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Hydronic Cooling webinar 6/20

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hot_rod
hot_rod Member Posts: 22,472
edited June 20 in THE MAIN WALL

this seems to be a hot, or cold topic now a days

Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
PC7060

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  • DCContrarian
    DCContrarian Member Posts: 301
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    How do we sign up?

  • hot_rod
    hot_rod Member Posts: 22,472
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    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • DCContrarian
    DCContrarian Member Posts: 301
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    Video is here:

    So I love John Siegenthaler, I've found his articles inspiring and influential, and I just love to hear him speak. But I found this presentation kind of missed the mark.

    There are two fundamental advantages to an air-to-water heat pump. The first is that if you want to have an all-electric house, and you want to have heated floors, it's the only way to do it and get the efficiency of a heat pump. That's probably why 90% of people look into A2W. The second is that you can zone as minutely as you want, you can put a thermostat in every room. This is a general advantage of hydronics, but with a heat pump you can apply it to cooling as well as heating. With every other form of cooling, once you get below the minimum modulation of the heat pump you start running into problems.

    You can get hydronic air handlers rated as low as 3000 btu/hr — and you can run them at 10% of capacity with no ill effect. Try that with a minisplit or air-to-air heat pump. You can have one side of the house pulling 30,000 BTU/hr and the other side pulling 300 BTU/hr with no problem. And you can do that in the morning, and then reverse it in the afternoon when the sun is on the other side, still no problem.

    These are fundamental advantages that are baked into the technology. They are what the manufacturers and installers should be pushing. And we should be pushing the manufacturers to produce equipment that does a better job of exploiting the advantages.

    John breezed over the subject of small air handlers. He pointed out that many have poor air filters which can cause maintenance issues. Which is a fair criticism. Then he talked for a long time about 3-ton air handlers. There is no fundamental advantage to running water through a 3-ton air handler vs. running refrigerant from an air-to-air heat pump. It completely gives away all of the advantages of the hydronic system. And the bill of materials is going to be triple for essentially identical performance.

    He then advised that you not try zoning for cooling. That's good advice — if you're running a 3-ton air handler and ducting air all over the house, whether that air hander is air to water or air to air. Big air handlers don't like being choked down. But if you take advantage of what hydronics has to offer, and instead put twelve quarter-ton air handlers all over the house, each with its own thermostat, every room in the house will be precisely at the temperature the inhabitants want.

    He also talked a lot about ground source and even lake source heat pumps. Sorry, that's irrelevant. And DHW. That just makes the system much, much more expensive without any fundamental advantage.

    There are real issues that we should be pushing the manufacturers to solve. The filter issue is real, there's no reason small air handlers can't have high-quality disposable filters. The other is the look of air handlers. They're ugly. This is a problem they have in common with minisplits. A hydronic system is going to be expensive, it's a hard sell to get someone to shell out tens of thousands of dollars for something that looks like it came out of the Soviet bloc. As far as I can tell the only manufacturer who takes appearance seriously for cooling-capable air handlers is Jaga, but even they are half-hearted, they don't make any units small enough for the one-air-handler per room where hydronics really shines.

    So in summary: push floor heat and one air handler per room. Everything else is noise.

  • hot_rod
    hot_rod Member Posts: 22,472
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    good feedback, thanks. The webinar was billed as small scale hydronic cooling so the geo lake systems did get as small mention as another source option. If you have access to a lake or river it is a viable option to drilling wells. With lake loops the entire system is hydronic, no pulling from air.

    The U.K. Has been the largest boiler/ hydronic market in the world. Most systems are panel radiators not Infloor. They also seem to be the most aggressive adopters of A2Whp with all the oil uncertainty. So properly designed HP are an excellent match for panel radiator systems, if you do the homework

    Other than IAQ requirements, systems should be 100% hydronic imo and can be if you address the dewpoint. Radiant floor cooling can in the air SW portion of the U.S. as he indicated a heat recovery unit to get the required ACH. I think the new Taco learning building has hydronic chilled beam cooling?

    DHW comes along at no extra charge and makes total sense when the HP is in cooling mode. May as well take the rejected heat to a place where it is needed, hot water production, instead of just blowing it outside.

    I agree Jaga has incredible well thought out and great looking emitters, but if price is a concern as you mentioned, Jaga is the first budget item to get cut from a proposal.

    The next Idronics takes a deeper look at what you need to consider when attempting to replace a boiler with A2WHPs. It will be math intensive as you need accurate data to come up with correct answers. Should be some new formulas included to make the math easier for designers and installers.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • DCContrarian
    DCContrarian Member Posts: 301
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    "DHW comes along at no extra charge and makes total sense when the HP is in cooling mode. May as well take the rejected heat to a place where it is needed, hot water production, instead of just blowing it outside."

