Study On Regulation Mode Of Air Source Heat Pump Centralized Heating System In Cold Regions

China's building heating energy consumption increased year by year,and the air source heat pump can achieve energy closed-circuit circulation of ecological heating and in China's coal conversion project has been promoted.The use of air source heat pump central heating system in the cold zone has attracted much attention,but unlike the traditional central heating system,the performance of the air source heat pump unit is greatly affected by the outdoor meteorological parameters and water supply parameters,and the energy consumption of the unit and the water pump energy consumption should be considered in consideration of the system energy consumption.Secondly,due to the low water supply temperature,the system is only use low-temperature terminals such as floor radiation or fan coils and the water system does not have intermediate heat exchangers.Therefore,it is necessary to study whether the regulating methods applied to the traditional central heating system is suitable for the central heating system of air source heat pump,what kind of regulating methods can make the system energy consumption is minimal,what factors affect the energy consumption of the system and how much do the factors affect the system.In this paper,the steady-state air source heat pump model is established through the EES simulation platform,in which the compressor adopts the efficiency model,the two heat exchangers adopt the total parameter method of partition set,and the throttle valve is reduced to one-dimensional insulation flow.Secondly,in order to make the unit performance close to the actual addition of frosting and defrosting loss correction and opening loss correction.The accuracy of the model is verified by comparing the measured data with the simulation data.The TRNSYS simulation platform couples the load model,the heat pump unit model,the regulating methods and the pump module to form the central heating system model of the air source heat pump.Using the model calculation and analysis,the optimal unit group control strategy is the optimal method of efficiency,which can save energy by 8.6% compared to other strategies.And according to the traditional central heating regulating modes to determine the three combination regulating methods:quality regulation-intermittent regulation,two stage variable flow quality regulation-intermittent regulation,constant temperature difference regulation-quality regulation-intermittent regulation.Select the typical cities of seven cold zones,and calculate the system energy consumption of each city in four building scales and three adjustment methods.For the two stage variable flow quality regulation,the economic flow rate to each city is calculated by Genopt software,and the decisive factor affecting the economic flow rate is the proportion of hours with a load rate greater than 40%.By analyzing the calculation results under each operating condition,the system energy consumption under the constant temperature difference regulation-quality regulation-intermittent regulation method is minimal,and the energy saving can be 8.47%to11.87%compared to other regulation method.According to the frosting map,the evaluation unit frosting degree index is put forward,according to this index,the extra work consumed by air source heat pump in each city due to frosting and defrosting can be calculated.By simulating the time-by-time room temperature under the three different regulating methods,it is concluded that in terms of heating satisfaction rate,the quality regulation-intermittent regulation method is optimal.The constant temperature difference regulation-quality regulation-intermittent regulation method is the worst,the time period of dissatisfaction is mainly concentrated in the early stage and terminal stage of heating period,when the system flow is low,but the most time of the room temperature is higher than 18? under the regulating method,and the average room temperature is closest to 20?,in general,more to meet the regulatory requirements.The cumulative energy consumption relational expression of the unit and the cumulative energy consumption relational expression of the pump were obtained by fitting the simulation result,and the relational expression was verified by a set of measured data and the simulation result of the another 5 cold rigion cities,and the maximum error of each relational expression was less than ±5%.Through analysis the index of relational expression,the average temperature of outdoor air and average water supply temperature during heating period have the greatest influence on the energy consumption of the unit,the factors influencing the energy consumption of the pumps in the three methods of regulation are different,but the building load and the number of heating hours have a great influence on the energy consumption of the pump.