At present, numerical simulation of room airflows is mainly conducted by either the Computational-Fluid-Dynamics (CFD) method or various zonal/network models. The CFD approach needs a large capacity of computer and a skillful expert. The results obtained with zonal/network models have great uncertainties. This paper proposes a new simplified method to simulate three-dimensional distributions of air velocity, temperature, and contan-finant concentrations in rooms. The method assumes turbulent viscosity to be a function of length-scale and local mean velocity.
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.
Mathematical models have been used by various researchers to provide both a fundamental understanding of indoor air quality dynamics and a platform for estimation of IAQ constituents in lieu of experimental measurements. Due to the diverse nature of these applications the complexity and hence applicability and accuracy of the models varies tremendously. Some models have been specifically developed for evaluation of the impact of a broad range of environmental conditions on IAQ constituents.
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.
The indoor air quality of an actual variable air volume (VA V) heating, ventilation and air conditioning (HV AC) system in a building on the campus of the University of Missouri, Rolla has been analyzed, modified, and monitored. Components measured include temperature, relative humidity, C02, volatile organic matter (VOM), particulates, outside air flow rate, and building pressure. In addition to these parameters, the building is studied in normal operation, and for operation when the economizer damper was controlled to maintain minimum outside air.
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