twin screw compressor, heat pump, industrial heating
In industrial applications, 90-150? hot water needed during production processes is traditionally provided by fuel-fired boilers. The usage of fuel-fired boiler has a low efficiency of energy use and potential danger of explosion. 30-60?waste water with large amount of energy is rejected to environment directly, which causes a great energy loss and thermal pollution. Seeking for a much high efficiency and safe heating pattern is essential to replace the boilers used now. High temperature heat pump is an ideal solution to recover the heat in waste water and to produce hot water needed. It has a higher efficiency than boilers through the use of energy contained in waste water. Water temperature provided by high temperature heat pump reached to 90-120?. In this paper, an industrial high temperature heat pump with twin screw compressor was developed. Optimized heat pump cycle was made and heat exchangers were designed for using in specific workplace. For operating at high condensation and evaporation temperature safely, the twin screw compressor used in high temperature heat pump should be modified, like the changes of inner volume ratio and motor capacity. Discharge temperature was regulated by liquid injection and oil cooling system. Moreover, extensive experimental tests were carried out under several working scenarios and the results showed high temperature heat pump can fully meet the requirement in industrial field to supply 90-120? hot water with excellent system performance.