{"id":1446,"date":"2026-05-07T07:04:05","date_gmt":"2026-05-07T07:04:05","guid":{"rendered":"https:\/\/mywarmhome.co.uk\/newsite\/?p=1446"},"modified":"2026-05-13T10:36:04","modified_gmt":"2026-05-13T10:36:04","slug":"heat-pumps-technical","status":"publish","type":"post","link":"https:\/\/mywarmhome.co.uk\/newsite\/2026\/05\/07\/heat-pumps-technical\/","title":{"rendered":"Technical side of Heat Pumps."},"content":{"rendered":"\n
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Heat pumps move energy so we can heat our homes and provide hot water.<\/h2>\n<\/div>\n\n\n\n
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Consider a heat pump to be a heat mover, not a heat maker.<\/h2>\n\n\n\n

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The technical side of heat pumps can be somewhat confussing as grasping the idea that we create heat from cold air still baffles most of us. Hopefully this section will shed some light and hep with understanding. We also include some regulations and the “best practices”.<\/p>\n<\/div>\n<\/div>\n\n\n\n\n

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The Science.<\/h2>\n\n\n\n
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To understand how heat pumps work, we need to cover some basic physics. At a temperature of 0\u00b0C (273 K) and a pressure of 1 atmosphere (average sea level pressure), water freezes. <\/p>\n\n\n\n

This condition is known as \u201cStandard Temperature and Pressure (STP)\u201d. While temperatures can drop below 0\u00b0C, the theoretical lowest possible temperature is called absolute zero. <\/p>\n\n\n\n

At absolute zero (0\u00b0K*, -273.15\u00b0C, or -460\u00b0F), there is no molecular motion and no heat energy within the medium. <\/p>\n\n\n\n

This understanding highlights an important fact: even when it feels freezing outside, the air, water, and ground still contain heat energy. <\/p>\n\n\n\n

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*The kelvin<\/a> (K) is the SI base unit for thermodynamic temperature, starting at absolute zero (-273c)<\/semantics><\/math> this is where all molecular motion ceases so anything above this movement exists and with movement temperature exists.<\/semantics><\/math><\/p>\n<\/blockquote>\n\n\n\n

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The key is finding a way to extract that heat and transfer it to a usable medium, such as radiators.
This is where refrigerants come into play. Instead of water circulating within the heat pump (like we would have in a gas boiler), a refrigerant (see below) is used.<\/p>\n\n\n\n

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These refrigerants absorb heat from the outside environment, even at low temperatures, and their temperature increases as they change state. <\/p>\n\n\n\n

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Heat pumps come in three main types: <\/h2>\n\n\n\n
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Air Source<\/strong>. (ASHP)<\/p>\n\n\n\n

Water Source<\/strong>. (WSHP)<\/p>\n\n\n\n

Ground Source<\/strong>. (GSHP)<\/p>\n\n\n\n

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Although their setups and installation methods differ, they all operate on the same fundamental principle: transferring heat from one place to another using a refrigerant cycle.
Once you grasp the physics of this cycle, understanding how heat pumps function becomes straightforward..ish.<\/p>\n<\/blockquote>\n\n\n\n

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Manifold Chamber GSHP<\/figcaption><\/figure>\n\n\n\n
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Coils for WSHP<\/figcaption><\/figure>\n\n\n\n
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ASHP<\/figcaption><\/figure>\n<\/figure>\n\n\n\n
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How it works! All heat pumps. <\/h2>\n\n\n\n
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Heat pumps move heat from the selected source into a building through a refrigeration cycle. Whether its air, ground or water they all work on the same principe but with different installation techniques.
ASHP<\/strong> use units outside that look like air condition units (they basically are).
WSHP<\/strong> use coils or matts submerged in water and GSHP<\/strong> use horizontal loops spread over a open space at a depth of around 2m or vertical loops bored deep at around 100m.
The heating side is the same and designed to suit the property and personal preferences. <\/p>\n\n\n\n

Properties need to be well insulated to reap the full benefits and cost savings. Radiators should ideally be a size and rating to match the system and property requirements. The delta rating<\/a> of radiators is becoming more important in the system design.
Most new builds and retrofitted properties opt for underfloor heating systems, as they naturally run at a lower temperature.<\/p>\n\n\n\n

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A radiator\u2019s delta rating<\/a>, or Delta T, is the difference in temperature between the water circulating in a radiator and the room temperature. It\u2019s calculated by subtracting the average room temperature from the average radiator temperature. <\/p>\n\n\n\n

For example, if the radiator water temperature is 70\u00b0C and the room temperature is 20\u00b0C, the Delta T is 50\u00b0C<\/p>\n\n\n\n

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Now that you know a bit about Delta T, you can see how important it is to size a heating system correctly for your home.
If the heat pump is too small, it will have to work too hard and may struggle to keep up.
If it\u2019s too large, it will use more electricity than necessary.
The aim is to find the right balance between comfort and running costs, something that\u2019s possible with good design and by using the system the right way.<\/p>\n\n\n\n

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It works a bit like a fridge in reverse:<\/h2>\n\n\n\n
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