Tuesday, October 7, 2014
Future Sustainable Homes will have Pools!
What will the sustainable home of the future look like? Will the solar space (the rooftops) be populated with evacuated tubes, PV, boxed and glazed, pool collectors, wind turbines, air conditioners or what exactly?
Over recent years thanks to enormous efforts on the part of governments to further solar electricity (photovoltaics or PV) the cost is down and technology has advanced, so much so that we’re competing with PV for roof space almost every time we try to solar heat a pool in California!
If we can cool a PV panel we can improve its performance by as much as 20%. That is solar thermal energy that we want to get rid of. The best place to dump it is into the backyard pool. Why not heat the pool as a bonus to cooling the PV?
Let's talk about home and water heating. This is a storage challenge more than it is a solar collection one. Its what holds us back on most large scale solar water heating opportunities. No place for a big storage tank. We need to store that solar energy when its available so we can use it when we need it. The perfect storage tank is the backyard swimming pool.
The future will be all about electricity. We have to get away from the localized burning of fossil fuels just for showers and space heat. We can do all that with electricity and we will. The future is electricity. Solar, wind, hydro, micro hydro are all carbon free and electric. But natural gas is cheap. That's the roadblock. To get more out of our electrons we employ heat pumps. These magical devices use low grade energy like that wasted from PV panels or collected by solar thermal panels, pump that energy up through a refrigeration cycle and deliver usable higher temperature heat. Heat pumps operate both ways. In other words they can cool your house and dump that excess energy. Again, where better to dump that energy than the backyard swimming pool?
The future low energy home has a great big storage tank out in the yard and its part of the home. You can swim in it. If a warm pool is the sacrifice we have to make to go green then so be it.
Thursday, February 28, 2013
Commercial and Municipal Solar Opportunities
Selling solar hot water or large scale pool heating into municipal facilities has always been a very difficult task. City people have to protect the interests of their taxpayers at all times. They are under tremendous scrutiny and every snake oil salesman out there is trying to dig his claws into municipal coffers. Cities tend to hire engineering companies in order to distance themselves from the sensitive decision making.
Domestic solar hot water heating systems use evacuated tubes or boxed and glazed collectors. These small scale systems don't have good economics because they are small scale. The cost of tanks and controls and plumbing and roofing is high compared to the area of collector exposed to the sun and the collector choice is naturally an expensive one because if you're going to all this trouble you'll want something that delivers maximum bang, not maximum bang for the collector buck. When we start looking at larger scale systems like preheating showers for Aquatic Centers we start to see much lower fixed costs per collector area. Solar gets a lot more viable a lot quicker. What happened of course is that engineers specified the old school boxed and glazed or evacuated tube collectors. They didn't even consider unglazed collectors like Powerstrip.
When we look at these performance curves we see that unglazed collectors are affected by wind and as we move right on the x axis (water getting warmer relative to air temperature) we see why engineers like the evacuated tubes and boxed and glazed collectors. They retain their efficiency into marginal weather conditions and into the higher end of the heating range. What engineers failed to recognize or perhaps never thought to even look at was the fact that most hot water heating is done at the low end of the temperature range when Powerstrips are even more efficient per area than the other types and on top of better efficiency they are far less expensive. Finally an engineer recognized this in Canada post rebate era. Yes the conservative government abandoned the Eco Energy program for Renewable Heat in 2010 and as a result Associated Engineering was tasked not with spending the City of Richmond's money as fast as possible in the safest way possible. Instead Charlie Smeenk PEng was tasked with spending the city's money with the best return on investment in mind. Charlie and I met early in the process and he was the one who pushed me toward the idea that we needed to plaster low cost unglazed collectors all over the Aquatic Center roof and move the cold water through them on their way to the boilers.