    I don't see where you're getting "no extra charge," with the systems I've seen adding DHW is about a $5K upcharge.

    And I haven't seen one that scavenges rejected heat, least not in air-to-water. They do have them in ground-source system. The air-to-water systems just suspend cooling and switch to heating mode. Siegenthaler spent a few minutes talking about how when you switch from heating to cooling you have to have a way of purging the hot or cold water in the heat pump otherwise you end up blowing hot air on people in cooling season. Note that while the water heater is heating no cooling is delivered.

    I see no advantage to running DHW this way and a couple of disadvantages relative to a HPWH. First is cost, it's probably twice as expensive all-in. Second is it's less efficient, in cooling season the HPWH provides free cooling and dehumidification and in heating season it's a toss-up. Third, you get better comfort with the two systems de-coupled, you get heating or cooling from the heat pump whether or not the water heater is running.

    My bigger point is this is a distraction. Push the cases where the technology is strong, not the dubious edge cases.

  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
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    The Nordic air to water offerings have a desuperheater, you could reasonably call that “free” or close to it.

  • DCContrarian
    DCContrarian Member Posts: 301
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    One of the test cases presented was a 3-ton air handler being used to provide chilled air for a high-velocity, small-diameter ducted system.

    To my mind this just seems daft.

    The only reason to use high-velocity ducting is in existing construction where there's no feasible way to fit regular ductwork and you need something that you can run through the joists. But if that's the case, why not take advantage of one of the primary advantages of hydronics: its volumetric efficiency. I mean, John spent time in the introduction talking about a hydronic pipe can move 1900 times as much heat in the same space as ductwork. So why use air to move cooling around when space is limited?

    If you put a quarter ton or half ton air handler in each room, you'd only need a 1/2" PEX line and a 3/4" condensate drain line for each unit. That's much better than trying to wrangle "small" ductwork between the joists.

    If all you're using the hydronics for is feeding a single large air handler, there is zero advantage to hydronics over conventional air-to-air. The output is going to be the same — but the hydronic system is probably going to cost three times as much. There's not ever a space advantage for the piping. For a 3-ton air handler, if you used an air-to-air heat pump and ran the refrigerant to the air handler, you'd use 3/4" and 5/8" tubing. Running chilled water you'd have to run at least 1" lines.

  • hot_rod
    hot_rod Member Posts: 22,472
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    Just showing options. You don't have to like or use any of the suggestions :)

    With AHs in all the bedrooms of that project you would need a place to mount them, power to each one and a condensate drain for each one, filters in each one which are cheesy at best as you noted, most are ugly as you also rightly noted. Plus the fan noise related to a blower in each room. May as well use a window shaker or PTAC at that point.

    Properly done the high velocity systems are unobtrusive and very quiet, and there is a niche for them.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • DCContrarian
    DCContrarian Member Posts: 301
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    In order for hydronic cooling to be appealing to people, it has to have some advantage. It could be lower installation cost, lower operating cost, or better comfort. If you can't deliver at least one of those three thing it's time to hang up your hat and go home.

    A centrally ducted system, whether high-velocity or regular, isn't going to care whether the coolant flowing into it is chilled water or refrigerant, the comfort delivered is the same. And the energy usage is going to be about the same. Let's take a quick peek at installation costs. On the one hand, you could have a Unico 2.5 ton air handler https://shop.unicosystem.com/vertical-fan-coils/vertical-ahu-2430-b-coil-e-coated

    at a cool $4,565.25, coupled with a Chiltrix CX34 at $4889, total $9424.25.

    On the other hand you could have a 2 ton Mitsubishi heat pump with air handler https://hvacdirect.com/mitsubishi-svz-ka24na2-24-000-btu-18-seer-ductless-mini-split-heat-pump.html

    all-in at $4499.

    Note that the installed cost of the hydronic system is going to be a lot higher, because you still have to add accessories like zone valves, buffer tanks and circulators, whereas the air-to-air comes complete. And the Mitsubishi has much better cold-weather performance.

    But even so, the hydronic system is twice as expensive — and offers nothing to justify that cost. Can you imagine going to a customer and saying, "I have this idea for a neat system. It's going to cost you twice as much, it's a lot more complicated, it won't save any energy and you won't be able to feel any difference"? Because I can't.

    The only selling point for air-to-water is improved comfort. And that boils down to the emitters. In the heating season it means being able to have heated floors, and in the cooling season it means being able to have an air handler in every room, with its own thermostat.

    That's the value proposition. All the other stuff is a solution in search of a problem.

  • hot_rod
    hot_rod Member Posts: 22,472
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    Heat pumps sales are going up every year, HP have surpassed boiler sales in Germany for the past several years, same in the UK.

    Someone has figured out how to sell, and install these systems properly.

