Using Simulation Models for District Chilled Water Distribution Systems Design

Abstract

The capital investment for the distribution system is often the most expensive portion of a district heating and cooling system, which usually constitutes 50 to 70% of the total cost. Because of high initial cost, it is very important to optimize the design. The focus of this paper is to demonstrate how the using of the computerized simulation model can give the engineer the ability to explore many more alternative design scenarios and to identify more cost-effective and robust designs. The University of Texas at San Antonio needs to expand their central chilled water distribution system as a result of planned additions to the campus. After a simulation model was constructed and calibrated for the existing campus chilled water distribution system. Six different alternatives have been tried and compared with each other. One of the scenarios was identified to be the optimal design. More detailed models were built for preliminary design. Based on the simulation results, pipe sizes were selected for each scenario. The results indicated that though there are many scenarios, the optimal scenario is the one which has the lowest cost and it can be identified through simulation. The simulation models are very useful to find acceptable designs and to let the engineer to consider the most optimized and cost-effective designs.