Load management on closed loop underground fridge plants and the effects on working conditions

Load management projects are widely implemented in South Africa. Eskom Demand Side Management (DSM) endorses these projects as they aid in reducing Eskom´s peak demand. There is also a cost benefit for participating entities billed on time of use (TOU) tariff structures. The continuous increase of electricity costs ensures that the financial impact of load management remains significant. This article investigates load management on closed loop underground fridge plants. These systems present unique challenges as the limited storage capacities of chilled water result in service delivery being affected. The impact on underground working conditions will therefore receive specific attention. The impact of a proposed project is determined by an experimental shut down test. Data from the experiment is analysed to gauge the impact of plant operation on working area temperatures. Regression models built using the data are used to estimate the recovery period required to offset the proposed load management. Post-implementation data is analysed to determine the long term impact of the project. The results indicate that the proposed load management is possible. It also highlights the impact of unplanned stops on working conditions.