DATABASE CREATION AND ANALYSIS EXAMPLE OF RELATIONSHIP BETWEEN DWELLING UNITS AND COOLING LOAD

Basic study on thermal environment of condominium dwelling units, Part2

Abstract

 Introduction: The Japanese government has created a global warming countermeasure plan based on COP21^*1) and are targeting an approximate 40% reduction in CO2 emissions in the home department by FY 2030 compared to the levels in 2013. However, a dwelling unit design that improves the thermal environment and includes performance criteria has not yet been clarified. Based on the above, this study continues with the specimen and research method used in a previous report¹⁾ and focuses on thermal environment indicators. The following the design criteria related to insulation have been added: “period cooling load (hereafter, cooling load),” “heat loss amount (hereafter, q)” and “solar heat gain amount in cooling period (hereafter, mc)” and “eaves depth/opening height,” a Building envelope element. A database has been created to evaluate both “period heating and cooling loads”. This study aims to illustrate successful management of a large quantity of data and show analysis examples of trends in dwelling unit design elements and the design criteria related to insulation.
 Method: The data sample used in this study is obtained from the Dwelling Units of the Condominiums selected for study in the previous report¹⁾ (1603 cases). Using this sample, the validity of the indicators was verified using a Scatter Diagram of the 2 variables: the elements of the Dwelling Unit Design and the design criteria related to insulation. Next, by elimination of the external conditions from the sample and using the Scatter Diagram subject to a Differential Analysis for each orientation, the trends of an optimum Thermal Environment were verified for each element of the Dwelling Unit Design.
 Results: First, “Cooling Load” and “the design criteria related to insulation” were compared for each element of the Dwelling Unit Design using a Scatter Diagram. Consequently, the effectiveness of the indicators used for the Thermal Environment could be confirmed for each element. However, it was revealed that to perform a factor analysis, including the external conditions is necessary. Then, the external conditions were eliminated from the sample and a correlation of each element with the Dwelling Unit Design was established. Accordingly, under certain conditions, a correlation was observed between the elements of the Dwelling Unit Design and the design criteria related to insulation so that the trends for Dwelling Unit Design elements that could improve the indicator results for the Thermal Environment could be determined.
 Conclusions: We clarified the indicator validity in each thermal environment using building envelope elements. Next, we excluded external conditions and showed examples of analysis using building envelope elements to clarify the possibility of reducing the cooling load through a dwelling unit design. In the future we intend to identify the elements with largest impact by means of a factor analysis.