RACA Journal February 2020 | Page 46

Projects instances a fully-evaporative solution will be the most efficient. Benefits from an adiabatic unit are, energy efficiency, water saving, redundancy, plug and play system with built in controls, to name a few,” he says. The project was another successful joint venture between BAC and Mechanical Cooling Maintenance. The design specification and energy simulation considers the following: • • • • • • • • • Cycles of Concentration = 6. Peak heat load = 1381kW. 35°C water temperature in, 29.5°C water temperature out, 22°C wet-bulb temperature. The original unit used a Baltiguard drive system, which has a larger motor with a smaller motor to kick in based on demand. The units also used to alternate operation based on demand with a single unit operating at times. The minimum speed of the EC fans has been set to 21%. A typical HVAC load profile has been estimated. Despite the significant layout requirement of the adiabatic unit, sufficient space was available. Adiabatic total footprint is 31.9m 2 compared to 13.7m 2 . No free cooling has been calculated. RACA The units are expected to save not only water, but electricity too. 44 RACA Journal I February 2020 www.hvacronline.co.za