Renovation costs reduced by 20%
December 1st 2007

Working with CYNA, a multi discipline building services consultancy,George Fischer PVC-U pipework and valves have made a considerable contribution towards an overall saving of 20% in the refurbishment of the Lakeside high voltage cable cooling system connecting Dinorwig hydro-power station to the National Grid network

irst task", explained David Frise,Managing Director of CYNA,"was to crane in a mobile cooling unit so that the station, built in the early 1980's, could be bypassed and the existing valves and stainless steel pipework could be replaced by +GF+ PVC-U pipework and valves.A similar increase in technological advancement over the 25 years has enabled the cooling fans and related equipment to be replaced.

"Considerable cost saving stemmed from our ability,working from our 3D design, to prefabricate the relevant sections for the project in our own workshops.This not only saved on-site working time, and eliminated time-consuming confined space positional welding, but more importantly simplified the transport logistics as, +GF+ PVC-U pipework, was lighter and easier to transport to the secluded site by narrow gauge railway than stainless steel"David Frise concluded.

The use of heat pumps for cooling eliminated the need to extract water from the lake which helped to prevent environmental impact on the Arctic Char, a fresh and saltwater fish and one of the rarest fish species in Britain. In areas where cooling towers are used the heat pumps also enable the redesigned system to have their efficiency maximised and their latent cooling system removed.

While 110 mm diam +GF+ pipework was the most common, sizes ranged from 20 mm to 250 mm diam.The system also incorporated +GF+'s 567 Butterfly valves, Signet instrumentation and Actuated valves. CYNA carried out the design and project work, valued at £2.5m, using 3D Computer modelling linked into +GF+'s CAD software.

Dissipating approximately 700kW of thermal energy to atmosphere, when operating at full capacity, the cooling stations, along the 3 km cable route, are designed to circulate water through pipes, buried adjacent to the high voltage cable, once the cable circuits become more than 50% loaded.

Providing a clear and smooth bore, +GF+'s 567 innovative Butterfly Valve reduces actuation torque by up to 50% which increases valve life and extends service periods.With contact between the valve disc and the seal, when in the open position, designed out, formation of deposits around the 'seating area' are eliminated.With a bi directional rating of 10 bar, the 567 Butterfly Valve provides better protection against pressure surges, and pressure pulses.

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