19 December 2009

A lot of Figuring

1) Opening roof stuff
2) Water pressure stuff

These two things bring on the challenges. First the second. I had a dreamy vision of 4 feet of head working with a small on-demand propane system, thereby keeping the whole plumbing gravity fed. Basically I'm bummed to learn that to meet the 15 psi requirement for the on-demand propane water heater I was given I would need 35 feet of head. Not gonna happen. At least not in my next location. This makes me consider a small water pump. Or some other kind of small on-demand propane water heater. If I want to use this water heater, I need to learn about pressurized water systems. Hmm... hot water... that luxury... how / when / why / hmm...

OK, I NEED TO THINK MORE IF I CARE. "Tankless heaters are limited to a choice between expensive and CO2 problematic energy sources: gas and electricity. This makes it impossible to include other heat sources, including renewable energy. Tank-type systems have a much wider choice of heat sources available, such as district heating, central heating, solar heating, geothermal heating, micro CHP and ground-coupled heat exchangers." (source) I need to have some conversations with some local visionaries.

Second the first. Which directions to put the hinges? Use a 2" x 2" angle iron as a frame to fend off warping problems in the future? Some kind of pinion gear (used to convert rotation into linear motion)? How to fully waterproof? As my dad said, you want strength, precision, and waterproofness. Thus the challenge.


  1. I realize that you have a donated tankless heater, but I know that there are variable flame tankless heaters that are used in renewable systems. Using a solar heater and storage the heater will only create enough of a flame to heat the solar heated water up to temp. I also have it my head that in a small house situation a tankless heater could also be used in conjunction with an in floor heating system, saving the expense of an additional heating source.

  2. Thanks Tom. Do you have any suggestions of particular variable flame tankless heaters that are good for renewable systems??

  3. Bosch Aquastar 1600PS

    Heating & hot water system
    Thats a bit much for your application. I'm no plumber, but the way i see it is run a series of loops of tubing in your floor. One end into a tee fitting on the heaters hot out, the other end into a thermostat controlled water pump, then connected to a tee at the cold in of the heater, the tee from the main water source is plumbed before the heating tube returns and supplies kitchen and bath cold taps. the other tee at the hot out from the heater supplies hot water to kitchen and bath hot taps. not using hot water at the taps makes the heating system close looped and the thermostat calling the pump to run would fire the heater. A check valve after the tee to the cold taps and before heating return would prevent hot water from entering the cold taps when the pump runs. Add a solar batch heater from an old hot water tank. have to think about how to best use solar pre heat. in line to heating loop or inline to cold in to heater. Or valve it to change based on seasons, devote solar hot to heating in winter, and hot water in summer. What do ya think? Heat and hot water, one appliance, quiet operation, maximum comfort from in floor heating, solar assisted. I think with that much efficiency you could sleep well with your CO2 use. :)