Case study: The effects of a variable flow energy saving strategy on a deep-mine cooling system

Cooling systems consume up to 25% of the total electricity used on deep level mines. These systems are integrated with the water reticulation system to provide chilled service water to the mine as well as cooling for mine ventilation air. Although there is definite potential for demand-side management on these systems, it is critical that the service delivery be maintained so as not to adversely affect productivity. An energy saving strategy based on variable water flow was developed for the unique demands of integrated mine cooling systems. The strategy is based on matching the evaporators with the demand of chilled water; condensers adapting to the heat load; and the bulk air cooler matching the demand of ventilation air requirements. In this paper, a case study is presented in which the savings and consequences of implementing the developed energy saving strategy are investigated. It is shown that a decrease of 31.5% in overall electrical energy usage is possible without affecting the service delivery or performance of the cooling system.