Energy-saving Analysis And Multi-period Optimization Of Heat Pump District Heating And Cooling System

The heat pump District Heating and Cooling(DHC)system can utilize concentrated low-grade energy(such as air,geothermal,surface water etc.)efficiently to meet the heating and cooling demands of a wider range of users,and it is a potential way for renewable energy use.In view of the characteristics of the DHC,the energy efficiency and economic analysis were carried out,and then the multi-period optimization models were established.Finally an engineering example was used to verify the accuracy of analysis and practicality of mathematical models.First of all,the analysis of energy efficiency and economy of heat pump DHC system in practical application was the primary task in this research.The primary energy utilization rate was used as the energy saving evaluation index when the DHC system was compared with the traditional boiler heating system and the conventional air conditioning system.The main factors influencing the economy of the system were analyzed by comparing the investment and operating costs of the heat pump DHC system with the traditional cooling and heating system.Secondly,on the basis of analysis of energy efficiency and economic of the DHC system,heat pump unit(as the largest part of energy consumption and cost)was separated from the whole system.Energy-saving optimization mode and investment-operating costs optimization model of heat pump DHC system were established by the multi-period optimization theory.Finally,a sea water heat pump DHC system in the engineering example has been optimized using the multi-period optimization model.The calculation results of optimization were compared with conventional programs.The conclusion shows that the multi-period investment-operating costs optimization was the best solution when the investment and operating costs was taken into account.The multi-period optimization models of the heat pump DHC system based on the energy saving and economic analysis have been proved to be effective by practical examples.This method is significant to improve energy saving and economy of actual DHC system in terms of design and operation.