A Novel Response Factor-Based Method for In Situ Measurement of Wall Thermal Resistance

Abstract

The heat flow meter method (HFM) is one of the most-used methods for the in situ measurement of wall thermal resistance. However, the standard HFM method has some issues: it is challenging to balance simplicity and accuracy in data analysis and the measurement period needs to be shorter. In this paper, a new dynamic data analysis method for the in situ measurement of wall thermal resistance is introduced, which is based on a truncated form of the infinite response factors for a wall heat conduction process and has a theoretically deducted convergence criteria for the automatic termination of an in situ measurement. The efficacy of the proposed method is validated by a theoretical analysis and by experiments from one simulation dataset and one measurement dataset. Preliminary experimental results show that the proposed method can reduce the measurement time by about one-third on average while maintaining the same accuracy as the standard average method. Due to the advantages of a clear physical meaning, a simple principle, and a short measurement period, the proposed method contributes to the quick and accurate estimation of the wall thermal resistance in buildings.

Keywords

• wall thermal resistance
• wall response factors
• heat flow meter method
• automatic termination criteria
• building energy diagnosis