For some time now, data centers have been in the spotlight when it comes to sustainability. Rightly so, by the way, because this new growing industry not only consumes a lot of energy but can also have a major impact on the energy transition required in many countries.
Personally, I believe in transparent reporting in the area of sustainability. The ISO/IEC 30134 is really useful for this. Only with proper reporting are we able to become more sustainable in our own industry and also serve as an example for other industries.
However, what amazes me is that at the moment a lot of attention is paid to reporting and “other things to do with the outside”. Currently, I am approached almost weekly about required ESG reporting by various companies,
What strikes me is that there seems to be less and less focus on the actual technical modifications (read opportunities) needed in data centers to save energy.
Shouldn’t we all just go back to basics ? A phased approach to continuous improvements?
The question, then, is whether all conditions are met for the cooling plant (generally the largest energy consumer besides the customer IT energy) to function optimally.
Phased approach
The next four phases can be identified to become more energy efficient in data centers:
Phase 1: Optimize air flow
Energy efficiency in data centers starts with separation of cold and hot air. This can be achieved with the installation of hot or cold aisle containment together with blanking panels within the 19” cabinets. Next to that, all gaps should be sealed and make sure there is no inverted airflow from customer IT equipment anymore
Phase 2: Optimizing and upgrading cooling controls
Only when phase 1 has been completed changes can be made safely on the computer room cooling units. There are several changes to be made, depending on the circumstances. Air control strategy based on supply air and not on return air is a very important one. The fan speed should be decreased to a setpoint which makes sure there is enough but not too much airflow within the computer room. By doing this, there is a direct energy saving on the fan and next to that the computer room cooling unit will become more efficient because of an increased delta T (difference between the supply and return air temperatures). Once the fan speed has been decreased the supply temperatures can be increased. There are a couple of more steps which can be taken but these are the most important ones.
Phase 3: Optimizing cooling distribution
Once the computer room cooling units has been optimized, we can start optimizing the cooling distribution which provides cooling capacity to the computer room cooling units. A 3-port valve on a computer room cooling units should be replaced / changed to a 2-port valve. There should be no open bypass circuits to guarantee an increased return temperature to the cooling generation plant. Converting to variable volume control and decrease the pump speed would be the next important step to make.
Phase 4: Optimizing cooling generation
The cooling generation plant can optimized by using more hours of free-cooling if possible, this is depending on the design. When phase 1,2 & 3 has been completed, the chilled water temperatures can be increased. Once these has been increased, the cooling generation plant could operate with more hours of free-cooling which saves a lot of compressor energy.
Of course we need the transparent ESG reporting, especially now with the EED and Taxonomy for example but let’s not forget the real work which needs to be done to become more energy efficiency and sustainable
These are just some simple steps which can be taken, there is a lot more you can do.