| Summary: | 碩士 === 國立臺北科技大學 === 能源與冷凍空調工程系碩士班 === 96 === Water pumping is one of the major energy consumption of central air-conditioning systems. Presently inverter controlled secondary zone pumps are commonly used to save pump energy by reducing water volume during partial air-conditioning load. Until now, annual dynamic analysis on pumping energy and the effects of pipe sizing have not yet fully studied and compared. This thesis used an actual office building as a base case, and DOE-2 is used to build a 3D model for the dynamic energy analysis. A detailed analysis on the pumping energy saving potential due to the water pumping design was conducted.
Variable water volume control strategy and pipe sizing were used as the parameters in this analysis for flow resistant and pumping energy. Both primary and secondary pumping were considered in the analysis. The initial cost of piping versus the annual running cost were analyzed for financial payback. Both AHU and fan coil systems were considered in the thesis.
It was found that water pumping energy differs little for AHU and fan coil systems, for the same building under the same conditions. Variable water design has great advantage over constant volume system. In the comparison with the base case, the saving on the initial cost will suffice only 1.2 years of extra pumping energy. However, a large pipe sizing will allow a payback return of within 3.4 years. Moreover, the sizes of pump power for the secondary zone piping are 8.99 kW, 4.67kW and 2.91kW, respectively for 5 inches, 6 inches and 8 inches of nominal pipe diameters. This shows that the cost of pump and the electric installation will also be saved due to different pipe sizing.
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