Multi-use solar collector inspired by lotus flower


March 1, 2012

Artist's impression of an installed Lotus solar collector (Image: Monarch)

Artist's impression of an installed Lotus solar collector (Image: Monarch)

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This rather novel solar collector draws inspiration from the lotus flower to provide small-scale solar energy - both electric and thermal - to domestic and small business users. The aptly named Monarch Lotus (rebranded from the Solar Umbrella) has 18 petals which unfold to to form a 4-meter (13-foot) diameter flower solar collector that will, if development goes to plan, produce 3 kW of photovoltaic electrical power and 3 kW of solar thermal power per 100-kg (220-pound) unit in ideal conditions.

Even in less than ideal weather, Monarch, the company behind the Lotus, hopes the device will be good for a solid 2 kW of PV, and the same again for thermal. The plan is for the collector will use high-efficiency solar cells capable of converting 40 percent of captured solar energy into electricity, while the Lotus will absorb another 40 percent as heat energy. Water is required to cool the solar cells, so hot water is a useful by-product.

Monarch claims that, connected to a water purification unit, the collector would be capable of producing a 10,000 liters of purified water per unit per day (based on an ideal 3 kW of power dedicated solely to purification). The company reckons that this is enough purified water for a community of over 100 people.

The ability to open and close like a lotus flower is more than a gimmick. As well as aiding transportation, a closed Lotus is better able to withstand wind and rain. The Lotus is opened by pulling open the center six petals, with a network of "strings" opening the rest.

Though Monarch says that the collector would be ideal for a cafe, its potential for water purification and off-grid electricity generation do cry out for a role in international development. Because the Lotus is free-standing rather than roof-mounted, such an innovation may prove ideal in rural parts of developing countries where homes are not built to withstand the weight of solar panels. And because the Lotus is light enough to be transported by truck, Monarch says it is ideal for emergency deployment in disaster zones.

Monarch hopes that an installed cost of under US$9,000 per Lotus can be achieved, which the company equates to an installed cost of $1.5 per watt. The incorporation of photovoltaics is not finalized, as Monarch is investigating connection to a high pressure steam engine is an alternative, potentially more efficient, means of electricity generation. Though it's evident Monarch has created a physical prototype, it's not yet clear how far the company is from achieving its performance targets.

Source: Monarch

About the Author
James Holloway James lives in East London where he punctuates endless tea drinking with freelance writing and meteorological angst. Unlocking Every Extend Extra Extreme’s “Master of Extreme” achievement was the fourth proudest moment of his life. All articles by James Holloway

They should use a sterling cycle engine cooling the cold side by dumping the heat into a absorbent type refrigerator and heat the water off the condenser and heat exchanger for the low refrigerant fluid on the way to reabsorb the refrigerant. The more work you can get out of a given amount of energy the greater the efficiency.


While I applaud those trying to accelerate the transition to solar energy, this device has a lot of questionable assumptions. It is obviously a concentrating mirror system and as such will generate almost nothing when the clouds cover the sky. Straight, flate-plate photovoltaic panels generate in everything but twilight, darkness and dawn. Plus, concentrating solar need to have very clean and well aligned reflectors to focus the sun. This means high maintenance and mechanical, moving parts that will need calibration. Plus the windage on those large flimsy reflector/petals is an accident waiting to happen in a situation where the stowing mechanism fails. I like the sci-fi looks but we really need to concentrate our resources on basic, bullet-proof photovoltaic panels with no moving parts. I have been living with them for 3 decades and never had a power outage. Living with solar energy is viable right now. Especially if you place any value on the preventing the wholesale extermination of the biosphere.

Jonathan Cole

Slowburn - Sterlings don't last. There has been a lot of testing and R&D with Sterlings but they still haven't come up with a reliable set up. Low pressure sterlings work great. But in order to get max efficiency, you need to pressurize the cycle which leads to seal failure.

JC - You are right about the down side of CPV (concentrating Photovoltaic). I've done extensive R&D in this field for 20 years and have seen what works and what doesn't. United solar technologies put together the best system so far and Doug Woods up on Fox island near Tacoma, Wa. makes the best concentrator dishes. His hold up in hurricanes, are literally bomb proof, simple, and cost effective, and they look like a piece of art. They are simply amazing to look at. The problem with concentrators is getting a specular surface that will last for decades and not corrode. Tangentially speaking however, the crux of the problem is recognizing the matrix. This might not seem irrelevant, but if you read the book THE MEDIA MONOPOLY by Ben Bagdikian, it really explains the problem. An even better explanation is available by watching the movie THRIVE. Hanford nuclear waste dump gets $11 Billion/year to store nuke waste which is leaking into the columbia river. Oil companies get billions of tax breaks for drilling. They also get tax payer to funded invasions of countries that have oil. We pick up the tab on that in lives and debt and they turn around and screw us at the pump. Those same companies also get the contracts to feed soldiers, drill for oil, supply security to private contractors getting the no bid contracts, and they deliver diesel to the troops for $400/gallon. They use electric generators to heat water in a dessert. This is insane. The entire renewable energy budget is less than $200 million. If we diverted 2% of energy funding and the pentagon budget to solar PV we could generate half the power we need. Put a 4' windmill on every telephone pole and we could get another 25%. It's that simple. We waste 50% of what we generate right now so if we simply had a rational energy education program, we could shut down our Fukushima style reactors right now. But what are we doing? We just approved 2 nuke plants for Georgia, we are pretending Fukushima fallout is not blanketing the northern hemisphere at hemicidal levels.


i could go on but who's got the attention span these days?


How about adding some blades to the top of each petal to funnel air and act as a windmill and generate power that way too. I'm sure you could gain some efficiency that way as well as help with the cooling. I bet you could catch enough breeze around the edges to double the output on breezy days. You could also give it some color there since it doesn't have the reflect more sunlight. Just a thought.

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