immerSUN installation and first impressions
Posted by Jane Richardson Hawkes on 27 January 2016 at 9:40 am
Jane Richardson Hawkes shares her first impressions of her new immerSUN unit. She recently had this installed in her home in the South East of England where she lives with her partner. This is her first report in a series of three:
Why an immerSUN?
Using as much of our PV generated electricity as possible in the home has been exercising our minds since the panels were installed in October 2012. We have a 3.84kW PV system installed on a south facing roof which has generated 11,955 kWh* of electricity over a full three year period to date.
We try to use high energy consuming appliances like the washing machine only on sunny days and during peak PV output times such as 11.30am – 2pm.
We have an energy monitor which glows green when the house is not importing grid electricity. This is helpful for gauging when the use of other appliances tip us into importing electricity.
Having heard about the immerSUN, we decided to trial it as an energy saving option for optimising our use of PV generated electricity.
What our immerSUN is supposed to achieve
The immerSUN monitors the electricity which is about to be exported to the grid and diverts it to the immersion heater. It then automatically directs any excess generated electricity, not used by the house, to the immersion heater in the hot water cylinder.
If the electrical load from the house increases the immerSUN reduces or stops the electricity diversion to help maintain independence from the grid.
Installing our immerSUN
The immerSUN was installed in early December by one of the company’s electrical engineers. The installation took about 3 hours and went smoothly.
It wasn’t possible to connect the immerSUN with 4 eco’s server at the time of installation due to server maintenance. Once this maintenance was concluded the immerSUN automatically transmitted data and we were able to register on the 4eco immerSUN website and view the data from our PC/android Smart phone.
The results so far
During sunny winter days, the immerSUN diverts electricity to the immersion heater, as long as our base load electricity demand is reasonably low. One clear sunny morning the water was up to the required 60 degrees centigrade temperature by midday.
We normally heat our water via the gas boiler for 15 minutes a day to provide our normal daily hot water needs. Consequently, if the forecast is sufficiently sunny I can confidently rely on the immerSUN to heat the water without needing to use the gas boiler, but not on cloudy days.
Here are some graphs showing the diversion of solar electricity to the immersion heater in action over the course of a day - these are taken from the myimmerSUN app, which allows you to monitor your results on a tablet, PC or smartphone.Graph: A sunny winter day when we were at home all day
Graph: A sunny winter day when we were out of the house
We’re really pleased with the way that the immerSUN is performing, and it has been quite gratifying to hear it quietly whirr into action when the sun comes out. It’s fitted neatly into its location next to the consumer unit in the cloak room, and the data screen on the front of the unit is clear to view and easy to understand and use.
The online My immerSUN monitoring data has proved to be an unexpected bonus in that it also allows us to visualise the amount of electricity the panels generate over time as well as what’s diverted by the immerSUN. When the PV was installed we didn’t opt for the generation visualisation software due to the cost.
We’re pleasantly surprised that we’ve only had to resort to using the gas boiler to heat the hot water intermittently, even though we’re currently in mid-winter. I confess that we wouldn’t contemplate using the immerSUN ‘Boost’ function to use grid electricity to heat the water if needed, basically because the boiler is so quick and the fuel much cheaper.
We’re expecting that by spring with the longer, and hopefully sunnier days, we won’t need to use the gas boiler at all. We’re also hoping on longer sunny days to be able to heat the hot water before noon and then use the electricity generated during the peak sunshine of the day for the washing machine or the oven/microwave. So we’re planning on making some lifestyle changes to maximise the advantage the immerSUN has given us. We’ll let you know how it goes!
About the immerSUN
The immerSUN is designed to help you get the most value out of your solar PV, especially if you are often out much of the day. It does this by diverting your surplus solar electricity to an immersion heater in your hot water tank (or to an underfloor heating system) at times when it would otherwise export that electricity to the grid. This means your surplus solar electricity is providing higher value hot water you can use instead of lower value export tariff returns.
* Not 3,268 kWh as wrongly stated in the first published version of this blog article.
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About the author: Jane is a specialist in sustainable energy policy with responsibility for advising local authorities on sustainable energy technologies and policies in the context of land use planning and climate change strategy. She has a degree in Environmental Studies, a post-graduate diploma in Urban Planning and is a member of the Royal Town Planning Institute. Currently she works for the National Energy Foundation as a Senior Energy Specialist.
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