THE USE OF SOLAR DESIGN DAYS IN A PASSIVE SOLAR HOUSE CONCEPTUAL DESIGN TOOL

Traditional passive solar house design is cumbersome because of the effort required to vary the design parameters and interpret performance results. When this process is aided by building simulation software, the designer is not given adequate feedback on the relationships between key design parameters and their effects on passive solar performance. To improve the efficiency of the design process, the use of solar design days (SDDs) is explored. The days represent a cold sunny, cold cloudy, and warm sunny (shoulder season) day for the climate of interest. Unlike traditional equipment-sizing design days, the SDDs are used as performance indicators. Limiting the period that is studied can put the designer in touch with exactly how the window size, window type, thermal mass, and effective envelope U-value affect performance. While energy performance is a key metric, thermal comfort is also important. The warm sunny day will allow the user to prevent overheating and reduce cooling loads. Since there is a good correlation between cold sunny day performance and annual performance, it is adequate to design a house based on cold sunny day performance alone in the early design stages. This paper will explain how SDDs can be used as a tool to design passive solar houses and the associated methodology.