Modeling of a portable electric spa: Model development, experimental validation and application to winter demand response

This paper presents a new model for portable electric spas, also referred to as spas or hot tubs. The developed model is implemented in the TRNSYS simulation tool, and is referred to as Type 3252. It uses two thermal nodes to model the water temperature and the air temperature in the cavity below the spa. The model is calibrated and validated using experimental data and the results show that the thermal behavior of the spa is adequately simulated, both for quasi steady-state performance and transient performance. The validated model is used to assess demand reduction strategies in a cold climate context, with the aim of reducing peak demand during critical days, both for the morning (from 6:00 to 9:00) and the evening (from 16:00 to 20:00) peak periods.