Tallaght University Hospital energy audit – Dublin

About the organisation

The Tallaght University Hospital treats over 410,000 patients per year and employs almost 3,000 staff. With 562 beds, 12 theatres and 14 critical care beds in operation, it is one of the largest hospitals in Ireland.

When the hospital decided to improve its energy efficiency, it commissioned Maximpact energy expert Gerard to undertake an energy audit at the hospital.

What Maximpact did

Due to the diverse nature of the activities in the hospital, there is a need for heating and cooling via ventilation in the hospital all year round. There is a large range of mechanical and electrical plants installed in the hospital to satisfy the needs of the patients and staff, all of which use electricity and/or natural gas as their primary energy source.

The audit examined the operation of all the systems, with a view to improving each system’s energy efficiency and to control energy wastage.

Findings from the energy audit

The Tallaght University Hospital was not initially designed with energy efficiency as a priority, but there are some notable energy-related features incorporated in the building. These include the provision of an extensive building management system (BMS) to monitor and control the large heating, ventilation and air conditioning plant and associated boilers and chillers.

The hospital also operated a sizable vacuum plant and air compressors for medical reasons. The hospital’s lighting systems accounted for over 20% of its total energy usage. There are also six waste anaesthetic gas extraction locations around the hospital.

The analysis found that energy savings of over 35% were possible, with an overall payback period of under 3.3 years.


Considerable savings were found in the operation of hot water boilers, by better controlling the combustion efficiency and temperature levels associated with space heating and hot water. Improvements to the controls of the HVAC system and chiller plant were also identified, and these improvements required minimum investment. Improvements to the lighting systems required retrofits and better control in some areas.

Investigations showed potential for installing a combined heat and power system. A feasibility study for a solar thermal hot water generation was also conducted.

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