21 January 2011

STOKVIS CUTS ENERGY BILL IN NEW EDINBURGH HEALTH CENTRE

Stokvis Energy Systems is providing the complete solar heating system for the new Chalmers Sexual Health Centre in Edinburgh .  The system is forecast to produce impressive energy savings of around 8,500 to 10,500kWh.  It comprises seven Ecotube DF120 solar evacuated tubes, a solar thermal single coil, a 1,600 litre buffer vessel, unvented mains kit, a bare plate heat exchanger and a free issue transfer pump.

The solar and domestic hot water plate heat exchanger is controlled by a building management system, while conventional gas-fired boilers support the heating system. When the domestic hot water storage system needs to be topped up the control system is designed to switch on the boilers and a plate heat exchanger that is located between the boilers and the hot water storage vessel.

“The entire system must be integrated to allow the solar system always to pre-heat the vessel. If extra heating is required, a sophisticated time clock control system opens the necessary valves and brings in the boilers,” explained Malcolm Aitken , Regional Sales Manager – North of England & Scotland of Stokvis Energy Systems.

“Supplying the solar heating system demanded close co-operation between ourselves, the project consultant, Arup based in Edinburgh, and the controls company to ensure that the building management system (BMS) was integrated in such a way that it could control both the conventional and renewable elements of the heating,” he added.

“Control is particularly challenging because the BMS has to respond to a number of temperature sensors within the storage vessel and interpret them accurately in order to know when to switch the heat generators on and off. It also has facilities to circulate the stored water on a regular basis to prevent the formation of legionella, a critical feature for any healthcare application.”

The Stokvis evacuated tube solar collector is designed to maximise the solar energy absorbed and minimise heat loss through radiation.  It has substantially reduced the amount of ‘parasitic’ energy lost by most evacuated tube systems (energy used up by the system itself during the process of converting solar energy to heat).

As a result, the system requires smaller pumps to circulate the fluid in the evacuated tube collector, which means that there are fewer drops in pressure through the system, giving a more sustained level of heat than almost any other system.

Independent laboratory tests prove that the Stokvis Energy Systems solar collector produces over 750kWh per sq m per year in direct heating mode and  850kWh per sq m per year in pre-heat mode.

Chalmers Hospital is being refurbished and extended to provide a new integrated sexual health service. The original hospital building built in 1860 has been retained, but previous additions have been demolished to make way for a new extension, creating a new facility designed especially to meet the needs of patients attending family planning and well woman service and genitourinary medicine.

The Stokvis heating system has been installed by contractor Vaughan Engineering, based in Broxhill near Edinburgh .  The new building will be connected to the original hospital by an atrium space providing a light and airy atmosphere.