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10-23-14, 11:49 AM | #1 |
Apprentice EcoRenovator
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Using a mini-split for both air cooling and hydronic floor heating
This concept seems like a perfect solution for heating and cooling a garage or other area (likely under 1000 sq ft) with a concrete floor. I'm certain this has been done. It is an obvious extension to heat pump technology. No "new inventions" required.
However, none of the major brands of mini-split seem to offer any type of heat exchanger for creating radiant floor hot water. A bonus would be heated forced air for quick warm up. Balancing floor temp and air temp could be a challenge. What am I missing ? |
10-23-14, 05:51 PM | #2 |
Supreme EcoRenovator
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Look into the European market. They have been using hydronic systems much longer and more efficiently than the USA. A high emphasis has been assigned to alternative and innovative technology in building science across the pond.
Most homeowners in America are still coached into some sort of forced air gas or straight electric heating system by the industry at large. Even though it is almost always more energy efficient to use a heat pump system, due to the large natural gas resources in America the dollars favor natural gas. Therefore, even when hydronic systems are employed, a gas boiler is the heat source of choice. That being said, there are many domestic manufacturers of mini split and full sized heat pump systems in the USA. You just have to hunt for the hydronic loop configuration and do lots of research on the subject to find a setup that will work for your site. All of the major manufacturer s have their flavor to sell you. A good portion of the offerings are marketed as commercial products. Office space zone based water source units are common in the commercial sector. Last edited by jeff5may; 10-23-14 at 06:09 PM.. |
10-23-14, 07:39 PM | #3 | ||
Apprentice EcoRenovator
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10-23-14, 09:53 PM | #4 |
Supreme EcoRenovator
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There is a very miniscule market for hydronic heating in general in the USA. The industry is geared 99.998% to sell central ducted systems. The remaining 0.002% of systems sold are divided between boilers, mini-splits and hydronic/solar/biofuel/other. I'm sure that air-source hydronic systems are in the very low parts per million in unit sales.
We are literally spoiled rotten by cheap energy! Literally the second thing I hear people ask about the subject in general goes something like this: "You're telling me this $5500 system is going to save me only $35 a month??? Bah!" An armchair calculation from another ecorenovator (thanks BBP): My Cost of heat (per 100,000 BTU) $.16 / Kwh Electricity = $4.69 $.78 / Therm with 85% Efficiency NG boiler = $0.92 (He figured any installed heat pump boiler would need to operate above a COP of 5 to be cost effective vs. a NG boiler) Check out: Daikin Altherma NorAire Nibe Hydronic Furnace w/Heatpump |
The Following User Says Thank You to jeff5may For This Useful Post: | buffalobillpatrick (10-24-14) |
10-23-14, 10:35 PM | #5 | |
Apprentice EcoRenovator
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well I have to agree with you there !
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I do understand, that a mini-split heat pump has limited practical application, but a garage or large 1-2 room addition, IMHO, is a perfect candidate for one. Most mini-split compressors now have 2 - 4 sets of ports so multiple indoor units are simple to install. Adding a hydronic heat exchanger to the suite of indoor units that each manufacture sells seems like a "no brainer". There are several suppliers of refrigerant to water heat exchangers that could be used. The only thing the company would have to do is provide the appropriate sizing charts to their installers. |
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10-28-14, 04:27 AM | #6 | |
Helper EcoRenovator
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But who needs MFRs, anyway? If you want that, make it. If you can't make it yourself have your A/C guy do it for you. The parts are on the shelf, just need to be creative. |
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10-28-14, 09:18 AM | #7 | ||
Apprentice EcoRenovator
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The problem is, you have to run the A/C to heat the pool. In the NW, how many days in May and September do you run the A/C ? But, I am certain that you would run the "heater" for the pool some days even in June, July and August ! This should really reduce your A/C electric consumption on those days. Quote:
The second problem is feedback/temperature control. On the pool heater, you probably don't need any controls, just crank down the temperature on your inside thermostat when you want to heat the pool ! Do NOT run the filter pump when you do not want to heat the pool water. Maybe add a pressure/temperature relief valve in the water circuit at the heat exchanger. I am surprised that this addon is not more popular. Temperature/feedback from the hydronic heat would be much more difficult, especially with modern computer controls and wireless thermostats. (Where is that universal heat pump controller when you need one ? ) Last edited by theoldwizard1; 10-28-14 at 09:31 AM.. |
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10-28-14, 10:57 AM | #8 |
Supreme EcoRenovator
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Im working on it. To satisfy the anticipation and end the suspense, I will post a few sketches that have reduced functions. That way, everyone interested can slap in a controller and start fiddling. Then when we have a robust sketch, it can replace the preliminary release.
Last edited by jeff5may; 10-28-14 at 11:00 AM.. |
10-28-14, 11:14 AM | #9 |
Supreme EcoRenovator
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You can install a plate exchanger in the vapor line, along with a thermostat to turn on the pump when the line gets above 90F or so.
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To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her... |
10-29-14, 12:55 AM | #10 | |
Helper EcoRenovator
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I'd also love to see a fridge and deep freezer somehow worked into this system powered with cold air that would otherwise be thrown out. |
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