In this study,we theoretically analyzed that in a refrigerator using the reverse Carnot cycle, lowering the cooling water temperature has an energy-saving effect similar to that of raising the cooling water temperature. We also analyzed the characteristics of the refrigerator and cooling tower to show that the system power can be reduced by operating a cooling tower with a capacity larger than that of the refrigerator and confirmed that a similar energy-saving effect can be achieved in an actual facility. A verification test was conducted at an existing facility where two cooling towers were operated while one chiller was in operation. The cooling water temperature dropped by 3°C to 6°C, and with the added effect of improved efficiency due to the partial load, the chiller power was reduced by 18% to 30%. For the entire system, a 13%-20% reduction in power was confirmed even though the cooling tower power increased, and the verification results confirmed that there was little difference in the analysis due to equipment characteristics. It was confirmed that lowering the chiller cooling water outlet temperature is the main factor in reducing chiller power, as the reduction was close to the prediction based on the manufacturer's data analysis. When the cooling water piping is of a combined type, this energy-saving method can be achieved by simply changing the operating method. However, even if the cooling water piping is not of a combined type and if there are multiple cooling towers, the same effect can be achieved by connecting the piping and passing the water through a cooling tower with a capacity greater than that of the chiller.