Variable Air Volume system use VAV boxes that serve open areas for five or more occupants, each zone is controlled with a single space temperature sensor. But VAV zone control strategies remained the same for the last years, so the designers have to consider that system : it provides a high quality environment for occupants, it permits the use of a smaller air-distribution system that is low cost and does not compromise building comfort or operating efficiency.
Air quality in conditioned spaces can be improved even in humid locations, in Florida. A field experiment in a Florida school confirmed that the use of a dual-path air-distribution system with low temperature air can maintain lower and more comfortable humidity levels.
Furthermore, that system coupled with a thermal energy storage (TES) keeps energy use as low as possible, and makes costs savings.
Five air terminal devices (ATD) have been tested in a typical office workplace with a breathing thermal manikin. Tracer gas used to identify the amount of air inhaled and the amount of exhaled air re-inhaled. An index was used to assess the performance of ATD.
Advantages of floor supply and floor return systems (UFAD: under floor air distribution systems) are described. They are presented by the author as being capable of better performance (thermal comfort, indoor air quality) than floor supply and ceiling return system. They also offer flexibility and ability to allow individual control.
That paper presents the results of a thermal comfort evaluation research in a brazilian office building : the measurements show that an underfloor air distribution system can provide comfortable conditions for both sitting and standing occupants along with a reduction of the energy consumption .
This paper presents the behaviour of a thermal plume combine with a forced ventilation. A method to locate the position of the thermocline in a ventilated room is shown. It also gives and compares the results obtained by means of a solutal simulation on an hydraulic model and from full-scale experiments in a climatic chamber.
Experiments were carried out in a scaled test room equipped with 9 vortex inlets uniformly distributed, exhaust outlets near the floor and 64 mannequins to simulate cooling loads. The study describes the air flow pattern observed and the relationship between the air velocity and the cooling load per m2 for mixed flow.
Experioments has been conducted with a ice thermal storage and a ceiling plenum. This ductless air supply system can be an alternative to the use of chilled water tubes. This system supplies air to the ceiling plenum chamber by mixing return air and low temperature air.
A model of an UFAD system in a ventilated room is proposed , the room is ventilated with one heat source and one cooling vent as a two-layer stratification.
Measurements and CFD simulations are compared for 4 different ventilation systems using the air change index and a new ventilation parameter. It is shown the advantage of impinging jets
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