A publicly-owned office building in Eskilstuna, Sweden, has been retrofitted with high-frequency with self-regulating controls for the lighting and ventilation systems. The building has a total floor area of 19,000 m2 and contains more than 3 00 offices, a conference room, lunch rooms, and a recreation hall. Before retrofitting the total annual electricity consumption was 1/300 MWh and the district(heat consumption was 950 MWh. The total annual energy consumption was reduced by 20% as a result of the new installlations.
Central Europe is, especially in the residential sector, a region using mainly hydronic systems with static heat transfer surfaces, which operate noiselessly and with slow air movements. Cooling is - as yet - not required. This implies that air-heating systems are not very common in Austria. However, new improved building standards may change this situation, because the specific heat load is significantly reduced. In the building sector, both energy savings and a reduction in C02 emissions can be achieved relatively quickly.
Research scientists at the BRE and De Montford University have carried out tests examining the performance and operation of stack ventilation systems in auditoria.
Macroscopic flow numbers relating to the jet momentum of air diffusion terminal devices are studied in this paper. Diffuser jet momentum, jet momentum number and jet momentum ratio are reviewed in the literature. New expressions for jet momentum ratios and jet volume numbers are proposed for specifying the mean room air speed in mechanically ventilated enclosures. The proposal is validated against experimental data from seven sites under fifteen operating flow conditions. Two macroscopic flow numbers correlate with the measured mean air speed in the room.
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