Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Energy kinetics frontier hot water -storage tank or indirect tank?

bobzel
bobzel Member Posts: 8
I've tried to read through various Ek posts but haven't really been able to distill an answer to whether to pair a new Ek1 frontier installation with an Ek storage tank or an Ek or other indirect tank. Calling Ek resulted roughly in a "both installs are good" analysis without much detail.

I have well water and am currently getting by fine with an old 40gal indirect paired with an inefficient old oil boiler. Our water usage is not extreme in any way. My main concerns about the tank choice are which will save more on heating costs and which will last longer?

For the storage tank, I assume I need the scale stopper and regular back flushing of the plate heat exchanger, right?

For the indirect, does it need any special maintenance? Will an Ek indirect outperform the stainless Super Stor I'm replacing?

Comments

  • Roger
    Roger Member Posts: 265
    Thank you for your question, @bobzel .
    To get the best of both worlds, you should always use a plate heat exchanger and a scale stopper or water treatment system. This will typically save 5% to 10% on annual fuel consumption (not just hot water). Since 2020, our plate heat exchangers have also had an exclusive Sealix silicon dioxide non-stick coating to further prevent mineral build up. Plate heat exchangers can also be cleaned like tankless coils.
    Here's some background as to why a low mass boiler with a plate heat exchanger and thermal purge will always outperform tanks with coils (it's July, I'll go for the long answer...):
    When Energy Kinetics designed System 2000, our founder, John Marran, knew that the key to the best efficiency was to make sure that no heat was left wasted in a boiler. He then set about developing a heavily insulated low mass boiler with thermal purge, which works exceptionally well for heating efficiency, longevity, and serviceability. When the last thermostat call is completed, the burner shuts off and heat remaining in the boiler is purged out to that zone. Because the boiler is low mass, it will not overheat the zones as this remaining heat is delivered to the home.
    John knew the same concept was needed for hot water as hot water tanks are replenished 3 to 5 times a day in active households. The problems were: 1) Low mass thermal purge operation is the opposite of tankless coil boilers which have very little insulation and need to maintain high temperatures just to deliver very limited poor quality hot water. This is of course very wasteful as well. And 2) When an indirect tank with a coil's thermostat is satisfied, the tank may be close to 140°F and the boiler around 180°F to 200°F. The boiler can only purge down to 140°F at best (the tank temperature), and because the coil has limited heat transfer by convection, the boiler can really only purge to 150°F to 160°F degrees, nearly eliminating the benefit of thermal purge 3 to 5 times a day.
    The answer: Develop new, simple technology to be able to thermally purge the boiler to the hot water tank. John had a background in pumps and heat exchangers and he helped found the first small brazed plate heat exchanger company in the world to enable this simple technology. How does this work? The plate heat exchanger can take nearly the full output of the boiler and convert it to 140°F hot water. This design heats the tank from the top down, so hot water is available to flow to fixtures within minutes. Further, the thermostat location turns the burner off with just enough cold water left in the bottom of the tank to balance with the heat left in the boiler. The boiler then thermally purges to the tank, and the boiler ends cold and the tank finishes fully heated. An elegant, simple solution without any complicated technology.
    Since the boiler takes about 2 minutes to heat up, if thermal purge were not available, about 2 minutes of energy would be left wasted in the boiler. High mass boilers can take 8 to 15 minutes to heat up, so 8 to 15 minutes of energy is left wasted in the boiler every time the final thermostat call ends; if this were thermally purged, it would also overheat the zones. All the elements are needed for the best efficiency: A heavily insulated, low mass boiler, a plate heat exchanger and tank, and an effective thermal purge control. Cutting corners on any part of this design, just using a temperature reset control, or using any coil in the boiler or tank can waste alot of energy.
    Best,
    Roger
    President
    Energy Kinetics, Inc.
  • bobzel
    bobzel Member Posts: 8
    Okay, that explanation helps a lot.

    Is my understanding correct then, that the best pairing for an EK1 would be with a *storage* tank, and not with an *indirect* tank which has a coil? Is there any significant advantage of the High Flow thermoplastic storage tanks vs the EK glass lined Storage tanks?
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,983
    The 'well water' is a cause for concern to me. @Roger are their any extra precautions you recommend for this scenario?
    steve
  • Roger
    Roger Member Posts: 265
    Thank you, @bobzel .
    Yes, a plate heat exchanger with storage tank and thermal purge is the most efficient vs an indirect tank.
    Hopefully your heating professional can provide some insight as to the longevity of glass lined tanks in your area. If there are well or water quality issues that prevent long life, then the High Flow thermoplastic tank may be a good solution.
    Roger
    President
    Energy Kinetics, Inc.
    STEVEusaPA
  • Roger
    Roger Member Posts: 265
    Thank you for your 'well water' question @STEVEusaPA .
    For water conditions up to 25 grains of hardness, we have had exceptional success with the scale stopper. Of course some well water has high mineral content and other well water does not, so knowing the hardness/mineral content is key to making the right decision.
    I'd recommend Sealix coated heat exchangers for hard water applications, and they will typically be included with any system as virtually all our heat exchangers are Sealix coated anyway. The Sealix permanent non-stick coated surfaces prevent lime and mineral build up for exceptional long term performance in hard water applications, so the combination with a scale stopper or water treatment is very solid.
    If the well has high levels of silt, then a silt filter is appropriate and will also benefit the home overall.
    Of course a tank with a coil can be used in very hard water applications (and the coil will foul over time), although the hot water production rate and efficiency will be lower. If the water is that hard, a scale stopper or water treatment system would also be recommended.
    Best,
    Roger
    President
    Energy Kinetics, Inc.
    STEVEusaPA
  • bobzel
    bobzel Member Posts: 8
    In terms of water hardness, what minerals am I looking for? I did have a well water analysis done, so I have the concentrations of all minerals, etc. Nothing was out of EPA limits, but I'm guessing that's not enough to say the water is not hard.
  • bobzel
    bobzel Member Posts: 8
    One line of my report listed hardness as:
    Hardness: 71.8 mg/L (75 or higher is considered hard)

    Also,
    Magnesium: 6.26 mg/L and calcium 18.45 mg/L
  • bobzel
    bobzel Member Posts: 8
    Or if I'm doing it right, it looks like 71.8 mg/l converts to 4.19 grains. If that's correct, then does it sound like the thermoplastic tank is necessary?
  • Roger
    Roger Member Posts: 265
    You're on the right track - your water is not considered hard, good calculation.
    Low pH (less than 7.0 is acidic) and low total dissolved solids (TDS) can lead to corrosion, and anode rods can help provide protection. Anode rods should be inspected, but that is not usually an easy task.
    Dissimilar metals and stray current can also cause corrosion.
    President
    Energy Kinetics, Inc.
  • bobzel
    bobzel Member Posts: 8
    Hmm, I'm slightly confused again. I thought the EK storage tanks didn't have anode rods as feature - or is that something I just made up?
  • Roger
    Roger Member Posts: 265
    The glass lined tanks all have anode rods. The High Flow tanks are highly corrosion resistant thermoplastic and stainless steel, so they do not have anode rods.
    President
    Energy Kinetics, Inc.
    GGross