Working towards net zero – What can be done with low-grade waste heat during the summer?
23rd September 2020
EcoCooling looks at solving the problem of data centre waste heat in the summer with a biomass dryer setup at Boden Type One DC.
More than two years in and the Boden Type One DC (BTDC) project is still evolving with the team seeking new ways to increase efficiency and achieve carbon neutrality in the testbed facility.
The recovery of waste heat from data centres is becoming a major issue. In a normal data centre, all of the electricity supplied is rejected as low-grade heat. There are working examples of linking data centres to district heating schemes but this is not always practicable due to the low temperature of the exhaust air and seasonal variations in heat rejection and heating requirements which are not synchronised.
The latest focus for the BTDC project is to see how the waste heat can be utilised in a way that overcomes these issue.
Fresh air cooling and waste heat
During the winter the majority of the heat produced by the servers is recycled back into the fresh air stream to heat the incoming air to the desired temperature, therefore reused. During these colder months, the facility rejects a small percentage of the heat produced by the servers consistently, however, this significantly increases in summer when the ambient temperatures are high and there is no requirement for warming of this incoming air.
The objective was to find a good use for this large amount of waste low-grade heat in the summer months, when there is no requirement for heating offices or houses directly, therefore solving the problem of synchronisation.
How can waste heat be used?
Although not part of the initial H2020 project, in this latest trial, the waste heat is being used to dry wood chips for biomass. This involved linking the data centre building to a container with a dryer inside. The dryer was supplied by SFTec using technology from the University of Oulu.
The aim is to use the waste heat from the data centre to reduce the moisture content in the wood chips to 30% so it can be fired in combined wood chip and flue gas heat recovery boilers. These boilers are a requirement to preheat the district heating water before it is released to homes.
The test will see a total of 150 cubic meters of raw chips dried at Boden site in September.
What will happen after the trial?
If successful, it will provide a viable use for the waste heat generated by fresh-air cooled data centres. It will also allow data centres to become part of the circular economy by creating materials that can be used to heat people’s homes and offices, reducing the carbon footprint of the entire cycle. By building these reuse processes into the design of data centres, the aim is to eventually create a carbon positive facility or ‘energy prosumer’.
Since its inception, EcoCooling has been at the heart of the Boden project with the cooling of the facility being an integral part of making it the world’s most efficient data centre. Being part of this trial and the wider Boden project enables EcoCooling to get a holistic understanding of what it takes to make a data centre sustainable from a community perspective. It is this type of knowledge that will inform future developments of EcoCooling’s data centre specific CloudCooler range and ensure our solutions provide customers with the best possible solution.
What’s really exciting about this trial is that the benefits of it could be felt very quickly by the world outside of the data centre. The team at Boden is confident that it can achieve the right level of moisture content to make this use of waste heat a viable initiative that can be scaled up and deployed with relative ease.
Find out more about the Boden Type One DC project and keep up to date with all the latest developments here.
You can also discover EcoCooling’s data centre specific CloudCooler range here.