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Text and/or other creative content from this version of Heat pump was copied or moved into Renewable energy with this edit on 19 Jun 2015 10:42. The former page's history now serves to provide attribution for that content in the latter page, and it must not be deleted as long as the latter page exists.

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How to reduce duplication with the air source heat pump article?

Possibly excerpts - if so how -if not what do you suggest? Chidgk1 (talk) 11:12, 11 September 2023 (UTC)

COP variation with output temperature

I moved the below table here for discussion because the sources are more than 10 years old so I suspect it is not really useful for readers;

Chidgk1 (talk) 16:22, 13 September 2023 (UTC)

I noticed the multiple edits you made to the article, concluding with removal of the above Table on the grounds that the sources are more than 10 years old. Misplaced Pages has no guideline or recommendation that text or other information should be removed when the supporting sources reach 10 years old.

There are likely to be many Users who have an interest in this article, and an interest in this Table. By removing the Table you are showing that you think the views of such interested Users are irrelevant. Misplaced Pages doesn’t work that way. That is the reason we have a Talk page for each article.

I suggest you restore the above Table to the article, and use this Talk page to explain your view as to why you think removal of such a large amount of information is warranted. You might be pleasantly surprised at the views expressed by others. If nobody comments, or nobody objects after, say a couple of days, you can remove the Table with some justification because you gave interested Users the opportunity to see your point of view, and to give you their point of view. Dolphin (t) 06:09, 14 September 2023 (UTC)

@Dolphin51: If you or anyone else wishes to restore the table of course you are welcome to do so to do so under the principle of WP:BRD.

The table may well have been useful when it was first added, but here are a few reasons why I think it is no longer useful:

1) In many Misplaced Pages articles a table with sources over 10 years old would be fine, so you are correct that "Misplaced Pages has no guideline or recommendation that text or other information should be removed when the supporting sources reach 10 years old" and I am fine with that. However in this case the technology has advanced quite a lot since those days, so the numbers in the first 6 rows of the table are no longer reliable.

2) The rest of the table (last 4 rows) are theoretical limits but it is difficult to check whether those rows are correct as it is hard to find out how they have been calculated as they are not cited.

3) The refrigerant propane is not mentioned in the table.

I would be happy to discuss this further with you or anyone else as I am not an expert on the subject Chidgk1 (talk) 06:32, 14 September 2023 (UTC)

@Chidgk1:: Thanks for your response. I will comment on your three observations:

1) Misplaced Pages is not a design manual so no professional engineer should be using this Table for the purposes of designing a space heating system in a home or building. The first-mentioned COP in the Table is 2.2 and this is valuable information. The latest technology may have changed that to 2.7 or 3.2 but that is of secondary importance. The primary information is that an ASHP taking air from -20 to +35 has a COP of around 2. It isn't zero and it isn't 5, whereas other COPs in the first six lines in the Table are as high as 7.2. If you believe it would be useful for this article to provide more current data, the appropriate step would be to update the Table, not remove it.

2) Three of the rows in the Table are theoretical limits associated with a Carnot cycle operating between the nominated temperatures. You have written that it is hard to check this information because the method of calculation is not cited. That is incorrect. The method of calculating these Carnot COPs is presented at Coefficient of performance#Theoretical performance limits. For example, COP of the Carnot cycle that goes from -20 to 35 is calculated as follows: The temperature range is -20 to 35; a difference of 55 degrees C (55 Kelvin). The output temperature is 35 degrees C or 308 Kelvin. Dividing 308 by 55 yields 5.6 as shown in the Table.