The system has been installed for a year now and we've monitored it with our web based monitoring . The monitoring is not internet connected so the data is not always up to date and we've lost some data but we've still proven that we've displaced more energy here with this system than we would have with more expensive technology. We've also proven that cost effective solar hot water is possible. Its possible to deliver solar at $100/GJ That's $100 in capital cost up front in exchange for 1 GJ of annual energy production. If energy costs $10/GJ after boiler efficiency is included (which is close even with today's low natural gas prices) then its a simple ten year payback period. Others will brag that they are doing better than 10 years. They are incorrect. There's no way to do better than this kind of economics against cheap natural gas .......or is there?
Some municipalities like Sechelt, Esquimalt, and Kimberley have installed our solar panels at their municipal facilities. They have gone one step further with all this. They are using the Powerstrips to heat a tank of water and that tank of water is the source for a heat pump. Heat pumps utilize low grade heat. Ground source heat pumps for example might take ground heat at 10C and use it so the ground cools down to 5 degrees. That 10C to 5C drop in ground temperature is converted through the heat pump to heating water at 60C or air at 20C or a pool at 29C. Heat pumps take low temperature energy and pump it up to a higher temperature for use. Solar needs to operate at low temperature in order to be able to take advantage of unglazed collector cost efficiency. Heat pumps are the means by which we can utilize that low grade heat. We've known this in the solar industry for decades but we've been distracted by grants for the tried and true conventional approaches.
Since this is a blog posting about municipal pools I need to mention something. Solar heating municipal pools has been a failed experiment. Its usually a bad idea because the pool temperature can not fluctuate and it needs to in order to store solar energy, otherwise the only gains made are gains that can be made during a sunny day and at these times there is usually too much heat. The sun is heating the space (indoor pool) and the heat pumps are dumping that heat outside or if needed into the pool water. Municipal outdoor pools are only used in the heat of summer. Not much heat needed then and again thru half that season the sun on the pool is increasing the pool temperature and it started the day at setpoint so its a heat dissipation requirement and solar heaters never turn on. The only way solar works is when you are allowing the pool temp to fluctuate and its most beneficial in early and late season, before and after municipal pools operate. When we see solar on Aquatic Centers these systems are heating water for showers, not heating the pool.
Monday, December 3, 2012
Carbon Capture and Storage Viability?
I had an argument with my friend over the viability of carbon capture and storage (CCS) at a dinner party Saturday night. To avoid public humiliation we'll give my friend the fake name Thor because nobody could really have that name. Thor has a phD in Chemistry. He's sensible and intelligent but he took the position that CCS is a farce and I immediately took the position that its only a few dollars a GJ and the only reason we aren't seeing it is cost.
Thor is right and I am wrong but Thor is still wrong and I am still right because if I wasn't I'd have lost the argument. The biggest hurdle we all face in this battle and many others is the fact that reality is complex. So complicated is the world that we need to defer to scientists and engineers who make studying these things their life's work. Thor dismissed Carbon Capture and Storage as a farce based on what a smart guy he knows said. And I was too quick to take offense to that and react with my claim that the only reason we aren't capturing carbon is cost. Truth is I don't know much about CCS. Turns out after only 15 minutes of research on my part Sunday morning that there's a little truth to what Thor was saying and there's a lot of truth to what I was saying. Or maybe its the other way around? Its not straightforward. There are no published viability numbers and that means the numbers aren't pretty. I was quite wrong to think it was just a matter of a couple of dollars per GJ stopping us from localized CCS and an electric car future full of easy transportation solutions. Thor was also wrong that CCS isn't part of the broad base of solutions that will be needed moving forward. Its real. It works sometimes in certain situations and the mitigation effects can be fantastic but not anywhere and everywhere. You need to be careful where you store the CO2 and how. The viability of the site itself is crucial to the success of projects case by case.
