Comparison between simplified and dynamical calculation of highly glazed spaces

Because of the EPBD (2002), the EU member states have to provide simplified calculation procedures to assess the energy performance of buildings. Highly glazed spaces (sunspaces) can have a large influence on that performance and should be implemented accurately in these calculation procedures. Because of the high glazing percentage a modified calculation procedure is required for such spaces. This paper starts with a literature review regarding the main parameters that are important for the modelling of sunspaces. The main problem is the correct estimation of the net solar gains, which requires knowledge of the distribution of the direct solar radiation over the internal surfaces of the sunspace. Three simplified calculation procedures from EN 13790:2007 (detailed and simplified) and DIN 18599-2:2007 are discussed and applied to a fictitious case study. The same case was also simulated over one year using an adapted version of the dynamical simulation program TRNSYS 16. Consequently, the resulting monthly values are compared, focussing on an accurate calculation of the solar gains and the transmission heat losses. Though all simplified methods are limited in applicability, the procedure from DIN proved to be more successful in predicting the monthly energy flows and is considered to be more flexible for further development of the method.status: publishe