I picked up a really interesting website from KyotoCooling that has a very interesting new approach to low energy cooling systems. The firm takes it’s name from the Kyoto Conference where our governments met and agreed Carbon reduction targets that none of them had any intention of meeting. The Hot Aisle is firmly of the opinion that in a capitalist world, costs drive change and the costs of cooling are now at the top of the CTO / CIO agenda.

Kyoto Cooling offer a new approach that gets rid of CRAC units and uses outside air to regulate the temperature of the raised floor area. Here is what Kyoto have to say:

For the proper operation of customer equipment in a data centre, stable air temperature and humidity levels are important. The ASHRAE recommended equipment input temperature is between 20°C and 25°C and the humidity should be between 40% and 55%. The customer equipment heats the cooled air and so it becomes important to remove the heated air and cool the supply air into the data centre in order to keep a stable working environment.

To cool the data centre, cold air is normally supplied through vented tiles from a raised floor. A cold air stream is blown through these vented tiles and up into the room where the installed customer equipment can access the supplied cold air. The heated air leaves the customer equipment and normally makes its way back from within the room to the installed cooling system to be cooled, filtered and humidified (or dehumidified) before being supplied back into the room again.

The air stream is normally cooled by means of a computer room air conditioner (CRAC) unit. This is normally a compression cooling unit in which a refrigerant is compressed, although various systems are available. The heated air stream gives off its heat to the refrigerant or to a cooling liquid functioning as the intermediate medium. Usually, water is utilized as the intermediate medium to carry the released heat out of the room.

Traditional room cooling designs, where hot and cold air mix, have been shown to be very inefficient and require the supplied air temperature to be lower than necessary in order to make up for the amount of hot and cold air mixing that occurs in these designs. As a result, the effectiveness and number of hours that outside air could be used is reduced dramatically. Furthermore, recirculated air is cooled with relatively complex cooling units and the total process produces a lot of unused cool air and wasted energy used to cool and supply it. As a consequence, a lot more energy than is really necessary is consumed and the costs for cooling the room are considerably higher than they could be. The costs for cooling consequently accounts for a considerable part of the total operational costs of running a data centre.

A new solution for data centre cooling, KyotoCooling, is based on the use of a “rotary heat exchanger”. The concept of KyotoCooling comprises an air-to-air heat exchanger designed as a heat wheel, where recirculated air that has been heated by customer equipment is supplied as a first air stream to the air-to-air heat exchanger, and this first air stream is then cooled using a separate second air stream which is supplied by Mother Nature from outside. By providing an air-to-air rotary wheel heat exchanger, a sufficiently large and very efficient cooling capacity can be realized for a data centre. Cooling is achieved much more efficiently and can yield considerable reductions in energy and running costs. The environmental impact is significantly reduced, because of the substantially less energy that is needed to cool the room. 

Apparently KPN are using the technology to cool some of their sites.