SIG SolarCAD II: Solar Thermal Delivering 80°C Daily Even in Winter Months

The new SIG SolarCAD II solar thermal power plant, designed and installed by the Geneva-based TVP Solar and inaugurated in February this year, has proven its high performance in winter conditions.

More than 157 MWh (1.92 kWh/m²/day) of solar hot water at over 80°C were delivered to the district heat network (CAD) between January and April, i.e. 30% of the annual energy performance target of 516 MWh set between the Services Industriels de Genève (SIG) and TVP Solar.

Michel Monnard, thermal director at SIG and project instigator, is delighted: "the solar plant's performance significantly exceeded our expectations, being remarkably efficient during the cold and poor sunshine winter period when the CAD has the most need for heat."

The TVP solar thermal plant reached the target temperature of 80°C for 96 days of the 102 days recorded, supplying solar hot water to the CAD network (see the graph below); the other days saw intense rain or snowfall. This wintertime performance is unheard of for a flat panel solar thermal installation!

The high-vacuum flat panels capture enough diffused light to melt snow deposited on the surface and quickly reach required operating temperatures. No maintenance or cleaning was carried out on the panels during the 4 months; rain naturally cleaned the surface sufficiently to continue reaching the solar thermal production objectives.

The SIG SolarCAD II results demonstrate the pertinence of TVP Solar's vacuum panel technology for any and all existing district heating networks operating at temperatures above 70°C and wintertime heat demands.

With the winter period now over, the TVP solar thermal plant is expected to deliver over the coming months. The longer hours of sunlight and overall better weather conditions can only further boost this already impressive performance.