Study On Operation Mode Of Boiler-assisted Air Source Heat Pump Heating System

As a result of the shortage of energy development and environmental issues coming to the fore,a new development trend of replacing traditional forms of high temperature water heating with coal and oil boilers in the dedicated clean energy sector has arisen.In this general trend,air source heat pump units are commonly used.As a kind of equipment and system that,with the help of consuming a small amount of heat energy,raises the low level of heat energy in the outdoor air to a high level of heat energy and uses it,air source heat pumps have the advantages of being highly efficient,environmentally friendly,clean and energy efficient.But in the northern region when applied to large central heating there are a number of problems that arise,one of the various reasons for the low-temperature environment affects the system is unstable start-up difficulties,more likely to affect the heating to enhance the effect.The second is to seek to reduce the initial investment in the future,equipment system design is small,it is difficult to meet the extremely cold weather heating demand generated.The third large-scale outdoor machine application to achieve the existence of serious cold island phenomenon,affects the operation of the air to Air Source Heat Pump.Therefore,most of the projects need to add auxiliary heat source to compensate for the inadequate part of the unit heating.Shijiazhuang City,a small area to electric boiler auxiliary air source heat pump operation for district heating,air heat pump technology from small-scale to small-scale district heating process,due to unreasonable operating strategy,unit array of cold island effect,etc.,low operating efficiency,high power consumption problems,this research project from the project led to a long-term study of the electric boiler auxiliary air source heat pump heating system,to explore This project is a long-term study of an electric boiler-assisted air-source heat pump heating system to investigate the factors affecting the operation of the heating system and to propose a reasonable,energy-saving and efficient operation mode.Firstly,some of the operational data of the electric boiler-assisted Air Source Heat Pump when the heating system is in operation the heating period were collected through experimental methods to investigate the problems of high operating costs,low operating efficiency and high energy consumption during the operation process and to analyse the causes.Secondly,the main components of the heating system are theoretically analysed and their respective mathematical models are established.Due to the cold island effect of heat pump units affects the operation of the unit due to the site and layout,a correction coefficient for raising the issue of the cold island effect of heat pump units and a numerical simulation method is used to obtain the correction coefficient of the cold island effect as a function of the change in outdoor temperature.The correction coefficient of the cold island effect first becomes smaller and then increases with the outdoor temperature,with the smallest value of 0.75 at around-2°C,while the coefficient basically remains at 1 at 6°C and above,at which time the cold island effect has almost no effect on the heat pump heating performance.Similarly,on the basis of the past heating system,three regulation modes are proposed for the electric boiler-assisted air source heat pump heating system.All three regulation modes are mass regulation on the electric boiler side,and on the heat pump side they are mass regulation,mass regulation with phased flow change and isothermal regulation-mass regulation.The corresponding mathematical models for each of the three regulation modes were developed and programmed using MATLAB software.Finally,the three regulation modes were calculated and compared separately,using the meteorological data of the 2020 heating season,and the calculation results were: compared with the mass regulation,the energy consumption of the system operation of the mass regulation with phased flow change was decreased by 20.63%,while energy consumption of the system operation of the isothermal regulation-quality regulation was reduced by 61.71%.Compared to the other two modes of regulation,isothermal-mass regulation has a lower water supply temperature,a lower circulating water flow rate and a lower overall energy consumption.Compared to the mass regulation mode,the energy consumption of the unit is reduced by 7.72% reduces the energy consumption of the pump 65.23%,so the isothermal regulation-quality regulation has a better effect on reducing the total energy consumption of the electric boiler-auxiliary heating system with air-source heat pump.