This article recommends practical methods for achieving high, i.e., 15°F (8.3°C) or greater, chilled water temperature differentials (D Ts) in new and existing variable flow hydronic cooling systems. Once high chilled water DTs are realized, more Btu's (J/s) of cooling will be accomplished per gallon (liter) of chilled water distributed (Figure 1). Pressure losses and pumping energy will decline considerably in existing hydronic cooling systems, and smaller pumps and piping may be installed in new hydronic cooling systems. Also, water chillers will no longer be limited by maximum evaporator flow rates, and chilled water storage tanks will store many more ton-h (MJ) of cooling. This fundamental approach provides significant, enduring improvements in the performance of variable-flow hydronic cooling systems.

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