Energy Products
High quality, reliable, easily installed solar hot water systems at a brilliant price! How?
Solartwin costs less to buy because there is less kit to buy.
Solartwin costs less to install because there is less kit to install.
Solartwin consumes no mains electricity, by having no solar controller and a pump that is powered by sunshine.
Solartwin can also require less top-up heating (which old solar too often requires) because it delivers hotter, not tepid water.
The Solartwin System
Solartwin’s specification...
Freeze-tolerant direct solar thermal water heating with variable speed photovoltaic powered circulation.
The dimensions of the whole panel are: approx. 2.5m wide by 1.3m high. It projects no more than than 100mm above the surface of roof. It weighs under 40kg. The flexible pipes are no thicker than a finger, and the pump is about the size of a large egg. The absorber’s nominal aperture is approx. 2.8 sq m.
The materials of the main frame and roof mountings are anodised aluminium, the double glazing is UV-stabilised polycarbonate, the heat absorber is mainly aluminium and elastomer, the insulation is rigid foam, the paints used are 95% water-based. The photovoltaic panel is a silicon type and the pump requires less than 24 volts.
The piping materials are approved for water use in UK.
Safe, reliable, low maintenance, and a five year warranty
You get a 5-year components warranty with Solartwin. Comprising very few parts, which we manufacture with strict quality control, Solartwin is intrinsically reliable. As for safety, Solartwin frees you from concerns about toxic antifreezes, mains voltages and smashable glass panels or tubes.
100% solar
What could be better? Having eliminated heat exchangers, and the fast water flows that they demand, Solartwin is able to perform efficiently by circulating water less rapidly, usually needing just one single pass instead of several through the panel. A further development means that in low levels of sunlight, the pump responds by slowing the flow.
Low flows mean low power requirements. So a small photovoltaic (solar electric) module drives the pump.
Eco-efficient
Shrink your home’s environmental footprint, your greenhouse gas emissions, and your energy bills!
Installs easily
Two people can get Solartwin up and running in less than a day. With less kit to fit, Solartwin means half the workload and very little disruption compared to conventional solar. You can install it yourself or use an installer. Either way, you save money.
Old solar requires three full skills in the installation team: roof working, plumbing and mains electrics. It can be hard to find triple skills all at once. But with Solartwin, you only need one full skill: roof working. As with old solar, you bolt our lightweight panel to the roof, and pass two pipes and a cable into the house. Mains wiring is eliminated because the pump runs on low voltage solar current.
Indoors, there’s almost no plumbing: two flexible pipes just “tee" into existing pipes. You don’t plumb in a costly new cylinder, nor vent pipes, nor a pressure vessel. Most indoor work is in the attic, keeping your home tidy.
Portable
Moving house someday? Pack your panel in the van! Easy to install, Solartwin is as easy to un-install, and to re-install.
Inhabits a roof, not your rooms
Solartwin uses no bulky pre-heat cylinder, so you don’t have to have a second airing cupboard built. Plus, having only one cylinder cuts heat loss by halving surface area.
Classic good looks
With its slate grey trim, Solartwin blends in, and looks like a double width roof window. Optional extra “glazing bars”, which are vertical and narrow, match the vernacular of many older buildings.
Simple, yet technically elegant
The Solartwin system has few components: a freeze-tolerant solar water heating collector panel, an "intelligent" solar powered water pump plus two thin, flexible pipes.
From the outside, Solartwin looks quite like a conventional solar water heating panel: a double glazed box with black metal inside. Inside the metal are small, flexible, water channels. The panel fits on a roof, wall, or the ground. It traps heat and light from the sun and warms up inside. The solar powered pump then brings this hot water into the house. That’s it.
Freeze-tolerant
A thermally conductive elastomer formulation within Solartwin’s patented absorber does the trick. This brilliant invention can freeze solid in winter without cracking when the water inside expands.
Achieving freeze-tolerance was the “Holy Grail” of solar heating. It makes Solartwin uniquely simple, with spinoffs such as:
- Eliminating most of the gadgetry, plumbing, electronic controllers, antifreeze chemicals, unreliability and high maintenance inherent in old solar.
- Letting you store your hot water, undiluted by cold water, where you need it, at the top of your hot water cylinder. Old solar usually delivers it to the bottom, cooling it and losing energy in the process.
- 100% solar capability. Solartwin powers its pump from a small photovoltaic panel, eliminating all pump running costs.
- Delivering hotter water, with roughly the same temperature rise, whether it is sunny or overcast.
Questions and answers
Hotter water, what’s the secret?
Solartwin delivers hotter water thanks to three design innovations, which all stem from its unique freeze tolerance:
Start with hot, not tepid, water with Twin-optimised coatings!
Inside the panel on the roof, Solartwin's unique 'Twin-optimised' coating system minimises heat losses and maximises heat gain at all water temperatures. So your solar water leaves the panel as hot as possible.
Hot water on dull days thanks to varispeed photovoltaic pumping!
Unlike conventional solar, Solartwin normally achieves a good temperature rise whether the sky is sunny or overcast. Solartwin's variable speed solar powered pump responds intelligently to sunlight as dull as 20% - not by switching off, but by pumping water more slowly through the panel. This way, on dull days, it spends longer in the panel: so it still heats up properly.
No heat exchanger, so you don't cool hot water unnecessarily!
Inside the house, Solartwin keeps this water hot by delivering it directly to the top of your existing hot water cylinder. Conventional solar delivers heat via a heat exchanger at the bottom of a costly new cylinder. But heat exchangers are inefficient: they all rely on cooling to happen in order to work. (Some 'glass tube' solar systems have second heat exchangers on the roof, penalising efficiency further.)
