Following the day of action I was looking forward to reading about this world-wide rally in the newspapers but I was quickly disappointed to discover that it only got a short mention on page four of one of the major weekend papers. Likewise the major TV channels only dedicated a newsflash type of segment to this news.

After learning about this international action day coordinated by 350.org (see blog on 20^th Oct) I decided to attend the local rally in the Dandenongs. Despite the best efforts of 350.org I believe that this climate change day was not getting enough attention in the main stream media. Most people would only have found out about it through alternative sources, such as the internet and perhaps from the banners and placards strategically placed by passionate environmentalists.

Nevertheless, a large number of grass root groups joined forces to take part in this campaign and it is believed that around 5,400 events in 180 countries took place all around the world. According to Bill McKibben, a writer and environmentalist who founded www.350.org:

“We had no idea we would get the overwhelming support, enthusiasm and engagement from all over the world that we’re seeing. It shows just how scared of global warming much of the planet really is, and how fed up at the inaction of our leaders.”

Let’s hope they will get the message before the Copenhagen Conference .

While back in the Dandenongs on Saturday the local chapter of 350.org managed to get around 150 people to take part. It was good to see the range of people who came to support this movement. There were the elderly, the mums with prams, school kids, quite a few young people and of course the more alternative types. Overall a good cross section of society was represented by this small group who marched up and down in the main street until arriving at the local MP’s office. Speeches included the discussion of Climate Change and our future.

The rally culminated in the passing of judgement on the current Labour Government’s policies on Global Warming. The list was long and the final verdict on all their policies so far was ‘GUILTY’. This list was mounted on the side of the MP’s office and the crowd continued to enjoy the day with a BBQ and live music. Local Councillor Samantha Dunn then handed out 350 native plants for the participants to take home and plant in their gardens to help reduce CO2 in the atmosphere.

According to dire news reported in the media last week Australians are losing interest in Global Warming. While in 2007 this issue was ranked as the equal most important foreign policy goal for the Federal Government the most recent polls indicate that out of ten possible goals it is in seventh place. Now fewer people see Global Warming as a threat to Australia’s national interests and it is perceived as the fourth most critical threat facing us out of twelve possibilities.

The fact that the current government was delaying action and the fact that the opposition party still hasn’t resolved its position on emission trading and the global financial crises have all been blamed for the loss of interest in Climate Change. The good news is that 76% of those surveyed in the annual Lowy Institute Poll still rated Climate Change as a problem and want some action. See full article here: (http://www.theage.com.au/environment/global-warming-drops-down-list-20091012-gu1w.html)

For those who still think that we should do something about Climate Change, this weekend is an important day. This Saturday on the 24^th of October it is the ‘International Day of Climate Action’. This is an international movement and people from many countries around the world will join in some form of protest to send a message to government leaders around the world. The message is clear: people want action on Climate Change. It is expected that thousands of images of people gathering in many cities and remote areas will be projected to the UN Headquarters and to Times Square.

The aim of this action -organised by www.350.org worldwide- is to focus the attention on the science and the citizens to remind world leaders that they need to take physical reality into account when they are making decisions about our collective future at the Copenhagen Climate Change Conference in December. People are not interested in backroom business deals and political interest groups but in one united goal; that is to reduce greenhouse emission and to ensure that the CO2 remains below 350 ppm in the atmosphere. Saturday’s campaign is expected to be the most widespread day of environmental action in the planet’s history with over 3000 events in 160 countries. 350.org will assemble all the photos for a gigantic, global visual petition and present to the UN before the conference.

If you want to get involved visit this website for nearest location: www.350.org/map#/map/-25.274398/133.775136/4

I have compiled the following information as a response to a friend of mine who has been following the reaction to Ian Plimer’s arguments against human induced Climate Change in his recently published book ‘Heaven and Earth’. I thought it would be a good idea to share the main points with others regarding the release of this controversial book. I can’t really analyse the scientific evidence because I’m not a climate scientist nor am I qualified in any similar fields. For this I rely on others who have the knowledge and experience. But I believe it is important to look at both views on the subject to keep the conversation going.

