Case studies/Projects

Lower-GWP enhanced range of condensing units provides cooling for hospital cold rooms


When a busy hospital needed to relocate its cold room condensing units, Consultant Neil Garnett knew it was time to upgrade to F-Gas compliant refrigerants. He chose OptymaTM Plus units, running with R134a and, crucially, R452A.

The Danfoss OptymaTM outdoor condensing unit ranges provide high energy efficiency, reliability and low noise operation. Easy to install service and maintain, they all use lower-GWP refrigerants and are Eco-design and F-Gas compliant.

For an efficient system control and reliability, Danfoss has a wide range of components, such as thermostatic and electronic expansion valves, and a brand new enhanced range of solenoid valves – EVR. All these components are qualified for use with lower-GWP refrigerants.

When a hospital in the East of England decided to create a new service building, it also meant relocating seven roof mounted condensing units that were cooling the hospital’s mortuary. The hospital turned to its framework consultant, Johns Slater and Haward (JSH) and as senior mechanical engineer Neil Garnett points out, it was no easy task. “The hospital can’t just stop working and you can’t predict a quiet period,” Neil explains. “I needed to come up with a design that would let the contractors work fast and at relatively short notice when the opportunity arose.”

The need
Transition to lower-GWP refrigerants
A recent survey revealed that the condensing units were due for replacement, but this presented Neil with an additional challenge of convincing a cost-conscious hospital to move away from the ozone-depleting refrigerant R22 to a lower-GWP (Global Warming Potential) alternative, thereby complying with F-Gas regulation.

He says: “I wanted to provide a solution which was fully compliant with F-Gas regulation and the 2020 phase down of higher GWP refrigerants whilst at the same time, ensuring that the new installation met all the operational requirements. “Capital expenditure and life cycle costs, are a priority at any hospital, but they could see it was in their interest to have a unit they could rely on in the future – without having to replace it again. We worked with the maintenance contractor on the specification, and everyone agreed we’re getting what’s best for the hospital.”

Danfoss’ intervention
R452A: A like-for-like replacement
Knowing that Danfoss offers a range of lower-GWP cooling solutions, Neil discussed his options with the company’s commercial consultant, Mark Fiddy. Neil recalls: “I knew Danfoss and the OptymaTM range very well. I met with Mark and when I heard about his experience, I felt reassured. I didn’t realise Danfoss had R452A OptymaTM units and I liked the sound of it.” With Mark’s support, Neil specified seven New Generation OptymaTM Plus condensing units, five MBP units running R134a plus two LBP versions using R452A allowing the mortuary staff the ability to rapidly drop the temperature in two smaller cold roomsto -18 °C.

Both R134a and R452A have a GWP level below 2500 and are therefore fully compliant with the F-Gas regulation. “With its lower-GWP refrigerants strategy, Danfoss was clearly the way forward,” says Neil. “The backup support has been good, and the fact that OptymaTM is a packaged unit makes it so much easier for the contractors to work quickly.”

Neil selected the following Danfoss equipment:

  • 5 x OptymaTM Plus condensing units with R134a for MBP application
  • 2 x OptymaTM Plus condensing units with R452A for LBP application
  • 7 x T2 thermostatic expansion valves
  • 7 x EVR solenoid valves

Its plug and play and that reduces downtime.
Another fan of the OptymaTM plus condensing units is Les Mitchell, branch manager at Pitkin and Ruddock Ltd, Bury St Edmunds branch, who installed the new system. “We need to make sure the design is right,” he remarks. “When we see OptymaTM outdoor units specified, it’s always a relief.” “We use OptymaTM ranges wherever possible, anywhere from small cold rooms to large freezer rooms. Everything is in there – filter drier and sight glass – it’s already housed and easy to install. It’s plug and play – and that reduces downtime. “The units are very quiet so you can use them without disruption or complaints.” Les was also impressed by the timing of the decision to switch to lower-GWP – echoing Neil’s view that it is in his customer’s best interests. He says: “Given the short lifespan of R404A, the number of those units still being sold seems strange. We’ve been trying to phase out R404A for the last twelve months so it’s helpful that Danfoss are providing clear advice on a compliant replacement.”

The Danfoss Solution
The longevity of the product
Despite unseasonable weather interrupting installation, the easy-to-use nature of the OptymaTM units meant Les and his team could meet the challenging schedule. He says: “The hospital is really pleased. We didn’t cause too much disruption and were able to decide on a day-to-day basis whether we could go ahead. Even with those gaps, we were still able to complete the job on time.” Eight months from the time that the first units were commissioned, there have been no reported issues, and the condensing units are performing well. “Danfoss condensing units are really efficient,” says Neil. “But it was the longevity of the product that appealed the most. You can’t put in something that’s only going to last for two or three years.”

Very straightforward
Importantly, the choice of R452A – and the support from Mark at Danfoss – meant switching to lower-GWP refrigerant was no more difficult than any other job. Les says: “R452A was a new refrigerant for us, but it was really easy. Its wide temperature scale made it a good like-for-like replacement for R404A. As far as possible, everything we install now will be either R452A or R449A.”

Neil agrees: “The Danfoss technology is ready and available now, making selection simple and straightforward.”

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