DSM opportunities in underground refrigeration systems

Abstract

This study will focus on the feasibility of demand side electricity management on underground refrigeration systems. It will include a relevant literature study, the investigation process, a simulation model, expected simulated results, implementation of DSM on an underground refrigeration system, actual results, recommendations of further study, and a conclusion. Eskom is presently struggling to adhere to the electricity demand in South Africa, specifically in the peak consuming periods. It was proposed that Demand Side Management possibilities must be investigated and evaluated on South-African gold mines. The gold mining industry consumes approximately 26% of the electricity supplied by Eskom. Mines possess extensive machinery which consume much power in their mining activities. One of the most energy intensive machines is the refrigeration system machines. Demand Side Management was previously successfully implemented on surface refrigeration systems and on cascade refrigeration systems. Mining depths increase continuously and surface refrigeration systems become inadequate. An underground refrigeration system is a viable option to aid this problem. The possibility of Demand Side Management in underground refrigeration systems will be investigated. A simulation model will be created of the system and various control strategies will be applied and evaluated. These strategies will endeavour to reduce loads during the Eskom peak consumption periods. The control strategy was implemented on the refrigeration system and load reduction results were obtained. The average load reduction for the evening peak, excluding condonable days, for the month of August 2009 was 6.60 MW. The average morning load reduction, excluding condonable days, was 6.06 MW. Load profiles from 1 October 2009 until 15 October 2009 show that the reduction for the evening peak, excluding condonable days, was 5.24 MW.