Solar water heating system

Solar panel system
Topology of the hot-water circulation system (click on the image to expand in a new window).

Solar panels W

Solar panels E
Solar panels:  
The lower array is a set of 16 photovoltaic (PV) panels giving a peak output of  4.56 kW. This energy is fed into the mains electrical system via an inverter, which is capable of exporting electricity in the event that our own consumption should fall below the solar yield.
The upper array consists of 6 Navitron SFB305818-AL evacuated tube solar collectors. These 30-tube panels each have a maximum output of 1.85 kW, giving a total of 11.1 kW for the whole system. Note that the area efficiency is vastly superior to that of the PV system. The downside of evacuated tube collectors is that the upper manifold will attain a temperature of around 220°C in the event that the water circulation should fail, producing a serious hazard for anyone working on the system, and the likelihood of damage to the components. Note therefore the presence of a 100 W PV panel in the gap at the middle of the array.  This is used to charge a 12 V 110 Ah lead-acid leisure battery, which can be used to run an inverter to power the circulation pump. The inverter is automatically activated, and the output of the panels is switched to the heat dump, in the event of a mains power failure during daylight hours.

heat dump
Heat dump (10.5 kW), with filling point, pressure gauge, air purge valve, and magnetic trap.


Updated 2018-10-14