. I know its hard for most people to get their heads around the fact that something is extracting “heat” from air that might be freezing cold but anything above absolute zero (−459 °F) has some heat energy in it. A heat pump would become totally useless long before the outside temperature got anywhere near absolute zero though. Both electric resistance heaters and gas heater would still work at these temperatures at the same efficiency as they do at higher temperatures though. — Preceding unsigned comment added by Slobeachboy (talk • contribs) 05:37, 2 November 2011 (UTC)

According to the 1st law of thermodynamics: what come's in must come out. In other words, the electrical energy (converted into heat) plus the energy extracted from the environment are produced at the condenser side of the heat pump, in an ideal situation. In this case the produced energy is always as much as, or more than, the input energy (the electricity), causing a system efficiency of more than 100% (COP>=1). Of course as is always the case, the heat pump does not work ideally and loses some energy on the way to the point of delivery. Also the boiling point of the working fluid (or the pressure) might be too high, causing the heatpump to malfunction (i.e. no evaporation). Please note that the above holds true for heat pumps in heating mode, chillers are slightly different as their efficiency depends on heat extracted instead of heat supplied. Rvanpruissen (talk) 10:11, 7 November 2011 (UTC)

Heat pumps dump cold in the heat source, thereby depleting it

The article obscures that when you heat a building by extracting heat from the ground source, you, so to say simultaneously dump the cold from the building in the heat source. I think it is necessary to add this explanation, because it makes the average reader understand that a potential problem with ground source heat pumps is that they accumulate cold in the ground source, year over year. Skipping over this fact results in people choosing to save costs by under sizing the ground source, which leads to installations that work reasonably for a year, and then starts to gobble more and more electricity every year. Cold accumulation is not a problem when the heat source is big enough, and its effect can be annulled by using summer heat to regenerate the ground source.Pieter Felix Smit (talk) 09:55, 1 November 2011 (UTC)

First of all the extraction of heat and the “dumping of cold” are not two different things. Cold is not an actual thing so you can’t dump it. Cold is simply a relative absence of heat. Secondly you cannot deplete the heat source because the heat source is the earth itself and it can never be depleted. All that happens is that heat is extracted from the ground, condensed, and then dumped into the building. This process obviously lowers the temperature of the ground immediately surrounding the coils to a certain extent but that heat is always being replenished by the surrounding earth. Since earth conducts heat slowly though there is a certain time delay involved. Still it’s not as if the unit would become less and less efficient over the coarse of several years. It might be more efficient for the first day or two and then as the average ground temp around the coils stabilized at its new average temperature the efficiency would stay the same from that point forward. Obviously if you used to few coils for the size of your system and in too small an area then you would be extracting heat faster then it could be replenished and this would make the system much less efficient. Hopefully the people doing these installations know how calculate optimum coil areas for a specific system though based on the size of the system and the soil composition in that area. — Preceding unsigned comment added by Slobeachboy (talk • contribs) 07:39, 2 November 2011 (UTC)

You are correct that you cold leave out the 'cold dumping' argument (maybe a bit too popular, although it is understood quickly by those with no technical background) and instead add that extracting heat form the ground surrounding the loops, lowers the temperature of that ground.

You assume that there is no long term effect beyond a few days. Not true. See http://www1.eere.energy.gov/femp/pdfs/hyhgp_tir.pdf first page second column, and http://dsp-psd.pwgsc.gc.ca/Collection/M92-251-2002E.pdf page 15 bottom paragraph. The standard computer programs for calculating the size of vertical loops, accept that during the first years, the average temperature of the ground around your vertical loops will go down with almost one Celcius, 1.6 Fahrenheit each year. The stabilization you mention, does not occur after a few days, but (if you make the loops according to advice) after ten years. Then there is a balance between heat flowing from surrounding ground, and heat extracted by the heat pump. This stable temp has to be above zero Celsius, assume current calculations.

