Absorption heat converter and the characteristic equation method.

The term absorption heat converter comprises the general concept of a heat pump, the type I heat pump (absorption heat pump for heating or cooling) and the type II heat pump (absorption heat transformer). As the main components of these three absorption heat pumping devices are the same, it is possible to design a device which enables all modes of operation: heat pump mode, chiller mode and heat transformer mode. This heat converter can be used as chiller in summer-season whereas in winter-season it can be used in heat pump mode or heat transformer mode, depending on the available heat source. Exemplary, a waste heat driven system can cover the cooling and heating loads by operating in chiller and heat transformer mode. The heat pump mode enables to cover overload heating demand during very cold periods in an efficient way being operated by means of an additional gas fired boiler. So the heating and cooling loads of e.g. an urban district can be supplied in a resource efficient way during the whole year by only one device. At Technische Universität Berlin a prototype heat converter is constructed and tested. The performance of such a device is mainly depending on the temperatures of heat sources and heat sinks. This dependence is described with the characteristic equations of the converter. In this study it is shown how the characteristic equation method can be used universally for both general heat pump concepts (type I and II). The respective equations will be derived and discussed. For a concrete absorption device it is shown that depending on the used concept of the technical realisation of switching between the two modes the heat flows working as heat transformer differ around 4 %.