Effect of thermal mass on natural ventilation in a single-zone building with two openings

This paper considers an ideal naturally ventilated building model that allows a theoretical study of the effect of thermal mass associating with the non-linear coupling between the airflow rate and the indoor air temperature.The thermal mass number and the convective heat transfer air change parameter are suggested to account for the effect of thermal mass heat storage and convective heat transfer at the thermal mass surfaces. The new thermal mass number measures the capacity of heat storage, rather than the amount of thermal mass. From the numerical analysis, the maximum indoor air temperature phase shift induced by the direct outdoor air supply without control was shown to be 6 hours. The use of thermal mass should be optimized, as excessive thermal mass is not beneficial when the phase shift approaches to its maximum value.