The settings for solar power will change between winter and summer months. In the winter, the amount of solar power generated falls off drastically, such that it is unlikely to exceed your daily electricity consumption. Even when it does do so, more than likely the surplus will be directed to recharging the battery. This means there will be no surplus for the immersion heater to heat water. So it's important to set your solar control panel to switch the immersion heater on at various times during the day, for example, before the evening meal, last thing at night, ready for people waking up in the morning, and so on. With careful planning you can do this in a money-saving way. For example, our power company's peak charge rate is between 5 pm and 7 pm, so we set the immersion to come on between four thirty and five, thus narrowly avoiding the peak rate. Similarly, we get a cheap night rate between 11pm and 8 am, so the late night immersion boost is set for 11pm and the early morning one for between seven thirty and eight.
In the summer, a reverse situation occurs. Not only are your panels generating a ton more electricity, your house is also using much less, due to reduced heating requirements compared to the winter. So there will be surplus solar power, which in most configurations will be fed to the immersion heater until the water is up to temperature. After that, the surplus is fed back to the grid and earns you money from the electricity supplier. It's a good idea in the summer, to turn off some of the times the immersion was being boosted for your winter needs. We turn off the 11 am and 4.30 pm boosts for example, leaving it to the solar to drive the water heating.
Intelligently managing the hot water in this way prevents you drawing electricity from the supply when you don't need it, thus saving money and also reducing your carbon footprint. In my mystery thriller novel, The Secret Resort of Nostalgia, written in 2017 but set in the year 1990, an isolated secret utopia uses a combination of water power, solar power and heat exchangers to power their community. It's available in paperback and e-book formats. Please take a look by clicking on the picture below.