Just do your own search on carbon capture viability, cost, economics, whatever and you'll soon see that this is a huge field. Oil companies are involved. The Weyburn oil fields in Saskatchewan are semi depleted so to extract more oil (enhanced oil recovery) Cenovus have started injecting CO2 and it has greatly enhanced oil production. They are actually piping CO2 from the US to this facility and buying the CO2. Storing it in exhausted oil fields is one of the safest and easiest methods it turns out and there is no cost in this one case because it enhances oil production. There are many other examples of major investments in CCS going on worldwide. The ocean storage option has to be done at low depths (pressure resistance to absorption) and there are lots of issues. In some schemes CO2 leakage and re-emission is a problem that is being studied and has been for 20 years. 1700 people were asphixiated in Cameroon in 1986 when naturally sequestered CO2 rose up from a lake after a volcanic event. Mechanical sequestering does cost energy. One case I just read about said sequestering reduced overall capacity of one coal plant 25%. That doesn't make the coal plant useless. That does raise the cost and reduce the capacity. That was my point in our little debate. There is a cost associated with carbon capture and few are going to pay that cost if they don't have to. The lack of a carbon cost or proper regulation greatly restricts adoption of all things clean-tech. How can we compete against free?
Friday, March 23, 2012
CO2 from natural gas is not 50% compared to coal
RE:March 23 "Gas industry tackles issues on "fracking" Financial Post
Travis Davies of CAPP states that natural gas burns 50% cleaner than coal. What do we mean by cleaner? The reference is to carbon emissions. The article goes on to say ... AND natural gas emits less nitrous oxides and sulphurous oxides. Perhaps if the SO's and the NO's are included with the carbon and the shorter term pollutive effects are combined with the longer term CO2 effects them somehow we could say the overall effect of burning natural gas vs coal is 50% cleaner but this is all very misleading. There's more to it than just burning. Yes natural gas burns cleaner in terms of pollutants that exist in the atmosphere for less than 2 years but the reference and the bigger concern is the CO2. Natural gas is not 50% less carbon intense than coal even just in terms of burning it. The number is much higher and depends on the usage. Natural gas doesn't burn as hot so more energy from natural gas is needed to produce electricity compared to coal for example. When natural gas is converted to liquid natural gas and transported the carbon footprint jumps even further. The article talks about the lack of regulation in the natural gas extraction industry. Its the lack of enforced regulations that lead to sloppy practices where methane leaks from well heads especially between the fracking and extraction processes and some studies have indicated the possibility that when this effect is included in equivalent CO2 terms with transportation effects never mind LNG compression that in fact the case can be made that natural gas from fracking is no less carbon intense than coal. The loosely used fraction of 50% is very irresponsible. Its really a key number because if we truly could reduce carbon emissions by 50% using natural gas vs coal then we'd be very motivated to move forward in a mad rush to exploit this resource...sort of like we are in the western provinces with no pressure to enforce or improve regulations. If low cost natural gas is going to delay the movement toward a renewable energy future then let's at least stop pretending that the need for monitoring and enforceable regulations in this industry are not critical. You don't have to leak much methane from a wellhead before you negate all the equivalent CO2 benefits of natural gas vs coal or oil sands oil.
Travis Davies of CAPP states that natural gas burns 50% cleaner than coal. What do we mean by cleaner? The reference is to carbon emissions. The article goes on to say ... AND natural gas emits less nitrous oxides and sulphurous oxides. Perhaps if the SO's and the NO's are included with the carbon and the shorter term pollutive effects are combined with the longer term CO2 effects them somehow we could say the overall effect of burning natural gas vs coal is 50% cleaner but this is all very misleading. There's more to it than just burning. Yes natural gas burns cleaner in terms of pollutants that exist in the atmosphere for less than 2 years but the reference and the bigger concern is the CO2. Natural gas is not 50% less carbon intense than coal even just in terms of burning it. The number is much higher and depends on the usage. Natural gas doesn't burn as hot so more energy from natural gas is needed to produce electricity compared to coal for example. When natural gas is converted to liquid natural gas and transported the carbon footprint jumps even further. The article talks about the lack of regulation in the natural gas extraction industry. Its the lack of enforced regulations that lead to sloppy practices where methane leaks from well heads especially between the fracking and extraction processes and some studies have indicated the possibility that when this effect is included in equivalent CO2 terms with transportation effects never mind LNG compression that in fact the case can be made that natural gas from fracking is no less carbon intense than coal. The loosely used fraction of 50% is very irresponsible. Its really a key number because if we truly could reduce carbon emissions by 50% using natural gas vs coal then we'd be very motivated to move forward in a mad rush to exploit this resource...sort of like we are in the western provinces with no pressure to enforce or improve regulations. If low cost natural gas is going to delay the movement toward a renewable energy future then let's at least stop pretending that the need for monitoring and enforceable regulations in this industry are not critical. You don't have to leak much methane from a wellhead before you negate all the equivalent CO2 benefits of natural gas vs coal or oil sands oil.