Solartwin doesn't exchange heat wastefully. It simply delivers it direct. And it maximises water temperature further by stratifying (floating) its hot water, unmixed, over cooler water below. So when you open the tap, your Solartwin hot water arrives first.
Is Solartwin just for cold places?
Not at all! While freeze tolerance makes Solartwin unique in areas with icy winters, it performs just as efficiently where winter is mild.
How much can the sun deliver?
In UK and Ireland, the sun typically delivers 30-70% of a household’s hot water over a year. As with all solar water heating, top-up heat (gas, oil or off-peak electricity) can still be needed, mainly in winter.
Is Solartwin suitable for me?
- Yes, if you want solar hot water for washing and bathing. (Central heating is poorly matched to solar, since the sun shines most in summer, when you need it least.)
- Yes, if you can face the panel towards the sun between 9.00 am and 3.00 pm. South, southwest or southeast are best. It should not be shaded for more than 3 hours.
- Yes, if you have a low pressure hot water system. Typically, this has a hot water storage cylinder, near the bathroom, and a cold water tank in the attic above. Low pressure is usually found in UK, Ireland and where Britain has had an historical involvement.
- Yes, if your hot water cylinder holds at least 80 litres. Most do.
- Yes, if there will be less than 6 metres in height (up or down) between the water surface in the cold tank and where you want the top of the Solartwin panel to be. This is no problem in most homes.
Where is Solartwin not suitable?
- Where hot water is kept at mains or high pressure (over 1 bar).
- Where a combi boiler heats water: this cannot store hot water.
- Where you have very hard water. If in doubt ask the water company.
Note: roof alterations may need consent in listed or historic buildings, conservation areas or national parks.
As easy to plumb in as a washing machine Solartwin is so easy to install....
This page shows why Solartwin's revolutionary new freeze-tolerant solar water heating system is so easy to install.
The last diagram simply shows how Solartwin requires very little extra plumbing, takes up very little space in the house and is quick and easy to install.
1. Conventional low pressure hot water system with no solar
2. The Solartwin system
- The Solartwin system is simply a 3 square metre (approx) solar water heating collector panel on the roof, plus an "intelligent" solar powered water pump and two strong, thin, flexible supply pipes.
- From the outside, Solartwin looks like most conventional solar water heating panels: a black sheet of metal in a double glazed box. Like all solar water heaters, this absorbs solar energy and heats up.
- Because the Solartwin system is freeze-tolerant, it collects the heat using ordinary water, rather than antifreeze. Also, because it uses a photovoltaic (solar electric) panel to power the pump, the Solartwin system is totally solar.
- The pump responds intelligently to reduced levels of sunlight by pumping slower. As a result, unlike most systems, it provides roughly the same water temperature increase all the time, even if is sunny or overcast.
- It delivers the hot water directly into your existing hot water storage cylinder along simple to install, flexible pipes. The solar hot water floats on top of the colder water in the storage cylinder, waiting to leave first, when you want to use it.
- Installing Solartwin is simple and relatively cheap, as you can see it requires minimal plumbing.
- It requires minimal technical skills. Only a single full skill is required in the installer: the skill of working on a roof. The need for plumbing skills is minimised although not completely removed since two simple "tee" connections need to be made to your existing plumbing. The remainder of the plumbing involves simply laying and clipping flexible pipes. No mains electrical skills are needed whatsoever because the system runs on low voltage solar electricity.
Solartwin offers minimum disruption when installing, and then is as equally easy to un-install and load in a van when moving house.
Installation Options
Self-install Solartwin kit
2.8 square metre (nominal aperture) kit: roof panel and fixings, pipes, tees, pump, installation guide. Installed Solartwin systems: from £1999 2.8 square metre (nominal aperture). Installation cost of the above kit is quoted, based on a survey. This price covers over 60% of homes. A standard installation at £1999 takes up to one day, is on a bungalow or a two storey house which has a loft hatch fitted and where access to the roof is uncomplicated.
4 decorative glazing bars, optional
Narrow vertical easy to fit slate grey bars re-create a traditional 5-paned roof window and minimise shading.
Bespoke for homes and swimming pools
Solartwin can be modularised from 1 - 10,000 square metres. Flush or surface mounted, glazed or unglazed modules are available. For example, unglazed modules can fit neatly below rafters covered with glass or polycarbonate. Please discuss your requirements with us.
Solar Twin products for industry and swimming pools.
SolarSwim and SolarModule are cost-effective modular systems.
Solartwin can be modularised from 1 - 10,000 square metres. Flush or surface mounted, glazed or unglazed modules are available. For example, unglazed modules can fit neatly below rafters covered with glass or polycarbonate. Please discuss your requirements with us.
Contact us with your needs:
Solartwin at work!
The pictures below were taken at a recent installation in York, England. Arriving after breakfast the installation team had finished before 3.30pm, giving minimal disruption. Click on the photographs to view them at a larger size.
Time: 8 am - Welcome to the York installation, a picture of the house before the installation.
Time: 9 am - The panel is unpacked and ready for assembly.
Time: 9.20 am - The photovoltaic panel which powers the variable speed pump is attached to the collector panel.
Time: 9.40 am - The bracket which securely supports the panel is ready for attachment.
Time:11 am - This photo shows the support bracket securely bolted to the roof.
Time:11.30 - The pipe holes are carefully drilled into the roof.
Time:1.30 pm - The panel is secured to the roof brackets. Time to connect the two pipes and the pump inside the house.
Time: 3 pm - With the panel fully installed the system is checked for commissioning.
Time: 3.30 pm - Finished in time for afternoon tea!
For more information contact Mearsecroft
Created and updated by Spiders Webs
