Solar Hot Water

HBH Solar can design and install a solar hot water system to suit all types of properties. In general, they work by using solar panels – called collectors – fitted to your roof. These collect heat from the sun and use it to warm water, which is stored in a hot water cylinder.

There are two types of solar hot water panels – evacuated tubes and flat plate collectors. HBH Solar installs the evacuated tubes.

On a hot, sunny day, flat plate panels will produce around the same amount of heat as evacuated tube panels of the same area. Under any other conditions, the vacuum tube panel will out-perform flat plate panels – usually by a very significant margin. Flat plate panels perform badly during windy weather and in cold or overcast conditions. Even the best flat plates may under-perform by 20% compared to a similar area vacuum tube panel in the UK.

How do evacuated solar tubes work?

Solar panels use the power in both direct and diffused sunlight, converting the energy into heat, to produce hot water for your home.

Each unit is made up of two strong glass tubes, one sitting within the other. They are joined together at the top and the gap between them is ‘evacuated’ creating a vacuum, rather like a thermos flask. The outer tube is made of clear glass that allows solar rays to pass through it with minimal reflection. The inner glass tube has a special coating that absorbs the sun’s rays whilst preventing any heat loss. Once the heat has been captured, it cannot escape due to the insulating properties of the vacuum. Temperatures in the tube can exceed 180 degrees Celsius.

A narrow copper pipe is inserted down the centre of the inner tube, which is partially filled with a fluid that boils at around 30 degrees Celsius. As the fluid boils, it turns to steam and rises to the top of the heat pipe where it disperses its heat via the manifold – a rectangular box at the top of the collector, which links all the tubes together. After releasing its heat, the fluid condenses and returns to the bottom of the heat pipe ready to start the process all over again.

The system is designed so that the water in the manifold never mixes with the fluid in the heat pipe, which means the whole system can work even when a tube is broken. This also means that broken tubes can easily be replaced without the need to drain any part of the system.

What equipment do I need?

A solar hot water system typically comprises of:

  • a solar collector (evacuated tubes) or series of collectors
  • a hot water cylinder
  • a control panel
  • a pump unit

HBH Solar can supply all components of this system.

Are evacuated tubes suitable for my home?

Most homes are suitable as the system has been designed for Northern European climates, and generates solar energy even on cloudy days. Our engineers will advise on the positioning of the tubes but in general, south, southwest or southeast roofs are ideal. However, even east or west roofs offer 85% performance.

Your property’s plumbing system will also need to be checked for compatibility, which can be done as part of our free consultation service.