OIl and Gas subsidies do so exist!
March 23, 2012
Re: Oil and gas industry does not receive federal subsidies by Tom Huffaker of the Canadian Association of Petroleum Producers.
I checked the facts in this article and found that the Greenpeace sponsored report being dis-credited is in fact a report on the economic effect of subsidies not on the existence of subsidies. 63 subsidies in total in the form of tax breaks and reduced royalties are mostly intended to increase exploration and development . The Canadian federal gov't provided 1.38 billion and provinces shared the balance of the total of 2.84 billion last year. There is no disputing these facts in either competing report. The study Mr Huffaker quotes that supposedly debunks the Greenpeace sponsored report argues the effect of subsidies not the existence of the subsidies. The CAPP is consistently guilty of mis-stating the facts about the effects of our continued overusage of fossil fuels and why? There is no threat from renewables, not with natural gas prices at all time lows. If the fossil fuel industries truly want to be more transparent they first need to stop pretending that the issues don't exist. Its not their fault we're burning up the planet. Its a collective problem and we need to work together to right the ship for the next generations. Let's stop pretending oil and gas exploration isn't subsidized by government in an attempt to keep fossil fuel costs down so we can all enjoy the benefits of burning up the planet today in exchange for frying our children tomorrow!
Re: Oil and gas industry does not receive federal subsidies by Tom Huffaker of the Canadian Association of Petroleum Producers.
I checked the facts in this article and found that the Greenpeace sponsored report being dis-credited is in fact a report on the economic effect of subsidies not on the existence of subsidies. 63 subsidies in total in the form of tax breaks and reduced royalties are mostly intended to increase exploration and development . The Canadian federal gov't provided 1.38 billion and provinces shared the balance of the total of 2.84 billion last year. There is no disputing these facts in either competing report. The study Mr Huffaker quotes that supposedly debunks the Greenpeace sponsored report argues the effect of subsidies not the existence of the subsidies. The CAPP is consistently guilty of mis-stating the facts about the effects of our continued overusage of fossil fuels and why? There is no threat from renewables, not with natural gas prices at all time lows. If the fossil fuel industries truly want to be more transparent they first need to stop pretending that the issues don't exist. Its not their fault we're burning up the planet. Its a collective problem and we need to work together to right the ship for the next generations. Let's stop pretending oil and gas exploration isn't subsidized by government in an attempt to keep fossil fuel costs down so we can all enjoy the benefits of burning up the planet today in exchange for frying our children tomorrow!
Thursday, February 16, 2012
Low Cost Natural Gas
The following piece was actually published in a newspaper. I'm learning to tone down the rhetoric.
FP Letters: ‘Low cost energy is Achilles’ heel of sustainability movement’
Special to Financial Post Feb 14, 2012 – 11:20 AM ET
Low electricity prices and extremely low natural gas prices in Canada mean that the majority of even the most viable clean tech solutions available to Canadians are not very attractive economically. In BC for example, a standard 6 square meter solar hot water heating appliance with 100 gallons of storage for a typical home costs 70 to 100 times more than the energy it is expected to deliver annually in natural gas dollars. There’s no better way to reduce hot water energy use in the home aside from reducing hot water use through conservation.
It’s not easy to find a sustainable appetite for many clean tech solutions like this. The low cost of energy is the Achilles’ heel of the sustainability movement.
