Spirax Sarco Easiheat Engineered Systems have cut water heating bills at Harefield Hospital by 30 percent and are saving £3,000 a year in maintenance costs. They have also overcome temperature control problems in the domestic hot water supply during peak demand.
Replacing the hospital’s calorifier-based domestic hot water system, the new engineered systems have eliminated a host of inefficiencies and problems that dogged the hospital.
Previously, steam was used to heat primary water to 81°C in the calorifier. This water then heated a secondary supply to 60°C in a shell and tube exchanger and the secondary water was stored in three, 1,500 litre cylinders before being pumped around the hospital’s ring main.
Heat losses during water storage made the system inefficient and costly to maintain. For example, the calorifier, shell and tube heat exchanger had to be stripped down annually for insurance inspections. Hygiene was another problem, with the storage tanks requiring frequent internal cleaning to prevent a build up of contaminants.
Furthermore, the system was unable to cope with peak demand. “It was always struggling with big loads,” said the hospital’s Estates Manager Mr Amjid Baig. “In the morning when everyone was having a bath, the water temperature would sometimes drop as low as 43°C.”
The three Spirax Sarco EasiHeat units eliminate all these problems. Rated up to 1,200kW, EasiHeat systems rely on plate heat exchangers to provide domestic hot water on demand. This avoids the need for water storage and its associated problems.
According to Mr Baig the new systems have cut 30 percent off the water heating bill at Harefield Hospital and have maintained the desired water temperature throughout the hospital at all times, even under peak load.
In addition, the plate heat exchangers at the heart of the EasiHeat systems are low maintenance and do not require annual insurance inspections.
