In this schematic, the return coolant from HeatTank is always going to the return line of the cooling system, through V1 for charging, and through V2 for discharging. This schematic is recommended for the precooling of the return line, which is mostly used in case of peak performance management. The cooling energy could be produced by a chiller or a free-cooling unit. It is possible to change the V2 3-way valve to a 2-way valve (like V1) and add a pump to the place near T4 temperature sensor.

Example: The cooling system operates at 7/12 °C, HeatTank is filled with a phase change material which changes its phase between 8-9,5 °C.

Charging of the storage: through V1 the 7 °C supply coolant is circulated through the HeatTank and freezes the phase change material (charges it with cooling energy). The coolant then goes to the return pipes of the cooling system. HeatTank acts like a cooling energy consumer (heat sink), and the chiller will adapt to the extra consumption and increase the cooling capacity of the chiller. (usually by monitoring the return temperature, the control of the chiller notices an increase in the return temperature, so increases the cooling capacity)

Discharging of the storage: through V2 the 12 °C return coolant is circulated through the HeatTank, the phase change material melts while the return temperature decreasing to 9-11 °C. The control of the chiller adapts to the situation and lowers the cooling capacity of the chiller.

Our control system makes sure to achieve the most possible energy saving, by collecting temperature data, electrical consumptions of the chiller and optimizes the time when to charge and when to discharge the HeatTank. The control system can connect to existing building management platform via GSM, ethernet, Wifi, or modBUS. The chiller is not controlled directly, just indirectly, through increasing or decreasing the return temperature and the chiller will adapt its cooling capacity.