The new hospital building had a ‘10% renewable obligation’ as part of its planning consent – 10% of the energy use had to be provided by a renewable energy source and the architects included solar energy as the means of meeting that obligation. The system sees solar thermal panel collectors on the south facing roof of the building to gather the solar energy into the system. The main contractor brought in ISO Energy as the specialist solar sub-contractor to deliver this part of the project for them and in turn ISO Energy turned to Sentinel to provide the means of delivering the optimum benefits from the installed solar system.

“Many local authorities insist that a percentage of the energy requirement for a new building comes from renewable energy sources so we’re used to responding in this way,” confirms Stuart Whiting. “We have worked closely with Sentinel previously when we have installed ground source heat pumps and found their specialist knowledge in these areas to be highly beneficial, so knowing they also specialised in providing bespoke solutions to solar thermal installation needs, I had no qualms approaching Sentinel to help us with this installation.”

And it’s a sizeable installation. 600 litres of glycol based thermal fluid takes some filling: “The benefits to us of using Sentinel are many,” he continues. “Not least of all the level of service we get from them. They supplied the product we needed at a good price and delivered within three days of order – that’s ideal for us. We didn’t want the fluid on site for weeks waiting to be used but equally we wanted to be able to order it so it arrived when we needed it. As well as the glycol based fluid product, they supplied the filling kit which made life much easier for us and they also supplied the check kits so we could monitor the system as the fill took place.”

The high performance solar heating system installed by ISO Energy and filled with Sentinel R100 heat transfer solution will meet the required 10% renewable energy target delivering an estimated 34,000kWh/annum and reducing carbon dioxide emissions by approximately 7,250 kg/annum.

The value of solar heating depends on the continued efficiency of heat transfer between the solar collector and the thermal store. Sentinel R100 glycol based fluid is formulated for solar heating systems operating up to 200^oC, containing special reversibly vapourisable inhibitors to protect all metals commonly found in solar heating systems when exposed to both liquid and vapour phases.  Whether the system is operating at its highest or lowest temperatures, system metals are afforded superior protection against corrosion, fouling and deposit formation. Sentinel R100, a clear blue liquid, is easy to use and effective straight from the container.

Sentinel R100 is best charged from its 10 or 20 litre containers into a system using the Sentinel SolarFlush unit. Easy to manoeuvre on pneumatic wheels, the Sentinel SolarFlush unit is the quickest, most efficient way to flush, vent and fill solar collector circuits to exactly the right pressure. The large tank that forms part of the unit is easily cleaned and allows users to observe the progress of the operation.

The SolarFlush unit comes with a ‘-40°C to 60°C’ temperature resistant hose, a dry self priming pump and a cast iron housing. It features an integral strainer and a manual drain valve.

It’s important to check and monitor the efficiency of any solar collector circuit and the Sentinel Solar Check Kit is invaluable for both first fit and on-going maintenance of solar collector circuits. The kit allows users to check the orientation of solar panels for optimum energy collection and can confirm the level and effectiveness of anti-freeze in thermal fluid, providing a reliable way of determining the need for and timing of thermal fluid replacement.

Sentinel’s Neil Davies says that this is an excellent example of the kind of installation where Sentinel can make a positive contribution:

“Whether domestic properties or commercial installations, the Sentinel solar product range is finding a very impressive niche as the quantity of solar installations increase year by year.

Many of the thermal fluids being used today were not designed for solar thermal use and struggle to cope with the harsh environment in which they have to operate. The top temperatures experienced on hot summer days can exceed 230⁰C and many of the non-specialised glycol mixes simply weren’t designed to work well at those temperatures and suffer from premature degradation.  It’s really key for renewable heating systems to deliver at their optimum levels of efficiency otherwise the investment in them is pointless, and if the glycol mix breaks down quickly, its ability to collect and transport the solar energy to the heat store is rapidly reduced, making the installation a pretty pointless exercise in the first place.