UK: A busy hospital’s need to create a new service building meant relocating seven roof mounted condensing units cooling the hospital’s mortuary and provided the ideal opportunity to comply with current and future refrigerant regulations.
The hospital in the East of England turned to its framework consultant, Johns Slater and Haward (JSH) but it was no easy task.
“The hospital can’t just stop working and you can’t predict a quiet period,” explained JSH’s senior mechanical engineer Neil Garnett. “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 R22 condensing units were due for replacement anyway, but this presented Neil with a further challenge.
“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. 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.”
Neil Garnett discussed his options with Danfoss’ commercial consultant, Mark Fiddy. “I knew Danfoss and the Optyma range very well. I didn’t realise Danfoss had R452A Optyma units and I liked the sound of it.”
Seven new generation Optyma 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 rooms to -18°C.
The packaged Optyma units are fully housed and include filter driers and sight glasses, making them “plug and play” and greatly reducing downtime.
Les Mitchell, branch manager at Pitkin & Ruddock Ltd, Bury St Edmunds, who installed the new system, is well aware of the Optyma range. “We use Optyma ranges wherever possible, anywhere from small cold rooms to large freezer rooms.”
He was also impressed by the timing of the decision to switch to lower-GWP refrigerants. “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.”
Despite unseasonable weather interrupting installation, the project was completed on schedule and with the minimum of disruption. Eight months since the first units were commissioned, there have been no reported issues, and the condensing units are said to be performing well.
Importantly, the choice of R452A made the installation no more difficult than any other job.
“R452A was a new refrigerant for us, but it was really easy,” reported Les Mitchell. “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.”
