Description

Design of chilled-water plants has a very large impact on building energy uses and energy operating costs. The paper proposes a design tool for optimal design of chilled-water plants. The tool that integrates system models with a genetic algorithm optimization solver minimizes the life-cycle cost by finding the design variables such as chilled-water and condenser piping diameters, chilled- and condenser water temperature differences, and chilled-water supply temperature. The proposed modeling methods dependon detailed cooling load analysis and head and energy calculations. The pump head calculations, including piping, all fittings, valves, and devices, are achieved by using the Darcy-Weisbach equation with given flow parameters. The energy calculations are done by using generic chiller, fan, and pump models. The hourly cooling loads need to be obtained from any energy simulation software. The method is tested on an existing three-story, 88,000 ft² (8175 m²) building. A whole-building energy simulation model is used to generate the hourly cooling loads and then the optimal design variables are found to minimize the life-cycle cost. The testing results show this approach will achieve better results than rules-of-thumb or traditional design procedures. The life-cycle cost saving could be up to 8% depending on project specifications and locations.

Citation: ASHRAE Transactions, vol. 123, pt. 2

Product Details

Published:

2017

Number of Pages:

8

Units of Measure:

Dual

File Size:

1 file , 2.2 MB

Product Code(s):

D-LB-17-005