Absorption refrigeration in buildings
Refrigerants are used in buildings:
- For heating, ventilation and air conditioning (HVAC) systems.
- To provide cooling for refrigeration.
- To provide cooling for industrial processes.
They provide cooling in a process that is essentially the same as that used in domestic fridges, based on either compression or absorption.
Absorption and compression refrigeration both work on a similar basis, in that a refrigerant boils at a low temperature and pressure, and is then is then pressurised, and condensed at a higher temperature and pressure. The process of condensing releases heat which is rejected.
In ‘conventional’ compression systems, a liquid refrigerant with a low boiling point absorbs heat from the body that is being cooled and boils in an evaporator to form a gas. The resulting gas is then compressed, which increases its temperature further. The gas is then condensed, releasing its latent heat which is rejected. The process then repeats.
However, whilst in compression refrigeration, the compression and refrigerant flow is achieved by an electrical compressor, in absorption refrigeration, compression is achieved by heating, and circulation is achieved absorbing the refrigerant into and absorber and by an electrical pump. This pump uses much less energy than a compressor.
The liquid refrigerant absorbs heat from the body that is to be cooled (in buildings this may be water that once cool is circulated back to the building) and the refrigerant evaporates at low pressure (in the ‘evaporator’). It is then absorbed into an absorber fluid and the refrigerant / absorber mixture is heated (in the ‘generator’). The refrigerant evaporates again, this time at higher temperature and pressure. The refrigerant is then condensed (in the ‘condenser’) and the heat rejected. The process is then repeated.
Double-effect absorption cooling repeats the process of heating and condensing with as second generator and condenser to increase cooling capacity.
The heat in absorption refrigeration can be gas powered, but absorption refrigeration is particularly suited to situations where ‘waste’, or other low-cost heat supply is available, such as; surplus heat from combined heat and power plant (CHP), heat from industrial processes, district heating, geothermal or solar thermal energy and so on.
Absorption refrigeration was first developed in France in 1850’s, but it was not commercially exploited until the 1920’s.
The most common combinations of refrigerant and absorbent fluid are:
Ammonia is not an ozone depleting gas or a global warming gas. However it is flammable and toxic so additional precautions are necessary in design and use.
[edit] Related articles on Designing Buildings
- Absorption cooling.
- Absorption heat pump.
- Absorption refrigeration.
- Adsorption cooling.
- Air conditioning.
- Air handling unit.
- BREEAM Impact of refrigerants.
- Chilled beam.
- Chiller unit.
- Chilled water.
- Compression refrigeration.
- Constant air volume.
- Evaporative cooling.
- Fan coil unit.
- Heat pumps
- HVAC.
- Passive building design.
- Refrigerant.
- Variable air volume.
- Variable refrigerant flow.
[edit] External references
Featured articles and news
The UK’s largest air pollution campaign.
Future Homes Standard, now includes solar, but what else?
Will the new standard, due to in the Autumn, go far enough in terms of performance ?
BSRIA Briefing: Cleaner Air, Better tomorrow
A look back at issues relating to inside and outside air quality, discussed during the BSRIA briefing in 2023.
Restoring Abbotsford's hothouse
Bringing the writer Walter Scott's garden to life.
Reflections on the spending review with CIAT.
Retired firefighter cycles world to raise Grenfell funds
Leaving on 14 June 2025 Stephen will raise money for youth and schools through the Grenfell Foundation.
Key points for construction at a glance with industry reactions.
Functionality, visibility and sustainability
The simpler approach to specification.
Architects, architecture, buildings, and inspiration in film
The close ties between makers and the movies, with our long list of suggested viewing.
SELECT three-point plan for action issued to MSPs
Call for Scottish regulation, green skills and recognition of electrotechnical industry as part of a manifesto for Scottish Parliamentary elections.
UCEM becomes the University of the Built Environment
Major milestone in its 106-year history, follows recent merger with London School of Architecture (LSE).
Professional practical experience for Architects in training
The long process to transform the nature of education and professional practical experience in the Architecture profession following recent reports.
A people-first approach to retrofit
Moving away from the destructive paradigm of fabric-first.
International Electrician Day, 10 June 2025
Celebrating the role of electrical engineers from André-Marie Amperè, today and for the future.
New guide for clients launched at Houses of Parliament
'There has never been a more important time for clients to step up and ...ask the right questions'
The impact of recycled slate tiles
Innovation across the decades.
EPC changes for existing buildings
Changes and their context as the new RdSAP methodology comes into use from 15 June.