Room Indicators in Miljöbyggnad - A Comparative Study of Simplified and Detailed Methods and Their Influencing Parameters

Abstract

Miljöbyggnad is a building certification system adapted to Swedish regulations and design practice with focus on energy, indoor environment and materials. The building is assessed according to certain indicators and the resulting grade is based on a fourpoint scale GOLD, SILVER, BRONZE and CLASSIFIED, where GOLD is the highest grade and CLASSIFIED means that some performance requirements are not fulfilled. Some of the indicators are defined on room level; solar heat load, thermal climate and daylight. They can be assessed through simplified or detailed methods, where the simplified methods are based on simple formulae including a few parameters. The intention is to encourage the use of detailed methods by criteria formulated so that higher grades are more easily reached. However, the detailed methods are generally more time consuming due to simulations. Thus, the aim of this study is to determine the conformity between the two methods for the room indicators. Additionally, key parameters are defined in order to pinpoint the most important input data regarding both methods. In order to evaluate the room indicators three building types with fictive representative room units are defined; a dwelling, an office and a hospital. For those, the room indicators are evaluated by simplified calculations and detailed simulations, the latter using IDA ICE and VELUX Daylight Visualizer. Then a parameter study of 17 parameters is performed. The results are divided into two parts; the results from the parameter analysis and the results regarding conformity between the two methods respectively. The study concludes that the two methods converge very well regarding the solar heat load. Concerning the thermal climate indicators, the detailed simulations are found to be less sensitive to varied parameters than the simplified due to the compensation of installed heating and cooling power as well as ventilation and airing. For the daylight indicator the detailed simulations are favourable.