3) I agree that propane is not mentioned in the Table. Neither is ammonia or any of the fluorocarbon refrigerants. At least theoretically, the COP of a heat pump is not altered by the choice of refrigerant. I agree that the Table mentions carbon dioxide in the context of transcritical systems but this information would be equally valid for any transcritical system regardless of the choice of refrigerant. Dolphin (t) 13:23, 15 September 2023 (UTC)

Thanks for that useful info but I still think the average reader would just be confused by this table. For example it seems pointless having ancient numbers for "Two-stage" as readers won't know what "Two-stage" means without searching the term, and anyway I understand nowadays "variable speed" is more efficient. Such confusion might put them off reading the rest of the article. Also "In general, coefficient of performance (COP) of heat pump is determined from physical and thermal properties of the selected refrigerant....." according to https://www.sciencedirect.com/science/article/pii/S2352484720313500Chidgk1 (talk) 13:59, 15 September 2023 (UTC)

I would like a 3rd opinion - could anyone else comment? Chidgk1 (talk) 14:01, 17 September 2023 (UTC)

There is a process for requesting a third opinion - see Misplaced Pages:Third opinion. Dolphin (t) 14:05, 17 September 2023 (UTC)

Have requested - by the way https://www.technologyreview.com/2023/02/14/1068582/everything-you-need-to-know-about-heat-pumps/amp/ says R410a more efficient in cold Chidgk1 (talk) 10:45, 18 September 2023 (UTC)

You have quoted "In general, coefficient of performance (COP) of heat pump is determined from physical and thermal properties of the selected refrigerant....." Sadly, this sentence is highly misleading. It suggests the choice of refrigerant is a primary determinant of the COP. Properties of the refrigerant may have a minor effect on the COP but the primary determinants are the temperature of the heat source, and the temperature in the space being heated - that is why, with any heat pump, the COP reduces as time passes and the temperature rises in the space being heated. See Heat pump#Principle of operation where it says "As the temperature of the interior of the building rises progressively to 300 K (27 °C) the coefficient of performance falls progressively to 9." (The COP changes even though the refrigerant in the heat pump never does.)

Carnot's theorem includes the sentiment that every reversible heat engine operating between the same heat reservoirs has the same thermal efficiency, regardless of the working fluid. A corollary of this theorem can be applied to heat pumps and it would say that every reversible heat pump operating between the same heat reservoirs has the same COP, regardless of the refrigerant. The reason that the choice of refrigerant has a small influence on the COP of a real heat pump is simply that real heat pumps are not reversible; they have irreversibilities that render their COPs slightly lower than the COP of the equivalent Carnot heat pump. Dolphin (t) 12:21, 18 September 2023 (UTC)

The above Table was first inserted on 29 March 2008 by User:Ralph Purtcher. See the diff. The Table was then substantially expanded on 19 April 2008, again by Ralph Purtcher; see the diff. Purtcher has not edited on Misplaced Pages since November 2022. Dolphin (t) 07:33, 22 September 2023 (UTC)

Response to third opinion request:

The content of this table seems overly complicated for the general reader. WP:TECHNICAL allows for this type of info to be included in Misplaced Pages articles but also instructs editors to make this content understandable to less knowledgeable readers. For example, the COE table in this article provides some of the same information but does not require the reader to understand variations in equipment type. That might be a good compromise for future edits to this article. However, I don't think we need to spend a lot of time debating whether or not the table is too technical, because its content is dated. Technology data that is over ten years old is rarely going to be accurate or helpful in today's fast-changing design environment. I found newer DOE publications that seem to provide different data. It is beyond my ability to understand but I can tell that the numbers seem to be different. Thus, I recommend either updating the table or removing it until someone else (with expertise in this area) can look at the info. Rublamb (talk) 22:50, 1 October 2023 (UTC)

@Dolphin51: As you are obviously more expert in the subject than me perhaps you would like to update the table? Chidgk1 (talk) 07:18, 2 October 2023 (UTC)

I have deleted it for now. Anyone thinking of updating it please consider the useful comments by Dolphin51 and Rublamb above - thanks Chidgk1 (talk) 12:59, 4 October 2023 (UTC)

The third opinion did NOT recommend or condone removal of the Table. User:Rublamb wrote that they recommended “either updating the table or removing it ....” Particularly notice the use of the word “either”. I will restore the Table to the article.

This thread began when Chidgk1 wrote “sources are more than 10 years old so I suspect it is not really useful for readers.” Chidgk1 provided no explanation or clarification to support this claim. The suggestion that Chidgk1 suspects it is not useful for readers invites several obvious questions for which Chidgk1 provides no answer. For example, if the Table provides no useful information for readers, what are these readers using the Table for? Are they designing the air conditioning systems in high-rise buildings and they need up-to-date information on which to base their designs? Are they delivering lectures to classes of engineering students in the field of ventilation and air conditioning? Obviously NO to these.

