Load-Adaptive Operational Control of an Indirect Evaporative Cooling System for Coordinated Energy and Water Use in a Modular Data Center in a Cold Region

An annual dynamic model is developed in TRNSYS 18 to coordinate thermal safety with low electricity and water use of modular data centers in cold regions. A heat and mass transfer model for the indirect evaporative cooler is established and validated against experimental data, with a maximum relative error of 4.5% in outlet temperature. Under full load, the effects of supply airflow rate, fresh/return air ratio, and spray efficiency are evaluated. At 2.1 × 105 kg/h airflow, an 80.0% fresh/return air ratio, and a 95.0% spray efficiency, room temperature maintains 26.6–27.2 °C. Annual electricity and water consumption are 7.3 × 106 kWh and 9.9 × 107 kg, with PUE, WUE, and CUE of 1.31, 2.37, and 1.46, respectively. At a partial load rate of 0.6, key parameter sensitivities are quantified. Airflow rising from 9.0 × 104 to 1.2 × 105 kg/h increases annual electricity by only 0.2% but water consumption by 33.4%, with fan and spray pump power indices up 7.0% and 0.1%. Reducing the fresh/return air ratio from 90.0% to 80.0% cuts electricity and water by 29.8% and 12.5%; lowering spray efficiency from 98.0% to 90.0% reduces them by 25.3% and 8.9%. Finally, a staged control method is proposed via joint assessment. Airflow matches load rate, spray intensity adjusts with room temperature, and a low fresh/return air ratio is prioritized. It provides a feasible approach for energy-saving, water-saving, and low-carbon operation of green data centers.