Energy Efficient Data Centre Cooling System

Dublin Institute of Technology (DIT) is seeking companies to license a novel data centre cooling plant arrangement that greatly reduces energy requirements and operational costs. The system makes maximal use of ambient cooling technologies and includes a patent-pending air flow control arrangement that reduces energy consumption further and helps eliminate hotspots.

Current systems based on Computer Room Air Conditioning (CRAC) close control units are expensive to run because all of
the heat generated by the servers is dealt with by electrically driven refrigeration machines. In addition, fan power, which is substantial in these applications, is generally constant and sized for the maximum cooling load presented.

Researchers at DIT have developed a system that utilises several low energy cooling technologies to reduce the refrigeration load and a novel fan control system to reduce fan power. The system is applicable to any internal environment requiring controlled temperature/humidity conditions and having long running hours and a high sensible heat ratio, e.g. telecoms equipment rooms, mainframe computer rooms and many manufacturing and light industrial applications. Energy cost savings for a large data centre in Dublin have been estimated to be in excess of 40% and carbon dioxide emissions are reduced. These estimates are for a data centre maintaining the recommended, rather than the allowable, operating environment specified by the American Society for Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).


  • Data centres, mainframe computer rooms, telecoms equipment rooms.
  • Manufacturing and light industrial environments having long running hours and a high sensible heat ratio.


  • Reduced running costs – substantial reduction in energy costs for new build; energy performance of
    existing systems can also be improved.
  • Low initial costs – patent-pending aspect requires little additional equipment.
  • Negligible additional maintenance costs – requires little additional equipment.
  • Improved server performance – hotspots due to recirculation are virtually eliminated.
  • Server noise reduction –server fan speeds are generally lower due to elimination of hotspots.
  • Reduced carbon footprint – CO2 production is reduced in step with reductions in energy usage.

Technology Description
The proposed data centre cooling plant arrangement integrates the following low energy cooling technologies to maintain the recommended ASHRAE operating conditions while substantially reducing energy costs:

• An air side economiser to maximise the use of ambient air cooling.
• A water side economiser to take advantage of depressed wet-bulb conditions.
• An adiabatic humidifier powered by excess server heat rather than electricity.
• Elevated chilled water flow temperatures leading to a better coefficient of performance (COP).
In addition, the system includes variable speed fan drives to reduce fan power and a novel air flow control arrangement that reduces fan energy consumption further and minimises hotspots by virtually eliminating air recirculation in the server room.

Stage of Development

Dublin Institute of Technology has filed a patent and continues research in this area.

Michael Crowley

Dr. Michael Crowley
Michael Crowley, a chartered engineer has over ten years industry experience as a design engineer and section leader with a number of mechanical engineering services (HVAC) consultants and contractors. He is a graduate of University College Dublin and Dublin City University and has lectured courses at DIT in Building Services Engineering (HVAC), Refrigeration, and Building Energy Simulation.

Michael’s Ph.D. investigates and develops numerical methods for stiff systems of ordinary differential equations, which arise in the simulation of energy flows in buildings. He is currently developing novel plant arrangements for (low energy) cooling of data centres. Other research interests include detailed computer simulation of heat and mass transfer – especially in the context of buildings and plant.

The Dublin Energy Lab
The Dublin Energy Lab (DEL) a research group in DIT specialising in the fields of electrical power, energy policy, solar energy and zero emissions buildings. They are leaders in science and engineering energy research in Ireland and have been involved in many large scale projects and applied research collaborations with national and international industry partners.

Posted in Cooling