Solar Water Heating
Alian Energy Solutions offers a range of cost effective solar water heating systems and can arrange a free site survey to ensure optimum performance for every customer. Our engineers are BPEC certified for solar
installations for both vented, unvented and thermal store systems.
What is solar water heating?
Why solar water heating?
How does it work?
Average Daily Insolation Figures (Annual)
Installing a solar water heating system
Planning considerations
Is my property suitable?
Prices
What is solar water heating?
A solar water heating system reduces your fuel bills by using the sun’s energy to pre-heat hot water for baths, showers and swimming pools – and it works all year round. Even on cold, overcast days, solar water heating panels will yield useful heat, and on sunny summer days they may provide 100% of your hot water needs.
Collecting the sun’s energy in evacuated tubes, solar water heating panels transfer heat into water which is then circulated to the boiler. This directly reduces fuel bills because any increase in the temperature of the water supply to your boiler will reduce the energy needed to bring it to the desired temperature. With fast rising fuel and energy costs, the economic case for solar water heating systems has never been stronger.
Why solar water heating? 
Quite apart from being an environmentally sustainable source of energy, solar water heating systems produce substantial long term cost savings and help both homeowners and businesses to become more energy independent in the face of ever more insecure and expensive energy supplies.
Vacuum tube collectors provide useful heat for 12 months of the year, and can even produce heat in overcast weather. On a cloudy day in April, a solar water heating system can heat a 210 litre hot water cylinder to around 40°C and, if the sun shines, this can rise to as high as 60°C!
How does it work?
The solar water heating systems supplied by Alian Energy are based on vacuum tube solar panels – a sustainable technology that was established more than a decade ago and has proved to be reliable, robust and effective. The vacuum tubes consist of a double wall glass tube (made from strong borosilicate glass i.e. Pyrex) with a space in the centre, which contains the heat pipe.
The sun's radiation is absorbed by the selective coating on the inner glass surface, but prevented from re-radiating by the silvered innermost lining. Operating rather like a one-way mirror that has been optimised for infrared radiation, it is very energy efficient.
Of the sunlight's energy hitting the tube's surface, 93% is absorbed, with only 7% lost through reflection and re-emission. The presence of the vacuum wall prevents any losses by conduction or convection - just like a vacuum flask. Consequently, solar water heating panels based on evacuated tubes will work even in very low temperatures, unlike traditional flat plate solar collectors.
The heat transferred to the tip of the heat pipe is then transferred to a copper manifold in which water circulates to heat the domestic hot water tank. If a tube is placed in direct sunlight on a summer’s day, the tip temperature can reach 250°C - so this form of solar water heating system has significant energy potential and can easily heat domestic hot water cylinders to 60°C, even in cooler weather!
The manifold is heavily insulated with a 2" thickness of pre-formed rock wool to keep the heat in. Unlike flat plates, these headers are so well insulated that they should not require antifreeze in normal operation: the temperature of the header is unlikely to fall below 10°C even in very cold weather.
The more advanced solar controllers include a low-temperature facility, which - should the temperature of the collector fall below a defined level - causes the pump to operate so as to allow the water at the bottom of the tank to heat the collector slightly. In normal conditions, this would never be necessary but it acts as a good safety device.
The more advanced solar controllers include a low-temperature facility- should the temperature of the collector fall below a defined level, the pump will operate to allow the water at the bottom of the tank to heat the collector slightly. In normal conditions, this would never be necessary - but it acts as a good safety margin.
Average Daily Irradiation (Insolation) Figures for Each Month of the Year
(Solar energy reaching each 1m2 of the earth’s surface at UK latitudes)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
| MJ/m2 day | 2.3 | 4.2 | 7.0 | 11.6 | 15.0 | 18.0 | 16.0 | 13.0 | 10.0 | 6.0 | 2.8 | 1.7 |
| kWh/day per m2 | 0.64 | 1.17 | 1.94 | 3.22 | 4.17 | 5.00 | 4.44 | 3.61 | 2.78 | 1.67 | 0.78 | 0.47 |
| Heat Gain from 1 Navitron panel per day (k Wh) | 1.15 | 2.11 | 3.49 | 5.80 | 7.51 | 9.00 | 7.99 | 6.50 | 5.00 | 3.01 | 1.41 | 0.85 |
Installing a solar water heating system
In most cases, installation can be carried out in 2 days for an average sized semi-detached property although this can be established with an initial survey.
Typical prices of systems can be found below in the solar water heating prices section. A basic 20-tube system will cost in the region of £2500 including solar cylinders up to 172 litres, which will supply hot water for an average 3-bed semi. The prices and sizes are provided only as a guide as individual properties, customer requirements and hot water needs can vary.
We can also connect to log burning stoves with back
boilers and other alternative heating sources where necessary by
providing hot water cylinders with multiple heat exchangers.
Planning considerations
Current planning guidelines in many parts of the North West are such that no planning is required as long as the collector or any part thereof does not protrude from the natural pitch of the roof by more than 6” or 150mm. The Navitron collectors provided by Alian Energy protrude by approximately 130mm. If you are planning to install a solar water heating system on a listed building or a property located either in an Area of Outstanding Natural Beauty or conservation area, then planning issues will need to be confirmed with your local authority.
Is my property suitable?
Most roofs are suitable for the installation of solar water heating systems. The perfect location would be on a south facing roof, which gives optimum performance but solar water heating panels can also be mounted on south-easterly or south-westerly facing roofs with only a slight reduction in performance.
If such roof surfaces are not available there are other options. The Navitron solar collector can be mounted on a vertical wall or on a flat roof with the aid of a flat roof mounting kit. It might be that the best place is on a gable end or a flat roof or lean-to. Solar water heating panels can also be mounted in your garden but in all cases they need to be fitted as close to your hot water cylinder as possible to reduce any heat losses over the length of the pipe run.
It is recommended that before you consider a solar water heating system you should ensure that your house is suitably insulated and that you have eliminated draughts as effectively as possible.
Contact Alian Energy for a survey
£ Pricing
The specifications for solar water heating systems can vary substantially from house to house, user to user and so a survey is necessary to establish the optimum system requirements and thus the price. Variations can be such things as the quantity of water used and required, the location and suitability of the installation, the current boiler type and the requirements of the system. Installation prices can also vary depending on the access, size of system and the customer’s individual requirements.
For this reason we can only give a guide price of £2,500 which is for an average sized 3 bedroom semi-detached property and allows for a cylinder up to 172 litres. DIY kits are available from £1,900.
