Electricity cost saving comparison due to tariff change and ice thermal storage (ITS) usage based on a hybrid centrifugal-ITS system for buildings: A university district cooling perspective

In this paper, the case study of a district cooling system of a university located in a South East Asia region (lat: 01°29′; long: 110°20′E) is presented. In general, the university has high peak ambient temperature of around 32-35 °C coupled with high humidity of about 85% during afternoon period. The total electricity charge for the Universiti Malaysia Sarawak Campus is very high amounting to more than $314,911 per month. In this paper, a few district cooling schemes are investigated to provide “what-if analysis” and in order to minimize the overall electricity charges. Few scenarios designed for the application of centrifugal with and without ice-thermal storage (ITS) systems on the buildings were investigated. It was found that, due to the local tariff status, marginally saving can be achieved in the range of 0.08-3.13% if a new tariff is adopted; and a total of further saving of 1.26-2.43% if ITS is operated. This marginally saving is mainly due to the local tariff conditions and lower local temperature range (ΔT) which are less favorable as compared with those reported in the literature elsewhere.