WHY DOES A PHOTOVOLTAIC SYSTEM WORK SO WELL IN WINTER?

Ice and slush are underfoot, occasionally the sun breaks through, and it's colder than a brass monkey's balls. When you finish work, all you look forward to is a bath full of hot water. But do you know that water can be efficiently heated by the sun even in the winter? And for free!

The photovoltaic effect was discovered in 1876 by William Grylls Adams and Richard Evans Day (sometimes incorrectly attributed to Edmond Becquerel). Due to cooling, the performance of photovoltaic cells is even higher at lower temperatures than it is in the summer when the sun shines the most. Of course, the total electricity production is smaller because the days are shorter in the winter and the sun is lower in the sky, but even in January, the sun's energy can reduce the cost of water heating by about twenty percent. Unlike the solar thermal collectors, photovoltaic cells use the light part of the sun's radiation, and it can do so even from the scattered light on a cloudy day.

Because batteries are still costly and have a limited lifespan, it's a good idea to heat water with the power produced by photovoltaic panels – in this way the boiler is used as an incomparably cheap battery.

But it's not that easy. In the past, there were systems in which the panels were connected to the heater by a relay, but that way we can use only fifty to seventy percent of the energy the panel produces. Photovoltaic cells are "nonlinear," so if you want to get the maximum amount of energy, they need to be used differently, depending on how the sun is shining. This is called MPPT (Maximum Power Point Tracking). To understand how it works imagine how a bicycle works. When you sit on a bicycle with one gear, you're able to peddle yourself forward, but when a hill comes, you'll probably have to get off and push the bike. Or when you're going downhill, you can move your feet as much as you want with little effect but a child could past by you in a much higher gear with no problem. Actually, the child wouldn't pass you on the way down because he would've already passed you going uphill using the lightest gear to use his strength efficiently. Well, that's how the MPPT inverter works in SOLAR KERBEROS. It uses every watt of the sun's energy, which is free of charge and heats the water for your evening bath. But there are many more benefits.