APPLICATION OF THERMAL ENERGY STORAGE SYSTEM FOR A LOWLAND GREENHOUSE

This article presents a study to estimate the potential saving in annual operating cost of a hypothetical greenhouse used for planting strawberry, in Johor Bahru, Malaysia. The greenhouse needs to be maintained at a constant temperature of 20°C at all time. The goal of this study is to select a suitable TES system that can save the annual cost of electricity usage to meet the cooling load requirement of the greenhouse, based on a 24 hours operating duration and local electricity tariff. Comparison is made with the annual cost for running a conventional air-conditioning (AC) system to meet the cooling requirement. The cooling load requirement of the greenhouse dictates the capacity and size of the potential TES systems, which was estimated based on the highest total annual cooling load. Three TES system operating arrangements were considered in this study: TES full storage combined with AC systems, TES full storage and TES partial storage. Among these three arrangements, the TES full storage was found to have the highest an annual cost saving of about RM 58,990 compared to the cost of using the conventional AC system alone. This represents about 68 % of annual operating cost saving, which is considered very significant.