Abstract
Hydrocarbons with thermodynamic properties similar to synthetic fluids are alternative working fluid for high temperature heat pumps without the negative environmental impact of greenhouse gases. Though hydrocarbons have good performance as a working fluid for high temperature applications, they are constrained by high flammability. Hydrocarbons such as butane also have a high cost per kg. This study theoretically evaluates the opportunities to reduce the charge of a 200 kW hydrocarbon high temperature heat pump module that is designed for industrial applications. The theoretical analysis is based on an experimental test facility for component sizing references and design alteration possibilities. A charge reduction of 50 % was achieved from the analysis. By optimizing the design for charge reduction, an equivalent charge to the reference model has a 12.6 % increase in COP.