Abstract
As a proportion of the fan power input occupied in the total energy consumption is significant, it becomes important to save air conveyance consumption recently in order to conserve air conditioning energy along with a reduction in the building air conditioning load. From now on, it is important to estimate the energy-saving volume of fan power input for VAV (Variable Air Volume) systems. And then we must evaluate the efficiency of fan power input. In the previous reports, efficiency of fan power input drop according to reduction of supply air volume and fan inverter frequency. In this report, we measured fan power input efficiency with the VAV systems being controlled by adapting air supply volume measurement. And then to analyze fan power input energy saving consumption in consideration of variable air volume. We employed the testing model of duct system equipped with VAV single unit in testing room. Firstly, we measure the characteristic tendency of fan power input inverter frequency according to supply air volume reduction. And then we measure the fan shaft power according to results of each inverter frequency at first time testing air volume. As a result, fan power total efficiency consists of two kinds of efficiency mainly. One is fan total pressure efficiency and the other is fan motor efficiency. The testing result indicates the reduction of two kinds of efficiency. For example, as the air supply volume reduces to about 39%, fan power total efficiency reduces to about 54% and fan motor efficiency reduces to about 56% as compared with the rated efficiency. As a result of these reductions of two kinds of efficiency, it is proved that fan power total efficiency reduces to about 30%. And then, we measured the air conditioning fan power input electrical consumption saved with the VAV systems being controlled by adapting air supply volume measurement of each VAV in the building space to be compared with the testing result. It is recognized that this actual measurement indicates an approximate ratios of reduction in the fan power input electrical consumption as compared with each rated fan power input electrical consumptions according to the ratios of reduction in supply air volume as compared with each rated air volumes.
