More than a month of data recorded in a Northern Italy installation of a 6 Tons (21 KW) POWERCube Thermal Battery with Organic Phase Change Material shows that is possible to supply the whole heating demand of a house reducing close to zero the costs. All the daily PV production is used to supply the energy required by an Air/Water HP that is scheduled to work mainly when the house appliance consumptions leave enough surplus of energy. During the Battery charging time the HP is set at the highest water temperature production in order to speed up the melting process and accumulate the energy into the PCM volume under latent heat form.
Despite the Battery has been located outside the building, the losses are been limited by the behavior of the organic PCM to not loose temperature for several hours because a low heat transfer coefficient. An indoor installation would have been much more efficient in any case, adding value at the already positive test. A multilayer insulated pipe supply water from the mechanical room and return after a complete loop into the exclusive patented Aluminum heat exchangers located inside the Aluminum double wall insulated container.
The 6 KW PV array supplies energy during the day to the whole house that is a "NO GAS building"; for this reason, it has been developed a unique control: PCDCube that is able to drive all the system and address all the available surplus of energy (surplus= PV production- Home appliances consumptions) to feed the HP that charges the Thermal Battery. When the sun sets the Thermal Battery is able to overnight supplying the heating demand .
The physical separation between the primary (energy production/storage) and the secondary (the indoor heating system) is done with a small buffer tank that allows smooth transitions between the different energy providers. The PCDCube control allows to switch between the HP and Thermal Battery whenever is convenient and the outdoor conditions are favorable. All the PCDCube software is remotely controlled and continuously updated with the improvements required.
Above we show the noticeable PV energy availability (in blue the PV production and in orange the HP consumptions), and in some days, decisively high . As the Thermal Battery charging cycle has been checked to be around 3 hours, the PCDCube software makes it possible during the whole sunniest hours to switch between the indoor household needs and the HP working slots. Based on what anticipated above and the data recorded we concentrated the Thermal Battery charging cycle between 09.00 to 13.00 as shown by the NET AVAILABLE energy diagram below. With these accurate diagnosis we are able to drastically reduce the energy supplied by the grid optimizing the use of our PV investment.
Further tests will be done for the cooling season that are expected to be encouraging for the next generation of thermal batteries.
