The most efficient solar panel designed for homes and buildings
DualSun designs and manufactures the world’s first certified hybrid solar panel (PVT): the SPRING 2-in-1 panel.
By producing both electricity and hot water, the panel generates 2-4 times as much energy per square meter than a standard PV panel, making it the most efficient solar panel for buildings today.
solar panel, 2 energy sources
FRONT SIDE Electricity production
Sleek, all-black finish
High-efficiency monocrystalline cells
BACK SIDE Hot water production
Ultra-thin heat exchanger completely integrated into the panel
Patented worldwide
A standard photovoltaic panel converts 20% of incoming solar light into electricity and the rest of the energy (80%) is lost as heat. In addition to being wasted, this heat is also detrimental to the solar panel’s photovoltaic efficiency, which drops when the panel rises in temperature.
With its 2-in-1 solar technology, the DualSun SPRING hybrid panel produces electricity on its front side, then recovers the extra energy to heat circulating water using an innovative heat exchanger on its back side.
The water flow in the exchanger has 2 benefits:
- DualHeat: The water can reach a temperature of up to 70°C and can therefore be used to cover the building’s various heating needs.
- DualBoost: The water also cools the photovoltaic cells and improves electricity output by 5 to 15% depending on usage.
A hybrid solar panel designed and manufactured in France
DualSun’s patented SPRING technology is developed by engineers in our research center in Marseille. DualSun also has a ISO:9001 manufacturing site located in the Ain region of France for:
- the manufacturing of the SPRING heat exchangers and
- the assembly of the SPRING PV laminates and patented heat exchangers.
The DualSun SPRING panels have an “IMF” certificate attesting that they are manufactured in France: FR-IMF-2019-198.
than a hundred controls and checks guarantee the high quality of each DualSun SPRING hybrid panel that leaves our factory.
DualSun warranties : Enjoy your solar installation with peace of mind
SPRING hybrid solar panels are designed to last over time. That’s why DualSun offers some of the most reliable warranties on the market:
- 10-year product warranty
- 25-year photovoltaic performance warranty
- DualSun will take care of all labor costs in case of a defective product
Our panels have an excellent lifespan which we have been able to prove through accelerated aging tests performed at TÜV Rheinland in Germany.
An environmental and recyclable hybrid solar panel
We continuously innovate to reduce the carbon emissions and environmental impact of DualSun SPRING panels.
- Ethical: DualSun is strongly committed to making its hybrid solar panels environmentally friendly.
- Recyclable: DualSun carefully selects all manufacturing materials. As a result, the SPRING solar panel is nearly 95% recyclable!
- Durable: the SPRING solar panel returns the energy needed for its manufacture in only 1 to 3 years. Its lifespan exceeds 30 years.
Quick and simplified installation
DualSun has developed the DualQuickFit, an innovative hydraulic connector. With DualQuickFit, you connect the panels together simply by clipping the fittings together.
The result: less time needed to get the job done !
DualSun SPRING panel certifications
In 2013, DualSun’s SPRING panel was the 1st hybrid solar panel in the world to obtain the new Solar Keymark “hybrid solar” thermal certification. Today, all DualSun panels are certified according to the European IEC (for the photovoltaic part) and Solar Keymark (for the thermal part) standards. The panels are also CEC certified in Australia and UL listing (photovoltaic) and SRCC (thermal) certified in the USA.
SPRING on your rooftop
Do a free simulation today with MyDualSun to find the best solar installation adapted for your energy needs.
A connected solar panel
Intelligence is integrated into the DualSun SPRING panel.
DualSun engineers have developed a system to monitor both your electricity and your hot water production in real time on your computer or your smartphone. For the hot water, a temperature sensor is placed in the heat exchanger of the DualSun SPRING panel and connected to a control unit. This monitoring system also notifies you in case of an anomaly or defection.
Frequent questions about the SPRING panel
The proximity of our branches allows us to ensure better control of our production line and limit transportation costs.
Developing a high quality and eco-friendly product is our priority.
The photovoltaic cells of the DualSun panels are manufactured and assembled in Asia. They are said to be “laminated”, i.e. hot pressed against the glass plate used in the front of the panels. The photovoltaic industry is evolving very quickly with the development of gigantic factories capable of producing several gigawatts (1 GW = 10 9 W) of solar photovoltaic panels per year. Read more
Yes! Thanks to SOREN (former PV CYCLE), DualSun panels are 94,7% recyclable. DualSun panels have a lifespan of 25-30 years. What happens to the panels once they have reached the end of their lifetime, or how do we manage broken or defective panels? DualSun panels are recycled via SOREN, the first worldwide take-back and recycling scheme for photovoltaic module waste. The cost of recycling is included in the initial price of the panel as an “eco-participation” cost. Solar power deployment took off 10 years ago, thus major recycling needs will be necessary in 10-15 years from now. However, the industry is already prepared – both technically and financially. Read more
Ready to start your solar project ?
