A refrigerator of the present invention includes a refrigeration system having a water-cooled condenser and a liquid line heat exchanger for additional cooling with the water, at a position upstream in the direction of flow of water from the cooling that occurs at the condenser. The use of water cooling at these two portions of the refrigeration system improves the energy efficiency of the refrigerator, while also significantly improving temperature responsiveness (e.g., reducing an amount of time necessary to “pull down” the temperature of a cooled space in the refrigerator to a desired set point temperature). The refrigerator may include one or a plurality of refrigeration stages, in various embodiments, and an additional sub-cooling heat exchanger may be provided in the refrigeration system downstream from the liquid line heat exchanger when the refrigerator includes multiple cascaded circuits.