A fault-tolerant control method of balancing valves for condenser fouling in water-cooled chillers

Abstract

This paper proposes a fault tolerant control method for condenser fouling in water-cooled chillers. Condenser fouling is one of the common faults in water-cooled chillers that degrade its energy efficiency. Studies were conducted to develop fault detection and diagnostics (FDD) algorithms to address this issue. However, the current FDD techniques are too expensive for some faults that are not very significant such as condenser fouling, and a cheaper alternative may be needed to remove the fault impact. This study addresses this issue by proposing a control method without FDD algorithms to reduce the impact of condenser fouling in water-cooled chillers. It controls the opening of the balancing valve in the condensing water loop to adapt the chiller plant for the effectively smaller condenser. Verification of the control method is conducted by a model of a real chiller plant and comparison with the ordinary operation case is made under two different months and two fouling levels. The results show that the method can help the chiller plant to reduce the impact of condenser fouling by reducing its electricity consumption by 2.0% under normal situation and reducing the impact of fouling by 0.2 to 0.4%. However, the result is not very significant, and more studies with other control inputs are needed for more effective control methods.