INAIL: Smart AC control in data centre helps cut energy consumption by half

The INAIL office building in Rome houses a recently renovated 1,200 m² data processing centre. A key element of the new air conditioning concept is the building automation and control system (BACS), which introduces real-time management of relevant parameters. The renovation resulted in a 50% reduction in electricity use, a fall in emissions of 1,530 tCO2eq annually, and better reliability and scalability.

Fact sheet

  • Company: National Institute for Insurance Against Accidents at Work (INAIL)
  • Location: Rome
  • Country: Italy
Benefits

  • 50% reduction in the annual electricity consumption of the data centre and its cooling system
  • 4-year payback time
  • 1,530 tCO2eq fall in emissions annually
  • Improved data centre fail-safety

What makes this site special?

The data centre at the National Institute for Insurance Against Accidents at Work (INAIL) in Rome was built in the 1970s. It consists of eight rack rooms with a total floor area of 1,200 m2. The temperature and humidity in these rooms are maintained below their threshold values by an air conditioning system.

The data centre was renovated in 2017 to improve fail-safety, scalability and energy efficiency. A major efficiency gain was achieved by increasing the maximum temperature in the rack rooms. The new air conditioning system allows the temperature to rise to 24-26°C, which corresponds with the current ASHRAE Guidelines, while the old system kept the temperature continuously below 20°C. Another crucial energy-saving measure was the decision to make use of outdoor air as a coolant when the ambient temperature is low enough, which proved to be the case 60% of the time during the first year of operation.

Major efficiency improvements were also achieved in the design and operation of the cooling system. The fans were equipped with variable speed drives and the water-cooling circuits with two-way valves. The air conditioners were designed to work simultaneously at 50% of their maximum power under normal conditions. This brings the advantage of 100% redundancy, allowing for maintenance operations without interrupting the cooling. It also reduces energy consumption, since air conditioners equipped with a variable speed drive achieve maximum efficiency at around 50% loading.

Inail Refrigeration System
Once the temperature around the building drops below 16°C, this refrigeration system in the basement is switched off and replaced by dry cooling units using outside air.

The building automation and control system (BACS) continuously measures temperature and humidity in each room, as well as the electricity consumption of each data rack and air conditioning system. The recorded data were of great assistance when adjusting the operating curves of the circulation pumps and optimizing the on-off regulation of the air handling units. They were also used to determine the ideal temperature below which the installation switches from forced cooling by refrigeration to dry cooling using outdoor air (16°C). By making those final adjustments, the energy efficiency of the cooling system was maximized.

A crucial function of the BACS is preventing the temperature and humidity around the data racks exceeding threshold values. It does so by feeding the microclimatic measurements directly into the air conditioning control systems. This optimized climatic control maintains the computer servers in optimal conditions and reduces the risk of downtime.

A major advantage for the operation and maintenance of the data centre is the flexibility and scalability of the control system. When new machines are added to the rooms, the BACS automatically adjusts the operating conditions and set point values of the air-conditioning units.

The recorded data were of great assistance when adjusting the operating curves of the circulation pumps

The energy savings achieved by the new air-conditioning system controlled by the BACS are remarkable. The annual electricity consumption of the data centre was reduced by 50%, resulting in a payback time on the investment of four years. The associated carbon emission reduction of 1,530 t CO2eq per year[1] is equally impressive. Coupled with this, the improved micro-climatic regulation in the rack rooms increases data centre fail-safety.

[1] Calculated using 431 gCO2eq/kWh for low voltage end-use electricity in Italy in 2013.

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