RISE Solar Hot Water Test Facility

RISE has a basic facility that provides the data required for calculating the energy consumption of a solar hot water system as set out in Australian Standard, AS4234-1994 (Solar water heaters – Domestic and heat pump – Calculation of energy consumption).

The required data for these calculations are a collector efficiency curve, measured in accordance with Australian Standard AS2535.1:2007 (Test methods for solar collectors.  Part 1: Thermal performance of glazed liquid heating collectors including pressure drop), and a storage tank heat loss coefficient, measured in accordance with Appendix B of AS4234-1994.

The apparatus used for the collector thermal performance tests is shown schematically in the Figure below.

A large, well-insulated tank is used as the inlet water supply to the collector.  A control system uses a small heater element to bring the tank to, and maintain the tank at, the required temperature.  The water flow during this pre-test preparation period flows through the covered collector so that the collector is already at the inlet temperature when the actual testing commences.  When the testing commences, the cover is removed from the collector and the outlet water from the collector is directed to a dump tank.  At the end of a test the water in this dump tank is emptied back into the main tank.

During the course of the test, measurements are made of the collector inlet and outlet fluid temperatures, the ambient temperature, the solar radiation on the plane of the collector, and the wind speed adjacent to the collector.  Mass flow rate of the test fluid is measured gravimetrically at regular intervals during the test period, by weighing the mass of water that is collected in a container over a period of 1 or 2 minutes.

By conducting such tests for a number of inlet temperatures, sufficient points are produced to enable the collector efficiency curve to be generated.

Below is a picture of a collector being tested at the RISE Outdoor Test Area.

The storage tank heat loss coefficient can be measured using a Constant Temperature Test Facility at the RISE Outdoor Test Area.

One off collector efficiency points can also be measured to test whether a collector complies with the stagnation test requirements of AS2712:2007.  This requires that the efficiency at that test point should be compared with the efficiency of a collector that has not been subjected to the stagnation test.

Although RISE can do this testing directly, the general approach has been to work under sub-contract to the Plumbing & Meter Testing Laboratory in Shenton Park in Perth.  The contact person there is Mr Hank Vandenberg.

For more information on this aspect of testing please contact Dr Trevor Pryor.

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