When Rublamb provided the third opinion they copied and pasted Chidgk1’s description of the Table as being out of date etc. Sadly Rublamb did not notice that Chidgk1’s claims were entirely unsupported. Rublamb repeated Chidgk1’s claims the way a parrot repeats the suggestion that Polly wants a cracker. Rublamb’s opinion shows little or no inquisitiveness about Chidgk1’s claims that the Table is no longer useful to readers.

The Table shows trends in the typical values of COP across each row: as temperature difference increases COP decreases and that is a very useful observation for readers. New technology won’t change that. Similarly trends are evident in the vertical columns; these trends are very useful and technological changes won’t alter them. The ideal COPs associated with the Carnot cycles are timeless and will never be altered by changes in equipment.

Who are these readers who need up-to-date information on heat pump equipment, and why are they coming to Misplaced Pages to obtain it? How does Chidgk1 know what they need with such authority that he can decide on their behalf that they are best served by removing the Table? Dolphin (t) 15:25, 4 October 2023 (UTC)

Chidgk1 wrote “more than 10 years old so .... it is not really useful for readers.” There are several obvious questions that come to mind after reading that claim. eg who are the readers and what are their objectives in looking at this Table?

Sadly Rublamb did not see the need for any answers, or at least did not ask any questions. Rublamb, in their opinion, wrote “Technology data that is over ten years old is rarely going to be helpful” This is the same sentiment. Instead of being curious about the validity of Chidgk1’s sentence, Rublamb just repeated it, leaving the obvious questions unanswered. Ideally, a third opinion is an incisive, critical response, demonstrating some penetrating thought processes. Dolphin (t) 15:49, 4 October 2023 (UTC)

@Dolphin51: So does that mean you or someone else is going to update the table? Chidgk1 (talk) 17:03, 4 October 2023 (UTC)

@Rublamb: I am not an expert on heat pumps or readability but I do have some knowledge of both so if you have any questions I will be happy to answer them to the best of my ability. Or should we ask for a 4th opinion which is an "incisive, critical response, demonstrating some penetrating thought processes"? If so I think it would be best if @Dolphin51: and I agreed beforehand to accept the 4th opinion to avoid wasting the time of your group. Chidgk1 (talk) 17:13, 4 October 2023 (UTC)

@Dolphin51, As someone who volunteered their time and spent well over thirty minutes researching and reviewing this topic in order to provide a third opinion, I find your comments offensive and completely against the spirit of this dispute resolution process. It is fine to disagree with my opinion but it is not appropriate to turn this into a personal attack.

I first read through this 3O request last week but decided not to take it on. with hopes that some with expertise might be available. However, when no one else helped and the request was reposted, I decided to give it a go. do have a science background (geology), worked in that field, took two semesters of college physics, and have been responsible for museum HVAC systems, so I can read scientific and engineering articles with some degree of understanding. Before writing my response, I looked at six different sources, including U.S. Department of Energy guidelines for heat pumps. I did not find any current source that had the same data set as the table in question. That is what led me to believe that this content in out of date. That being said, you may well be able to find a 2023 DOE info or fact sheet that includes this exact table and would, therefore, be able to simply update the source. Or, you might find slightly different data and decide that an update would be useful.

For the record, I did not cut and paste anything from the discussion above. In fact, I did not even re-read your discussion after conducting research and beginning to draft my response My response cited MOS, providing guidance that I believe was lacking in your discussion. I also provided an exmaple of another way to present this type of data that would be more user-friendly. I used the phrase "more than ten years old" because, in fact, when I checked, every single source for this table was published more than ten years ago. I guess I should have been more precise, coming up with an average; let's just say all sources were published eleven to thirteen years ago, and many have been removed from the Internet.

