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.
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.
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.
 Related articles on Designing Buildings Wiki
- Absorption heat pump.
- Air conditioning.
- Air handling unit.
- Chilled beam.
- Chiller unit.
- Chilled water.
- Compression refrigeration.
- Constant air volume.
- Evaporative cooling.
- Fan coil unit.
- Heat pumps
- Passive building design.
- Thermal comfort.
- Variable air volume.
- Variable refrigerant flow.
 External references
Featured articles and news
Here is our list of the top 25 buildings in London. Do you agree with our selection?
A blueprint for the construction industry from Canada's west coast.
China's elaborate idea for a mass-transport system has been abandoned.
Read this article about the theories that characterise life in the hyperreal post-modern city.
Polyisocyanurate (PIR) insulation and how it was tested.
"We can’t sustain low density suburbs, density isn't a choice, it's a necessity." - Read our interview with the award-winning social housing architect Peter Barber.
Conservation area designation can be crucial, but treatment of individual parks varies considerably.
ICE publish new NEC4 Design, Build and Operate contract.
Report states $2 trillion is needed over the next 10 years to fix American roads.
What is the client's strategic brief for construction projects?
Read the story behind the world's most iconic festival stage, Glastonbury's Pyramid Stage.
First ever BREEAM Communities innovation credit is claimed by Temple Farm Development.
Read the story of Ronan Point, another disastrous event which had profound consequences for the construction industry.
CIOB to help conservation specialists gain recognition for their expertise with launch of new Certification Scheme.
What is ACM cladding, what is it used for, and is it banned?