High-efficiency and Low-cost Operation Method of Chiller
The following best practices will improve cooler performance and reduce operating costs:
Operate multiple chillers to achieve maximum efficiency: A factory equipped with two or more chillers can save energy by matching the building load with the most effective combination of one or more chillers. Generally, the most efficient cooler should be used first.
1.Increasing the temperature of chilled water: Increasing the temperature of chilled water supplied to the building's air handler will increase its efficiency. Establish a schedule for resetting chilled water. The reset schedule can usually adjust the temperature of the chilled water as the outside air temperature changes. On centrifugal chillers, increasing the chilled water supply temperature by 2-3°F will reduce chiller energy consumption by 3-5%.
2.Reducing the water temperature of the condenser: reducing the temperature of the water returning from the cooling tower to the condenser of the chiller by 2-3°F will reduce the energy consumption of the chiller by 2-3%. The temperature set point of the water leaving the cooling tower should be as low as the temperature at which the chiller manufacturer allows water to enter the condenser.
3.Purge air from the refrigerant: The air trapped in the refrigerant circuit will increase the pressure at the compressor discharge port. This increases the work required by the compressor. Newer chillers have automatic air purifiers with operating schedules. Tracking the running time every day or every week will show if a leak has occurred, allowing air to enter the system.
4.Optimize natural cooling: If your system has a chiller bypass and a heat exchanger (called a water-side economizer), you should use it to handle the process load in winter. The water-side economizer produces cooling water without running the cooler. The condensed water circulates in the cooling tower to remove heat, and then enters the heat exchanger (bypassing the cooler), where the water is sufficiently cooled to meet the cooling load.
Verify the performance of the hot gas bypass and unloader: these are most commonly used on reciprocating compressors to control capacity. Make sure they are functioning properly.
5.Maintain the refrigerant level: In order to maintain the efficiency of the refrigerator, please check the refrigerant sight glass and the superheat and subcool temperature readings, and compare them with the manufacturer's requirements. The low and high refrigerant conditions can be detected in this way. Either case will reduce the capacity and efficiency of the cooler.
6.Keep daily logs: Best practices for chiller operation and maintenance start with keeping daily logs of temperature, fluid level, pressure, flow rate and motor amperage. In summary, these readings can be used as a valuable benchmark for operating system and troubleshooting issues. Many newer chillers automatically save a log of these measurements in their onboard control system, which may be able to communicate directly with the DDC. The following is an example of a daily log, which can be used with your chiller.