Heat recovery opportunities in UK industry

A database of the heat demand, and surplus heat available, at United Kingdom industrial sites involved in the European Union Emissions Trading System, was used to estimate the technical potential of various heat recovery technologies. The options considered were recovery for use on-site, using heat exchangers; upgrading the heat to a higher temperature, using heat pumps; conversion of the heat energy to fulfill a chilling demand, using absorption chillers; conversion of the heat energy to electrical energy, using Rankine cycles; and transport of the heat to fulfill an off-site heat demand. A broad analysis of this type, which investigates a large number of sites, cannot accurately identify site level opportunities. However the analysis can provide an indicative assessment of the overall potential for different technologies. The greatest potential for reusing this surplus heat was found to be recovery at low temperatures, utilising heat exchangers; and in conversion to electricity, mostly using organic Rankine cycle technology. Both these technologies exist in commercial applications, but are not well established, support for their development and installation could increase their use. The overall surplus heat that was technically recoverable using a combination of these technologies was estimated at 52PJ/yr, saving 2.2MtCO2e/yr in comparison to supplying the energy outputs in a conventional manner. It is thought that a network and market for trading in heat and the wider use of district heating systems could open considerable potential for exporting heat from industrial sites to other users.