The mistake has always been to try to do too much too soon. Converting Canada’s electricity grid to 100% renewable is a lofty goal that feels like a great idea but we have barely begun applying cost effective clean tech solutions appropriately. By starting the process aiming at 100% renewable electricity we automatically force ourselves into the most expensive solutions.
Instead we need to create a political climate where the financial incentive to pursue clean-tech initiatives exists starting with the most cost effective. Then we need to support development efforts along with demonstrating and quantifying competing technologies. As an example consider that only 2% of all public pools are solar heated yet this is one of the most proven and cost effective solar energy schemes available. In so many ways we have not yet begun. The major reason we have yet to begin is the low cost of fossil fuel and electricity in Canada. When we jump too quickly toward a bold far reaching solution we miss out on the low hanging fruit like solar swimming pool heating.
Ontario’s FIT for PV (photovoltaics) systems is a big success. Ontario Hydro pays $0.80/kwhr for electricity generated with PV. Electricity consumed normally costs $0.08/kwhr. This ten fold cost imbalance on the shoulders of ratepayers and taxpayers indirectly creates an economic climate where the energy from a PV system covers the mortgaged capital cost of the installation. It’s a wonderful program and a big success but compared to the cheap electricity its quite a costly endeavor.
Ontario slipped the program through the same way BC established a small carbon tax but these were challenging political tasks and now that we have an ongoing recession, there is even less appetite for this kind of energy policy elsewhere in the country.
In fact BC’s new energy policy relieves BC Hydro of the requirement to be self sufficient. Through simple regulation premier Christy Clark has assured British Columbians of lower cost electricity and ensured more jobs in the fracking and LNG industries. More natural gas to Asia does mean less coal burned globally but this works against Canada’s own goals toward energy sustainability. The focus politically is on jobs and the economy and a sustainable energy policy is taking its usual seat at the back of the bus.
The obvious first step is to level the playing field somewhat by addressing the fact that fossil fuels have the environment as a free dumping ground for their pollutants. A carbon tax would be very helpful of course and many have tried including Stephan Dion, leader of the federal liberal party, just before his political demise.
A far easier sell to the public would be the removal of subsidies for oil and gas exploration. This would create volatility in the energy marketplace. Energy price volatility is what the sustainability movement needs. Clean tech solutions are not volatile. They are an insurance policy against volatility. When a home is built sustainably it is sustainable for 100 years and conversely if it is built without sustainability in mind, its likely to stay that way for 100 years.
When we include some longer term thinking with some volatility we have a formula for a much quicker uptake of all things clean tech. Energy price volatility creates enormous long term financial incentive for a sustainable building approach. The reason Germany has a stronger clean tech industry is their electricity is ten times more expensive. Financial reality has provided the necessary motivation for energy consciousness and a culture of sustainability. A carbon tax bringing our electricity costs up to theirs would not go over well here. The risk that energy prices could go much higher could serve the same purpose.
We all want to act sustainably but with gasoline less expensive than bottled water, how can we blame anyone for drinking it up. Step one is to recognize the realities of the marketplace and come up with a realistic approach to energy policy that factors in the environment as well as our collective sustainability goals. We could all do our part by trying to get past the notion that the luxury of cheap energy is somehow a birthright of all Canadians. Then it would be OK for politicians to resist the oil and gas company lobbyists who fund politics in Canada in exchange for their subsidies. Without oil and gas exploration subsidies the resultant energy price volatility would do as much for the clean tech industry as energy prices that actually reflected their effects on the planet.
Ken Wright is President of Burnaby, BC-based Hot Sun Industries Ltd, a manufacturer of solar thermal technology
Posted in: Energy, Your Energy Tags: clean energy, Hot Sun Industries, Ken Wright
FP Letters: ‘Low cost energy is Achilles’ heel of sustainability movement’
Special to Financial Post Feb 14, 2012 – 11:20 AM ET
Low electricity prices and extremely low natural gas prices in Canada mean that the majority of even the most viable clean tech solutions available to Canadians are not very attractive economically. In BC for example, a standard 6 square meter solar hot water heating appliance with 100 gallons of storage for a typical home costs 70 to 100 times more than the energy it is expected to deliver annually in natural gas dollars. There’s no better way to reduce hot water energy use in the home aside from reducing hot water use through conservation.
