Indoor Thermal Performance Study Of Active Solar Building And Its Software Development

Building energy consumption is in a large proportion of total energy consumption in China. The strategy of reducing building energy consumption, in order to relatively reduce total social energy consumption, is essential to achieve sustainable development. Active solar energy heating system compared to passive solar heating one, the heating condition supplied is more stable. With economic and social development, active solar energy heating began to large-scale application. In order to ensure the stability of the indoor thermal environment and comfortable, the auxiliary heat source amount is very important and having accurate information of dynamic room temperature and load with the change of natural climate conditions is the premise of ensurance of auxiliary heat source rational allocation. Presently, to calculate the solar building energy consumption in China is the steady-state calculation method, dynamic calculation has not yet reached the practical stage. In addition, most domestic indoor thermal performance calculation softwares are mostly aimed at the general building systems, which could not apply to the calculation of solar building indoor properly. Therefore, this article did depth theoretical studies on the measured and theoretical calculated dynamic room temperatures, loads and auxiliary heat source amount of active solar buildings.This research established calculation model that can predict solar building room real-time temperatures and heat loads, and with the aid of the Visual Basic programming language visualization of the simulation program, verify the accuracy of math model results with experimental data. Using this model program, simulate the amount of solar radiation absorbed by floor, dynamic air temperatures, and loads of typical rooms. At the same time, also establish simulation software in view of solar building energy conservation and environmental protection. That could be adapted to the solar building indoor thermal performance parameter calculation. For example, in the program we used the floor radiation heating form and considered the floor concrete boundary layer absorption capability to the solar radiation. The software can predict all solar building thermal property results for different locations, in different time and different chamber extensively with the open form of database. The results are reliability and in the form of chart output, and with intuitive.From the software and the measured results we draw some conclusions that in the conditions of window-wall ratios, effective solar collector area and water tank volume of a typical room on1st January in Shenyang in sunny weather, the room heated by active solar energy needs auxiliary heat source to meet the requirement of18℃indoor air temperature. The heat load amount provided by solar heating system with the floor heating under whether the inlet temperature controlled or no controlled, are greater than50%of the room traditional design total amount. When the active solar energy floor radiation heating system is used, according to the heating design standards and the characteristics of the solar buildings, the quantity of auxiliary heat source under the controlled inlet water temperature40℃, is greater than that under the uncontrolled. At the same time, form the simulation of the floor hourly absorbs solar radiation heat with different window-wall ratios in heating period in Shenyang of China, it shows a linear relationship between the average floor heat absorbing amount from solar radiation and window-wall ratios in heating period. This study provides a reference basis for auxiliary heat source quantity on the stage of solar building design phase, so as to design reasonable auxiliary energy systems to keep the solar building working and indoor comfort in all kinds of weathers. This study has the application value and important significance to promote the development of the solar building. In Shenyang area, the radiation effect on the cooling load is far greater than the influence of difference between inside and outside room temperature that eliminates radiation influence factors (the ideal temperature difference heat transfer); during the daytime, the cooling load caused by radiation is up about3times above that by temperature difference; at night, the cooling loads from ideal temperature difference method keep a constant value almost.