fan

Residential ventilation has at least two energy penalties that must be considered when addressing the ventilation levels recommended in ASHRAE Standard 62. Energy is required to heat the fresh outside air used for ventilation. In cold climates with high heating costs, an air-to-air heat exchanger can lessen the operating expense. Energy is needed for the fan motor used to introduce fresh outside air andlor to exhaust stale indoor air.

The system of decentralized apartment ventilation has been successfully used for several years in multiple-storey apartment construction in the Federal Republic of Germany. With this tried and tested system, the individual apartments are vented into a common exhaust shaft with decentralized apartment ventilating fans. The special designs of the individual fans ensure a constant volume flow of the outgoing air in the individual apartments, in spite of the large pressure variations into the outgoing air conduits. Non-returnflaps prevent a back flow of the outgoing air.

The paper is presenting experience from a several year long time of operation in a group of apartment buildings in the Stockholm area, Sweden, having an extremely low energy usage, less that 110kWh/(m2.year), electricity supply to the building services included. The system solution used has a very low pressure drop in the exhaust ducts. Every exhaust point is connected to an individual duct leading to a fan chamber in the attic. The pressure in that chamber is kept constant.

The fan and the ductnetwork is designed for 100% ventilation rate. Because the fan energy is the main important energy consumption in systems all over the year it is worthwhile to control the systems correctly. By reducing the air volume rate the pressure drop in the ductnetwork drops nearly with the second power.

The relative energy use of PSV and extract fans has been a matter of considerable controversy, particularly in the UK. A steady state methodology is presented based on the approach of BS5250 and that of Professor Meyringer (Air Infiltration Review November 85).

It is a well-documented fact that the major cause of death in a fire is due to inhalation of hot toxic smoke. The control and effective removal of smoke from a burning building- especially in the vital first minutes, when personnel are being evacuated - has therefore become the central component of every fire protection scheme, writes Jim Wild, Woods' product application manager.