    If you are selling just on price, you may be missing a lot of opportunities.

    I see heat pumps HP as away for hydronics to stay relevant. The will be a learning curve as there was when mod cons came on the market.

    My current job is to show options to the hydronic industry and hopefully best practices for designing and installing various systems, be they solar, heat pumps, boilers of all types, and any combination of these.

    I don't sell or push one system over an other, just give the industry the tools to make educated decisions.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    PC7060
  • DCContrarian
    DCContrarian Member Posts: 301
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    Siegenthaler talked about a system like that, I don't know if it was the Nordic. He also said it doesn't always produce water hot enough for DHW so you need to have another device for heating water. It seems like a tough sell to a client to say the hydronic system has a hot water option that's like $5K, but you'll still need another water heater …

    Let me offer an analogy. I was born and raised in Massachusetts, which was the industrial heart of America in the 19th century. Massachusetts was famous for its textile mills, which were powered by water power. The basic design was you'd put the mill next to a river, and put a water wheel in the river, and there's be a long driveshaft attached to the wheel which would run the length of the building. Machines would be lined up along the driveshaft, with belts running down from the shaft to each machine.

    When electric motors came along, the mill owners were happy they no longer had to depend on the flow of the river. When the mills were electrified, they put a great big electric motor at one end of the building, and had it power the drive shaft. It took about thirty years of doing that before they realized it would work better to have a small motor in each machine, and to run a wire to each machine instead of a shaft with belts. And it took another thirty years to figure out that you could make an electric motor small enough to hold in your hand, so the machines didn't have to bolted in place any more. About the same time they figured out that the mill didn't need to be next to a river any more, nor did it need to be a long, skinny building.

    Hydronic heat pumps are kind of at the stage of putting a big electric motor at one end of long driveshaft. People want to use them the same way they've always used boilers. It's a mistake to think of them as just like boilers, only noisier. They have different strengths and weaknesses.

    Heating domestic hot water is an easy add-on for a boiler. You get one combustion appliance instead of two, and adding capacity to a boiler is generally easy, in many cases it's just switching in a bigger orifice. You can go tankless and save space. Heating domestic hot water is not well suited to a heat pump. Capacity isn't easy to add, doubling capacity basically doubles your costs. You still need a storage tank so you don't save any space. You're better off just running a HPWH.

    Instead of doing things the way they've always been done, we should be focusing on the strength of hydronic heat pumps: the comfort of hydronics with the efficiency of a heat pump. And not just in the winter, in the summer too! That's the pitch.

  • DCContrarian
    DCContrarian Member Posts: 301
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    Europe is instructive, they have a lot of nice stuff that isn't available here. I've already mentioned the Jaga air handlers. In my house I have a Midea air handler that isn't sold in the US, it's made for the European market. I self-imported it. It's great. It installs between the joists in the ceiling, it's very unobtrusive. It's very quiet. And winter or summer, it keeps the room within 0.1 degree of the setpoint.

    The combination of radiant floors and good-quality hydronic air handlers showcases the strength of hydronic heat pumps: comfort.

  • hot_rod
    hot_rod Member Posts: 22,472
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    The North American hydronic market is very small compared to the other countries. So it may take time for the unique equipment like micro air handlers make it to this market. If ever.

    Manufacturers first need to acquire all the U.S. Canadian listings, convert voltages and connection size.

    This can be a costly and time consuming process and a manufacturer would want to know the market here would support that $$ commitment.

    We have seen a number of hydronic brands come and go from this market when the numbers didn’t work out, Vaillant, MZ boilers, for example

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
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    Siegenthaler talked about a system like that, I don't know if it was the Nordic. He also said it doesn't always produce water hot enough for DHW so you need to have another device for heating water. It seems like a tough sell to a client to say the hydronic system has a hot water option that's like $5K, but you'll still need another water heater …

    Where are you getting this $5k from? Agreed, that's too much.

  • hot_rod
    hot_rod Member Posts: 22,472
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    The cutaway views show the DHW HX included on some A2WHP brands as well as the control logic.

    $5,000 may be for an optional indirect like the TurboMax?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
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    Yup. So two cheaper options are available.

  • hot_rod
    hot_rod Member Posts: 22,472
    edited June 24
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    if not, a plate HX and a circ pump could be added to most any hydronic system to generate DHW.

    I think ECR has a packaged DHW module with pump and HX.

