Calibration of Building Performance Simulations for Zero Carbon Ready Homes: Two Open Access Case Studies in Controlled Conditions

Abstract

This study presents a comprehensive approach to calibrating dynamic thermal simulation (DTS) models for accurately predicting whole-house heat transfer coefficients (HTC) in zero carbon ready homes. Using two case studies, The Future Home (TFH) and eHome2, situated in an environmentally controlled chamber, the research incorporates as-built measurements and additional modelling parameters to minimise the performance gap between predicted and measured HTCs. The calibration process involved updating U-values, air permeability rates, and modelling refinements such as roof ventilation, ground temperatures, and sub-floor voids. Results show a high level of accuracy, with performance gaps reduced to 0.5% for TFH and 0.6% for eHome2, falling within aggregate heat loss test uncertainty ranges by a significant amount. The study demonstrates the superiority of calibrated DTS models, which were compared with steady-state SAP calculations when predicting HTC, highlighting the significance of modelling sub-floor voids in suspended floor constructions. By providing openly accessible calibrated models and a detailed methodology, this research offers valuable resources for future studies in building energy performance. The findings support the UK's transition to dynamic modelling approaches contained in the recently announced HEM approach [1] and contribute to improving energy efficiency predictions in homes, aligning with goals for zero carbon ready housing development.

Keywords: Model Calibration, As Built Performance, Performance Gap, Open Source Data, Domestic Energy Performance, Energy modelling