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Saturday, August 13, 2011

Heating Water With Sunshine

I was going to write that I'm not at all sure how we did it, but our last PGE bill (Portland General Electric, that is) was only two thirds of what it was the prior month.  I thought it was because I wasn't home on my computer for many hours of the day, but Steve says that the laptop doesn't take enough power to account for the difference.  We haven't had the Solatubes long enough for it to be that, so the only other thing I thought I could attribute to it was good old fashioned diligence.  You know- turning lights off when you're not using them, and all that.  But then I remembered we're not using the dryer- we're line drying again because it's summer.  Now that I know what not using the dryer can do to the Garner bottom line, I've determined that we need a drying rack to go with the English clothes airer in the kitchen for winter drying, because it's too small to handle a full load by itself. But a rack should make all the difference.  It will be really interesting to see what the solar PV system will do for us, and we should find out in ten short days if PGE is going to qualify us for that.  I didn't realize it, but there's a whole application process we have to go through before we can even put one in, and they have the final say so.  I will be severely disappointed if that doesn't go through, but I think it will.

But I can tell you that our solar water heating system is in, and it's pretty cool.  It took the guys two days to get it in, and here they are.  What a bunch of nice guys.  If you look closely you can see the dog in the window.  I got to scratch his hiney for him, which was good for both of us.

So here is the system.  The fluid running through the solar collector seen here is propylene glycol, which is food grade, as opposed to ethylene glycol which is the stuff you put in your car radiator.  Propylene glycol doesn't freeze of course, so it circulates through the panel, picking up heat, and then goes down into the tank and circulates round and round on the inside before being pumped back up to the plate collector.  By the way, one of the things that sold us on this particular system is the fact that it's an entirely independent system; it has its own thirty-watt solar panel and generates its own electricity for the pump, so it will still pump glycol during a power failure.  Pretty cool, huh?

Cold water from the house gets pumped to the tank, which holds eighty gallons, gets heated up by the hot glycol, which by the way can get up to a hundred and seventy degrees (actually, it could get hotter but there's a thermometer in the pump that shuts it down if it gets too hot to prevent it from blowing).  Then the water that's been heated by the sun-heated glycol flows over to the regular water heater and gets warmed or cooled over there, depending on what it needs, and then goes into the house. The preheated water keeps the gas-fired heater from firing all the time, which saves on the gas.

Steve crunched the numbers, and since there are only two of us, we'll probably never get a pay back on this system, but that's not why we did it.  We did it as a hedge against the rising price of natural gas, and the very real possibility of hyperinflation in the future.  Or just not being able to get the gas, at any price.  If that happens, then the system will need to be re-plumbed to bypass the gas heater.

We'll use the wood stove for cooking winter suppers a lot, so we'll use a lot less gas this winter.  An outdoor pizza and bread oven is planned for the future, and I also want to build us a solar cooker for summer cooking.  But that's for next year; I already have a few projects started that need finishing.

But back to the solar water heater.  Wouldn't you know that the day after it was installed, the morning dawned overcast and the sun never came out.  In fact, it never got higher than sixty-nine today. (This August will probably go down as one of the coolest we've ever had- we're finally getting our spring, temperature-wise.)  At seven and eight this morning, the thermometer in the glycol read seventy, and the thermometer in the outgoing water line also read seventy.  But at the end of a long, cloudy day, they read ninety.  So even on an overcast day, the new system is going to help.

We're still working on the old-fashioned diligence- the first step to energy conservation is remembering not to use so much, and that means staying on top of turning lights off, and making sure that the laptop and phones get charges and then immediately unplugged.  The new Solatubes are great…it used to be I'd have to remember to go all the way into the master bath during the day, so I could use the natural light from the window.  Now I can use whichever is closest. I can't tell you how many times I've used the hall bath and reached for the light switch on the way out, only to remember that the light is coming without electricity.

It makes me laugh.


Miriam said...

Congratulations! I am really interested in the fact that even on an overcast day the system worked. That has always been my concern - our winters are so grey and cloudy!

You're so right about the need for diligence. We were so careful when we first moved out to Mucky Boots, and our electric bills were amazingly low, given that everything in our house (the well, lights, heat) is electric. But in the time since then our usage has crept slowly upwards, just because we're not being as vigilant. Time to do something about that!

Donna OShaughnessy said...

Oh, so happy I found this blog ! Great info just up our alley, as oon hubby and I will build our first efficient home and start our life of complete sustainablity. I can see your blog will be very helpful.

Toni aka irishlas said...

So jealous...

I love the solar tubes. We need them in the exact same places as you did!

You're such an inspiration.

Paula said...

We have neighbors that probably spent around the same amount on their house this year, but they spent it on a new outdoor bar and entertaining space, and it's really nice and I like it, but I'm far too practical to do something like that.

It really boils down to prioritizing those things on which you want to spend your money; making life easier for us as older folks just seemed like a good thing on which to spend money now.

Holly House said...

I get this magazine called Mary Jane's farm, and they had a whole article about drying racks, there's a family that makes them by hand and sells them to supplement their income. They're supposed to be much more efficient since they're built differently? The picture in the magazine looked pretty cool:

Paula said...

Thanks Holly House! I checked them out and I must say I have my eye on the extra large rack. I just want to know how it stays open and not open all the way and collapse, which I've asked them, so we'll see.

If I buy one, expect a review!