As part of the project ETS 300, eight selected technology locations were examined with respect to the following energy optimization measures:

• Automatic and variable volume current regulation in the free cooling as required

• Reduction of the electric power consumption from the parallel operation of fans in the compact systems

• Automatic switching on and off of HVAC equipment in free cooling

• No refrigeration operation with maximum air quantity in free cooling

• Flexible volume flow in refrigeration operation and flexible intake air temperature in refrigeration operation.

The result was the drafting of a self-optimizing regulatory strategy which regulates the volume flow at a constant intake air temperature at an outside temperature up to 18° Celsius. In the range up to 21° Celsius, the free cooling is used in conjunction with flexible intake air temperature and variable volume flow. In addition, the HVAC equipment switches itself on and off in self-regulation mode.

One example clearly demonstrates the energy savings. During optimized operation at a maximum room temperature of 33° Celsius and the use of the optimized regulating mechanism, annual energy consumption was reduced to 26.8 MWh/a, a ­reduction of 64%. At a smaller site with 37 MWh/a, the annual energy consumption was cut by 44% to 20.7 MWh/a.

Even for locations whose construction was planned according to energy efficiency criteria – using exclusively computer hardware in compliance with ETS 300/3.1 and design with free cooling – an increase in energy efficiency of 40% to 64% is technologi­cally possible. In the meantime, this innovative regulation ­strategy has been broadened to more than 5,000 HVAC machines.

With our sincere thanks to Johann Kiendl, PASM, for kindly supporting this article.