It’s not easy to find a sustainable appetite for many clean tech solutions like this. The low cost of energy is the Achilles’ heel of the sustainability movement.
The mistake has always been to try to do too much too soon. Converting Canada’s electricity grid to 100% renewable is a lofty goal that feels like a great idea but we have barely begun applying cost effective clean tech solutions appropriately. By starting the process aiming at 100% renewable electricity we automatically force ourselves into the most expensive solutions.
Instead we need to create a political climate where the financial incentive to pursue clean-tech initiatives exists starting with the most cost effective. Then we need to support development efforts along with demonstrating and quantifying competing technologies. As an example consider that only 2% of all public pools are solar heated yet this is one of the most proven and cost effective solar energy schemes available. In so many ways we have not yet begun. The major reason we have yet to begin is the low cost of fossil fuel and electricity in Canada. When we jump too quickly toward a bold far reaching solution we miss out on the low hanging fruit like solar swimming pool heating.
Ontario’s FIT for PV (photovoltaics) systems is a big success. Ontario Hydro pays $0.80/kwhr for electricity generated with PV. Electricity consumed normally costs $0.08/kwhr. This ten fold cost imbalance on the shoulders of ratepayers and taxpayers indirectly creates an economic climate where the energy from a PV system covers the mortgaged capital cost of the installation. It’s a wonderful program and a big success but compared to the cheap electricity its quite a costly endeavor.
Ontario slipped the program through the same way BC established a small carbon tax but these were challenging political tasks and now that we have an ongoing recession, there is even less appetite for this kind of energy policy elsewhere in the country.
In fact BC’s new energy policy relieves BC Hydro of the requirement to be self sufficient. Through simple regulation premier Christy Clark has assured British Columbians of lower cost electricity and ensured more jobs in the fracking and LNG industries. More natural gas to Asia does mean less coal burned globally but this works against Canada’s own goals toward energy sustainability. The focus politically is on jobs and the economy and a sustainable energy policy is taking its usual seat at the back of the bus.
The obvious first step is to level the playing field somewhat by addressing the fact that fossil fuels have the environment as a free dumping ground for their pollutants. A carbon tax would be very helpful of course and many have tried including Stephan Dion, leader of the federal liberal party, just before his political demise.
A far easier sell to the public would be the removal of subsidies for oil and gas exploration. This would create volatility in the energy marketplace. Energy price volatility is what the sustainability movement needs. Clean tech solutions are not volatile. They are an insurance policy against volatility. When a home is built sustainably it is sustainable for 100 years and conversely if it is built without sustainability in mind, its likely to stay that way for 100 years.
When we include some longer term thinking with some volatility we have a formula for a much quicker uptake of all things clean tech. Energy price volatility creates enormous long term financial incentive for a sustainable building approach. The reason Germany has a stronger clean tech industry is their electricity is ten times more expensive. Financial reality has provided the necessary motivation for energy consciousness and a culture of sustainability. A carbon tax bringing our electricity costs up to theirs would not go over well here. The risk that energy prices could go much higher could serve the same purpose.
We all want to act sustainably but with gasoline less expensive than bottled water, how can we blame anyone for drinking it up. Step one is to recognize the realities of the marketplace and come up with a realistic approach to energy policy that factors in the environment as well as our collective sustainability goals. We could all do our part by trying to get past the notion that the luxury of cheap energy is somehow a birthright of all Canadians. Then it would be OK for politicians to resist the oil and gas company lobbyists who fund politics in Canada in exchange for their subsidies. Without oil and gas exploration subsidies the resultant energy price volatility would do as much for the clean tech industry as energy prices that actually reflected their effects on the planet.
