Study On Thermal Performance Of Passive Solar Building Along The Coast Of Huanghai Sea And Bohai Sea

In the development of offshore spaces like island, coast and offshore cities, passive solar buildings are chosen for fully utilizing advantaged solar energy resource and resolving a series of economical and technological problems caused by the general energy supply for offshore buildings. That leads to obvious economic and environmental profits, and also has significant social meanings.Huanghai Sea and Bohai Sea coasts are located at cold area of the South Temperate Zone with ocean and monsoon climate. The annual thermal comfort level of passive solar buildings in this areas needs to be improved, especially the indoor overheat problem commonly exists in summer, which is one of the main reasons blocking the popularization of passive solar buildings. Therefore, study on the thermal performance and building design methods for passive solar buildings in Huanghai Sea and Bohai Sea coasts helps to provide the scientific basis for effectively solving energy supply and thermal comfort problems for offshore buildings, and promote the development of offshore space.Based on the former research and thoughts and considering the insulation demand in winter and eliminating the overheat problem in summer, the combined control with both inner rolling blinds and temperature-control vents is proposed to regulate the annual thermal environment in passive solar buildings. The rolling blinds in massive wall can be used for both insulation in winter and shading device in summer. The opening of vents in different places can be control the flow direction for heating or cooling room air. This kind of prototype test cell using above control measurements was designed and built, and the experiments comparing the insulation performance in winter and cooling effect in summer were carried out under ocean climate. The study results show that the use of both inner rolling blinds and temperature-control vents can decrease the radiation heat loss from massive wall and improve indoor thermal comfort in winter, and in summer eliminate indoor over heat. The indoor air temperature is below 29℃at the most of time, lower than the upper temperature limit of nor-air conditioning room. The optimal cooling pattern is dropping down the blinds in daytime and rolling up it at night. The outer vents are open for the whole day and inner vents are automatically controlled.Under the optimal operation pattern, the dynamic thermal process of the passive solar house is experimentally studied. The main factor influencing indoor air temperature is distinguished with the partial correlation method, and the improvement of building thermal performance is also analyzed. The heat charge and discharge of massive wall and natural convection characteristics of building are quantitatively discussed. Comparing with the theory of natural convection in the vertical plate, the empirical formula of natural convection coefficient in air gap is obtained.Based on dynamic thermal network and Frequency- Domain Regression method, the mathematical model for the whole passive solar building under combined control methods is firstly developed. This model considers the natural convect ions of the open and closed air gaps in the massive wall, transient heat conduction of wall, solar radiation and heat radiation exchange between envelops and so on. The air temperature in the gap can be determined by the exponential formula under heat balance analysis. The natural convection coefficient in open air gap is given from the experiment data. The developed program is iteratively solved. By comparison, the simulated results with the experimental agree well with each other, which validates the availability of mathematical model.The parameter analysis and optimal design of passive solar building in ocean climate is further discussed with the validated model. The simulated results illustrate that increasing the thickness of air gap will improve indoor air temperature, and increase the possibility of backflow of indoor air through the vents. The appropriate thickness is 0.3m. Under the fixed surface area of massive wall, the effective heat supply gets to the maximum as the width -height ratio is 1/4. The inner rolling blinds is closed to glass cover can improve the insulation level of close gap at night in winter.