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China solar greenhouses, built on south facing slopes, are an underdocumented innovation. A recent study looks at their history and suggests additional ways to improve them.  (Source: Energy Bulletin)
Chinese innovation starting to show itself on the world scene

One perpetual criticism of China, the world’s second largest economic super-power, is that its lacks the innovation found in the U.S., Japan, or European Union.  Perhaps that is a bit of an exaggeration, however.

A great deal of innovation in China has not been absent, but has merely gone undocumented until late.

Take China's advanced solar green houses, which were designed more than 20 years ago.  In a new peer-review study [abstract] published in the journal ASHS (American Society for Horticultural Science) HortTech, researchers at the China Agricultural University in Beijing have detailed how the Chinese innovation -- built on slopes -- offer great savings in power costs and emissions.

It's not surprising that China might know a thing or two about efficient growing.  It has to feed the world's largest population -- over 1.3 billion people, today.  That's no easy task.  To sustain the population, China had to figure out how to grow crops cheaply and effectively in the winter.  To do that it created the slope greenhouse design.

The greenhouses studied lie in regions north of Huai River and the Beijing area.  Like any greenhouses, their feasibility as winter growing sites relies on the temperature at the site and the amount of sunlight during the winter.

What is unique about the Chinese design is that they use the slope to provide a degree of natural insulation, while optimizing solar absorbance.  The back wall is situated directly into the slope and side walls jut out of the slope on a flattened plot of land.  On top, a thin roof is built.  This gives way to the sloping transparent curved roof/front wall, the first thing you see when looking at the greenhouse from outside.

The greenhouses are constructed using simple materials.  A frame made of bamboo, metal, or a combination of both supports the curved glass wall.  The transparent wall is formed of an insulating sheet and plastic film.

While the greenhouses have numerous advantages -- "energy savings, reduced pollution, and improved economic development" -- they also have disadvantages, which the authors note.  Namely, weather conditions can limit sunlight, causing growing problems.  The greenhouses are heavily reliant on sun and weather conditions.

Still their cheap, efficient, easy to construct design has been an alluring innovation for other nations, situated between the applicable 32°N and 43°N latitudes.  Among the countries implementing them are Japan, Korea, and Russia.  The greenhouses are used to grow warm-weather crops like tomatoes and cucumbers.

The report author, Zhen-Xian Zhang, speculates on how to improve upon the tried-and-true design, stating [press release], "Innovation and optimization of the greenhouse structure needs to continue. More work needs to be done on gutter-connected, double-arched, and semi-underground greenhouses. New wall insulation materials need to be developed to reduce the thickness of the wall while improving its insulation efficiency and expanding space utilization. The solar greenhouse has a very bright future, especially given the amount of concern over the global energy crisis and climate change. Additionally, significant energy savings can be realized from switching to solar greenhouses. We hope this technology can be applied to regions of similar climate to help reduce energy consumption and CO2 emissions."

Professor Zhang also suggested breeding special hybrid crops optimized for growth in the occasionally adverse conditions of the winter greenhouse.  Such crops might resist brief chills and add already more utility to this tested design.


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Only idiots believe that China is not innovative
By wordsworm on 3/21/2011 2:08:13 AM , Rating: 3
One perpetual criticism of China, the world’s second largest economic super-power, is that its lacks the innovation found in the U.S., Japan, or European Union.

There are so many Chinese inventions critical to modern technology that only the most racist and ignorant of people could ever make such a bone headed assertion.

By MGSsancho on 3/21/2011 3:25:15 AM , Rating: 1
possibly referring to ignorant stereotypes? sadly Mick does not need to cite sources regarding them =(

By phxfreddy on 3/21/2011 9:30:00 PM , Rating: 2
Don't get your panties in a twist! Its fair to make broad comments about societies.

...and it is true China has problems in the innovation area.


By PaterPelligrino on 3/21/2011 5:59:44 AM , Rating: 2
One perpetual criticism of China, the world’s second largest economic super-power, is that its lacks the innovation found in the U.S., Japan, or European Union.

But then that was true of Japan in the years immediately following the war. The joke at the time was that the Japanese would buy some American product and make such a slavish copy of it that they would even reproduce the bumps and scratches it acquired on the way to Japan. It's been a long time such anyone made fun of Japanese tech.

We don't teach it, but when America was first emerging as an economic power, we were criticized by the more developed European economies for stealing tech and making cheap knockoffs. There were even cases of poisoned American food exports similar to the Chinese milk scandal. This provided the initial impulse for the imposition of quality standards on American industry

Everybody wants the good life and wants it now. When a country first develops it makes economic sense to take shortcuts. That was true of Taiwan and Korea when I first came out to Asia 30+ years ago, and now they are doing advanced research. China will follow.

