CYLSOL

SOLAR HOT WATER CYLINDER

The solar hot water cylinder is an often under rated component of the solar system. For most people their need for hot water does not coincide with daylight hours. Hence the cylinder’s function is two-fold. Firstly it must effectively transfer heat from the solar collector to the stored water, and secondly to smooth the light energy fluctuations not just throughout the day but from day to night and from bright through dull days.

A balanced and well designed system will include an efficient cylinder as there is little point collecting free solar energy if it cannot be efficiently exchanged or stored for use as and when required. This is also why a good solar cylinder with sufficient insulation is important like the CYLSOL range which uses CFC free foam lagging to double the regulation standard.

 CYLSOL solar cylinders are tall and narrow by design as this increases stratification of the water within the cylinder. This will also mean relatively higher water temperatures at the top of the cylinder, where it is wanted. 

The boiler connects to the top coil as per standard practice. The solar coil at the bottom transfers energy from the solar collector, which then rises within the cylinder thereby reducing the energy required by the fossil fuel boiler during the winter. During the months from April to September the boiler will be largely dormant and may be switched off.

The solar coil incorporates spirally wound fins to give an extremely high surface area to volume ratio. Apart from minimal storage volume offset and high efficiency heat transfer, a compact coil also allows very low positioning where the water is coldest thus maximising solar collector efficiencies at all times. Whilst an in-efficient boiler coil will mean excessive fuel consumption, an in-efficient solar coil will make the difference between a warm or hot cylinder. The CYLSOL range solar coil has a surface area equivalent to 13 running metres of 1” copper pipe!

The boiler coil is positioned as high as possible, but low enough to give the minimum boiler heated/stored hot water at any one time. For example, 80 litres at 55oC (sufficient for a bath of 100 litres when mixed down to 43oC. Minimum stored boiler volume allows maximum storage of free solar heated water. The boiler coil as standard compares to BS1566, which requires that the coil heat the volume in 1 hour under gravity (approx. 35 minutes if pumped). High recovery boiler coils heat the same volume of water in ½ hour by gravity and 20 minutes if pumped. Basically the boiler coil is increased in size, to give a larger surface area. Pumped boiler circuits with optional high recovery boiler coils will further maximise the solar storage fraction, by reducing the boiler-heated volume

CYLSOL twin coiled solar cylinders are sized to suit 2, 3, 4/5 and 5/6 person households. 

Systems that employ a separate solar pre-heat cylinder are very rarely recommended. This approach whilst often convenient for the installer / retro installation is inefficient from the point of view of thermal efficiency.

Technical Information

Individual Specifications

Any specification of cylinder can be manufactured including mains pressure systems.

Additional coils, high recovery ½ hour boiler coils, mains pressure shower coils, immersion bosses, shower and secondary tapings can be supplied at any height and rotational position – which can often times ease cylinder replacement

Contact the Solar Sense technical department for information sheet, advice and prices.

Technical Specifications