But there is another Solar – Thermal Solar in the form of solar panels and solar evacuated tubes. This technology is for heating your hot water, your radiant floor, your swimming pool. This form of solar energy can be up to 80% efficient. It’s completely renewable and return on investment can be as much as 15% a year – so in 8 - 10 years (depending on location) it could have paid for itself. Imagine paying off your hot water bill in 10 years and never paying again!
There are two main types of solar hot water heaters – flat plates, which are popular in warmer climates, and evacuated tubes. The tubes were developed in Europe in the 1970s and the first Thermomax evacuated tube factory was established in the UK.
Patrick Spearing first became associated with Thermomax in 1979. When he moved to Canada in 1989 with his young family, he brought along the evacuated tube system and has never looked back. He became the representative for Canada, and, for a while, all of the US, out of his base in Victoria. Now, besides running his company Thermomax Industries Ltd., he has an excellent educational website www.solarThermal.com, and does trainings around the country for installers, architects, engineers and the general public.
“The vacuum tube solar collectors absorb radiant energy from the sun in all weather conditions. The tubes are a perfect fit for areas such as our rainy west coast and our latitude." Spearing explains. “And in bright, cold areas such as Alberta, the reflection from the snow can increase the performance even further. The light being collected within a vacuum means that we don’t lose the heat to the air – just like a thermos bottle.”
A 1994 study commissioned by BC Hydro’s Power Smart Technical Services for Atlin BC states: “The evacuated tube technology is particularly suited for high collector to ambient temperature differential applications and for the collection of energy under partial sunlight conditions”. This means it can reach high water temperatures even when it is cold and cloudy.
The study goes on to say: “Note that the evacuated tube collector is approximately 1.6 to 4 times more effective than a flat plate collector. The higher efficiency results in the evacuated system needing a frontal collector area of only 3 square meters compared to a flat plate collector area of 5.96 square meters”. So a smaller collector is needed for the same annual performance.
The www.solarthermal.com website has performance graphs calculated from Environment Canada data at locations around the country, and you can look up the average performance in your area under “Regional Performance” on the website.
The Thermomax system is easy to install (it is much lighter than a flat plate collector and the wind can pass through between the tubes) and in appearance, looks lean and elegant, like a modern-day sculpture rather than a grey box sitting on a roof. The tubes do not reflect sunlight and they discreetly blend into the roof. Pre-assembled, packaged components also make for straightforward and timely installation. The pump station contains all the fittings and safety devices for safe operation of the system, including valves to prevent heat leaving the hot water tank. The system is controlled by a differential controller. These can range from a simple one to a sophisticated one that can connect to the internet and log the performance of the system from a distance, an excellent tool for research and development.
First Nations have been on the forefront of proving the Thermomax technology. Municipal District of Opportunity of Wabasca in north-central Alberta began construction on the Wabasca Water World and Fitness Centre in 2002. At that time the planners researched solar power to offset some of the operating expenses. They sent a representative to Europe to search for the best technology and concluded that Thermomax had both the quality and track record needed for large jobs. The facility includes a 25 m swimming pool, whirl pool, sauna, steam room, and 2200 square foot weight training area.
The Centre then installed the largest vacuum tube system in Canada in August of 2004. To provide a sense of scale, usually on a house one collector could be expected to provide domestic hot water for a family. 47 collectors were installed on that recreation centre! This system heats the main pool and whirl pool, the in-floor heating (deck, change rooms, lobby, and viewing area), and domestic water. Backed up with natural gas, the facility has saved approximately $10,000.00 per year with very little maintenance. Not only has the Municipal District of Opportunity saved money, it has raised significant interest in green technology and created a well-respected landmark in the community of Wabasca.
"It's a matter of education and talking about this across Canada.” Spearing continues. “There is a lot of misinformation out there. We can operate solar heat generation in far lower temperature and sunlight conditions than most people believe possible. Proper design of the system is essential. Capital investment dollars are available for making these installations possible. And it truly is an investment: imagine putting a steel roof on your house. You know that roof is going to be trouble-free for a very long time.”
A lot of history bears out Spearing’s claims. Maintenance is low. Efficiency remains high over time. Replacing tubes is rare. "We have eight 25 year old systems operating in Seattle, Washington as we speak. I doubt you will find another vacuum tube system that can make such a claim.”
Okay, so this all may seem like rocket science....and then again, it might be as simple as feeling the sun warming your face.
