In-situ virtual heat flow meter model for monitoring heat flux of existing building envelope

Abstract

In the building sector, remodeling of existing buildings that have low energy efficiency is a required strategy to achieve carbon neutrality. To establish a cost-effective remodeling strategy for existing buildings, accurate measurement of the thermal insulation performance of existing building envelopes is necessary. In general, to evaluate the insulation performance of a building envelope, the U-value is calculated based on the heat flux measured using a heat flow meter, which is an expensive physical sensor. This study developed an in-situ virtual heat flow meter (vHFM) model that can replace existing heat flow meter sensors. The in-situ vHFM model satisfied ASHRAE Guideline 14 with an R2 of 0.989, coefficient of variation root mean square error of 15.24%, and normalized mean bias error of −0.06% compared to the data measured using a traditional sensor. In addition, the validation through two case studies demonstrated that the field applicability of the in-situ vHFM model was very high.