Talk:Heat pump

Conventional, Single-stage, 2-Stage, Multi-stage

I have been searching for an indoor thermostat for my residential heat pump. There are different thermostat models available and the selection decision is dependent upon specific system attributes. i.e. - "works with conventional systems or heat pump systems up to 2H/2C" or "Heat Pumps Multi-Stage" or "2-Stage Heat Pump Programmable Thermostat designed for a 2-Stage Heat Pump systems only." If somebody could add clarification about some typical commercial heat pump attributes, it would be of great service. 10:42, 15 May 2006

Expansion valve

I note that all descriptions of a heat pump have a simple expansion value; a throttle that obstructs flow of the refrigerant so as to lower its pressure. Theoretically this is wasteful, as it is possible to extract energy from the expansion which can then be used to offset the energy requirements of the compressor. You have to do this if you want to achieve the theoretical maximum efficiency (of about 6:1). Does anybody know why most designs don't do it? Is it because the liquid has a very low volume relative to the gas? I don't know much about how these things are designed. --Alistair

That's interesting... I didn't know there was a theoretical maximum. Some refrigeration cycles don't have an expansion valve(or AKA a throttling valve. I beleive most refrigerators only use so many feet of small diameter tubing. The length and diameter of the tubing controls the expansion. Generally the expansion valve seperates the high pressure/low pressure sides of the system. Best design practices control exactly where the refrigerant expands in the evaporator and absorbs heat. In refrigerator design the tube is sized so that all the refrigerant has evaporated at 2/3 the total length of the evap tube. If all the liquid does not evaporate, it can enter the compressor as liquid and damage the seals or something.

Generally design is equally guided by Operation and Maintenance (O&M) costs and efficiency. user:tom2146

Extra pictures + schematics link

• Dutch Useful publications on heat pump systems with drawings and explications of practically set-up systems). Notable publications with pictures include: "Warmtepompen voor woningverwarming" and "Warmtepompen- de natuur als bron van verwarming".

• Or see the direct link 1 and direct link 2

The diagram with advantages of the different systems should also be taken over from the publication noted above. The diagram is on page 18; (translation first required + wikification of table)

Include pictures of the different systems + schematics mentioned + info and pric info, ... in article. Thanks.

• UPDATE: following 2 sections have been updated with info from the brochures/folders:

Heat sources

A number of sources have been used for the heat source for heating private and communal buildings . Most commonly, heat pumps draw heat from the air (outside or inside air)or from the ground (groundwater or soil)

Ground-source heat pumps typically have higher efficiencies than air-source heat pumps. This is because they draw heat from the ground or groundwater which is at a relatively constant temperature all year round below a depth of about eight feet (2.5 m). This means that the temperature differential is lower, leading to higher efficiency. Ground-source heat pumps typically have COPs of 3.5-4.0 with little seasonal variation. The tradeoff for this improved performance is that a ground-source heat pump is more expensive to install due to the need for the digging of wells or trenches in which to place the pipes that carry the heat exchange fluid. When compared versus each other, groundwater heat pumps are generally more efficient than heat pumps using heat from the soil.

New rewrite

Following update has been done to make the article way more clear:

Heat sources

Most commonly, heat pumps draw heat from the air (outside or inside air) or from the ground (groundwater or soil) . The heat drawn from the ground is in most cases stored solar heat, and it should not be confused with geothermal heat, though the latter will contribute in some small measure to all heat in the ground. Other heat sources include water; nearby streams and other natural water bodies have been used, and sometimes domestic waste water which is often warmer than the ambient temperature.

pictures added

1 pictures as added in this article, hope its not removed:

A HVAC heat pump system

KVDP (talk) 18:38, 7 April 2008 (UTC)

I'm sorry, there are two major issues with this picture:

1) It does nothing to further one's understanding of the subject matter.

2) It is incredibly unencyclopedic (seriously, do you think there'd be a picture like this in Brittanica or World Book?)

Either issue alone would warrant removal of the image, yet it suffers both and has persisted in the article for over a year.  :(
--K10wnsta (talk) 05:16, 28 December 2009 (UTC)

Noise and popularity in residential areas

I'm pretty sure that one of the reasons more people don't use heat pumps for private use (apart from installation and initial outlay) is because of the noise these things create (which does seem to have improved lately). Would it be a good idea to include approximate decibel levels and/or reasons why heat pumps are not more popular despite their performance over other types of heating? --Skytopia (talk) 22:34, 24 February 2010 (UTC)

Noise from these devices is not a problem. You will have at least one heat pump (maybe two) in your house already. User A1 (talk)

Physics of slowly changing the temp of your ground/water source/sink

This is coming from zero background in physics or much of any science, so please forgive if this is an obvious and/or stupid question. If it has some value, however, perhaps it might also be addressed in the Entry.

If your ground-based system keeps pumping cold refrigerant into the buried pipes, and the adjacent soil is giving up heat to bring that liquid back up to 55 degrees, then the adjacent soil must also be cooling down.

I certainly understand that the great mass of the planet will not be bothered by one gallon of ice water dumped on the ground. But what about a home (or huge commercial building) system, where the heat is being extracted and the adjacent soil is being cooled CONSTANTLY, CEASELESSLY.... my question is, is the Earth able to re-heat the soil adjacent to the pipes instantly, or does the adjacent soil actually get cooler and cooler, therefore less and less efficient for heat pump purposes?

Seems to me that the area around the pipes will cool, until the system shuts off and the planet can warm it back to normal. Seems to me that an installed and ever-running ground installation will just get less and less useful. By the way, ditto for the reverse, when heat is being pumped into the ground. (If I'm correct, the system will be in balance just twice a year, for a short time when the system reverses for the opposing cycle.....).

Thanks!! 66.82.9.74 (talk) 05:38, 21 March 2010 (UTC)