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
Regulator of Social Housing publishes latest fire safety report
Covering remediation of 11 metre plus social housing sector buildings.
Apartment and Duplex Defects Remediation Bill 2024
Approved for priority drafting by Government of Ireland.
The long list with in the frame of key historical events.
Competence frameworks for sustainability in the built environment
Code of practice, core criteria consultation draft for comment.
UK Net Zero Carbon Buildings Standard Sept update
Pilot version for testing and feedback on its adoption due.
New Floods Resilience Taskforce
With a wet met office autumn prediction.
National Retrofit Hub takeover of Net Zero stage
At Birmingham UK Construction Week in October.
AT Awards 2024 finalists announced
With more to come, prior to the Awards ceremony in October.
London construction cools as hotspots appear nationally
Increases in the East of England, Yorkshire and Scotland.
ARB proposals for a new Architects Code
Announced in the shadow of the final Grenfell Inquiry report.
Combining human creativity and tech innovation now and in the future
Building automation and control systems market study
BSRIA 2024 North America BACS software & services.
Impact of digital technology on productivity in construction
New CIOB academy guidance for companies of all sizes.
Demolition and retrofit approaches in Planning Policy
MHCLG demolition and retrofit survey to inform future updates to national planning policy.
Expert taskforce to spearhead new, new town generation
Sir Michael Lyons given 12 months for recommendations.
Government policy statement on new towns
A coded vision for a new generation of new towns.