Thermal performance prediction of an existing building with framing system using the IRT method

Buildings energy efficiency problems are not limited only to the new buildings. In fact, the existing building is often energy-consuming, mainly due to its envelope. A good estimate of the existing building parameters will allow for a better contribution to define the rehabilitation strategies. This work aims to represent the current energy state of an existing building located in the north of Morocco (Mediterranean climate) using in-situ measurements. Firstly, infrared thermography was used to carry out a building thermal diagnosis and determinate the in-situ thermal transmission coefficient. Afterwards, we have proceeded to the energy modelling of this building using TRNSYS software, where each element of the envelope receives a U-value. A comparative study was carried out of three different cases of the building studied using the theoretical and measured U-value for both buildings without concrete frame and with concrete frame. The obtained cooling energy needs of the building diagnosed with the reinforced concrete framework are higher from about 7% to 48% for cooling and from about 2% to 44% for heating energy needs than those of the diagnostic building without the framework and the building reference.