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Combined Heat and Power (CHP) for existing buildingsJanuary 2008

BSRIA's guide to CHP for Existing Buildings is now available from the BSRIA Bookshop.

Combined Heat and Power (CHP) also known as co-generation, is the simultaneous generation of both usable heat and electrical power from the same source.

CHP had developed into an established technology and has become a key part of UK government's strategy to reduce CO2 emissions. The government has set a target of 10,000 MWe (Megawatt electrical) of good quality CHP capacity to be installed by 2010. This includes industrial plants, district heating and CHP in buildings. The quality is being monitored by the CHP Quality Assurance programme (CHPQA), which began in 2001.

CHP systems are most suitable for applications where there is primarily a significant year-round demand for heating as well as the electricity generated by the CHP unit. These are typically applications such as hospitals, leisure centres and hotels, although CHP is installed at a wide range of sites. The CHP systems installed for hospitals represent the largest generation capacity, with a total electricity capacity of 105.1 Mwe and a heating capacity of 220.8 MWth (Megawatt thermal). This is compared with CHP in the leisure sector (44.7 MWe and 68.1 MWth) and hotel schemes (37.4 MWe and 58.8 MWth).

In the UK, the procedures for designing and installing CHP plant may differ between CHP providers. Systems are implemented based on past experience and individual perception of what constitutes good practice. The main objective for CHP for Existing Buildings is to encourage uptake of small scale CHP by assessing the practical problems and devising solutions when retrofitting existing installations. The solutions are based upon the current practice by some the main CHP providers, giving examples of schemes that have been successfully installed, together with pertinent guidance.

While this publication provides guidance on the retrofitting of small-scale CHP systems, many of the issues are the same for a first time installation. Included is guidance on the issues, both technical and operational, involved with the practical installation of such systems. This includes thermal interfacing with existing plant, effective control, and heat rejection. In addition to the practical guidance there are case studies that illustrate sites with retrofitted CHP plant.


For more information contact the BSRIA Bookshop:

Tel: +44 (0) 1344 465529
or email