| Summary: | 碩士 === 國立臺北科技大學 === 冷凍空調工程系所 === 94 === This study analyzed the distribution of internal flow and temperature fields of the Damper Bypass VAV Fan-Coil Units by computational fluid dynamics technique. The effects of bypass damper opening to the distribution of air flow and returned air mixing as well as changes in air temperature were studied. In addition, because the size of the bypass damper and the placement position directly affect the homogeneity of returned air mixture as well as changes in air temperature, therefore the size and dimension of the bypass damper of the VAV fan-coil unit and its placement position value require further study.
During the simulation analysis, including three different sizes of bypass damper and different placement positions, we tried to look for the best dimension and size and placement position of the bypass damper. According to the simulation results, utilizing the bypass damper not only can increase the amount of circulated air and degree of air mix, but it can also raise the air temperature through the degree of damper opening, so that the VAV fan-coil unit can exhibit low temperature differential characteristic as evidence by the reduced temperature differential of the returned air.
When the indoor cooling load is stable, the system will adjust the fan-coil unit to maintain minimum amount of air flow, this minimum amount of air flow can maintain the indoor air circulation at the lowest standard, and is expected to resolve the dumping phenomenon produced by the traditional variable air volume fan-coil unit at low loading situation, as well as achieving the purpose of energy saving and comfort of the VAV fan-coil unit.
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