Do a free simulation today with MyDualSun to find the best solar installation adapted for your energy needs.
Hot water from photovoltaics
Electricity that you produce yourself by using a photovoltaic system is cheaper than electricity from the power grid. Even if you include the investment in a new system in your bill, it shows that the costs are quickly amortized. In order to make up for the investment costs quickly and to permanently reduce your energy costs, you should keep your self-consumption as high as possible. This means to use a lot of electricity from your own roof.
Depending on the size of the photovoltaic system installed, an average household uses no more than 30% of its own photovoltaic electricity. However, if you use excess solar power to produce hot water, less electricity goes into the grid and you can increase your self-consumption to around 70%. This way, you can completely switch off your heating system, which only provides hot water in summer, and also save money with the power of the sun.
Simple – Clean – Efficient
So far, hot water from solar energy was only known from solar thermal systems. These are relatively complicated and maintenance-intensive systems that work less efficiently, especially during the transitional period and in winter.
On the other hand, photovoltaics is associated with the supposedly relatively expensive technology for generating solar power. But this is no longer true today. On the contrary: photovoltaic modules are now much cheaper than solar collectors. Read more about it here.
Today, you can prepare your hot water much more cheaply with photovoltaics than with a comparable solar thermal system or with conventional heating systems.
Our principle enables you to use your self-generated solar power in the best possible way in your own household.
Our principle enables you to make the best possible use of your self-generated solar electricity in your own household. Because a lot can be done with electricity – and generating heat works particularly well, preferably directly.
We call this principle cables instead of pipes. In new buildings, laying power cables means significantly lower investment costs than laying pipelines. On the other hand, the refurbishment requires far fewer interventions in the building fabric than a replacement of the water-bearing system. In addition, photovoltaic yields can be used for all energy sectors (electricity, heat, electromobility) of the house.
PV electricity for hot water: How does this work technically?
Using heating rods, surplus solar electricity from the photovoltaic system is used to heat hot water tanks. A heating rod is an electrically operated heating element that is installed in a hot water or buffer storage tank and heats the water there electrically. It is as simple as it sounds. over, the energy losses of a hot water storage tank are low.
It gets even better: there are control elements that intelligently control the electricity generated by a PV system by dosing the heat output of the heating elements very precisely when surplus photovoltaic electricity is available. Solutions from my-PV fall into this category.
Is generating hot water with photovoltaic electricity economical?
There are various opinions on this question, but ours is clear: Yes, it is economical! But as a system owner, take a closer look at the economic efficiency of generating hot water with photovoltaic electricity and do the math. Important questions in this case are:
How high is the current feed-in tariff?
How expensive would the heat be if you had to buy it in or produce it in another way?
In which case do you gain more: if you feed the electricity into the grid or use it yourself?
In addition to heating, water heating accounts for a large part of the energy demand in the household. With our my-PV Power-Coach you can calculate your cost savings and self-consumption easily and quickly.
Your benefits from hot water with photovoltaics
What are the advantages of my-PV’s innovation in the area of hot water? Photovoltaic systems are less complicated and require less maintenance than solar thermal systems. Unlike solar thermal systems, photovoltaic systems do not have a heat fluid circuit. Here, power cables transport the energy from the solar module to the hot water storage tank. PV system owners need neither pipes nor pumps for this. So they don’t have to worry about antifreeze or maintenance costs either.
In the 1980s, solar water heaters took off in Israel, but stalled in the U.S. It’s a simple fix
Despite the huge global opportunity for reducing fossil fuel demand, solar water heating is virtually unheard of in the U.S. Here’s why, and how to change that.
This article originally was published on Ensia.
For Gershon Grossman and Ed Murray, 1978 was a big year. Grossman, then a solar energy pioneer at the Technion, Israel’s premier technological institute, was launching the first International Conference on the Application of Solar Energy. Murray, an idealist attending college, joined an upstart solar heating company in Sacramento, California’s capital, drawn by a prescient concern about climate change and, as he puts it, an impulse to save the world.
