- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 07 Jan 2022
Absorption heat pump
Heat pumps transfer heat from a lower temperature source to one of a higher temperature. This is the opposite of the natural flow of heat and is the same process that is used to extract heat from a fridge.
Generally heat pumps work using compression, and are powered by electricity. A refrigerant fluid is run through the lower temperature source. The fluid ‘absorbs’ heat and boils, even at temperatures below 0° C. The resulting gas is then compressed, which increases its temperature further. The gas is passed into heat exchanger coils, where it condenses, releasing its latent heat. The process then repeats.
Absorption heat pumps work on a similar basis, with a refrigerant that boils at low temperature and pressure, however, in this case, the refrigerant gas (generally ammonia) is then absorbed in a solution (the ‘absorber’, generally water) which is then heated in the ‘generator’ so that the refrigerant evaporates again, but this time at a higher pressure and temperature. It is then condensed through a heat exchanger, heating ‘cool’ return water from the building, and the process then begins again.
Other heat sources can be used, such as combined heat and power plant (CHP), solar heated water, (although this requires specialist flat plate collectors that raise the temperature of the water above that normally required), geothermal heat, district heat networks and so on.
Absorption heat pumps are most efficient when supplying low-temperature hot water, such as for underfloor heating. They may be used in combination with conventional boilers to produce higher-temperature water.
Unlike some refrigerants used in compression heat pumps, ammonia is not an ozone depleting gas or a global warming gas. However it is flammable and toxic, and so units are generally hermetically sealed rather than engineered systems and are located outside.
Absorption chillers and absorption refrigerators work on the same principal as absorption heat pumps, but with the flow of heat reversed, so that heat is absorbed from the interior and rejected to the exterior.
- Absorption refrigeration.
- Air handling unit.
- Air source heat pumps.
- BSRIA domestic hot water heat pumps testing.
- Coefficient of Performance CoP.
- Dynamic thermal modelling of closed loop geothermal heat pump systems.
- Earth-to-air heat exchangers.
- Exhaust air heat pump.
- Gas absorption heat pump.
- Geothermal pile foundations.
- Ground energy options.
- Ground source heat pumps.
- Heat pump.
- Renewable energy sources: how they work and what they deliver: Part 3: Electrically driven heat pumps DG 532 3.
- Room-based heat pumps.
- Solar-assisted heat pump.
- Solar thermal heating.
- Water source heat pumps.
Featured articles and news
The last few days, but action needed over the next decade.
80 construction leaders and companies from across the UK.
Promoting the importance of building and fire safety.
A brief run through essential training tips from a user.
A comprehensive guide from a Cohesive BIM wiki user.
From the basics to the future from our Cohesive BIM wiki.
As electrical sector feels skills shortage bite.
CIOB Academy’s course take-up inked to external factors.
Q and A with self-representing artist, Hannah Shergold.
And publishes three-year strategic plan.
Introducing changes to make it more effective from 2024.
Shortlist announced for 2023 public choice award vote.
The last of the Victorians. Book review.
An exotic name that is shrouded in mystery.
From practice to research and the business of materials.