A ‘world of difference’ and 70-80% savings with hospital heating pumps




The situation

Sligo University Hospital had an inefficient boiler plant and heating system. “Very inefficient,” stresses Declan McGoldrick of the hospital’s HSE Estates Department. 

Sligo is the biggest hospital in its region of northwest Ireland, serving an area of about 280,000 people. It covers 33,000 square metres (about 355,000 square feet), employs more than 1,700 staff.

“The circulation pumps we had were constant speed pumps. They were delivering hot water at medium temperature – 130 degrees C,” he says. “The seals were breaking on them. They were causing a multitude of maintenance issues. The heating circuits here at Sligo University Hospital are long. Consequently, we had substantial pipe losses occurring from them. This meant our Delta T was not working as efficiently as it could have and were at a lower rate than the original design.”

He adds that the index pipe circuit on the heating system is two air handling units. “We were finding that we weren’t getting temperatures in colder weather, and it was a necessity for us to upgrade our pump system.”

The solution

As part of an ongoing program with the Sustainable Energy Authority of Ireland (SEAI) to reduce the building’s energy use, the hospital targeted the boiler house and circulation pumps as an upgrade project. A Grundfos Energy Check on the existing pumps resulted in a report showing the savings that could be made by replacing them with intelligent MAGNA3 and TPE3 pumps, which the hospital did.

“Grundfos pumps are intelligent pumps,” says Declan McGoldrick. “They can auto-adapt to the particular load that’s on the circuit. And this is important in that we can match up the boiler load with the actual loads that are required by the heating system within the hospital.”

The new pump system also fixed the hospital’s Delta T problem. “We installed temperature stats in the return pipes,” he says. “We use those to determine the Delta T between the flow and the return, allowing us to calculate our heat output on the pump. The mass flow rate can be calculated from the pump itself.”

The outcome

“We are saving in excess of 70 to 80 percent on electrical usage on our new pump system,” says Declan McGoldrick. “And we are fine-tuning those savings further by reviewing the operating data through the Grundfos remote MI301 unit.” This Bluetooth interface connects the pumps to smartphones or tablets via the Grundfos GO app, a platform for mobile pump control. They use it to generate monthly energy and flow rate reports. 

He says that they made further savings recently via the remote app when Grundfos sales engineer Liam Kavanaugh noticed how the TPE3 pumps’ control mode could be set differently.

In addition, he says, the pumps’ Heat Energy Monitor automatically calculates the heat output and flow rates. “And the new pumps are controlled by BACnet communications cards that work over our BMS system here at the hospital. We use the information from this system to have better control over some of our processes within the hospital and to make further savings.”

Declan McGoldrick says the hospital’s old system had no communications at all. “So basically the pump was just switched on. There was no information coming back from the pump on energy use – both electrical energy use by the pump itself or by what the heat load was on the particular circuit. 

“So there is a world of difference between what we had before and what we have now,” he adds. “This is a real positive step for us in the control of energy on heating within the hospital.

”In 2018, Sligo University Hospital won the Public Sector Award in SEAI’s Sustainability Energy Awards for its boiler plant and pumps upgrade. 

“It has been a revelation for us to work with a supplier that has very good technology and more importantly, provides a backup service for that technology,” he says. “I’m proud of the savings that we’ve achieved here.”


Hospital heating system upgrade


Sligo, Ireland


Sligo University Hospital

The main entrance to Sligo University Hospital in the northwest of Ireland.


Liam Kavanaugh of Grundfos (second from right) checks the status on a TPE3 pump via Grundfos GO and an MI301 remote unit.


Michael O’Brien, Energy Officer, HSE Estates, inspects two of the hospital’s MAGNA3 pumps.


At a row of MAGNA3 pumps in the boiler room at Sligo University Hospital.




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