My suggestion was to remove the table or publish an updated version. Updating means refreshing data and providing current sources. Notice I did not suggest retaining the table as is as a third option. That was intentional as I do not support that option for the reasons stated. @Chidgk1, with regards to finding an expert, none of the conflict resolution processes of Misplaced Pages provide or guarantee an expert in the subject matter. What you typically get is an experienced editor with a basic understanding of Misplaced Pages's guidelines and mission, as well as a reasoned response. If you believe this topic requires an expert, please take it to WikiProject Engineering or WikiProject Electrical Engineering. However, I ask both of you to consider that if an expert is needed to interpret and moderate a decision on this topic, then the table may be conveying information that is too technical and too dense for Misplaced Pages. Asking who the audience is for this information is a really good start. Best of luck. Rublamb (talk) 20:12, 4 October 2023 (UTC)

Chidgk1’s question at WP:Third opinion was “Should this Table be removed from the article?” This was an excellent wording to use because it cut through the various threads and asked a question that could be answered with either a Yes or No.

Rublamb’s opinion was “I recommend either updating the table or removing it.” If the Table is updated, that means retaining it in the article. Considering Chidgk1’s question in its strictest wording, Rublamb’s opinion was “I recommend either or yes.” However, Rublamb’s opinion was actually aimed at the various threads visible in the numerous edits by Chidgk1 and me.

On several occasions I have tried to make the point that this Table is a comparative table to demonstrate the manner in which COP varies with output temperature. I haven’t yet seen any acknowledgement that either Chidgk1 or Rublamb understand the significance of this observation. The first 6 lines of this Table are not presenting details of, say a Westinghouse unit versus a Mitsubishi unit, to demonstrate that one is superior to the other; it is presenting a single number to represent a generic class of heat pump, solely to demonstrate the variation in COP with output temperature. This is a bit like saying that automobiles with 6-cylinder gasoline engines travel at 72 mph whereas those with 8-cylinder engines travel at 81 mph. Clearly the former class of automobiles generally have less power than the latter and travel slower under identical conditions - updating these speeds to represent the current automobiles on the market is not going to reverse this trend.

Chidgk1 and Rublamb have both written that they have explained their reason for advocating removal of the Table but I reject that view. I haven’t yet seen a plausible and legitimate reason for removing the Table. If the Table is removed it removes some useful and valuable information that is currently accessible by readers, leaving readers with only the equation to see how COP varies with output temperature; the equation is only useful for this purpose to those with an adequate understanding of linear algebra. In the absence of the Table, variation of COP with output temperature can be calculated, beginning by examining the following equation (which can be derived using the article):

$${\displaystyle {\mathrm {COP} }={\frac {Q}{W}}}$$

This Task can be simplified by assuming the heat pump is an ideal device operating on the reverse Carnot cycle so that the equation is:

${\displaystyle {\rm {COP}}_{\rm {heating}}={\frac {T_{\rm {H}}}{T_{\rm {H}}-T_{\rm {C}}}}}$

where T_H is the output temperature.

To examine the way COP varies with output temperature I think the majority of readers will find it easier to use the Table than the Carnot equation.

I have apologised to Rublamb for my intemperate language last night.

Dolphin (t) 10:55, 5 October 2023 (UTC)

I think your suggestion to consider the readers is useful. Perhaps we can step back from this narrow question for a while and ponder the readers in the talk section below. Chidgk1 (talk) 16:33, 5 October 2023 (UTC)

References

1. ^ The Canadian Renewable Energy Network 'Commercial Earth Energy Systems', Figure 29 Archived 2011-05-11 at the Wayback Machine. . Retrieved December 8, 2009.
2. Technical Institute of Physics and Chemistry, Chinese Academy of Sciences 'State of the Art of Air-source Heat Pump for Cold Region', Figure 5 Archived 2016-04-14 at the Wayback Machine. . Retrieved April 19, 2008.
3. ^ SINTEF Energy Research 'Integrated CO₂ Heat Pump Systems for Space Heating and DHW in low-energy and passive houses', J. Steen, Table 3.1, Table 3.3 Archived 2009-03-18 at the Wayback Machine. . Retrieved April 19, 2008.

Who are the readers of this article?