1. Fortunately we live in a free society where people can offer alternative views to what is accepted by others (even if it is the majority). This obviously applies to scientific stance as well. People have the right to hear both sides of an argument and make up their own minds. It is a radical move though on Plimer’s behalf to publish a book (Heaven and Earth) on such a ‘hot topic’ (excuse the punt) as Climate Change, thus giving ammunition to the deniers who don’t believe that humans have anything to do with global warming. No doubt there are lots of people out there who find comfort in believing that we humans are not responsible for destroying our environment and so they welcome the evidence proposed by Ian Plimer in his book on Climate Change.

2. Nevertheless, all media attention is useful because it brings the topic back into the limelight and initiates and/or continues a public debate on Climate Change. Just consider all the articles published as a result of Plimer’s book and all the other media interviews with both sides of the argument (The Guardian and The Spectator have widely covered this as has the The Australian – see references below). The public wants to hear answers from all the well-known scientists involved in the ongoing debate (and even politicians feel the need to comment on these issues). The blog spots are also running hot with comments on the book and on the exchanges between Plimer, Monbiet, Karoly, Lambert, Enting, Lambeck, Ashley etc. All this attention has resulted in keeping the debate alive and in the end it helps us in reinforcing the importance of doing something about Climate Change.

3. Drawing attention to Climate Change and the challenging of the general consensus in Heaven and Earth has worked because the debate has been taken up by the experts in the appropriate scientific disciplines. They (such as David Karoly and Tim Flannery) have disputed many of Plimer’s points by simply pointing out how unreliable and unsubstantiated the ‘scientific’ facts in his book are. There are lots of inaccuracies and reproductions of scientific explanations by others that were never properly cited or in some cases the actual results that were contrary to his points have been left out of his book. Meanwhile other evidence has been changed to support his arguments – according to these authorities on the subject.

4. The discussion of Climate Change in the media and on internet blogs is very timely as the United Nations Climate Change Conference is only a couple of months away from the 7^th December 2009 in Copenhagen.

The following are links related to this topic:

http://www.spectator.co.uk/melaniephillips/3659606/the-modern-heresy-of-true-science.thtml

http://www.theaustralian.news.com.au/story/0,,25433059-5003900,00.html

http://www.timesonline.co.uk/tol/news/environment/article6804961.ece

http://www.guardian.co.uk/environment/georgemonbiot/2009/aug/05/climate-change-scepticism

http://www.connorcourt.com/catalog1/index.php?main_page=page&id=14&chapter=0

http://campaigns.wikia.com/wiki/Monbiot-Plimer_Debate

You may have come across this news item a couple of months ago but it is worth taking another look. Although, the study was conducted by a major spam-ware corporation, it is clear that junk e-mails have a huge carbon footprint.

(image: www.fotolia.com)

Anything powered by electricity emits greenhouse gases. Recently research was conducted in the US to find out the amount of energy needed to transmit, process and filter spam globally. The results were startling. According to the ‘Carbon Footprint of Spam’ report the average greenhouse gas emission of a single spam message is 0.3 grams of CO2. Is this a lot? Well, if you multiply this by the number of spam sent annually it translates into a huge figure.

It is estimated that there are 62 trillion junk e-mails sent each year. In terms of energy this equals to the energy needed to drive a car around the planet 1.6 million times. If looking at the electricity needed to power these spam it equals to 33 billion kWh. This amount of electricity could power 2.4 million homes for a year! Spam-related emissions for all e-mail users around the world in 2008 totalled 17 million tons of CO2 or about the same as the emissions produced by 3.1 million passenger cars. That’s 0.2% of the total global emissions.

