Evacuated tubes are still a valuable solar technology today.
Evacuated solar tubes.
Evacuated solar tubes are an alternative water heating system, developed especially for northern European countries. The power of the sun to heat domestic tanks and swimming pools in the UK climate too.
In a nutshell.
Evacuated tubes, commonly known as solar tubes, are amongst the most efficient of all solar heating panels.
An evacuated solar tube installation is like converting a car into a hybrid running on LPG. After the initial investment, your car or in this case, your home will run efficiently and cheaply for the 30 years.
Contrary to popular belief, these work throughout all four seasons.
Size: 2040 x 1000 x 80 mm.
Weight: 50 kg.
Absorption area: 2.73 m2.
Standard pressure: 3 bar.
Evacuated tubes. Why not?
We don't recommend solar tubes today because installing PV solar panels can working alongside an Immersun or iBoost heating converter to heat up your hot water tank using excess electricity.
Alternatively, we suggest installing PV solar panels working alongside an Immersun or iBoost heating converter that heats up your hot water tank using excess electricity from your panels.
The benefits of this type of set-up over a standard set-up are the additional benefits of generating electricity and generating a revenue with the solar PV incentive.PV-to-heating converters »
The benefits of solar heating technology:
Thermodynamic panels work night and day, although these aren't eligible for the current incentives.
Independent testing has concluded that solar tubes perform best in the UK climate and flat-plate panels come a close second.Learn about incentives
Most homes are suitable, if you have an S/SE/SW or east/west facing roof space, then probably. Your internal plumbing will need to be checked for compatibility, but this can be done at the quotation stage.
No planning permission needed in most cases.Check your roof orientation.
Do evacuated tubes work well in the UK climate?
Evacuated tube installations are the most efficient technology for heating.
The UK receives 60% of the sun's radiation compared with the equator. Each square metre of the UK receives between 900 to 1,300 kWh annually of each year. Developed for northern European climates, creating the highest performing technology, even contributing on some cloudy days.
Evacuated tubes were developed for the UK climate; they use a thermos flask principle, which allows the inside of the vacuum tube to get very hot regardless of the external air temperature.Solar radiation map of the UK
How much will a system cost?
The cost of a system depends on several factors based on water tank sizes and the number of tubes required. A property assessment and consultation appointment can be arranged.We only recommend PV
What about Combi boilers?
Combi boilers are possible, but please bear in mind that we will need to re-install a hot water tank. Most homes with Combi's will not have the space to install a domestic sized hot water tank. If you can re-install a hot water tank, then yes an installation may be possible.Schematics
Can I install evacuated tubes myself?
All evacuated tube installations must be carried out and certified by an accredited MCS installer to qualify.
To undertake an evacuated tube installation requires competent, but basic knowledge of plumbing principles. If you are changing the hot water cylinder, then a Part P qualified plumber will be recommended.
The solar tubes come pre-built at the factory, so hoisting the pipes up to the roof using correct safety equipment is relatively straightforward. A scaffolding tower up to roof line level is required for a safe working platform.
The electric setup is essential, but if you are taking an electrical spur from the bathroom area, then a Part P electrical qualification will be required.DIY solar panels
What about combi boilers?
Combi boilers are possible but, please bear in mind, that we will need to re-install a hot water tank. Most homes with a combi will not have the space to install a domestic sized hot water tank. If you can re-install a hot water tank, then yes an installation may be possible.
Can I install myself?
In most cases no, however, if one has Part P electrical and plumbing skills, then it may be possible to install in a DIY capacity. DIY evacuated tubes and flat-plate kits are available.
All feed-in tariff eligible evacuated tube installations must be carried out and certified by an accredited MCS installer to qualify.
Why is it important to update my hot water tank?
Old copper hot water tanks run exceptionally inefficiently, especially after many years of use. Limescale will reduce performance even further. When installing this technology, it is essential to establish a modern more efficient tank to get the most out of your generated heat gain.
"Adding this technology to an old tank would be like converting your car
to LPG and running it on semi-flat tyres"
Will it contribute towards my central heating?
This answer depends on the type installed. We would need to inspect your home to see if the heating management system is suitable. In most cases, this technology can contribute to your central heating using underfloor heating technology, but not all companies, offer this technology.
The evacuated tubes collectors gather accumulated heat, which it uses to heat up a fluid within the panel. This fluid circulates through the solar panel and then through pipes into a heat exchanger. The heat can then be used for hot water or space heating with under-floor heating.
How long will it take you to install my system?
Only a few hours in most cases.
What basic's should I consider for an installation?
1. Can you face the array roughly towards the sun? South, southwest or southeast roofs are ideal. Even east or west roofs offer 85% performance.
2. Is your hot water cylinder is twin-coiled? It does not matter if not, as we can locate a compatible and more efficient tank as part of your fitting process.
3. Listed buildings, conservation area homes, national parks may require permission. Please consult with your local planning officer.
How long will I be without water during installation?
Only 4-5 hours.
Do these systems work on cloudy days?
This depends on which technology is installed and the density of cloud; flat-plate panels do not contribute as much as this technology in these conditions. In average cloud density, the sun's energy can still be used. With very heavy dark, dense cloud cover, probably not. Use your solar powered calculator out on a cloudy day, and it will always work.