The Chinese are a highly intelligent, highly creative people. It seems like half the contributors of the studies quoted in the science journals are Chinese.

You want to divide mankind up into competing tribes and keep score - go ahead. But it's OK by me if the guy who finds a cure for cancer or a revolutionary energy source is Chinese or Nigerian or whatever.

By Jammrock on 3/21/2011 1:40:12 PM , Rating: 2
I think the assertion is based on the "modernization" of China. There is still a lot of personal coal heat used in Beijing and all over China, and other emissions issues that lag behind other parts of the modern world. Speaking strictly from a western perspective on the "green" front. Much of this was caused by the media coverage of China during the last summer games. But, as the article states, the assertion is misleading because a lot of China's "green" innovations have gone mostly undocumented.

From a tech perspective they lag behind on some modern technological achievements in things like the advanced semiconductors and aerospace industries (yes they manufacture most of it, but most of it is still designed elsewhere). This is rapidly changing, however, as China has an excellent educational system, tons of very smart people and boatloads of cash reserves.

From a broad historical perspective Europeans look like out-right cavemen compared to the Chinese when it comes to technological advancements. The Chinese would be double the super-power they are now if it hadn't been for the 150-years lost to conflict caused by the opium trade and the Communist revolution.

solar greenhouses ehh?
By Bubbacub on 3/21/2011 5:59:39 AM , Rating: 2
ever heard of a non solar greenhouse?

RE: solar greenhouses ehh?
By JediJeb on 3/21/2011 4:13:06 PM , Rating: 2
Non-solar greenhouses are used all the time growing marijuana in basements and attics.

RE: solar greenhouses ehh?
By Natfly on 3/21/2011 4:58:07 PM , Rating: 2
I think by definition greenhouses use sunlight for convection. If you are growing indoors you don't need the additional heat and in most cases try to get rid of the heat that lamps output.

This whole article is not news
By XGene on 3/22/2011 1:49:42 PM , Rating: 2
I am grasping to understand why this is news at all. As an Irrigation Professional I understand the benefits of greenhouses and I can see where they can be used to advantage in many areas of crop production. However, greenhouses have been around for a long time and I don't see how these "Chinese" solar greenhouses are any more innovative than anyone else's greenhouses. These appear to be cheaply built mass produced frame with plastic film run of the mill greenhouses. All the advantages you list are standard to all greenhouses. All the disadvantages you list are standard to all greenhouses. Where is the news? What a waste of time. You might as well write about Chinese manual powered knives are being used to great advantage cutting things over in china and the rest of the world should be amazed. /rant

RE: This whole article is not news
By XGene on 3/22/2011 1:55:00 PM , Rating: 2
Oh and did I mention how often CO2 emissions are pointed out in the article... What does C02 emissions have anything to do with these greenhouses? This article smacks of propaganda through and through...

By mmcdonalataocdotgov on 3/20/2011 7:42:17 PM , Rating: 1
From what I recall in my horticulture classes, all things being equal, the number of degrees of slope to the south is equivalent to moving the piece of ground the same number of degrees south latitude on the surface of the earth. So if the slope is 5 degrees south, and you are at latitude 30 north, the ground has the equivalent heat profile of a flat plot at 25 degrees north. As long as you don't exceed the angle of repose of the plot, you could do quite nicely with this technique. Now that is something.

By FaaR on 3/21/2011 5:32:46 AM , Rating: 2

I'm not sure how far south these greenhouses are located (too lazy to look up on a map), but the major cause of winter on this planet is that the sun does not reach as high in the sky during wintertime.

So with the sun's rays being more parallel to the ground, and plants growing...well, on the ground, perhaps the use of mirrors - appropriately aligned - mounted up above the plants to reflect additional sunlight down at the plants' leaves could improve growth and size of harvests.

Just a thought...

By MonkeyPaw on 3/20/2011 8:00:58 PM , Rating: 2
While the greenhouses have numerous advantages -- "energy savings, reduced pollution, and improved economic development" -- they also have disadvantages, which the authors note. Namely, weather conditions can limit sunlight, causing growing problems. The greenhouses are heavily reliant on sun and weather conditions.

If I'm not mistaken, pretty much all agriculture is heavily reliant on sun and weather conditions. Some years, you lose, others you have a bumper crop. You can sometimes beat nature with lights and irrigation, but that's at a huge cost relative to nature doing its own thing.

hardly Inovative
By Ammohunt on 3/21/2011 2:54:45 PM , Rating: 2
You are aware that most Bell peppers are grown in greenhouses in the UK and other parts of the world?

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