Research On Solar-air Source Heat Pump Heating System For Low Energy Houses In Alpine Regions

In a new development period,energy is the driving force for development,people’s demand for energy is constantly increasing.However,the problem of energy shortage is more prominent in Qinghai alpine regions.How to make full use of the local abundant solar energy resources has become the focus of people’s attention.However,the discontinuity and instability of solar energy cannot meet the requirement of continuous heating in winter.Therefore,this paper adopts a hyprid solar-air source heat pump heating system.Based on a low energy house in Xining City,Qinghai province,this paper studies the operating characteristics and economy of the solar-air source heat pump heating system in Qinghai alpine regions,and optimizes the key parameters of the system and analyzes the economic influence factors.First,the characteristics of natural room temperature and heat load in a low energy house were analyzed.The characteristics of year-round outdoor climate in Xining were analyzed from the hourly solar radiation intensity and outdoor dry bulb temperature.The influence of clothing thermal resistance on human thermal comfort under different indoor temperatures in heating season was analyzed.TRNSYS software was used to establish a load calculation model for the low energy house,natural room temperature and heat load characteristics of the low energy house without heating were analyzed for the whole heating season and typical days respectively.The operation principles and strategies of solar fresh air heating system and solar-air source heat pump system were introduced theoretically.Next,the mathematical models of the main components for the heating systems were established and the equipment selection was carried out.The mathematical models of key equipment were established,such as solar collectors,air source heat pump,heat storage tank,water-air heat exchanger and heat recovery device.And system control and thermal comfort models were also established.The solar collectors,air source heat pump,heat storage tank and circulating water pumps were calculated and selected.Then,the operation characteristics of solar-air source heat pump system were studied.Based on the established mathematical models of the main components of the system,appropriate modules were invoked from TRNSYS software to establish the simulation platform of solar fresh air heating system,and the reliability of the system model was verified through measured data.Based on the reliable simulation platform of solar fresh air heating system,the simulation platform of solar-air source heat pump system was established,and the operating characteristics of the system in heating season,coldest month and typical days were analyzed,respectively.Finally,the system benefit analysis was made from the perspectives of energy saving,economy and environmental protection.Finally,the system optimization and economic influence factor analysis of solar-air source heat pump system were carried out.Based on the simulation platform of solar-air source heat pump system,the solar fraction,system COP and annual cost value were taken as evaluation indexes,respectively.Orthogonal analysis method was adopted to optimize the system based on three key factors,namely collector area,collector installation angle and tank volume,thereby determining the optimal combination.Based on the determined optimal combination system,the influence of equipment price and energy price changes on the economy of solar-air source heat pump system was analyzed.