    I added a circ, HX and flow switch to the bottom of my boiler for DHW. A few hundred bucks for the parts. Plenty of HX available on E-bay :)

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • DCContrarian
    DCContrarian Member Posts: 301
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    Let's look at Chiltrix, because they put prices on their website ( https://www.chiltrix.com/documents/price-list.html )

    At a minimum, you're going to need a tank, a 3-way valve and a circulator. You're probably going to need the 70 gallon tank at $2299, the 35 gallon tank saves a few bucks but that's really small, especially considering you won't be able to be heating hot water and heating or cooling the house at the same time. To warm that at a reasonable rate you're probably going to want the 3.5 ton heat pump, the 3-way valve for that is $199 and the circulator is $349. (The 2-ton saves you $67 on those bits). So just those three pieces get you to $3850, that doesn't include all the other fittings you'll invariable need. And you'll have to pay someone qualified to install it.

    I might be low-balling at $5k.

    And I'm not including the cost of potentially having to upgrade from 2 tons to 3.5 tons. If necessary that's $3100.

    And what does this get you? It gets you nothing that a HPWH doesn't get you. It doesn't save space, it doesn't cost less to operate, and it certainly doesn't save you money on the installation.

  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
    edited June 24
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    DC, I’m speaking of the Nordic desuperheater built into their air-to-water heat pump which comes with a circulator, not whatever you’re describing. Like in hot rods diagram. You’d need, at most, an unpowered storage tank. You could also just use the existing tank and save less.

  • Bob Gagnon plumbing and heating
    Bob Gagnon plumbing and heating Member Posts: 1,368
    edited June 25
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    I put a Radiant Cooling System in my house back at the turn of the century, it still works good, but the cost of running it this way is significantly more than today's heat pumps. I'm looking to install an air to water heat pump, and take the well out of the picture. I can tell you that Radiant cooling comfort is amazing. It's the comfort equalivent of Radiant heating. The btu's get pulled away from your body. It's like being in a basement. I built a fan coil unit out of about 100' of baseboard element that cools the air and removes humidity. Radiant heating systems are a perfect fit with these heat pumps…

    thanks, Bob Gagnon .

    To learn more about this professional, click here to visit their ad in Find A Contractor.
    hot_rod
  • DCContrarian
    DCContrarian Member Posts: 301
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    What happens with a desuperheater in cooling season when the cooling load isn't enough to meet the domestic hot water load? Isn't the case that Siegenthaler talked about where you have to have another source of hot water?

    It's not a question of whether it's possible to get domestic hot water out of a hydronic heat pump, sure it is. It's a question of whether it's a good idea. It isn't. There's just no benefit compared to running a HPWH.

  • DCContrarian
    DCContrarian Member Posts: 301
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    There you go again, thinking of a hydronic heat pump as just like a boiler but noisier.

    Yes, you can hot water out of a heat pump. Yes, you can plumb it just like a boiler. It just doesn't make sense to do so. Why does it makes sense to use a boiler for domestic hot water? Because the capacity is already there, one big combustion appliance is cheaper than two small ones, and adding capacity to a boiler costs very little.

    The cost of capacity just scales completely differently for heat pumps. Again, let's look at Chiltrix because they put their pricing out there. They offer two heat pumps, a 2 ton and a 3.5 ton. The costs are $4889 and $7989, respectively. The 2-ton costs $2444 per ton. The incremental cost of the 3.5 ton is $3100 for an additional 1.5 tons, or $2067 per ton. There is very little economy of scale.

    This is important because heat pumps tend to run really small compared to boilers. Even the 3.5 ton, at 42,000 BTU/hr, is really small by boiler standards. That would be really small for a standalone water heater. Asking it to heat your water and heat the house at the same time? That just isn't happening. And in fact won't happen, the software insists that one load be given priority.

    I'm not saying it isn't possible, it just isn't practical.

  • PC7060
    PC7060 Member Posts: 1,240
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    I think this thread is at the beating dead horses phase of its life cycle.

  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
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    DC, research it a bit. It’s a lower output method but it’s cheap and you’re just reliant on 1 compressor. Seems easy enough and you avoid the problems which seem to exist with many HPWH.

  • DCContrarian
    DCContrarian Member Posts: 301
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    I'm here to learn. Honestly.

    So I'm looking at the Nordic, the 2-ton version is a cool $10,564.00. Not sure I'd call that cheap.

    Fundamentally, I do like the architecture — the only thing outdoors is the heat dump and fan, compressor and heat exchangers are all indoors out of the weather. All hydronic piping is indoors. Two heat exchangers, one for hot water and one for cool, only the difference between them goes outdoors to the heat dump.

    Actually being able to produce hot and cold water simultaneously is a neat trick. You could send both to a room to dehumidify without heating or cooling. Or you could heat the basement while cooling the attic.

    Hot_water_fan
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,917
    edited June 25
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    ha DC, it’s hydronics. Nothing is cheap here. I’m only talking the desuperheater cost vs a HPWH. Obviously air to water is pricey overall.

    Yeah it’s a neat design to put all of that inside. Involves some refrigerant work but seems worth it.