Solar panels can generate significant amounts of electricity for example on March 25th our 4kW panels generated 22.4 kWh over the course of the day as shown.
This generation typically substantially exceeds the load being drawn by the house leading to export of electricity to the grid – 12.3 kWh in this example or more than half the generated energy.
Moving loads such as the washing machine or dishwasher from night to day can help use this electricity, but done to excess risks increasing day time electricity import if changing cloud cover or other factors reduces generated power. The varying power demand from such devices is also unlikely to coincide the the surplus power available leaving some unused surplus. I was thus pleased to come across the ImmerSUN system.
The ImmerSUN is a device which diverts surplus power to a range of possible consumers such as an immersion heater. It has a current sensor that measures any surplus power being exported and then diverts a similar amount of power into the immersion heater. Normally of course an immersion heater is either on or off, but the ImmerSUN provides proportionate control between 0 and 100%. It can control several devices diverting power to a lower priority device once, for example, a higher priority immersion heater has raised the water temperature to the set point and power for that purpose is no longer required. In the top illustration the blue bars show 4.7kWh being diverted into water heating (and thus reducing my gas bill) that otherwise would have been lost to export.
For further details see ImmerSUN website .
At the time of writing if you order online quoting Referral Code 206505 you will receive £25 in department store discount vouchers or a free system upgrade to remote monitoring.
Well like many UK homes our central heating and hot water is fuelled by natural gas. We also use natural gas for cooking on the stove top (the oven is however electric) and we have a gas fire in the living room, but these latter two uses are much less significant.
I’d lived here for 10 years before I started actively trying to reduce my energy consumption. During those 10 years I used an average of 562 units of gas annually.
Since then I’ve reduced my consumption by two routes, firstly to reduce heat loss so that less energy for heating was required, and secondly by replacing gas with renewable sources. It’s however also the case that my circumstances have not been constant during that time so, for example, when I started this I lived alone then 4 years or so ago I married and my wife joined me here; and now my wife is at home during the day with our baby daughter much of the time. Consequently the demand for hot water for washing and heating has increased.
The steps taken to reduce gas consumption include:
- Having insulation installed in the cavities of the house walls. Houses here conventionally have a double skin of brick or block and, when this house was built, the cavity between the inner and outer layers was usually left as an air gap. We’ve had that gap filled with insulation as you would find in newer homes.
- Increasing the thickness of insulation in the loft.
- Replacing the old wooden windows with new PVC ones with higher “A” grade insulation – most easily seen by the larger air gap in the sealed units.
- Installing solar water heating panels on the roof in conjunction with a larger hot water tank. In the summer these provide almost all our hot water (no heating is required), although at olther times of the heat they don’t provide enough heat alone for hot water they can help to pre-heat the cold water leaving the gas less work to do to achieve a usuable temperature.
We didn’t do this all at once, but if I compare the last 2 years to the original 10 year baseline then we’ve reduced average annual gas consumption by 23%. I think that the reduction would have been higher had our circumstances between constant.