Ken Wright is President of Burnaby, BC-based Hot Sun Industries Ltd, a manufacturer of solar thermal technology
Posted in: Energy, Your Energy Tags: clean energy, Hot Sun Industries, Ken Wright
Tuesday, April 27, 2010
Solar Heating is Flexible
Up until just a few years ago, solar swimming pool heating was far and away the largest use of "solar energy". The reason is simple and straightforward. It makes economic sense. It competes head on against very inexpensive natural gas for heating swimming pools. The unglazed (no glass over the collector) plastic collector is low cost per area exposed to the sun and when heating low temperature water like a swimming pool (or even pre-heating domestic hot water) the efficiency is high. In other words a large portion of the solar energy exposed to the collector is collected and delivered as energy to the load. This simple and obvious combination makes for the most cost effective and therefore most viable solar energy solution. Over the last 37 years this solar energy market has thrived but there have been ups and downs.
The first low cost unglazed solar collectors for swimming pool heating were introduced around 1969 under the trade name "Solaroll". The product was made of a synthetic rubber called EPDM. It was a flexible collector. It thrived. In 1972 "Fafco" introduced the first rigid collector. This collector, still in production today, was made of a type of polypropylene. The header pipes are permanently attached to the absorber sections in the factory resulting in fixed size collectors. 4x12 has become the most common size. The advantages to this design are that they are low cost to manufacture and low cost to install. Solaroll by comparison, required the installer, dealer, or homeowner to attach all the headers to the flexible fin-tubing after cutting the fin-tubing to length. This extra work traded off with the extra capability in terms of being able to fit the collector to the space. In addition these original flexible collectors could be used in areas where freezing was an issue. If water is trapped inside a rigid collector and it freezes the tubes break and the remedies require sealing off entire flow cores. The flexible Solaroll on the other hand could be mounted flat on a roof where water will not drain out. It could freeze solid with water in it. This was the state of the art in the industry 30 years ago? What happened since? Solaroll no longer exists and Fafco was mimicked over and over again and today 75% of all solar pool heating is done with rigid polypropylene boards floating around under straps. Most in the industry can tell you flexible EPDM synthetic rubber collectors like Solaroll had a fatal flaw. Chlorine in the swimming pools caused the flexible material to break down. One of the big chemical companies proposed a solution. It was a polypropylene based flexible extrusion called Santoprene. As the story goes, it broke down faster than EPDM and the result was an industry calamity. From this point forward the rigid polypropylene collector industry thrived.
But the rigid 4x12 panels were limiting. They couldn't be applied to flat roofs without fear of freeze damage. Available space could not be fully utilized and what could be less esthetically appealing than big black rectangles on a rooftop? Where there is demand there is supply. The epdm rubber tubing collectors came back, slowly and gradually. Its been 30 years since the major fallout. Hot Sun installed a 2000 sq ft system in North Carolina using EPDM and it took only 3 years in the field for the system to start churning black crud into the pool.
Luckily Hot Sun had decided this was risky and had already switched to a plastic based alternative. The experience in North Carolina was the final straw and we went 100% non EPDM after that point... because we could!
There is an undeniable appeal to using EPDM. Its tough. It usually lasts long enough that these issues occur well into the lifespan when most people don't even remember who they bought their systems from. Hot Sun's solution is not without its downsides too. There is no perfect answer. We have to use a mechanical or an adhesive connection to join the tubing and the headers. It takes more time to assemble. Theoretically flexible plastic is not as strong as flexible epdm so we have to be more careful with system pressure but what we've found are better and better thermoplastics such that today our flexible plastic is as strong as most competing epdm products with one major distinction. Powerstrip is guaranteed not to break down for 25 years. Some manufacturers of some EPDM products can't have water left in them over winter due to "freezing issues". That mindbender really means that if you leave water in the epdm tubing and it heats up the black crud will come off the solar panel and go into the pool. Freezing seems to trigger the release, we think just due to the physical stretching. We don't believe anyone else has even tried to resolve the issues with epdm in the solar business. My point is we can guarantee it won't happen for 25 years. EPDM solar manufacturers can't guarantee it won't happen in 10. The seal manufacturers have certainly acknowledged this problem. Here we're talking about chlorine in drinking water (much lower concentrations) and city water temperatures. The effect is thought to double with every 10 degree increase in temperature. The solutions are special compounds that are very expensive and even then the effect is just reduced.
