The effect of thermal mass and intermittent occupation on energy demand in student halls of residence
Vicki Tink, Loughborough University
This research explores the relationship between intermittent occupancy in a thermally lightweight student halls of residence and energy demand. A building with high thermal mass can be beneficial to occupants due to the smoothing effect it has upon external temperature and can lead to energy demand reduction. However within buildings that are intermittently occupied energy can be wasted heating up the fabric of the building if occupants are not present when the external temperature cools and the fabric releases the heat stored.
Two flats in a lightweight modular modern method of construction building had temperature, humidity, window opening behaviour and electricity use monitored. This was made possible in this master’s dissertation through sharing equipment and data from Ella Quigley’s project: W1LP4. The thermal capacity of each room was calculated from the data, which was compared against design values. This comparison revealed that the furniture had a large effect on the capacity. A cyclic admittance model was built and a sensitivity analysis performed to find the size of radiator required due to the duration of occupancy and the thermal response factor of the construction. This model revealed that within a lightweight building if residents are only present for 8 hours a day a 77% smaller plant can be used when compared to a heavyweight building. This gives an indication of the magnitude of energy that could be wasted heating up the mass of a heavyweight building. Occupants may benefit from living in lightweight buildings through winter due to their fast thermal response, however overheating may occur in summer.