I guess most of the readers of this article are either:

1) Homeowners considering buying a heat pump

or

2) Teenagers being taught about heat pumps

But I don't have any evidence to back up my guess. Does anyone have a better idea who the readers are? Chidgk1 (talk) 17:19, 4 October 2023 (UTC)

The article focuses on the practicalities of heat pumps, but it also relies in one or two places on the concept of the reverse Carnot cycle and the second law of thermodynamics. This distinction is significant for our present discussions. The Carnot cycle and the second law are high-level topics typically only taught in college-level courses in applied physics and mechanical engineering. My point is that I think this article will attract a high proportion of its readers to the practical information about heat pumps; but only a small proportion of its readers will have knowledge of, or an interest in acquiring knowledge of, these two high-level topics.

In pursuit of WP:Make technical articles understandable we must provide a path through the article that avoids Carnot and the second law. The article itself, and one or two of it’s subordinate articles, present the math associated with the Carnot cycle so we must provide a path that allows readers to side-step this math if they wish. One example is the linear algebraic equation that defines the COP in terms of two temperatures - one high and one low. The Table titled “Variation of COP with output temperature” is the means by which readers can see clearly the way in which COP varies across each row, and down each column, and thereby avoid the algebraic equation associated with the reverse Carnot cycle.

In the bottom 4 lines of the Table, readers can see the way in which COP varies in a perfect heat pump operating on the reverse Carnot cycle. In the top 6 lines, readers can see that in real, practical heat pumps, the COP varies with output temperature in exactly the same way. This is a quick and easy way for the majority of readers to absorb this information. Dolphin (t) 01:52, 6 October 2023 (UTC)

OK so I take it you agree with me about who most of the readers are. As I suspect the 2 groups have somewhat different needs I am going to start a couple more talk sections below to try and keep things clear and will reply there to your interesting points about the theory. Chidgk1 (talk) 06:42, 6 October 2023 (UTC)

What do homeowners want from this article?

I totally agree with you that very few of these readers will want the reverse Carnot cycle and the second law of thermodynamics and if they do they can click through to those articles.

By "homeowners" I also mean people with commonhold of flats. I think homeowners will need

1) The basic idea that they work like a refrigerator and are more environmentally friendly than fossil fuelled heating.

2) Overview of the types so they can rule out some of the options and click through to a more detailed article - for example someone with a small garden will rule out GSHP and likely click through to ASHP, whereas someone in a flat in a block which already has fossil fuelled district heating will likely want to (also) go through to GSHP to prepare for talking to the managers of the block or local politicians for the district.

3) A little info comparing the types so that someone with a lot of land or building their own new house can have an idea of the pros and cons of GSHP versus ASHP. For example that GSHP will likely be more expansive to install but use less electricity especially in cold weather.

4) To know that they need to decide whether they want cooling as well as space heating and whether they want water heating. But not lots of detail as that can be in the articles such as ASHP. Possibly also a link to Heat recovery ventilation for people building their own new house.

5) To know that some governments give purchase subsidies so they can then find out subsidy details either in a country level article such as Energy policy of Australia or non-Misplaced Pages national sources. Or if the incentives stay here they should be put in a table which can be split off to a new list article if it gets too big.

I may have missed something but this article should not have detail which is better put in more specialized articles. Chidgk1 (talk) 07:22, 6 October 2023 (UTC)

Oh yes I think just the most common refrigerants with a link to the details article Chidgk1 (talk) 08:02, 6 October 2023 (UTC)

I have had a number of conversations with new purchasers of heat pumps who are suspicious of claims that 1 kJ of electricity can cause significantly more than 1kJ of heat to be transferred into a house. They think this claim might contravene the law of conservation of energy; and they know it would be impossible from a combustion heater. Dolphin (t) 08:25, 6 October 2023 (UTC)

What do students want/need from this article?

Well of course they want the answer to their homework but without the person marking it complaining they copied from Misplaced Pages. Or they want the answer to the question on tomorrow's exam. However we should probably give them what their teachers/lecturers want them to learn. So I think they need a wide overview of the subject with wikilinks in case they need to drill down to details - including scientific theory, technology, environmental benefits, economics and maybe more Chidgk1 (talk) 07:42, 6 October 2023 (UTC)

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