How do solar thermal panels work?

If you’re looking to lower your household energy bills and cut your carbon footprint, you might be considering installing solar thermal panels. Harnessing the natural energy provided by the sun, this technology lowers your dependence on mains gas and electricity and reduces carbon emissions. With energy prices set to rise considerably, now could be the perfect time to make the switch. But what exactly is solar energy and how do these systems work? Keep reading to find out.

The term ‘solar thermal’ simply refers to energy created by the sun. When talking about heating solutions specifically, solar thermal is a type of technology used to generate heat for use in homes and commercial properties.

Solar thermal systems are increasingly used in houses and apartments in a bid to drive down energy costs and make properties more eco-friendly. There are different types of system available, but broadly speaking they are used to provide hot water for bathing, showering and hot taps. This low-carbon, renewable technology is a sustainable alternative to traditional heating and hot water systems that are powered by fossil fuels such as gas or oil.

They feature panels, called collectors, that absorb energy from solar rays and use it to heat up water that is stored in a cylinder. These systems provide hot water throughout the year and can be combined with regular boilers or immersion heaters as a backup to ensure that there’s always enough hot water.

Solar thermal panels are a key component of all of these energy systems. Typically fitted on roofs, they are responsible for collecting the energy to heat water for the home. There are two main types of solar thermal panels: flat plate collectors and evacuated tube collectors.

Flat plate collectors are fixed onto roof tiles, or in some cases they can be integrated into roofs. With a flat, smooth, dark surface they are designed to absorb maximum radiation and to reflect as little solar energy as possible to ensure the greatest level of efficiency. The plates absorb solar energy, which is transferred via a heat carrying fluid that circulates in pipes below the absorber surface to a water tank. These collectors are a popular option among consumers for various reasons, including their sleek appearance and relatively low price tag.

Also highly popular, evacuated tube collectors have a very different appearance to flat plate designs. Rather than a smooth continuous surface, they contain rows of glass tubes. These tubes feature a vacuum that eliminates conductive and convective heat loss. In turn, this means the collectors are extremely efficient and are virtually unaffected by air temperatures. Their efficiency is further enhanced by a highly selective coating that absorbs maximum energy from the sun. Although the design of evacuated tube collectors differs significantly from flat plate systems, the basic idea is the same. They absorb heat from the sun to create hot water, which is stored in a cylinder for use in the home.

As outlined above, solar thermal energy systems work by capturing the energy provided by the sun. Through a sophisticated process of heat exchange, this energy is transferred to a highly insulated water tank, ensuring that hot water is there when needed. These systems work throughout the year, although their peak output is during the summer when the days are longer and the solar rays are at their strongest. Averaged out over a 12-month period, our solar collectors can save around 60 per cent of the energy required for domestic hot water and they could lower your household’s total energy consumption by more than a third. So, if you invest in this technology for your home, it may pay for itself in just a few years and go on to save you a considerable amount of money over the long term.

Solar energy systems are often used in conjunction with a condensing boiler. Having a dual system in place means that you benefit from the energy savings of the solar technology while also having the comfort of enjoying hot water on demand throughout the entire year, regardless of the weather conditions.

To get the most from your system, it’s important to ensure that you take as much of your hot water as possible from the solar supply. For example, if you currently have an electric shower, you may benefit from replacing it with a mixer shower that takes water from your heating system. Before you do this, check with your plumber that you have sufficient water pressure. Also, if your boiler or immersion heater is programmed to come on first thing in the morning to heat your water tank, you may want to adjust this once you have your solar thermal system installed, otherwise your heating system will always start the day with a hot tank, meaning there is nothing for your solar collectors to heat.

It’s a common misconception that solar thermal systems don’t work during the winter. In fact, as previously mentioned, these solutions work through all seasons. Even on cold, cloudy days, there is still solar radiation and so the plates or tubes will collect energy. However, the systems do generate less heat during the winter, so you will rely more on your boiler or immersion heater during these months to get the hot water you need.