Performance analysis of an innovative PCM-based device for cold storage in the civil air conditioning

• Cold storage system coupled with air conditioning systems.
• Peak shaving logic using phase change materials storage tanks.
• The innovative technology allows a reduction of the energy expense due to air conditioning in buildings.
• The study is based on a dynamic energy model to evaluate the temperature profiles during time.
• The model is validated by experimental data collected from a first 5 kWh prototype.

An innovative solution to store cold energy for civil application based on phase change materials (PCM) is presented and evaluated. The storage tank is thought to be installed in a traditional chiller-fan coil system to shave the electricity peak loads required by the users, thus allowing a better management of the electricity grids (by avoiding the summer peaks for air conditioning) and a significant energy saving thanks to the improvement of the chiller Coefficient of Performance (COP).A 5 kWh prototype has been tested to prove the technological feasibility and has been simulated by a physical-mathematical model based on the energy balance and heat exchanging equations. The model, once validated against experimental data, has been implemented to assess the technology behavior changing operating parameters as the filling ratio, the initial temperature of the PCM and the charging power.The optimization of the heat exchanging configuration can lead to a minimum loading time of 54 min for the 5 kWh storage tank (charging power of 5.7 kW). Globally, the mathematical simulations confirmed the capability of the system to operate at high charging/discharging power, thus making it optimal for the integration in a chiller-fan coil system with the “peak shaving” logic.