| With the rapid development of China's economy and the rapid growth of energy demand,the exploration of new methods of energy conservation and emission reduction has become a hot spot.In recent years,it has been widely used in China.The sewage source heat pump is to recycle waste heat resources,which is a new energy-saving technology.Aiming at the hot water system project of a college bathing center,this paper proposes a sewage source and air source combined heat pump hot water system with waste water for recycling bathing water.The system not only overcomes the shortcomings of the low energy efficiency of the air source heat pump under the cold weather conditions in winter,but also highlights the advantages of the waste heat recovery and utilization of the bath sewage and the high efficiency of the water source heat pump.Thereby reducing the influence of the external environment on the energy efficiency of the heat pump operation,and realizing the uninterrupted hot water supply of the hot water system in the cold winter.Firstly,this paper has completed the calculation of hot water system load,the selection of main equipment and system design for the operation of a university's bathing center,and monitored the discharge of bathing water in the bath center.The results showed that the bathing water and the ambient temperature change trend were basically consistent.But the tendency is more gradual.In the winter ambient temperature of about 6 ?,the bathroom can use the bath sewage temperature of about 23.3 ?.The calculation shows that the bathing water can bear about 37%of the heat of heating the tap water.Secondly,this paper starts from the air source heat pump hot water system alone operation and the composite heat pump hot water system operation.Through the analysis of the unit's water temperature,hot water tank temperature,system heating capacity,COP and other data,the operating characteristics of the hot water system were studied.The results show that when the ambient temperature is 5.5-12?.the air source heat pump operates separately,and the system heat and COP average about 1160kW and 3.1,which meets the demand for hot water supply in the bathroom;When the composite heat pump is running,the operating characteristics of the two sewage source heat pump units are compared in series and parallel under the same sewage inlet water temperature and flow rate.The results show that the average heating capacity and COP of each unit are about 82.1 kW and 3.12 respectively in series,and the heating capacity and COP of the unit in parallel are about 81.3 kW and 3.11,respectively.The difference is not very large.In addition,through the comparison of the two operating modes,the results show that the hybrid heat pump hot water system is more energy efficient in winter conditions.Although the COP of the composite heat pump hot water system fluctuated greatly,it was about 3.7,and the energy efficiency is increased by about 19%compared with the air source heat pump hot water system alone,and the energy saving effect is obvious.Finally,the comparison between the composite heat pump hot water system and the traditional hot water system is carried out in terms of economy,energy saving and environmental protection.The results show that the composite heat pump hot water system has the lowest energy consumption,and the hot water energy consumption is only 11.8kWh/t;The initial investment of the system is high,but the operating cost is low,the annual cost is 675,000 yuan,only about 38%of the oil-fired boiler,and 55%of the electric boiler;It is much smaller than other electric water heating systems.Therefore,the composite heat pump hot water system has obvious advantages in economic and environmental protection. |
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