Wednesday, 20 April 2016
Final Diagram of Dual Input Heating System
The gutter and solar collector are (obviously) external to the van body. The balance of the system is all contained in the 'Plant Room' or 'Toilet'. The towel rail is mounted in the kitchenette. CW and HW feed to the kitchenette go to the two taps on the kitchen sink.
The power for the electrical control systems and pumps can be provided from solar PV via an inverter rated at 300W but the 400W element is a bit too meaty for this so can only really be powered from the electrical hook-up to the body. To be fair, on days when the electrical heating needs to be used, I'll be running from grid power anyway. When running as a solar only system, total consumption is 60W (for the low power impeller pump). With electrical heating on and no solar, the total consumption is 480W (400W for the element and 80W for the pump). If there is some solar input and I'm using electric as backup, then maximum loading is 560W, although the element will be cycling because of the thermostat and the solar pump will only be operating in cycles because of the temperature controller.
I'm guessing that if I monitored this over time on the kWh meter, the mean consumption will be about 500Wh, or about 6p an hour for heating and hot water.