Cost-effective design of thermal energy storage components for HVAC plants

This paper compares the results obtained with the simplified sizing methodologies for thermal energy storage components usual in HVAC current practice and those obtained from an optimised procedure based on hourly simulations. The PC version of the building energy analysis programme DOE2.1E was used in energy simulations of a central hospital in Lisbon, as part of an energy audit. The audit enabled the simulation model to be calibrated. Based on this model, the sizing of energy plant alternatives including thermal energy storage systems with ice banks or chilled water storage were determined. It was concluded that the usual practices of sizing storage systems are quite ambiguous. The best methodology involves determining power and energy consumed on daily and annual terms, variable functional strategies throughout the year and corresponding costs in relation to energy supplier tariffs.