The influence of thermal mass on the space conditioning energy and indoor comfort conditions of buildings

This paper describes a modelling comparison between three very similar medium sized educational buildings located in the temperate climate of Nelson, New Zealand, each designed using structural systems made primarily of timber (actually built), concrete or steel (both hypothetical).  The buildings were analysed using two different insulation values in the thermal envelope, one sufficient to comply with the New Zealand Building Code and another with ““best practice”” insulation levels. The thermal mass in the structural material was added to each room in the model as a stand-alone internal wall. The HVAC system in the buildings includes hydronic heating, mechanical ventilation with heat recovery, and cooling in a computer room only. HVAC energy consumption, and indoor comfort conditions using Predicted Mean Vote (PMV) are assessed.