Heat pump modelling

In this chapter, detailed consideration is given to some of the established approaches for constructing mathematical models of heat pump systems, either for use in standalone modelling applications (eg, for implementation in a spreadsheet) or for embedding into a parent simulation code. The treatment is limited to ground-source heat pumps (GSHPs) and, as such, the focus is on liquid-source and water-sink systems (ie, hydronic heating). Section 14.2 considers the steady-state modelling of conventional vapour-compression heat pumps by considering each of the cycle components in turn followed by a practical application example in which the component models are drawn together into a complete plant simulation. Special consideration is given to the steady-state modelling of single-effect absorption cycle heat pumps in Section 14.3. The focus is on the aqueous lithium bromide and water cycle because of its superior performance when using intermediate grade sources such as ground and ground water. In Section 14.4, consideration is given to the use of heat pump models using regression fitting to experimental, field and manufacturers' performance data. Finally, Section 14.5 gives detailed consideration to fully dynamic approaches to modelling heat pumps in which the primary interest is control system design and stability. In each section, a practical interpretation of the modelling methods described is provided by means of a practical illustrative example.