Heat pumps, experimental simulation, heat recovery, high temperature, water vapor
Currently, improving energy efficiency becomes a main challenge for all industrial energy systems. This challenge involves an improved recovery of wasted heat generated by several industrial processes. Large energy savings and potential environmental benefits are associated with the use of industrial heat pump mainly at high temperature levels. A laboratory flexible industrial scale heat recovery system is able to reproduce the operating conditions of real case simulating energetic losses and requirements in high temperature industrial applications. The integrated heat pump is an electrically-driven vapor compression using a twin screw compressor. Water vapor has been adopted as a working fluid using a modified screw compressor to carry out a dry compression process at high temperature levels. This heat pump generates vapor using flash evaporation. A purging valve is implemented in order to eliminate non-condensable gases present in system. Experimental simulation of the start-up phase has been presented showing the non-condensable purging process and the evolution of some parameters of the heat pump. Several scenarios of industrial processes for high-temperature heat recovery (heat sources between 80°C and 90°C) and heat upgrading are numerically simulated. The presented results show the global energy savings and the environmental benefits of using water as refrigerant at high temperature levels.