Solar Fraction In Heating System Of Residential Building In Northwest Of China

Solar energy is a renewable energy and draws more and more attention,for it is great,clear,and can be used for a long time and so on,comparing to conventional energy.Although there are already many research overseas about the solar energy heating system and the solar fraction,the law and the scope of the solar fraction under the conditions of the combination of different parameters by using the dynamic simulation software are few.In view of this,this paper studies the rules of the solar fraction under the parameters through numerical simulation.Specific research contents include the following several aspects:In the establishment of mathematical models,several sub-models in solar hot water heating system were involved,including the building dynamic thermal analysis model, the collecting,storing,as well as auxiliary heating system model.Parameters which have the impact on the efficiency of the collecting and storing respectively were summed up;Energy equilibrium was analyzed to the solar energy system,combining function sectors of various thermal parts in a cycle,and the energy equilibrium equation of the dynamic cycle of solar systems has been gained.The relationship between solar fraction and all parts of the energy were talked about。And the relationship between the energy consumption for heating and building heating load were analyzed qualitatively. Heating energy consumption and the running ways of the auxiliary heating systems also explained.Building heating load was simulated and calculated,and its law was analyzed under different meteorological parameters,different insulation conditions and storey of the building,and calculation results showed under the same simulation conditions,solar fraction of Lhasa is the highest among three cities is due to its high solar irradiance and relatively low heat loads and when insulation conditions and the floor number are certain,solar fraction will be improved if the window-wall ratio is increased.The heating load of conventional single-storey house with or without sunspace-attached room in Lhasa city also was studied,according to the simulation results,the roof of conventional single-storey house in Lhasa may completely meet that the heat loads need when the solar fraction reaches 100%.And the collector area of active solar heating system will be obviously reduced if the house is insulated and sunspace-attached room is set up.Some valuable referential data are given about engineering in Lhasa,Xi'an,and Xining.And proposals related were put forward,which have the practical significance on optimal design of systems.