Modeling of Chilled Water Storage for Improved Daily Chiller Plant Efficiency in Masdar City

Abstract

The difficulties of efficiently operating a chiller's cooling-system (CCS) are manifest in higher energy consumption under partial cooling loads. Operating away from the optimal design point, typically 75% of chiller capacity, the CCS shows a non-proportional performance regarding the needed power. A thermal energy storage (TES) technology is proposed to mitigate the part load and climate deficiency in chiller plants, in addition, to saving operating expenses resulting from UAE future vision for electricity tariffs during peak load hours. A local CCS is identified and modeled (static model) using the available data, and then the plant is simulated for twelve days of every month along one year with TES (dynamics model) and without using TRNSYS under UAE ambient conditions. Parallel to that, a TES design takes place to find an optimal system capacity for both sensible and latent TES media using simple algorithms. Finally, a smart control is needed to run the new integrated system and investigate its feasibility where chiller model is implemented in GAMS optimization framework including the TES tank. Results show a good potential for energy saving resulting from operating the chillers integrated with TES near the optimal point load under all conditions. Energy saving of 5% is estimated using the TRNSYS programming in addition to the saving in the energy cost due to the peak load shaving while the electricity tariff is higher than the rest of the day.

Date of Award	Dec 2017
Original language	American English