For both, the excitement was palpable. Solar water heaters were surging into the market, solar thermal energy showed broad potential, and the two were riding the wave.
Four decades later, however, they live in two different worlds. In Israel, 85 percent of households get hot water from a dud shemesh, or sun boiler. But in the U.S., despite decades of advocacy by Murray and others, the number of households that have a solar water heater is less than 1 percent. In California, many people don’t even know the technology exists.
America’s solar water heating deficit is often portrayed as a historical accident driven by the vagaries of politics and comparatively cheap fossil fuels. However, interviews with academic and commercial players on the front lines of the solar thermal industry, and a recent in-depth report on the now-expired California Solar Initiative–Thermal (CSI-T) program, suggest that the desire for simple, magic bullet solutions to climate change also has played a significant role in relegating this practical technology to the sidelines.
A mandate, an election and two roads diverged
Heating water accounts for 25 percent of residential energy use worldwide, mostly achieved by burning fossil fuels. Solar water heaters do the job without combustion. Unlike solar photovoltaic (PV) systems, which convert sunlight into electricity, solar thermal systems collect solar energy as heat.
Solar water heaters transfer this heat to water in a holding tank. Other energy sources, such as natural gas or electricity from a power grid, serve as a backup for cloudy days.
By tapping the sun, solar water heaters can reduce a household’s water heating fuel consumption 50 percent to 70 percent. Israel is just one of dozens of countries with a variety of climates where this technology has been deployed. Solid performance and wide applicability have made the technology one of Project Drawdown’s top 50 climate change solutions.
So why did solar thermal technology soar in Israel and sputter in California, setting Grossman and Murray on such different life paths? A pair of political decisions in the 1970s and 1980s had dramatic impact.
In 1976, Israel mandated solar water heaters for all new residential buildings up to eight stories tall.
The Yom Kippur War of 1973 and subsequent oil embargo made energy independence a matter of national security worldwide, but the pinch was particularly painful in countries lacking oil production. For Israel, the threat was existential; as former Israeli prime minister Golda Meir famously quipped, [Moses] took us 40 years through the desert in order to bring us to the one spot in the Middle East that has no oil. In 1976, Israel mandated solar water heaters for all new residential buildings up to eight stories tall — a mandate extended to all residential buildings last December.
For Grossman, now a professor emeritus at the Technion and head of the Energy Forum at the Neaman Institute for National Policy Research, mandating solar water heaters made sense environmentally, even beyond Israel’s political agenda. You just can’t argue with the numbers on how much [energy] you can save using solar water heating instead of electrical heating.
The U.S. also felt the jolt of the oil embargo and feared running out of domestic oil. Supported by President Jimmy Carter’s 1978 federal tax credits for renewable energy, Americans installed nearly 1 million solar thermal systems by 1990, supplied by more than 200 U.S. manufacturers, including leading corporations such as Grumman Aerospace Corporation and Sears Roebuck.
Renewable solar heats 85 percent of households in Israel, who get hot water from a dud shemesh, or sun boiler. In the U.S., it’s a different story. Photo courtesy of Yaniv Hassidof.
However, in contrast to Israel, America’s commitment to renewable energy proved ephemeral. Under President Ronald Reagan, the federal incentives lapsed, dealing the solar thermal industry a body-blow. We went from 650 companies in California that were installing solar [water heaters] to about 37 overnight, recalls Murray, currently president and CEO of two California companies dedicated to manufacturing, distributing and installing solar thermal systems, as well as president of the California Solar and Storage Association.
Recent attempts to revive the residential solar water heater industry have had limited success. The CSI-T program, begun in 2010 as a larger push to incentivize solar installations statewide, aimed to add 200,000 systems, but received only 6,237 applications for residential retrofits in 10 years, according to the program’s December report. I could put a sign over the front door of my office that says ‘free solar water heating,’ and they’d probably still stay away in droves, Murray says with a wry laugh.
Larger installations for apartment complexes, hotels and universities and home pool heating have helped keep Murray’s solar thermal businesses afloat despite the lack of other residential demand. Ironically, the commercial sector isn’t as robust in Israel because the country’s original mandate only applied to residential properties — a move Grossman views as a significant oversight. Indeed, Grossman believes that an industrial mandate could increase Israel’s renewables usage up to fivefold.
The limiting psychology of renewables
The woes of the American solar water heater industry go far beyond politics, however. The industry also suffers a more insidious challenge: For the average consumer, going solar means just one thing: solar PV.
