Solar Flat Plate Collector
Solar flat plate collectors work in a similar way to other solar thermal systems, with the sun heating the water inside the panel which is connected to a water cylinder. Solar flat plate collector panels are capable of delivering between 50% - 90% of a household’s hot water totally free. Savings and efficiency are dependent on several variables, including the size and type of panels installed, volume of hot water used in the household and size of the water cylinder.
At SolarTherm UK, our expert team of solar thermal installer have installed thousands of solar flat plate collector systems throughout the UK. To find out more or to get a free no-obligation quotation, enquire online or call us today.
How do solar flat plate collectors work
A flat-plate collector consists of an absorber, a transparent cover, a frame, and insulation. Usually, iron-poor solar safety glass is used as a transparent cover, as it transmits a significant amount of the short-wave light spectrum.
Simultaneously, only very little of the heat emitted by the absorber escapes the cover (greenhouse effect).
In addition, the transparent cover prevents wind and breezes from carrying the collected heat away (convection). Together with the frame, the cover protects the absorber from adverse weather conditions. Typical frame materials include aluminium and galvanized steel; sometimes, fibreglass-reinforced plastic is used.
The insulation on the back of the absorber and the side walls lessens the heat loss through conduction. Insulation is usually of polyurethane foam or mineral wool, though sometimes mineral fibre insulating materials such as glass wool, rock wool, glass fibre or fibreglass are used.
Flat collectors demonstrate an excellent price-performance ratio, as well as a broad range of mounting possibilities (on the roof, in the roof itself, or unattached).
Types of flat solar collector
There are two main types of solar thermal system available – direct & indirect.
Direct Solar Thermal
With direct solar thermal systems, the water that circulates through the panels is the water that you use throughout your household. This water is typically linked to your hot water cylinder, with cold water from the cylinder being pumped into the panels and hot water heated by the panels following directly back to your cylinder for use in your household. In climates such as the UK, a shut-off valve is typically installed to stop water from going into the panels when the outside temperature drops below freezing temperature.
Indirect Solar Thermal
Indirect solar thermal systems are the more common type of solar thermal system, especially in countries with colder climates. Indirect solar thermal systems heat a coil inside the hot water cylinder, which in turn heats the water that you use in your home. The water in the panels are typically mixed with antifreeze, which can’t be used with a household, but allows the panels to continue working during colder days when direct solar thermal systems would be at risk of freezing and potentially causing expensive damage to the system.
Solar Thermal Distribution Systems
Passive (Gravity Circulation)
Passive systems rely on gravity and the natural tendency of water to circulate when heated. This type of systems doesn’t involve any pumps, therefore no electricity has to be used to pump the water through the panels. Due to less parts being involved with the system, these systems are often more reliable and easier to maintain.
Active Circulation (Pump Circulation)
Active circulation systems are the most popular type of solar thermal system in the UK. Active circulation systems incorporate a pump that circulates cold water in the cylinder to the panel for heating. The pump uses sensors located in the water cylinder and solar thermal panels to ensure water is only sent to the panels when the water in the panel is hotter than in the cylinder. Advantages of an active circulation system include integrated freezing protection, overheating control, and reduced heat loss through pipes, all of which leads to greater levels of efficiency from your solar thermal system. Disadvantages to an active circulation system are that they’re typically slightly more expensive to install and that the pump uses electricity, however, this can often be offset by installed solar PV panels.
Enquire about Solar Thermal Panels Today
Enquire online, chat to us via live chat or request a call back from one of our friendly team to find out more about solar thermal panel installation. We will be in touch to find out some more detail about your solar thermal panel requirements and to answer any of your questions.