J & E Hall has designed, built and installed a new natural refrigerant cooling system at a London hospital by employing the latest technology, protecting the environment and delivering efficient cooling for critical medical areas. The ammonia-based system at Homerton University Hospital in Hackney is responsible for cooling the operating theatres, the maternity and the intensive care units – so safety is a high priority.
Stand-out features are U-tube suction separators fitted to the chillers – reducing the refrigerant charge by a third – and a safety shutdown program ensuring that any leaks are contained within the system. The two J & E Hall special Aquachill units with a half a mega-watt of cooling capacity each are employed to cool water from a temperature of 12oC to 6oC.
This system for the hospital was designed, built and installed by J & E Hall. Mark Colley, sales and marketing manager for J & E Hall Special Products, said that the hospital authorities had at first been hesitant to consider a natural refrigerant option to replace an existing J & E Hall’s cooling system, running on R22. But they had been won over once they had been told about the efficiency of the equipment and safety measures in place to support the system.
The two special Aquachill units give the hospital authorities a 50 per cent increase in cooling capacity, although they had to fit into the same small plant room with the existing system still meeting the demands of a busy hospital.
The system was designed by J & E Hall Special Products Division in Dartford and installed by the company’s Peterborough-based Regional Contracting Division. Applications engineer Steve Gowing coordinated the installation on a day-to-day basis. He says the safety features will ensure that if there is a leak not a drop of ammonia will escape into the atmosphere.
“We have installed an ammonia scrubber behind the system,” he explained. “There are extract fans to remove the motor heat and an ammonia detection system near the exhaust fan. So any air that passes to the outside has to go over the ammonia detector. Even if the smallest amount of ammonia escapes, the system will shut the extract fans down and start the air scrubber."
Hall’s natural refrigerant system is suitable for large public buildings and sports stadiums. There are plans to extend the system to other parts of the hospital. The key to success at Homerton is thinking ahead. Steve Gowing said: “When installing a system like this in such a small space while an existing system continues to operate needs careful planning. The Hall’s design team did a great job on this. Equipment needs to arrive just in time – we had nowhere to store anything. So good planning and design was crucial and it paid off in the end.”
