Talk:Ground source heat pump

This extra part was added:

Geothermal heat pumps in combination with cold/heat storage

is used extensively for applications as the heating of greenhouses.^[1] 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.^[2][3] 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. ^[4] In the described system, everything can be automated (eg with the systems as those from HortiMax or other suppliers ^[5]

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: ^{[6] [7] [8]} 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)

One picture was added, hope its not removed:

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)

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)

yes, as long the loop is deep enough to work properly as a heat-exchanger. I have PV-T (water-cooled Photo-Voltaic solar energy collectors) and I dump the "waste heat" from the panels into three x 100m 'slinky' coils buried 1.2m deep. I have built vegetable beds above each coil. There is a significant difference in soil temperature, measured at a depth of 0.3m, compared to adjacent beds. In January, in South-East England, the difference is circa 3 centigrade. There is also a significant difference in productivity between the beds of about 15%, by weight, of harvested vegetables.AncientBrit (talk) 17:08, 20 March 2019 (UTC)

"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)

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.^[1] 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)

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)

There is significant confusion in the discussion above concerning what Direct Exchange is. Direct Exchange refers to a direct expansion of a refrigerant fluid by the earth, rather than using an intermediary fluid, such as water.

1. DX is not tolerant of 'small' leaks: no refrigerant system is. The machine will soon lose pressure and shut down. Nor is a system that uses an intermediary source, as the hydronic circuit will no longer function properly. However, this is a non-issue. Installation and maintenance of machines using refrigerants is now regulated, and leaking is not more of an issue any more than it is an issue for air conditioning, air-source heat-pumps, commercial refrigeration, etc.
2. You are right that it is important to clearly state that the potential risks of using refrigerant in the ground. There is no material safety risks and the environmental impact is non-existant in the ground and there is no impact over and above the use of refrigerants generally, with the greenhouse-gas effect if leaked. (For environmental reasons, regulations surrounding refrigerants have been tightened to prevent non-qualified people to buy and use the refrigerants themselves.) As a reference : "Evaluation of the Environmental Fate of Refrigerant 22 and 502 in ECR Heat Transfer System" by R. Jerry Murphy Ph.D. P.E. (1986), the impact of refrigerant was evaluated. You need only ask any engineer who works with refrigerants (or your local professor of physics) and they will explain that the size of refrigerant molecules prevent their absorption in the environment, and having low toxicity and flammability, there are only two risks: confinement in a small enclosed area, with the risk of oxygen displacement, and greenhouse gas effect when breaking down in the upper atmosphere. The facts haven't changed. Only R-22, which had an impact of ozone depletion, has been phased-out. Ytrottier may object to the fact that glycol poses a risk whereas refrigerants don't. International treaties cover the use of refrigerants because the HVAC industry is a $100b industry, and there are alternative refrigerants which require innovation and adaptation if there are to replace the existing systems. The use of propylene glycol as anti-freeze is insignificant on a global scale and there are no direct replacements offering the need for a transfer process.

• Ethylene glycol is poisonous to humans and other animals. (Ref: wikipedia: Antifreeze). Concerning propylene glycol, it is readily absorbed by the water table. According to the wikipedia page, "serious toxicity generally occurs only at plasma concentrations over 1 g/L". The concentrations used in installations is generally around 40% (between 20 and 50%, depending on the local climate). So, relative to ethylene glycol it has low-toxicity, this level of toxicity is still pollution and can be harmful at high concentrations: in the following WHO report, serious toxicity relates to the administration of a minimum dose of 20-50 ml. Therefore, one glass of propylene glycol antifreeze mixture can be toxic, possibly causing lactic acidosis, haemolysis, coma, convulsions and cardiorespiratory arrest. http://www.who.int/ipcs/publications/training_poisons/basic_analytical_tox/en/index11.html

Propylene glycol is relatively safe in normal use, but cases of poisoning associated with its use as a vehicle for drugs or vitamins given intravenously or orally have been described. Plasma concentrations associated with serious toxicity are over 4 g/l, corresponding in adults to the administration of 100-200 ml of intravenous fluids containing 200-300 ml/l propylene glycol over a relatively short time.

There is no simple qualitative test for propylene glycol.

Clinical interpretation

Overdosage with propylene glycol may cause lactic acidosis, haemolysis, coma, convulsions and cardiorespiratory arrest. Increased plasma osmolality can be a useful but nonspecific indicator of poisoning with this compound (see section 3.1.3).

1. Copper has an unlimited lifetime in the earth, as opposed to plastics, which break-down gradually over time. In acidic or corrosive environments, metals may corrode. This is why the earth loops are generally protected with a cathodic protection in acidic soils. This is indeed the same technology as in ships or gas pipelines. Pieter Felix Smit: no, this does not require multiple anodes. The loops are the cathode, and being electrically conductive, brings the protective electrical field to the entire loops field. The expected half-life of a 1m anode is around 100 yrs, not 2-3 years.

