The idea for the Data Centre Heat Company (DCHC) started, as all good things do, with a home renovation project to replace an old oil-fired boiler with a new ground source heat pump. As our HVAC consultant patiently explained to us about the Coefficient of Performance or COP, that even a small increase in the temperature of the input heat source leads to scaling COP. The low grade heat recovered from data centres, which typically is around 25-30C, can be used to supply input heat to a heat pump at double or even triple the efficiency of a standalone air source heat pump, especially in cold weather.
Ok, so we need to get the heat from data centres to where it is needed. But for data centre operators looking at doing this themselves, it turns out that it is prohibitively expensive for them to build out their own network. Their best bet is where there is an existing district heating network (DHN) that they can feed into. But there is a problem even with this, in that most DHNs is that the input temperatures need to be much higher, around 60-90C, or more in the case of steam-based DHNs. So the data centres need to put in place a heat pump to uprate the heat, and pay for the electricity to do this as well as the upfront capital expenditure. No wonder the business case struggles to add up and operators put the idea of exporting waste heat into the bucket of public good works rather than hardnosed business decision.
This sent us down the rabbit hole of how District Heating Netorks are developed, and we realised why they are so expensive and why generally speaking they are created as a civic utility rather than a private venture. The hot water in DHNs must be sent through heavy, insulated pipes which are extremely expensive to install and maintain, and can only be built over a relatively small area to avoid excessive heat loss.
But there is a new type of heat network which potentially solves a lot of these problems. So-called fifth generation networks, which are only just starting to be developed at scale, keep temperatures low at around 20-30C which means pipework doesn't need to be insulated and heat loss is less over long distances. Where required, water-source heat pumps uprate the temperature at substations near the end user. In some cases, such as new build developments with liquid underfloor heating, a heat pump isn't even necessary meaning no additional energy is expended other than from the pumps circulating water through the network. As such, the cost of developing these networks can be significantly lower than traditional DHNs. But 5th generation heat networks have even more benefits over earlier DHNs, in that correctly configured they can supply both heating in winter and cooling in summer. Taking advantage of energy cascading, for example, waste heat can even be used to create chilled water which can be used for the benefit of end consumers from homes to data halls.
It was marrying these two concepts together - first the idea of aggregating waste heat recovery and removing the requirement for data centres to go it alone, and secondly of taking advantage of new 5th generation heat network technology capabilities, that compelled us to start the Data Centre Heat Company and empower the data centre sector to scale heat recovery for the data centre sector.
