Modeling a Phase Change Material Storage Unit for Solar Thermal Cooling in Masdar City

Abstract

In the last years cooling supply has become a topic of major interest in the Middle East region. Estimates of daily cooling load for the city of Abu Dhabi are derived based on the relationship between weather variables and daily total electricity consumption. The lower bound cooling load estimate for Abu Dhabi Island corresponds to over 40% of the total annual electrical load and over 60% of the peak electricity demand of Abu Dhabi. Temperature and humidity are the largest factors influencing cooling load. This high cooling demand together with the vast supply of solar resource in Abu Dhabi, and more generally in the Middle East, suggests that solar energy for cooling is a highly practical approach. However, solar energy is a time dependent resource and therefore a disparity exists between energy generation and demand. For this reason, a new storage alternative is necessary. Of the possible options, phase change materials (PCMs) seem the most promising because of its higher storage density compared with sensible heat storage. The advantages of PCMs are well known, but literature regarding the use of these units in a solar thermal cooling system is limited. This thesis examines the results of simulations of a Shell-and-tube PCM storage unit using water as a working fluid in connection to a triple effect absorption chiller. The solar thermal energy is harnessed using the Beam-down pilot solar plant in Masdar City in Abu Dhabi. A detailed model of heat transfer and fluid flow has been developed and simulations carried out using MatLab and COMSOL Multiphysics to estimate the potential performance of these three elements together and to evaluate the advantages of using PCMs for cooling supply purposes. The current project combines these three units aiming at the provision of round-the-clock cooling to Masdar City without producing CO2 emissions.

Date of Award	2011
Original language	American English
Supervisor	Matteo Chiesa (Supervisor)