Mr Garnett selected Danfoss's Optyma Plus units, running with R134a and, crucially, R452A.
West Suffolk Hospital had decided to create a new service building, which meant relocating the seven roof mounted condensing units used in cooling the hospital’s mortuary.
The hospital turned to its framework consultant, Johns Slater and Haward (JSH). Senior mechanical engineer Neil Garnett explained: “The hospital can’t just stop working and you can’t predict a quiet period. I needed to come up with a design that would let the contractors work fast and at relatively short notice when the opportunity arose.”
Transition to lower-GWP refrigerants now
A recent survey had revealed that the condensing units were due for replacement, but this presented Mr Garnett with a further challenge: convincing a cost-conscious hospital to move away from the ozone-depleting refrigerant R22 to a lower-GWP alternative, complying with F-gas regulation.
He said: “I wanted to provide a solution which fully complied with F-gas regulation and the 2020 phase down of higher GWP refrigerants, whilst at the same time ensuring 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.”
R452A: A like-for-like replacement
Knowing that Danfoss offers a range of lower GWP cooling solutions, Mr Garnett discussed his options with the company’s commercial consultant, Mark Fiddy.
Mr Garnett recalled: “I knew Danfoss and the Optyma range very well. I met with Mark and when I heard about his experience, I felt reassured. I didn’t realise Danfoss had R452A Optyma units and I liked the sound of it.”
With Mr Fiddy’s support, Mr Garnett specified seven Optyma Plus New Generation condensing units, with five MBP units running on R134a and two LBP versions using R452A, allowing the mortuary staff to rapidly drop the temperature in two smaller cold rooms to -18 °C.
Both R134a and R452A have a GWP level below 2500 and are therefore fully compliant with F-gas regulations.
Mr Garnett added: “With its lower GWP refrigerants strategy, Danfoss was clearly the way forward. The back-up support has been good, and the fact that Optyma is a packaged unit makes it so much easier for the contractors to work quickly.”
Plug and play and reduces downtime
Another fan of the Optyma Plus condensing units is Les Mitchell, branch manager at Pitkin & Ruddock's Bury St Edmunds branch, who installed the new system.
He commented: “We need to make sure the design is right. When we see Optyma outdoor units specified, it’s always a relief.
“We use Optyma ranges wherever possible, anywhere from small cold rooms to large freezer rooms. Everything’s in there – filter drier and sight glass – and 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.”
Mr Mitchell was also impressed by the timing of the decision to switch to lower GWP, echoing Mr Garnett’s view that it’s in his customers’ best interests.
He added: “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 12 months, so it’s helpful that Danfoss are providing clear advice on a compliant replacement.”
Longevity of the product appealed most
Despite unseasonable weather interrupting installation, the easy-to- use nature of the Optyma units meant Mr Mitchell and his team could meet the challenging schedule.
He explained: “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 since the first units were commissioned, there have been no reported issues and the condensing units are performing well.
Mr Garnett added: “Danfoss condensing units are really efficient, 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.”
Importantly, the choice of R452A – and the support from Mr Fiddy at Danfoss – meant switching to lower GWP refrigerant was no more difficult than any other job.
Mr Mitchell said: “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.”
Mr Garnett agreed: “The Danfoss technology is ready and available now, making selection simple and straightforward.”