The first low cost unglazed solar collectors for swimming pool heating were introduced around 1969 under the trade name "Solaroll". The product was made of a synthetic rubber called EPDM. It was a flexible collector. It thrived. In 1972 "Fafco" introduced the first rigid collector. This collector, still in production today, was made of a type of polypropylene. The header pipes are permanently attached to the absorber sections in the factory resulting in fixed size collectors. 4x12 has become the most common size. The advantages to this design are that they are low cost to manufacture and low cost to install. Solaroll by comparison, required the installer, dealer, or homeowner to attach all the headers to the flexible fin-tubing after cutting the fin-tubing to length. This extra work traded off with the extra capability in terms of being able to fit the collector to the space. In addition these original flexible collectors could be used in areas where freezing was an issue. If water is trapped inside a rigid collector and it freezes the tubes break and the remedies require sealing off entire flow cores. The flexible Solaroll on the other hand could be mounted flat on a roof where water will not drain out. It could freeze solid with water in it. This was the state of the art in the industry 30 years ago? What happened since? Solaroll no longer exists and Fafco was mimicked over and over again and today 75% of all solar pool heating is done with rigid polypropylene boards floating around under straps. Most in the industry can tell you flexible EPDM synthetic rubber collectors like Solaroll had a fatal flaw. Chlorine in the swimming pools caused the flexible material to break down. One of the big chemical companies proposed a solution. It was a polypropylene based flexible extrusion called Santoprene. As the story goes, it broke down faster than EPDM and the result was an industry calamity. From this point forward the rigid polypropylene collector industry thrived.
But the rigid 4x12 panels were limiting. They couldn't be applied to flat roofs without fear of freeze damage. Available space could not be fully utilized and what could be less esthetically appealing than big black rectangles on a rooftop? Where there is demand there is supply. The epdm rubber tubing collectors came back, slowly and gradually. Its been 30 years since the major fallout. Hot Sun installed a 2000 sq ft system in North Carolina using EPDM and it took only 3 years in the field for the system to start churning black crud into the pool.
Luckily Hot Sun had decided this was risky and had already switched to a plastic based alternative. The experience in North Carolina was the final straw and we went 100% non EPDM after that point... because we could!
There is an undeniable appeal to using EPDM. Its tough. It usually lasts long enough that these issues occur well into the lifespan when most people don't even remember who they bought their systems from. Hot Sun's solution is not without its downsides too. There is no perfect answer. We have to use a mechanical or an adhesive connection to join the tubing and the headers. It takes more time to assemble. Theoretically flexible plastic is not as strong as flexible epdm so we have to be more careful with system pressure but what we've found are better and better thermoplastics such that today our flexible plastic is as strong as most competing epdm products with one major distinction. Powerstrip is guaranteed not to break down for 25 years. Some manufacturers of some EPDM products can't have water left in them over winter due to "freezing issues". That mindbender really means that if you leave water in the epdm tubing and it heats up the black crud will come off the solar panel and go into the pool. Freezing seems to trigger the release, we think just due to the physical stretching. We don't believe anyone else has even tried to resolve the issues with epdm in the solar business. My point is we can guarantee it won't happen for 25 years. EPDM solar manufacturers can't guarantee it won't happen in 10. The seal manufacturers have certainly acknowledged this problem. Here we're talking about chlorine in drinking water (much lower concentrations) and city water temperatures. The effect is thought to double with every 10 degree increase in temperature. The solutions are special compounds that are very expensive and even then the effect is just reduced.
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