Performance Comparison between Water-Cooled and Air-Cooled Chillers with Natural Gas and Electric Resistance powered Boilers for Use in a Libyan Hospital

Abstract

Libya is a large country in northern Africa and the majority of its land area is desert with high temperatures during the summer and cold temperatures during the winter. Therefore, HVAC systems are a very important aspect in building design and management. This research is a comparison of the performance of two HVAC systems in Libya, which are water-cooled and packaged air-cooled chillers for large buildings. This study utilized the simulation software eQUEST which is based on DOE-2. Chiller systems are designed for a large hospital where the water-cooled (cooling towers) and packaged (dry condensers) are the heat rejection options. The boilers used for these systems will use natural gas and electrical resistance as the source of heat for both chiller designs and their performance will be compared. The performance will be determined based on the energy consumption, the energy efficiency ratio, and total energy cost. Results showed that a water-cooled system, which needs water to operate, spends less electrical energy than a packaged air-cooled system, which does not need water to operate, to reject heat for the hospital building. Results also showed that using natural gas for the boiler was far cheaper than electrical resistance. The study concluded that using a water-cooled chiller with a natural gas powered boiler is the most efficient option for Libyan hospitals.