Can the water in a solar kettle overheat dangerously?
There is no way that pressure can build up in the solar kettle. There is a vent in the cap under the thermometer, which we have tested extensively, and the pressure is always vented. We have also tested having a sealed cap. In that case, as soon as boiling point is reached the pressure simply pushes the cap out. So dangerous pressure cannot build up.
There is no problem leaving the kettle unattended (as long as there are no children or pets around). You stick it outside and leave it until it gets to boiling. It doesn’t matter if it is left boiling for several hours. But, when you have a cuppa, fill it up and stick it out again, so it’ll get hot in time for the next one.
Does the solar kettle store energy?
Yes, the Solar kettle does store thermal energy. It acts like an energy sponge, absorbing the energy from the sunlight, very efficiently turning it into heat, converting about 70% of the sunlight into thermal (heat) energy. This is stored in the water which gradually heats up to boiling point. The specific heat of water is 1 calorie/gram/°C = 4.186 joule/gram/°C The kettle holds half a litre (approx 1 pint) of water = 500 grammes Putting cold water at 20°C and heating up to 100°C (delta T= 80°C) means that the energy absorbed and stored. 80 x 500 = 40,000 calories of energy or 80 x 500 x 4.186 = 167,440 Joules of energy.
To put this in context, a high power AA battery (you know the copper coloured top one) stores about 9000 Joules of energy, so it would take 19 of these to boil the same amount of water as the solar kettle.
How do I purchase a solar kettle?
Order from this page on our website.
How does a solar kettle work?
At the heart of the solar kettle is an evacuated vacuum tube. This absorbs solar energy, converting it directly into heat which heats the water inside. Each tube is constructed like a Thermos™ flask, so the heat energy goes in but doesn’t come out. The vacuum tube consists of two glass tubes made from extremely strong borosilicate glass (same as Pyrex™). The outer tube is transparent allowing light rays to pass through with minimal reflection. The inner tube is coated with a special selective coating (Al-N/Al) which features excellent solar radiation absorption and minimal emission/reflection properties. The ends of the tubes are fused together with the space between them being evacuated. The insulation properties of the vacuum are so good that while the inside of the tube may be 175°C, the outer tube is cold to touch. This means that the solar kettle can perform well even in cold weather.
How long is the solar kettle guarantee?
The solar kettle is guaranteed against manufacturing defects for 24 months.
You can view our full Terms and Conditions HERE.
I have just received my solar kettle but haven’t been able to open it. It did turn slightly at first but I don’t want to force it.
We have not encountered this problem before. It could be one of two things:
If the reflectors are stuck, these are held closed by strong magnets. Usually simple hand pressure pulling them apart is sufficient. But if these are stuck a closed knife could be inserted in the slit between the reflectors allowing them to be prised apart. Once freed in this manner they should be able to be opened by hand.
If it is the bung that is stuck, this is held in by friction of the rubber seal. This is usually easy to twist off. If you are finding it hard to move I’d suggest pulling, wiggling and then twisting off the bung in a cork-screw movement. When doing this the reflectors should be open and the glass tube should be held firmly to gain maximum purchase.
Is the solar kettle fragile?
The tubes are durable and have been tested to withstand hail up to 25mm in diameter. The borosilicate glass is toughened to make it strong. The reflectors provide additional protection during transit. However like with a thermos flask you should handle the kettle with care and not drop it.
Is there enough sunshine for the solar kettle to work?
The Solar Kettle works brilliantly in the UK climate. It works best in direct sunlight, but will still work effectively on diffused solar radiation, and hence can produce hot water (not boiling) even on cloudy days.
What about cooking with the solar kettle?
Experiment with cooking using the solar kettle. You will be delighted with the results!
What is the capacity of the solar kettle?
Unlike old fashioned kettles the Solar Kettle should be filled to the top whenever it is used.
Model Length (mm) Capacity (ml) Capacity (cups) Solar Kettle 460 500 3
Where should I place the solar kettle?
Place it outside in direct sunlight facing south. Try to choose a relatively open spot with no shading where it will stay in the sunshine as the sun moves across the sky. It has a built-in e.g. metal stand. If the kettle casts a shadow it will be working.
Any tips for using the Solar Kettle for the first time? What about taking off the film from the reflectors?
It can be hard to to see the protective film, it is sometimes quite tricky to remove and can need a firm scratch. It is best to do this near the edge and scratch parallel to the edge. Don’t be afraid of scratching hard, the reflectors are very tough and once the film starts to come away it peels easily (but it can be hard to get going).
The video below shows unboxing and removal of the film. We have prepared this short video to show how to unbox the solar kettle and safely remove the protective film from the reflectors. It also shows how to safely handle the solar kettle, especially when it contains very hot water.
How do you fill it with water. I’m afraid of breaking it. How do you open it?
The stopper is a push fit. To remove it you just turn it and pull off in a turn-and-pull motion. If it is hard to budge try wiggling it or pushing up with your thumbs, as you would for a Champagne cork.
MY QUESTION HASN’T BEEN ANSWERED HERE
You can post your question using our Contact Form. We will respond as soon as possible.
Visit Solar Kettle Ordering to get one for yourself.