Solar thermal technologies, including solar water heating, provide a direct, thermodynamically efficient and cost-effective method for decarbonizing heating. And for households in mild climates with low electricity bills, solar water heating can be one of the simplest ways … to use renewable energy and save on energy bills, says the CSI-T report.
But solar PV has exploded into the global electricity sector, thanks to manufacturing innovations and strong government support. Leveraging economies of scale, the price of solar PV panels has dropped by over an order of magnitude in the past decade. In California, additional boosts came from government-instituted solar feed-in tariffs, cheap financing plans and private-sector investments. And, in a major coup for the industry, California mandated solar PV on new residences up to three stories starting 2020.
California’s residential solar water heater industry finds itself in a vicious cycle of low consumer demand and high prices.
On the other hand, California’s residential solar water heater industry finds itself in a vicious cycle of low consumer demand and high prices. As the CSI-T report notes, In contrast to conventional gas and electric water heaters, which are typically installed by plumbers, solar water heaters are installed by a range of firms and public entities. In other words, consumers actively must seek out solar water heaters by relying on nonstandard sales channels.
This additional friction reduces consumer demand among all but the most motivated consumers, leading to higher marketing costs that drive up the customer’s bottom line. in California are further exacerbated by past industry failures, which have led to strong, self-imposed regulations in the name of consumer satisfaction, says Murray. For example, after many cheaper solar water heating systems froze during the unprecedented 1990 freeze in California, only more expensive systems were allowed through the CSI-T program.
All told, the cost of the average solar water heater sold in California through the CSI-T program was 7,400, compared to less than 1,000 for a fossil fuel alternative. By contrast, a solar water heater in Israel can cost as little as 700.
Going all-in on one technology available to solve the carbon emissions problem satisfies the very human need for ‘magic bullets.’
Today, drumming up excitement for solar thermal remains difficult. According to CSI-T report interviews with solar water heater adopters, Some interviewees remarked that it seemed tough to get others interested, theorizing that PV was so dominant in neighbors’ minds that solar water heating hardly registered.
It’s just the sizzling, sexy PV [that] really captivates the audience, says Murray.
Portfolios, not magic bullets
Entrepreneurs routinely caution, Fall in love with the problem, not the solution. In this case, the problem is carbon emissions, and, against entrepreneurial advice, individual governments have tended to fall in love with just one solution. For Israel, Cyprus, Hawaii and others, solar water heaters were that solution. For California, it’s solar PV.
By committing to a specific technology, governments fall prey to a conceptual error that science journalist Ed Yong recently referred to as a monogamy of solutions. (Interestingly, he argues this fallacy also shapes the government’s response to COVID-19.) Rather than embracing the growing portfolio of technologies available to solve the carbon emissions problem, going all-in on one satisfies the very human need for magic bullets.
Europe’s Green Deal may model such a portfolio approach for the rest of the world, according to Bärbel Epp, a German physicist-turned-journalist with nearly two decades of experience studying the global solar thermal market.
According to Epp, representatives from the European solar thermal market have lobbied the European Commission for over a decade to use solar thermal technologies to decarbonize the heating sector. It took [the solar thermal industry] I don’t know how many years, at least 10, of just continuously repeating the sentence that heat is 50 percent of our final energy consumption in Europe. … It was hard to lobby in Europe, but it’s now obvious that we have to do something for heat. Whether these efforts will succeed in providing solar thermal a seat at the table remains to be seen.
To Grossman, solar water heaters are the first piece of Israel’s portfolio. As Israel struggles to meet its Paris Agreement goals, Grossman says he believes solar PV panels will take their place alongside solar water heaters on Israel’s rooftops.
Back in Sacramento, Murray is still battling for solar thermal. This year, he’s lobbied the California legislature to extend the state’s recently expired solar thermal subsidy program for one more year, citing COVID-19 as a barrier. The legislature hasn’t budged, but Murray vows he’ll keep going. He may be a lot older than he was in 1978, but the idealism is still alive.
Editor’s note: Dina Berenbaum and Manoshi Datta wrote this story as participants in the Ensia Mentor Program. The mentor for the project was Peter Fairley.
Editor’s note, Nov. 3: This story was updated to give more information about Gershon Grossman’s current role.
The Best Way To Heat Your Water – Solar PV Or Solar Thermal?
From flat plate thermal systems to heat pumps and solar PV diverters, in this video Finn takes a look at your solar hot water options.
Did you know that there are two fundamentally different ways to generate solar energy and therefore two fundamentally different types of solar panel?
