Data centers have popped up in many places around the world to handle our appetite for web-browsing, online purchasing, and commercial information services. These facilities are very energy intensive and use 1-2% of the world’s energy demand. This is expected to be 20% or more in the near future. Almost 100% of the electricity used is rejected as heat – often from HVAC units in the data centers that keep the computers and power supplies cool. Currently, these large HVAC systems transfer the heat to a refrigerant, which is then rejected to the environment directly in an air-cooled condenser, or using cooling towers with evaporative cooling. A Dublin startup company is looking using this heat to heat a town instead.
The heat rejected to cooling tower is not hot enough to be used directly, but if used in a water source heat pump, the heat could be boosted to 60°C. This would require additional electricity, but for each unit of electricity used, three or more units of useful heat can be provided for heating purposes. A study performed by John O’Shea, an energy systems analyst with the Tallaght District Heating system, suggested that 10% of the EU’s energy demand for space heating and hot water. They have a system in place to capture the heat from local data centers to heat the nearby university and several county buildings. Such systems could be expanded throughout the continent to heat 1.6 million homes and offset a significant portion of the carbon generated to operate the data centers. The systems aren’t cheap, but when financed provide a cost for heat equal to natural gas, without the price volatility. – Steve Terry, DTC HVAC & Refrigeration Instructor
