The influence of realistic schedules for the use of appliances on the total energy performances in dwellings

The use of lighting and appliances influences buildings energy performance by affecting electricity and thermal loads. Nevertheless, their use is often predicted by arbitrary assumptions during the design phase. The paper focuses on the realistic description of domestic equipment use and its impact on the prediction of energy consumption in homes. A method for creating schedules of domestic appliances use, based on dwelling field monitoring is proposed. The method is validated by calibrating the simulated electric consumption with the monitored one. A baseline simulation model is developed in IDA Ice, in which the developed schedules (named Calibrated Realistic Schedules) are implemented. Then, the same model is used to implement the schedules for domestic appliance use proposed by the Italian reference standard for energy calculation UNI/TS 11300. The simulated energy performances are finally compared. Results shows that values for usage times and power from UNI/TS 11300 are appropriate references for predicting the equipment energy use at the design stage. However, standardized schedules do not take into account the lower use of equipment in summer, leading to higher predicted internal gains and consequently to oversizing the cooling system. The paper demonstrates the need for more realistic descriptions of appliances use to be included in simulation software, particularly in high performing buildings. Moreover, it gives evidence of the impact that actual occupant behaviour has on building energy performance.