Aztext Press

Life Off-the-Grid

Go With the Flow, Roll with the Punches and “Put a Curtain Around It”

By Michelle Mather

Last year, as part of our Eco-Energy Audit, we decided to add a solar thermal unit to our home. We already use the sun to generate most of the electricity for our home. The next logical step for us was to begin using the sun to heat our hot water. This is called solar domestic hot water (SDHW) and as Cam has described in previous blogs, it is one of the best things that any homeowner can install in order to incorporate renewable energy in to their home and enjoy the fastest financial payback.

We chose an EnerWorks system which was designed by engineers at Queen’s University in Kingston and is built right here in Ontario. This type of system has a flat plate solar collector¬† and there is a different type of collector that uses vacuum tubes. We felt that it was important to choose a unit that was designed here, in this climate, and manufactured near London, Ontario.¬† (see http://www.enerworks.com/ for more information)

On a sunny day, glycol is circulated through the flat-plate collector and is warmed up by the sun. This warm glycol is then circulated through a heat exchanger where it transfers its heat to water.  Even though we installed the unit at the end of January (in order to meet our early February deadline for the EnerGuide audit) it began to work right away in the frigid January temperatures. As long as the sun was shining, the unit was working to preheat our water.

At our house we actually have 3 hot water heaters now. There is a propane tank that was here when we moved in to the house. Obviously when it was our only hot water heater it ran all year long. At some point we added an electric hot water tank. This might seem like a strange thing to have in an off-grid house, but on really sunny days, eventually our batteries become fully charged and we would end up “wasting” any electricity generated by our solar panels or our wind turbine after that point. So we installed an electric hot water tank and as soon as our batteries are fully charged on a sunny or windy day, we divert the excess electricity in to our electric hot water tank and our water is heated by electricity before it goes in to the propane tank. Adding the electric hot water tank helped us to cut down on how much propane was being used to heat our water.

Then we added the SDHW system, and so now our water is heated first by the sun and then by the electric tank (if it’s on) and then by the propane tank. There are times when months go by without the propane tank coming on.

Cam on the roof installing the flat plate panel

Shortly after installing the EnerWorks system I was telling Cam’s grandmother about it. As I’ve mentioned the system consists of a flat plate collector, which is located on our back porch roof, facing the south. It also consists of a hot water tank and the heat exchanger and the control unit. Normally you would install the hot water tank and controller etc. in a basement with your furnace and other hot water tank. However, our basement, which was dug years after this house was built, is damp much of the year and actually floods during the springtime of most years! Unlike a flooded basement in the city which tends to become flooded with sewer water, our basement floods with lovely, crystal clear ground water. There have been years, especially when we have had a lot of snow and a quick spring thaw, when up to 12 inches of water will creep in to the basement. The only thing of importance in our basement is our freezer, which we keep up on cement blocks, higher than the flood level.

Obviously, it was not a good option for our EnerWorks hot water tank. So Cam and I discussed other options and essentially there was only one other room in the house that had enough space for a hot water tank – our bedroom! So yes… we have a lovely hot water tank and the accompanying control panel and tubes and wires in our bedroom. I like to call our decorating style “Early Industrial”. Luckily I care more about my carbon footprint than I care about my decor!

As I mentioned, I was telling Cam’s grandma about our system shortly after we installed it. Cam’s grandma is 98 years young. She is as sharp as a tack and still living in her own home. Obviously Grandma has been doing something right all of these years! When I jokingly complained to Grandma about the new hot water tank in my bedroom, her response was absolutely priceless and it made me realize that her easy-going, “go with the flow” “roll with the punches” type of attitude is probably one of the reasons she has survived for so long. “Oh Michelle,” she said, “Just put a curtain around it!”

I still haven’t gotten around to putting a curtain around it and one of the biggest downsides of having a solar thermal hot water tank in my bedroom is the parade of interested folks that Cam has ushered through my house and in to my bedroom for a look at the unit!

Cam showing off the unit IN OUR BEDROOM

See previous blogs about our solar domestic hot water heater;

http://aztext.com/blog/index.cfm?a=showone&EID=41

http://aztext.com/blog/index.cfm?a=showone&EID=45

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4 Comments

  1. Cory

    Have you thought about replacing the propane water tank with a tankless heater? They have both propane and electric models.

    • aztextpress

      Hi Cory!
      Yes, tankless water heaters are an excellent alternative! There are two reasons why we’ve been reluctant to use one and perhaps you can share your experience to shed some light on these issues. First off, we are on well water, which means that the water going into the tankless heater might be very cold and secondly, our water is very hard and we have been concerned with the potential for scale build up on the tankless heater unit. Do you know whether or not either of those conditions might be of concern?
      With using both an electric tank (as our diversion load) and a solar thermal unit, the propane tank rarely turns on now anyway, but if we were to replace it in the future, we’d certainly look at a tankless model.

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