Apparent in the air-tight sealed refrigerant circuit of a heat pump, which experiences pressure and temperature changes due to particular components (compressor, expansion valve) and can thus absorb and give off energy.
See regenerative energy
Energy sources that are not in decline according to human measurements. These include wood, solar energy, geothermal energy, etc.
The return temperature is the temperature of the heating water used by and flowing back into the heat generator.
Room temperature-controlled controller
The room temperature is controlled by recording the indoor temperature via room temperature sensors.