A high-efficient centrifugal heat pump with industrial waste heat recovery for district heating

The urban construction area and heating energy consumption in northern China have been increasing greatly in recent years. At the same time, a large amount of low-grade industrial waste heat is released directly to the environment in most industrial plants. To meet the district heating demands and recover the industrial waste heat simultaneously, high-efficiency centrifugal heat pumps are applied for district heating and heat recovery. A permanent-magnetic synchronous frequency-convertible (PSF) centrifugal heat pump is developed which has a much higher COP in comparison with that of conventional heat pumps. In a district heating project with waste heat recovery from industry, testing results have shown that COP of a 500RT PSF centrifugal heat pump could reach 7.1, and the total system COP of the district heating system reaches 4.8. The operating cost for one heating season is just 40.3% of gas-fired boiler heating system. The emission of Carbon Dioxide is reduced by 60.6% and 56.3% when compared with coal-fired boiler and gas-fired boiler heating system, respectively. This shows that application of PSF centrifugal heat pumps to recover the low-grade industrial waste heat for district heating are quite attractive in the north of China cities.