Abstract
A 20 kW heat pump test rig has been built to investigate and validate heat delivery up to 110 °C using a vapour compression cycle. The heat pump is a cascade cycle with propane as the working fluid in the low temperature cycle and butane in the high temperature cycle. The technology will recover low temperature (30 °C) waste heat from industrial processes and upgrade to high temperature heat for applications such as drying, sterilization, pasteurization and other heat demands within 100 – 120 °C. The heat pump will replace equivalent capacities of existing cooling towers and boilers or direct electricity heating systems in the industry. A modified compressor prototype was implemented for the high temperature cycle and was found to have an average total compressor efficiency of 71 %. The heat pump had a heating COP up to 2.6 and a combined heating and cooling COP of 4.1 for a temperature lift of 80 °C.