We stock a couple of power optimising Immersion heater controls to make the most of on-site generated electricity by heating water with your excess PV or Wind power production. Currently the feed-in tariff is paid of every kWh generated and an additional 3.5p or 4.7p is paid for each kWh exported to the grid. with PV systems below 30kWp the energy exported is assumed to be 50% of the total generated, commonly though this value is much higher especially when the building is unoccupied during the peak generation periods (during the day).
Using as much of the electricity on-site as is possible will only improve the financial gains you make from your PV system. These solutions are of advantage to both occupier owned systems and those which are rent-a-roof.
Our original unit we designed in 2010 and field tested early in 2011 was specifically designed to replace Immersion Heater Timers. At the time (and even now), we were coming across customers with gas or oil central heating systems that had installed timers on their immersion heaters to switch on for a couple of hours around midday. While this method will use the free PV power in midsummer sunny conditions, the timer would not know if the weather is overcast, and many people were actually importing power quite a bit of power off the grid, going against the power saving principle.
We realised back in 2010, that most of our customers will actually use only fraction of their generated power and it made sense to find a method to store this generated power. Our first unit was also published as a blog on YouGen as Chris Rudge is an energy expert for PV for the website. We also blogged it on our own blog here, which has been since improved. The basic idea is to simply use that power off the PV system to heat water in your hot water tank. By far the most straightforward way to store energy in a house without buying an expensive set of batteries.
That unit is no longer available as since then, we have introduced a couple of additional units, which are cost effective and offer more facilities than our original unit and will provide a far better performance, especially if the house is occupied during the day.
Further information on two of the systems are listed on the left, click the links for further information and data sheets.