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.
The flow-pressure characteristics of the AHU/VAV air-conditioning system in an open-plan office building is assessed by site experiments under various conditions. The effects of VAV supply pressure setting, return fan pressure setting and damper operation on energy consumption, fresh air intake and ex-infiltration flow rate are evaluated analytically on the basis of the VA V/ A.HU system and component characteristics.
The detailed dynamic simulation of coupled units in HVAC-systems and buildings is gaining increasing importance as strong tool in HVAC-engiiieering and operation. This investigation deals with the basics in the development of an universally applicable dynamic simulator. General fundamentals are formulated some moduls are outlined. Shnulation of a heated 4-room-residence, a solar system. and a storage tank as applications demonstrate the mode of functioning and the potential of the simulator.
Recently, a lower type free-access floor system which realizes improved ease of walking and less sense of confinement has been attracting attention. However, it is known that the lower the design of the air supply chamber, the larger the non-uniformity of the diffuser air velocity profile and the greater the deterioration in room temperature distribution. In this paper, an analytical model is proposed for predicting the non-uniformity of diffuser air velocity at the design stage.
In line with its work on the positioning of gas air-conditioning systems in the commercial sector, the Gaz de France Research and Development Division conducted both experimental and theoretical studies. An air-conditioning system, known as the 'reference solution", was installed and equipped in a building on Division premises. The purpose of the system modelling and simulation study was above all to analyse the building's behavior regarding various criteria, while a technico-economic study compared the various (Generation systems.
Indoor air flow induced by a fan-coil unit in an air-conditioned environmental chamber is studied experimentally. The supply Archimedes number which is a macroscopic number describing indoor air flow is measured and related to the
centreline velocity and temperature decay of the cold air jet issued from the fan-coil unit. The space air diffusion and the thermal comfort using respectively the Air Diffusion Performance Index (ADP]) and the Predicted Percentage of dissatisfied (PPD) are evaluated. Evolution of these indices with the supply Archimedes number is discussed.
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