Development of Dual Compressor System using Compressor Combined with Expander for CO_2 Heat Pump Hot Water Heating System

摘要

In order to prevent the global warming, reduction of CO_2 emissions, including the emissions from the domesticrnsector, on a global scale is required. In regions with cold climates, such as Europe, hot-water room heating,rnpowered by fossil fuel-burning boilers, composes the majority of energy consumption for heating. One of the CO_2rnheat pump hot-water heating equipment’s features is that it is capable of delivering high-temperature hot waterrnequivalent to that provided by the boilers. By focusing on this feature, we have aimed to construct high efficiencyrnCO_2 heat pump that can replace boilers to reduce CO_2 emissions through the reduction of primary energyrnconsumption. Thus, we constructed a compressor combined with an expander and the hybrid density proportionalrncontrol technology to develop high-efficiency heat pump system control, and enabled 15% improvement of anrnannual coefficient of performance (COP).