The report found that about 85 to 91% of all e-mails globally is spam. Nearly 80% of the spam-related GHG emissions came from the energy used by the PC users viewing, deleting and searching for legitimate e-mails amongst the junk e-mails. But spam filtering itself accounts for about 16% of spam-related energy use. To view and trash a piece of spam takes about 3 seconds.

If every inbox were protected by spam filters, organisations and individuals could reduce today’s spam energy by 75% or by 25 billion kWh per year. This would save the same amount of greenhouse emissions as produced by 2.3 million cars. In late 2008 a major source of online spam was taken off line and global spam volumes dropped by 70%. However, there are always new ones to take its place.

(Part Two) The first part of this topic was published on the 8th of May.

Flat Plate Solar Collectors

Flat panel (aka flat plate) collectors work on the principle of copper pipes running through a glass covered collector, often connected to a water storage tank on the roof. The hot water can then thermosiphon itself in and out of the tank, thus heating the water. Finally the hot water is gravity fed into the house from the roof. This is an extremely efficient way of gaining and storing hot water and can be over 90% efficient in the right climate. The simplest combination is the close-coupled system (see photo below).

However, the water tank may be located in the roof space or on the ground as a separate unit in which case a pump is necessary to circulate the water. This is known as a split system. Flat panel collectors are still the most commonly used collectors in domestic hot water applications in warmer climates due to their affordability and reasonably easy installation. The collectors should last well over 20 years and can handle an operating temperature up to 80 degrees.

Evacuated Tube Solar Collectors

Evacuated tube collectors consist of glass tubes with a layer of heat absorbent coating inside them. As the tubes encasing the water pipes are a vacuum it greatly reduces heat loss. The thermal energy retention can be up to 97%. Copper pipes run through the centre of these evacuated glass tubes in a U-shape. These are all connected to a common manifold which is then connected to a slow flow circulation pump which pumps water to a storage tank below. The hot water can be used at night or the next day due to the insulation of the tank. Evacuated tubes are often used in commercial applications or in applications where hotter water is needed, since they are capable of generating temperatures above the boiling point of water (for example on dairy farms). While evacuated tubes have a long life similar to flat plate collectors, they are composed of fragile glass tubes which may occasionally need replacement.

Comparisons

As pointed out in Part One of this blog it is not a simple matter of using evacuated tubes or flat panels as each circumstance is different. Each collector design has its own merits. Both systems can save over 3 tonnes of GHG emissions per year and can reduce heating energy consumption in a home between 50%  to 80% especially when electric hot water storage systems are being replaced. In addition both systems can be up to 70% efficient when heating water and heat losses in the system are taken into account. So instead we should look at the benefits and the short comings of each system.

Evacuated Tubes

Advantages

• No heat losses due to convection and conduction because glass collectors are hermetically sealed.
• No change of performance during the service life of the collectors as there is no corrosion.
• Thermal diode operation principle, the hot water flows one way only from the collector to the tank and never the other way around.
• It is able to harness sunshine from all directions due to its cylinder-shaped glass tubes.
• Well-suited for colder climates with reduced hours of sunshine, where frost may be a problem or where the roof is prone to overcast from clouds.
• Freeze free so can be used in sub-zero temperatures and in the presence of snow.
• Easy installation due to light weight and no maintenance needed afterwards.
• Requires smaller roof area for installation.
• It is less apparent on roof because of the absence of a water tank coupled to it.
• Each glass tube is independent from each other so in case of breakage it can be replaced.
• Minimum greenhouse emissions when combined with gas boosting.
• Saves about 3 tonnes of CO2 annually when compared to electric storage.
• Very low running cost when used with gas or off peak electricity.
• On average it is about 5 years payback on investment.
• Suited for commercial and industrial applications.

