Innovation fund – roof integrated solar water heating

With the assistance of the Innovation Fund, Wellingtonian Stuart Dickson has developed an integrated unglazed solar water heating system that makes innovative use of thermal storage and a heat pump to provide space and water heating. The prototype system was designed and tested using his own house and garage as the testing site, so Stuart has had real-time feedback on how the system is operating.

Solar heat is collected through a large collector comprised of tubes installed under the north-facing side of an existing coloursteel roof. The solar collector has an effective area of approximatley 75m². The collected solar energy is stored in a 1000-litre insulated tank. The heat pump has a number of modes of operation that allow the system to efficiently provide water heating and space heating services throughout the year no matter the weather.

Aspects of the design that are unique to this project:

• Collector design - water channels integrated into a conventional roof or wall cladding
• A highly reconfigurable system using the solar collector, thermal storage tank, and heat pump to draw heat from the most suitable heat source at any one time, and supply it to the hot water and space heating services by the most efficient means possible. This means that on bright sunny days, the solar collector might be supplying heat directly to the domestic hot water system while on dull overcast days, the heat pump can utilise the energy collected from the roof and supply that to the domestic hot water system and space heating system at a usable temperature.

The system designed has been given the name ‘Solclad' and is the subject of a patent application. The project is now complete. To learn more about the product and the results see the reports at the bottom of this page.