Aspects of air and heat distribution in low energy residential buildings

In highly insulated residential buildings, complying with the Passive House Standard, the space heat demand can be covered by air heating at air flow rates given by air quality requirements, without the need for additional air re-circulation or for a water heating system. The air distribution system is kept compact. In a common concept the supply air terminal is located above the door to the corridor. Such configurations were evaluated for typical air transfer devices and extreme supply temperatures. This paper gives results from measurements in the room air flow test chamber at EMPA, showing that room air distribution efficiencies and draught risk values remain within acceptable limits Also the risk for low indoor air humidity at low outdoor temperatures is discussed. Wood stoves offer a chance to cover the remaining small space heat demand by renewable energies. The capabilities of the ventilation system to distribute the heat from the stove, placed in the living room, are investigated for a two storey apartment with an open staircase. Requirements in order to avoid overheating are specified for this type of stoves.