Will you need to change my hot-water cylinder?
No, if your tank is compatible or has a twin-coil unused. In most cases, we update your hot water tank when installing this technology to allow the system to work at its full capacity.
How much CO2 will my system save?
Around half a tonne each year, but this is dependent on how much hot water is used and how you heat your water at present.
What water temperatures can I expect?
A good proportion of the year, temperatures of above 60° Celcius are reasonable, but on a sunny day as high as 80° Celcius.
Is there a danger that the water could get too hot?
The system may never rise above 85° Celcius.
Does my roof have to face directly south?
South is the optimum and southeast and southwest are suitable.
How long does a system last?
This answer depends on quality type; with a robust quality system, it will easily last 25-30+ years, but a poor quality system may only last a couple of years.
How does this work?
Evacuated tubes work alongside your boiler.
Evacuated tubes work on the same fundamental principle of how your car feels warmer during the day. Under the right circumstances, heat builds up, and it is this principle that solar tubes use, but much more efficiently than your family car.
This super-efficient technology tubes that collect and retain heat through solar radiation that hit our roofs every day of the year.
The principle of solar heating has been around throughout human history and can even be used to sterilise water. If you leave unsterilised water in a plastic bottle for a few hours in the sun, then the sun's radiation will decontaminate water - making it safer to drink.
Today, with the advantage of modern technology, we can use this same principle to heat our hot water tanks or thermal stores. Commonly known as a solar collector, the efficiency of this technique is also boosted by a smart management system that continually monitors and makes adjustments depending upon the level of heating.
This type of system is so efficient that restrictions to temperatures of 85 degrees Celsius apply. And, if that weren't amazing in itself, the system works well on some midwinter and snowy days too. Contrary to popular belief, solar heating panel's ability ain't connected to the outside air temperature. The collecting glass tubes trap and store radiation waves directly from the sun, and it's this ability that makes them ideal for northern European climates.
From my experience, evacuated tubes work best alongside a conventional boiler and will significantly increase the lifespan of that boiler as a result of reduced usage and can easily save you a tank full of oil annually.
Now, this is where it gets interesting because of the increasing cost of traditional fuels, a solar tube system installed today, will still be providing you with significant savings and free hot water for the next three decades if adequately serviced.
Now, this system is not for everyone, and one of the problems encountered today is with people who have had a Combi boiler installed in recent years and lost their storage tank. If this is your situation, then I would recommend photovoltaic solar panels instead.
Most plumbers today would recommend a Combi boiler installation, but for no other reason than, it's an easy installation for them to do. Long-term, solar heating technology will be far more useful to you.
I look at the bigger picture like this. The long-term trend for traditional fuel is predominantly upward, and this is why your energy company cannot price fix for any longer than two years.
If or when the fuel to power a Combi (no matter how efficient) becomes too unaffordable for most, my family can at least enjoy a lovely warm shower for free.
Solar heating panels including evacuated tubes, can provide over half of a home's hot water requirements, according to recent field trials with low carbon and green energy technologies.
Domestic tariff levels, under the government's 860m GBP renewable heat incentive (RHI) scheme, are not being announced until April 2012 but will be on the same standards as larger-scale, commercial solar heating systems and householders could still expect and additional feed-in tariff payment of around 126 GBP per annum (index-linked).
The RHI payments, which are similar to those paid to owners of PV (photovoltaic) solar panels and wind turbines under the feed-in tariff scheme, will be launched soon after. This incentive will encourage homeowners to install solar water heating panels and use the sun's energy to heat water using flat panels or evacuated tubes on the roof of their property.
The system works by heating glycol (anti-freeze), which is then pumped to the hot water cylinder in the home and can store until the hot water is required.
I was originally impressed by how well evacuated tubes worked in the UK climate. I have highlighted the need for quality solar heating systems early in my eighteen years within the solar industry because some solar heating systems performed better than others.
The difference in performance from the best-performing systems (usually evacuated tubes), which provide around 60% of hot water needs.
Today, evacuated tubes are a proven technology.
Evacuated tubes systems are now a technology proven to work, and it works well in the United Kingdom.
A significant factor in a system's performance figures is how well-insulated hot water tanks and pipes are. Once solar power heats water, there is a need to prevent cooling, so quality, solar-ready hot water cylinder is essential. However, not all solar companies upgrade the cylinder, and this omission will affect the overall performance of the system.
The market for solar heating panels in the UK has grown each year despite the economic downturn. There are an estimated 220,000 homes with solar heating panels in the UK currently.
This latest research demonstrates that homes with solar heating panels or evacuated tubes really can benefit as the household understands how to use it to its best advantage.
Solar panels, in general, are a fantastically cost-effective way for this country to reduce its demand for more expensive, imported energy. As 47% of energy usage is domestic, solar technology really can help to reduce the nation's carbon footprint while encouraging other countries to follow our lead.
Unless we all reduce our dependence on increasingly expensive fossil fuels, homes and businesses will continue to pay the price, with soaring future bills.
The Renewable Heat Incentive will provide households with a real cash incentive to help families make the switch to cleaner energy with which to heat their homes.
Welcome to the solar panelled century.
"Forward with confidence."
Founder of Power My Home.