Solar Hot Water (Solar Thermal Panels) in Shetland

There are two different types: flat plate, where lots of thin tubes carry water through a flat absorber panel, and evacuated tube, where vacuum glass tubes capture the sun’s energy directly. There is little difference in performance between the two but evacuated tube panels do more obviously extrude from the roof.

If you’re considering getting a solar thermal system, one of the first things that comes to mind is the possibility of the system functioning properly during the cold months. The short and simple answer to this question is yes, a solar thermal system works in the winter. However, the downside here is that it’ll be a lot less efficient when compared to how it operates during the warmer months or summer. As a result of this fact, you’ll likely need to rely more on your boiler, immersion heater or any other backup heating system during this period as your solar thermal system will fail to contribute as much as it does during the warmer months. So what exactly is the reason why solar thermal is less effective and less efficient in the winter period? Let’s have a look!

As you know, solar thermal system banks on the sun’s energy to heat the water for your home’s use. During the cold months or winter, the sunlight becomes a lot less available when compared to the warmer months, as a result, there’s less sunlight that’s available to be used for its solar energy. And even more so at the periods when the days are shorter or skies are clearly overcast.

Also having a great impact on a solar thermal system’s output is heavy snow. Flat plate collectors normally have the capacity to cope better during snowy conditions as the light that’s able to travel through the snow will heat up the absorber plate - thereby making the snow slide off more quickly. However, the case is contrary with evacuated tube collectors which possesses a form of vacuum insulation that’s crafted to minimize the loss of heat, meaning they can’t generate heat to melt and cause the snow to slide off in a similar way.

If you’re thinking about installing a solar thermal system in your house, it’s always important to put into consideration numerous factors before you proceed. While some solar thermal systems are suitable for use at home, there are also some that are suitable for businesses or organizations which normally requires a big amount of hot water like hotels, restaurants, schools, hospitals and many more. You’ll also find some types available in the market that are suitable for communities to satisfy communal hot water demands.

It should, however, be noted that solar thermal systems do not have the capacity to produce all the hot water demand of a house. In the UK, an average household will need an annual water heating of between 3000kWh to 5000kWh. Whereas, a solar thermal system is only able to meet about 40 percent to 60 percent of this demand.

With that in mind, it’s also worth noting that during the summer months when the solar radiation is at its peak and hot water demand is relatively lower when compared to other seasons, a solar thermal system may be able to provide all of your household’s hot water needs. This implies that during this period you may not find the need to operate your boiler at all. However, during winter or colder months, when you have a higher hot water demands in contrary to a lower solar radiation, a solar thermal system will only be able to take care of about 20 percent of your household’s hot water needs. And that ultimately implies that during this period, you’ll need to rely more on a alternative or backup source of heat like gas, coal, electricity, oil or LPG.

Unlike the photovoltaic (PV) power which works to turn a part of the electromagnetic radiation of the sun directly to electrons and electricity, a solar thermal can simply be referred to as the absorption of the sun’s heat for human use. As a result, the solar thermal has a wider range of uses than the PV does in several ways. This is due to the fact that the sun’s heat can be absorbed and transported via a medium and the stored energy incorporated for several great purposes such as to heat water, to heat and cool a home or living space, to prepare a meal as well as to generate electricity. All these functions are useful for both residential and commercial spaces.

There are generally three different ranges of solar thermal energy that are being used which includes the low temperature ( for heating, cooling as well as ventilation), the mid temperature ( used for preparing meals, heating hot water and the likes) as well as the high temperature ( used for generating electricity). To focus more on generating electricity, there are a wide array of ways through which the sun’s heat can be directed at creating electricity via a heat exchanger which operates to super heat water or inert gas to power an electricity- generating plant or to produce electricity via a Stirling engine.

In order to increase their output or make them more efficient, evacuated glass tubes are used to encircle the tubes which in turn helps them to collect more heat energy while also protecting them from re-radiating the heat energy absorbed. The trough are normal positioned north to south as well as to keep tabs on the travels of the sun throughout the day.