Heat recovery for buildings
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Heat recovery is the process of collecting and re-using heat that is generated from any process where the heat would otherwise be lost (ref The Carbon Trust, 2011). This can help reduce the energy consumption of the process or the heat can be used elsewhere, reducing running costs and carbon emissions. Heat recovery devices can be used in most buildings since the majority use energy for heating, cooling, ventilation or some may house industrial processes that generate heat.
Sources of waste heat that might provide opportunities heat recovery include:
- Ventilation systems.
- Refrigeration units and chiller units.
- Power generation plant.
- Plant cooling systems.
- Hot liquid effluents and high-temperature exhaust gasses.
This 'waste' heat can be recovered and re-used for applications such as; heating water, pre-heating fresh air for building ventilation systems, drying processes, power generation, pre-heating combustion air for furnaces, boilers and so on.
Methods for heat recovery include:
- Gas (or vapour) to liquid heat exchange.
- Air-to-air heat heat exchange.
- Liquid-to-liquid heat exchange.
- Direct ducting of hot air.
- Use of steam power blowdown.
- Heat captured during phase change.
- Heat recovery from condensers.
The government document The Future of Heating: Meeting the Challenge (March 2013) highlighted the potential of heat recovery for helping reduce UK carbon emissions. In June 2013, a more detailed study was commissioned which found a total of 48 terrawatt-hours (TWh) per year of industrial waste heat across eight energy intensive industries; oil refining, iron and steel, food and drink, pulp and paper, chemical, glass, cement and ceramics. It identified 11 TWh/yr with technical potential and 8 TWh/yr with economic potential. The study identified commercially viable heat recovery for all eight industries.
 Related articles on Designing Buildings Wiki.
- Air conditioning.
- Air handling unit.
- Chiller unit.
- Coefficient of Performance CoP.
- District energy.
- Ecobuild 2016 - Making the business case for large scale retrofit investment.
- Exhaust air heat pump.
- Geothermal pile foundations.
- Heat exchanger.
- Heat pump.
- Heat recovery ventilation.
- Mechanical ventilation.
- Variable refrigerant flow.
- Zero Bills Home.
 External references
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