Evaluation Of Solar Heating Potential And Development Of Design Software For Combined System With Air Energy

Currently,the heating system of buildings is still dominated by the fossil fuel-based boilers in China.As a result,the emissions of carbon dioxide and air pollutants lead to environmental pollution and related respiratory disease,which are getting worse.Clean energy heating is one of the primary means of improving air pollution.For people living in northern China,they are eager to improve their living conditions through achieving clean heating.As a renewable resource,solar energy has become an integral source of energy of the clean heating because of its clean and pollution free characteristics.Considering the instability of the solar,the solar heating system together with other heating sources is generally combined to form a hybrid heating system.For rural buildings far away from the urban heating network,the decentralized air-source heat pump heating is the dominant system during the clean heating reconstruction.But the air source heat pump has the defect of repeated frost and melting frost in cold weather,resulting in high energy consumption and poor indoor comfort.Hybrid heating systems focus on respective strengths of solar energy and air source heat pump,which can make up for their lack of independent operation,and meet the heating needs of rural buildings.Hybrid heating system is one of the rural clean heating alternatives.However,in order to economically and reasonably design and develop the solar-air hybrid heating systems,we need to understand the available solar energy resources on different rural building roofs and a convenient software which can be applied to design simulate the hybrid heating system.Therefore,this dissertation studies the potential of the solar energy resources on rural building roofs and develops the design simulation software for engineering applications.In this study,the GIS spatial analysis method is used to establish a model to evaluate the solar thermal potential on building roofs firstly.Taking Caishi town buildings in Jinan,Shandong Province,as the research object,the solar thermal and solar energy resources available for the roofs of existing local buildings are evaluated in terms of theoretical potential,geographical potential and technical potential.The results show that for the existing residential buildings with 3,5 and 6 floors in Caishi Town,the proportion of the daily average solar energy collected on the roof to the building heating load is 40%,24% and 20% respectively,which has the potential to use solar energy for auxiliary heating source.For the residential buildings with 17 and 18 floors,the daily average heat collection on the roof only accounts for 6% of the building heating load.Therefore,for the residential buildings with lower than 6 floors,the solar energy can be considered to be an auxiliary heating source.Then,solar-air hybrid systems connected in parallel is built for new rural communities.Meanwhile,the mathematical models and control strategy of the main equipment of the system are established,and the system design simulation software is developed.Java language is used to develop the design/simulation program with a user-friendly software interface.The software makes it easier for users to operate in the form of dialog box,and makes the engineers and technicians avoid complex theoretical derivation and calculation.The engineers and technicians can easily carry out equipment selection and optimization design of hybrid system.The software has two main functions: one is to simulate the overall performance of an existing or designed solar-air hybrid heating system based on the life cycle analysis method;the other is to optimally design the solar collector area according to the range of collector laying area and given design temperatures.Finally,this paper selects an actual project to design the solar-air hybrid heating system and simulate the system performances using the developed software.At the same time,the developed model of the parallel hybrid heating system is also built in the TRNSYS platform.The simulation results of TRNSYS are compared with the simulation results of the design simulation software developed in this paper.The error between the two programs is within the acceptable range.Through the development of the simulation software,the visual operation of the solar-air hybrid heating system design is realized,which can provide a reference tool for the engineering designers.