Process cooling demand in districts
Process cooling includes cooling demands such as server cooling, food refrigeration or cooling demands in industrial processes.
Cooling demands for servers and IT infrastructure
As a result of increasing digitization, commercial buildings are increasingly being provided with dedicated areas for IT infrastructure. In new office buildings in particular, there are server rooms in which large cooling loads occur in a small area. These cooling loads must be dissipated via refrigeration technology, whereby waste heat from IT infrastructure can also be reused to cover heat demands of the same building, for example. A very efficient approach is, for example, centrally installed heat pumps, which can provide heating and cooling for a building at the same time. In this way, they can generate space heat as well as server cooling.
What specific cooling loads occur for server rooms?
The electrical consumption of server rooms can be up to about 60 % of the total electrical building demand. The internal cooling loads of IT infrastructure depend on their utilization. If the servers are heavily used, the loads are higher. For an office building, for example, a simplified estimate can be made that the loads during normal office working hours are about twice as high as at other times. For server rooms, the usual target temperatures are 23-26 °C. Exceeding this temperature range can cause thermal damage to the IT components. The cooling capacity to be dissipated is basically based on the electrical power consumption of all IT equipment. On average, an heat output of 30-40% can be expected, i.e. server capacities with an electrical power consumption of 50 kW result in an average cooling output of around 15-20 kW, which must be dissipated. The area-specific electrical power for IT infrastructure varies greatly. Cho et al [1] gives an average waste heat power of 685 W/m² and the classification for IT infrastructure shown in Table 1.
| Size class | IT infrastructure | Electric power |
|---|---|---|
| IT cabinets | 1-3 IT racks | 1-18 kW |
| Simple server rooms | 1-5 IT racks | 3-30 kW |
| Small data centers (<93 m²) | 5-20 IT racks | 7-100 kW |
| Medium-sized data centers (93-465 m²) | 20-100 IT racks | 28-500 kW |
| Large data centers (>465 m²) | >100 IT-Racks | >200 kW |
Sources
- J. Cho, T. Lim, B. S. Kim: Cooling Systems for IT Environment Heat Removalin (Internet) Data Centers. Journal of Asian Architecture and Building Engineering. 7:2, 387-394. 2008. DOI: 10.3130/jaabe.7.387
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