hot water flow sensor

[SteveB]

Hey Jessy,
Here is a link to the Tankless system I've been using for the last year: http://www.seisco.com/pages/internal-dia4.html. May help with the conceptual ideas. Of note, notice there are individual cambers for each heating element. Allow for future easy replacement of the heating elements, as this is the most likely component that will require replacement. Can't really speak to the corrosion issue (The one I have is actually made out of a non metal polymer). If you have hard water, you sould allow for easy cleaning out of the cambers to get rid out the scale build up. Also keep in mind, these can draw a lot of current. So make sure your electric service to your house is up to the task. The sight above has some good info on that as well. If you look around a bit on the web, you may find some temp probe products that would work well. If you construct your own, here is an epoxy designed for heat transfer that would work well.

As for using the solar heater as a preheater, you need to "protect" the backup heater (and people) from the excessive temps possible from a solar system. Simply put, use a passive temperature controlled mixing valve between the solar water heater and the backup water heater. This will allow water temp into the backup heater to be at, or below, a preset temp, which would be 5-10 degrees above the max output temp of the backup heater. This way, the backup heater only comes on when the solar has run out. And the hot water from solar water heater, when it is really hot, will be used at a slower rate, increasing its effeciency.

Darrel:

I never really understood the Solar Idea too well. You end up spending Thousands of dollars, just to save a few hundred bucks in electricity. Kind of like buying one of those Hybrid cars. Pay an extra $10,000 to save $500 a year in gas. Doesn't add up.

I've seen some set-ups for between $1000-1500 (here's one). With this setup (where I live) I could probably recovery my costs in three years. Even if the thing only lasts 10 years (likely more), I am money ahead, especially if energy costs continue to climb. I am actually planning to go this route in the fall (at the same time my roof is replaced). We have so many good solar heating days here that I my not really need a backup heater for 10-11 months out of the year.

Good luck jessy. Keep us updated on how things work out.

Steve


BTW, if you would like a closer look at one of these let me know. I could take some close-up pics.