Disadvantages

• Expensive to purchase due to more components, such as pump, separate water tank and associated plumbing and electrical work.
• Less cost effective than flat panels based on initial investment.
• Glass tubes could break easily in a hail storm or from falling branches.
• In higher ambient temperatures it is less efficient than flat panels.
• In direct summer sun it could be too efficient making the water too hot which results in wastage.
• Evacuated tube collector’s aperture area is typically between 60 and 70% of the gross collector area (meaning that’s how much of the total area exposed to sun is doing useful work).
• Some heat pipes are prone to cracking rendering the system useless especially at the braising points. These don’t like repeated heating and cooling down especially if it is very sudden.
• The welding should be done with silver alloys to prevent this from happening.
• Mainly made in China, thus not supporting Australia.

Flat Panels

Advantages

• Operates extremely efficiently in warmer climates and in higher ambient temperatures especially when water tank is horizontal and adjacent to the collectors.
• It can be between 44% to 76% more cost effective in warm climates than evacuated tubes.
• Losses are minimised because of water tank being located next to collectors.
• Thermosiphon operation minimises maintenance – no moving parts or distant pipes.
• Simple to install as system can be purchased as one unit with collectors and tank together.
• Affordable to purchase for the above reasons and because of less plumbing involved.
• No electrical installation required in most cases where stand alone system is used (ie the tank is not separate from the collectors).
• Space saving as water tank is located on roof and not in or around the house.
• Robust construction.
• Large collector area.
• Flat plate collector’s aperture area is typically between 90 and 95% of the gross collector area.
• Mostly made in Australia for Australian conditions, which supports the local industry and economy.

Disadvantages

• Can corrode.
• The air gap between the absorber and cover pane could result in heat losses during cold and windy days.
• It can rob the water of built up heat if the collector becomes colder than the water temperature.
• No internal method of limiting heat build up and have to use outside tempering devices.
• In colder climates it may need extra protecting devices from frost or freezing.
• It is more reliant on accurate northern exposure in order to operate efficiently.
• Installation could be difficult due to weight and size.
• Circulates water inside insulated areas. Prone to leakage, corrosion and restriction of flow due to possible airlock.

The graph below compares the three main types of solar hot water systems and their efficiency.

Explanation: Solar collector efficiency is plotted as a straight line against the parameter (Tc-Ta)/I, where Tc is the collector inlet temperature (in °C), Ta is the ambient air temperature (in °C), and I is the intensity of the solar radiation (W/sq. m.). Notice that inexpensive, unglazed collectors are very efficient at low ambient temperatures, but efficiency drops off very quickly as temperature increases. They offer the best performance for low temperature applications, but glazed collectors are required to efficiently achieve higher temperatures.

Summary

From the above descriptions and considering the merits and drawbacks of each system the following conclusion can be drawn. In warmer climates and most temperate zones, where there is good exposure to sunshine throughout the year, and the ambient temperature is fairly stable the flat panel collectors are recommended to be used. Also, if there is good uninterrupted northern exposure available the flat panel is more economic. The flat panel is extremely efficient and the systems can produce sufficient hot water for most households. The use of a flat panel system will result in up to 80% reduction of hot water cost when compared to electric storage units. These are also more affordable with a faster payback period on investment. They are designed and made in Australia for Australian conditions.

On the other hand the evacuated tube systems have an advantage of being able to operate in colder climates or where there isn’t enough sun light (ie. some alpine or mountain areas, prone to overcast or where there are more trees). These systems also work well in the presence of snow or sub-zero temperatures. The unique design of the glass tubes allows it to capture sunlight from various angles thus heating the water for longer periods. In some cases where very high water temperatures are required – even in warmer climates- the evacuated tubes have the ability to produce water at higher temperatures than flat panels. Being smaller in surface area these units could be more suitable where there is a lack of space. Again 80% reduction in hot water cost and GHG emissions are quite achievable from such a system.

Please take note of the references for the graphs and information in this article. Where possible we have used information stemming from government websites, academic resources, and manufacturers data. If you need more information or actual references please contact us.