ABSTRACT
Waste heat is available from gaseous, vapour, liquid or solid sources. Examples of gaseous or vapour sources include combustion products and extract air from buildings or processes such as drying plant. These sources will contain sensible heat and often a significant quantity of latent heat from associated vapours. The latent heat content can significantly increase the potential energy of the source. In liquid form, heat is available from process effluents example from washing processes, condensed liquids in chemical processes, cooling liquids or condensates from steam systems. Waste heat from a solid source may be the heat contained in a heated workload which is allowed to cool after its process cycle, the heat being lost to atmosphere representing a potential source for heat recovery. The heat content of a waste source can often be calculated from direct measurement of its flow rate and temperature, combined with a knowledge of its composition.
