In summer, picea produces hydrogen. The conversion produces waste heat that can be used as service water. This summer heat is provided at a temperature of 55 °C. This can be used to heat a buffer or drinking water storage tank. This enables picea to relieve the heating system when producing domestic hot water in summer.
In winter, hydrogen is used in the fuel cell to generate electricity. The resulting waste heat is released into the house via the ventilation unit. Used air is extracted and used to cool the fuel cell. It is then passed over a counterflow heat exchanger and releases the heat to fresh air, which is then preheated and prehumidified and fed into the house. This means that picea not only uses the waste heat from the fuel cell, but also keeps the heat in the house that would otherwise be lost during ventilation. If there is no central living room ventilation, the heat can also be used via the buffer or drinking water storage tank.