Modelling the thermal energy demand of a Passive-House in the Gulf Region: The impact of thermal insulation

Abstract

The built environment has a direct impact on the Gulf Region natural environment, the economy and human health. Buildings have to respond to local climate and site conditions to maximize building users’ comfort and health while minimizing energy use. Global Sustainability Assessment System (GSAS) developed a simplified, standalone, building energy standard to support Qatar's and the MENA region building energy ratings. Air conditioning counts for more than 60% of the electricity consumption in GCC countries. Consequently, GSAS limited the maximum annual cooling demand for new-build housing compliance in Qatar to 121 kW h/m2. High rated energy-efficient houses must call for 72 kW h/m2 or less. GSAS targets raised the need for innovative passive design technologies to reduce the cooling demand in hot humid climates. A prototype house was constructed to test new technologies and variant insulation techniques, such as dynamic insulation. The house has two operation modes, the static mode and the active mode. This paper presents the Passive-House pilot project construction details and the monitoring results within the tested period. The study compares the annual cooling demand from the simplified GSAS Energy Calculator model and the detailed Dynamic Simulation Model (DSM). Neither model can handle the thermodynamic and fluid dynamic processes of the active insulation. An independent model is used to calculate the heat-transfer coefficient of the dynamically insulated walls, validated experimentally and then coupled with the energy models. The discrepancies in the predicted annual cooling demand between the simplified and detailed models did not exceed 15% for both static and dynamic operations of the Passive-House. Energy assessors can use GSAS Energy Calculator to predict the annual cooling demand with more confidence to demonstrate buildings compliance. Energy models should account for in-use factors to allow for differences in practical installation and performance compared to the laboratory test conditions for selected systems and technologies, which require field trials.