To keep it simple, I’m going to call them solar PV and solar thermal. PV stands for photovoltaic, which is the conversion of light into electricity. When most people talk about solar, this is what they mean – panels that generate electricity.
Flat Plate And Evacuated Tube Solar Hot Water
Solar thermal panels on the other hand, do not generate any electricity at all. They simply use the heat from sunlight to warm up water inside the panels, and they come into types – flat plate and evacuated tube.
Flat plate systems look similar to solar PV panels, except there are about three times as thick. An evacuated tube system looks very different to both flat plate and solar PV.
“I get it,” I can hear you say, “I should put both solar PV and solar thermal panels on my roof and get all my electricity and hot water from the sun. ”
Actually no, and I say that for economic reasons. Solar thermal used to be the cheapest form of solar water heating, but now since solar PV have plummeted, solar thermal has been dethroned.
To put things into perspective, the cheapest form of solar thermal is a flat plate system. That’s going to run you about 4,000 to put on your roof – and all it will do is heat your water. Meanwhile, a 6.6 kilowatt solar system these days costs you around 6,000 and could offset the electricity usage of your entire house, including your hot water if it’s electric.
So the cheaper options for solar water heating are, these days, powered by electricity – specifically solar electricity. I recommend either heat pump or diverted PV systems. Let’s look at them in a bit more detail.
Heat Pumps
A heat pump system kind of looks like a small air conditioner hooked up to a traditional hot water tank. You can also find some newer, sleeker units that look like this one.
Heat pumps extract heat from the air and transfer it into the water. Now, you may be wondering why it’s considered a form of solar water heating if the sun doesn’t seem to be involved. Well, as the heat in the air originally came from the sun, you can think of it as a solar heat pump.
Most importantly, you can claim STCs otherwise known as the solar rebate, on a heat pump, which brings their cost down considerably. An entry level model will set you back about 2,000 fully installed. If you live outside Queensland or the tropics, then a modern heat pump is about as efficient as flat plate solar thermal hot water, but it doesn’t require gas to boost them in winter. A good heat pump is as quiet as a good quality air conditioner and will work well even in freezing temperatures, albeit with a reduced efficiency.
A heat pump is also a good choice if you have a generous feed in tariff, say over about 15 cents a kilowatt hour ; as its efficiency leaves more electricity available for export.
If you buy a heat pump, it’s important to try and run it off solar PV as much as possible. That means two things. One, running it in the day, and two, having enough PV to power it over and above your other appliances. I’d say at a minimum you should have 6.6 kilowatts of solar PV.
Solar PV Diverter
Now, no matter where you live in Australia, whether it’s in the tropics or in Tassie, there is a potentially even cheaper upfront option for heating water with the sun; provided you buy it at the same time as your new solar PV system. This is known as a diverted PV solar hot water system. This is the cheapest in terms of upfront costs, most reliable and lowest maintenance system, for heating hot water from the sun.
If you have it put in at the same time as your solar panels, it could only cost you about a thousand dollars extra.
A diverted PV system uses an intelligent control box to divert “spare” solar electricity from your solar PV panels into a conventional hot water tank. So, electrically it is about four times less efficient than a heat pump, but many people are cool with the low efficiency if it only uses solar electricity. This “spare” electricity would have otherwise been sold to the grid for a feed in tariff.
If your self-consumed solar is more valuable than your exported solar, it’s more valuable to use that solar to heat your water. But, if you have a cheap off-grid hot water tariff that is lower than your feed in tariff, diverted PV makes no economic sense. You may as well export the solar and pay for the hot water heating with that credit.
“But Finn,” I hear you cry. “If I’m powering my hot water as well won’t I need extra solar panels?”.
Yes, you will. But because of the diverter’s intelligent controller, which scavenges spare solar energy whenever it’s available, you might get away with only 1.5 kilowatts of extra panels. Meaning a 6.6 kilowatt system is the minimum size you should be aiming for – 8 kilowatts plus is probably better.
So, to summarize, if you use gas to heat your water and you want to reduce this cost by around 70 to 80% you should seriously consider transitioning to an all-electric home. The most efficient way to heat your water with solar electricity is to use a heat pump. But if you don’t want to pay thousands up front for a heat pump, a cheaper option is to get a PV diverter installed. And that’s assuming you have plenty of spare solar electricity, and assuming you’re feed-in tariff is less than your hot water tariff.
Discover everything you need to know about solar energy for your home in Finn’s book, The Good Solar Guide – free to read online.