St. Michael’s Hospital, Warwick

Project: St. Michael’s Hospital, Warwick

Some years ago, Baxi Commercial equipment was selected as their preferred option by Coventry & Warwickshire Partnership NHS Trust, which provides mental health and learning disability services for the people of Coventry and Warwickshire, as well as community health services for the people of Coventry.  The latest property to be refurbished by the Trust is the main block at St. Michael’s Hospital, Warwick where the existing heating and water heating plant has been replaced by Potterton Commercial condensing boilers, Andrews Water Heaters high efficiency condensing storage water heaters and an Andrews air source heat pump. A spokesman for the Trust commented: “St Michaels is our largest property and our knowledge of the performance of these boilers, which we have used on a number of previous occasions, gave us the confidence to use them here. Baxi Commercial came up with a proposal for St Michaels and we were able to reduce the number of boilers, based on the outputs of those originally installed, from four to three. With regard to the Andrews water heaters, they have a good reputation and we have already installed a number of these across our estate.”

The refurbishment was carried out due to obsolescence of the heating plant and in order to reduce both operating costs and carbon footprint. The system was designed by the Trust in collaboration with the installers, Mitchell Heating & Cooling Ltd. and Baxi Commercial. The existing four boilers were removed from the plant room and replaced by three Potterton Commercial Sirius FS 160kW condensing boilers which serve existing LST radiators, air handling units and radiant overhead panels. Also installed in the plant room were two Andrews Water Heaters ECOflo 380/980 high efficiency gas-fired storage water heaters supplying DHW to showers, wash hand basins and kitchen with approximately 65 outlets. Each has a capacity of 380 litres and a recovery rate of 980 litres per hour through a temperature rise of 50oC.  An Andrews AMBIflo 20kW air source heat pump provides a pre-heated water supply for the Andrews ECOflo units via a single coil storage cylinder. The new space and water heating system is linked to the site Building Energy Management System.

Potterton Commercial’s Sirius FS is a technically advanced range of floor standing, stainless steel condensing boilers, backed by a comprehensive five year warranty. Using the latest stainless steel heat exchanger technology in conjunction with a sophisticated controls system, the range delivers maximum condensing boiler performance.   Sirius FS commercial boilers are easy to handle and install and, with ample internal space providing easy access to key components, is convenient to service and maintain.
Features of the Sirius FS range include a modulating pre-mix burner adjustable between 30% and 100%, energy efficiencies up to 107% net at 50oC flow and 30oC return and Part L2 seasonal efficiency of 96% gross. An in-built weather compensation facility optimises seasonal efficiency and encourages the boiler to condense whenever possible. The range offers a full fault diagnostics system and in-built time controls as standard with system controls options available and, as in this case, BEMS connectivity.

ECOflo condensing storage water heaters are high efficiency units featuring a low NOx pre-mix power burner that is quiet in operation, and a gross efficiency up to 98%, keeping running costs to a minimum.  The water heaters incorporate Vitraglas® silica  lined tanks which provides protection against the corrosive effect of hot water and guarantees a longer working life. All models incorporate Correx maintenance free powered anodes as standard, which substantially reduce service time and costs. The factory fitted Hydrojet® sediment reduction system on the cold inlet connection helps to prevent sediment build-up at the base of the tank giving a longer and more efficient working life. All ECOflo models can be flued either vertically or horizontally as room sealed, balanced flue appliances, offering the ultimate in siting and installation flexibility. As with all Andrews Water Heaters, heat input and flow are carefully regulated to produce a closely controlled water temperature and a high temperature anti-Legionella program is incorporated as standard.  

The AMBIflo Air Source Heat Pump from Andrews Water Heaters offers a solution for pre-heating mains cold water to support domestic hot water production via a gas fired water heater such as an Andrews ECOflo. The unit captures latent heat from the outside ambient air and uses this to raise mains cold water to a higher temperature. This is achieved using a system which is similar to a reverse refrigeration process. The unit consists of four main components: evaporator, compressor, condenser and expansion valve. Refrigerant (R407C) is circulated around these components, changing state as it transits through the four elements of the cycle.

The AMBIflo system is enclosed in a weatherproof steel casing with circuit connections available from either left or right hand side and is suitable for internal or external location. Features of the heat pump include: a self-contained one piece unit with a closed and pre-charged refrigeration circuit - no need for external refrigerant pipework or refrigerant handling during installation; a CoP of 3.2 based on an air temperature of 2oC and water at 35oC; anti-vibration mountings are included and the unit has an operational noise level of 44.1 dBA (at 10 metres); a BEMS interface is provided and duplex stainless steel pre-heat cylinders are available as an option.

In addition to supplying equipment serving the main block at St. Michael’s Hospital, Baxi Commercial has previously supplied heating and water heating equipment for two other facilities on the site: Hazelwood Terrace and Rosewood Unit, as well as another unit located at Woodhoes House. All have been fitted with Potterton Commercial Sirius floor standing condensing boilers and Andrews’ water heaters, either ECOflo or NEOflo models.