Regarding the safety of DX overall, I provide a letter from the atmospheric pollution prevention division of the EPA.

Direct exchange has been used continually since the 1970's. I have visited references in the USA.

I have already corrected Pieter concerning the fact that DX is indeed allowed in the Netherlands and all the surrounding countries.

Wrgj (talk) 12:16, 3 January 2013 (UTC)

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)

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)

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)

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)

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)

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)

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)

Passing note ten years after: the above applies to heating-driven climates. The opposite applies to cooling-driven climates, where ground hearing becomes an issue. The goal is to have sufficient wells or coils for the situation, and the necessary measures are decidedly location-dependent. Acroterion (talk) 17:30, 24 May 2021 (UTC)

I think most of us live in a bi-thermal climate: we need to heat in the winter, and cool in the summer. In which case I would think the year-over-hear effect would be effectively zilch. Mcswell (talk) 20:41, 21 July 2022 (UTC)

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)

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)

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• Added archive https://web.archive.org/web/20100626095818/http://www.hvac.okstate.edu/research/Documents/Orio_Johnson_Rees_Chiasson_Deng_Spitler_05.pdf to http://www.hvac.okstate.edu/research/Documents/Orio_Johnson_Rees_Chiasson_Deng_Spitler_05.pdf
• Added archive https://web.archive.org/web/20090403212025/http://oee.nrcan.gc.ca:80/publications/infosource/pub/home/heating-heat-pump/gsheatpumps.cfm to http://oee.nrcan.gc.ca/publications/infosource/pub/home/heating-heat-pump/gsheatpumps.cfm
• Added archive https://web.archive.org/web/20120813041725/http://carsologica.zrc-sazu.si:80/downloads/392/Sass.pdf to http://carsologica.zrc-sazu.si/downloads/392/Sass.pdf
• Added archive https://web.archive.org/web/20070903210053/http://www.econar.com:80/faq.htm to http://www.econar.com/faq.htm

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Hello fellow Wikipedians,

I have just modified 7 external links on Geothermal heat pump. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

• Added archive https://web.archive.org/web/20081004020606/http://www1.eere.energy.gov/geothermal/geothermal_basics.html to http://www1.eere.energy.gov/geothermal/geothermal_basics.html
• Corrected formatting/usage for http://apps1.eere.energy.gov/geothermal/projects/projects.cfm/ProjectID%3D108
• Corrected formatting/usage for http://oee.nrcan.gc.ca/publications/infosource/pub/home/heating-heat-pump/gsheatpumps.cfm
• Corrected formatting/usage for http://carsologica.zrc-sazu.si/downloads/392/Sass.pdf
• Added archive https://web.archive.org/web/20081206122801/http://www.capitalelec.com/Energy_Efficiency/ground_source/index.html to http://www.capitalelec.com/Energy_Efficiency/ground_source/index.html
• Corrected formatting/usage for http://www.econar.com/faq.htm
• Added archive https://web.archive.org/web/20150224174436/http://toolbase.org/Technology-Inventory/HVAC/geothermal-heat-pumps to http://www.toolbase.org/Technology-Inventory/HVAC/geothermal-heat-pumps

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Cheers.—InternetArchiveBot (Report bug) 15:17, 14 October 2017 (UTC)

Ground heat exchanger is a small orphan that seems to cover the same topic as Geothermal heat pump, and therefore the two should be merge towards the better article. Klbrain (talk) 23:11, 16 December 2017 (UTC)

• Support Klbrain's proposal. Makes sense. I would say consider it uncontroversial and go ahead. Rehman 01:51, 24 February 2019 (UTC)

  Y Merge completed Klbrain (talk) 07:53, 7 April 2019 (UTC)

Hello fellow Wikipedians,

I have just modified 2 external links on Geothermal heat pump. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

• Corrected formatting/usage for http://www.epa.gov/etv/pubs/600etv06063.pdf
• Added archive https://web.archive.org/web/20080222100703/http://www.dsireusa.org/searchby/searchtechnology.cfm?&CurrentPageID=2&EE=1&RE=1 to http://www.dsireusa.org/searchby/searchtechnology.cfm?&CurrentPageID=2&EE=1&RE=1

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Cheers.—InternetArchiveBot (Report bug) 00:08, 26 January 2018 (UTC)

In addition to the above, the link to the openthermal website (currently link #45), while not broken (and therefore I would guess not detectable by the bot), does not go to anything having to do with geothermal heat pumps. It's supposed to link to a 2012 or so Maryland study, which I couldn't find with a quick search. Mcswell (talk) 20:44, 21 July 2022 (UTC)

The claim is made that ground source heat pumps can achieve a COP of 3 to 6. 3 I believe. 6 I do not, or at least not for any commercially available equipment and not for any real life building , because, if achievable, delta T would have to be extremely low. The link provided does not contain anything about COP. I will remove the line after a week if not substantiated. Nakashchit (talk) 22:25, 21 April 2018 (UTC)