Building dynamic thermal simulation of low-order multi-dimensional heat transfer

GAO Yan(高岩)^{1, 2}, FAN Rui(范蕊)³, ZHANG Qun-li(张群力)², J. J. ROUX ⁴

(1. Beijing Key Lab of Green Building and Energy Efficient Technology, Beijing University of
Civil Engineering and Architecture, Beijing 100044, China;
2. Beijing Key Lab of Heating, Gas Supply, Ventilating and Air Conditioning Engineering,
Beijing University of Civil Engineering and Architecture, Beijing 100044, China;
3. Sino-German College of Applied Sciences, Tongji University, Shanghai 201804, China;
4. Centre de Thermique de Lyon(CETHIL), UMR CNRS 5008, INSA Lyon, 69621 Villeurbanne Cedex, France)

Abstract:Multi-dimensional heat transfers modeling is crucial for building simulations of insulated buildings, which are widely used and have multi-dimensional heat transfers characteristics. For this work, state-model-reduction techniques were used to develop a reduced low-order model of multi-dimensional heat transfers. With hot box experiment of hollow block wall, heat flow relative errors between experiment and low-order model predication were less than 8% and the largest errors were less than 3%. Also, frequency responses of five typical walls, each with different thermal masses or insulation modes, the low-order model and the complete model showed that the low-order model results agree very well in the lower excitation frequency band with deviations appearing only at high frequency. Furthermore, low-order model was used on intersection thermal bridge of a floor slab and exterior wall. Results show that errors between the two models are very small. This low-order model could be coupled with most existing simulation software for different thermal mass envelope analyses to make up for differences between the multi-dimensional and one-dimensional models, simultaneously simplifying simulation calculations.

Key words:building envelope thermal mass; thermal bridge; model reduction; buildings simulation