You speak of the optimum coil size. Currently, the calculation is not geared towards optimum, but towards having a system that won't freeze up at the end of the tenth winter. The optimum in terms of energy saving would be to vastly increase the size of the coil or loop. The economic optimum depends on your time perspective. A loop or coil system made from PE will last 50 years, so if you have the funds to take that time perspective, the depreciation per year is very low.

If your aim is to reduce electricity costs to the max, then the optimum coil or loop length is only limited by the extra energy for water circulation, and if you take a modern AA-label pump for that, then optimum length is 3 to 5 times longer then what is now current.

So my proposal would be to add: "Using heat from the ground, structurally lowers the temperature of the ground surrounding the coils or loops. This reduces efficiency considerably. If that leads to the ground freezing up, efficiency drops spectacularly, because frozen ground is much less conductive to heat. The heat flow into the system will almost stop, and after a few weeks the heat pump will out. A second problem is, that if there is a risk of freezing up, then the circulation water needs much more anti freeze, which reduces efficiency of fluid pumping and of heat transport, long before actual freezing up. The solution is always to 'oversize' loops or coils. (And, in the case of horizontal coils, to have them deeper under the ground.)

I make the point because producers of heat pump machines tend to suggest that the efficiency of the system is largely determined by the heat pump machine. But in reality, efficiency is much more influenced by ground loop size and heating temperature, then by the difference between A-brand machines. Pieter Felix Smit (talk) 11:20, 8 November 2011 (UTC)

Size of heat source has huge influence on the energy efficiency of heat pump system

I came across several heat pumps that used much more electricity then the specs promised. In almost all cases this was caused by slightly underdimensioned ground source piping, or by one or some of the loops not functioning.

On the other hand I came across two heat pumps that used significantly less electricity then specs. Both had ground source piping, longer then advised for the capacity of the heat pump.

Appearantly, the size of heat source (the amount of meters of underground pipes) has huge influence on the energy efficiency of heat pump system. The more the better. The influence is much bigger then the 4.3 or 4.6 difference in theoretical COP between two competing A-brands. There is huge potential to achieve energy reduction even with existing heat pumps, simply by putting double the amount of pipes in the ground.

I know that most developers of heat pump systems innovations also earn lots of money in selling electricity and electricity plants, so I understand their focus is not on making current generation heat pumps use less energy. But for the sake of neutrality and for serving those who want to go further in carbon reduction, this angle deserves more exposure then it had.

I already put it in the article, I hope everybody accepts.Pieter Felix Smit (talk) 10:07, 1 November 2011 (UTC)

Environmental impact section is inaccurate by omission and skewed

This article takes the most pessimistic view possible for geothermal emissions – tying it primarily to coal generated electricity - while taking the opposite tact for natural gas and overlooking the fact that AFUE doesn’t account for the electricity used/required by a furnace. Not only do natural gas furnaces get a free pass for electricity usage and emissions, they also get a free pass on total GHG emissions since methane is 21 times more potent in the atmosphere than carbon dioxide. The section is missing key facts and the end result is misleading.

At least the text makes an attempt to explain that not all energy is derived from inefficient coal - and that GHPs overall impact can be 0 with renewable energy. Unfortunately, this is negated by a large table that draws attention away from the text (as all tables and graphs tend to do) to reinforce the idea that GHPs are dirtier than natural gas – despite the facts being skewed in favor of natural gas. — Preceding unsigned comment added by 184.18.132.230 (talk) 13:08, 31 March 2012 (UTC)

There was a sentence in this section about open loop systems which misconstrued what an open loop system is. (It said open loop is when the ground water is discharged on the surface -- a practice which is not legit.) I have changed the sentence to indicate that systems when extract and reinject water are open loop systems, and why reinjection is necessary. I added a "citation needed" flag since I don't have time to provide a reference (and the original sentence didn't have a citation either). Coastwise (talk) 09:16, 3 January 2013 (UTC)

Also, I broke the above open loop material and the material about Staufen into separate paragraphs because they are really separate topics. One is about a system characteristic, the other is about a poorly done job. Coastwise (talk) 09:16, 3 January 2013 (UTC)