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  1. #1
    Join Date
    Aug 2010
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    Brockvegas
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    13

    Mitsubishi Zuba Central system and heat pumps

    I have some quotes for the Mitsubishi Zuba system for our house and I have a few questions:

    1 - from anyones experience, will the system work well on a 33 year old brick raised bungalow of 1,110 sqft and a heat load calc of 44,000 (ish) btu/h? The windows are mostly new, and the attic has been insulated from R11.9 to R50+. From what I have read online, it should be fine but...

    2 - for the size of home, again from what I have read here, should I be getting an estimate on a York system as well?

    3 - does anyone have one installed where I could get some info on yearly heating cooling costs and type/size of homes installed?

    4 - what kind of longevity will the Mitsubishi's have? Similar to the r12 Ac units that ran for 20+ years? Are the heat pumps from York etc as good as they used to be?

    Thanks a lot for any help, its just after years of living with a FAG system, and all the NAY sayers out there against the heat pumps, I need a little confirmation... of course the estimators said no problem, but I would love some real world figures, and they had installed so few that they had no testimonials for it.

  2. #2
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,826
    Well that's a new one on me. I've never heard of a Zuba system from Mitsubishi. In fact, I've never heard of a Mitsubishi central system. But then again, I'm in the USA. Could you be in Canada? Not all products are sold in both countries.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  3. #3
    Join Date
    Aug 2010
    Location
    Brockvegas
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    13
    Just google it, and you will find the info on it from Mitsubishi... its finding information from other sources that is difficult. But after minutes on here, I have a local guy coming by tomorrow to take a look and quote me a price. He also has some testimonials which help as well...

  4. #4
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,826
    Well that's what I thought. It's a product only sold in Canada. So we down here in the lower 48 can't help you. Never have seen or heard of it.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  5. #5
    Join Date
    Aug 2010
    Location
    Monroe County, PA
    Posts
    99
    Zuba looks VERY similar to the Nordyne iQ system (Broan). Different manufacturer of course, but very similar technology.

  6. #6
    Join Date
    Sep 2006
    Posts
    1,253
    Zuba is a response to being able to replace an existing conventional North American type heat pump with the technology used for years now around the rest of the world - inverter driven compressors for operating efficiency and flexibility.

    Mitsu is simply using a conventional style indoor unit and their hyper heat outdoor unit. The Mitsu hyper heat uses an oversized compressor to provide the high heat output at the single digit temps. In cooling more they limit the compressor speed to keep it at the nominal rating of 3 tons.

  7. #7
    Join Date
    Aug 2010
    Location
    Monroe County, PA
    Posts
    99
    Quote Originally Posted by mchild View Post
    Zuba is a response to being able to replace an existing conventional North American type heat pump with the technology used for years now around the rest of the world - inverter driven compressors for operating efficiency and flexibility.

    Mitsu is simply using a conventional style indoor unit and their hyper heat outdoor unit. The Mitsu hyper heat uses an oversized compressor to provide the high heat output at the single digit temps. In cooling more they limit the compressor speed to keep it at the nominal rating of 3 tons.
    Oversize compressor for heating, but run it at 3 ton capacity for cooling. Hmmmm.

  8. #8
    Join Date
    May 2010
    Location
    New Jersey
    Posts
    1,309
    Quote Originally Posted by Tom Campbell View Post
    Oversize compressor for heating, but run it at 3 ton capacity for cooling. Hmmmm.
    I didn't realize that is how they did it but it makes sense. Might have worked better if it was multiple compressors though. They rate it at 40mbtu, but don't state the ambient temp. It is rated to -22F, but they don't give its capacity at that temp. They rate the COP as varying from 3.4 to 1.4; since power probably remains constant with 15%, that would imply it loses over half its capacity. It has optional electric resistance heaters up to 17.5kw (60mbtu). It would seem a hot water coil may be a better supplemental solution, although the Zuba may not have a control mechanism for it.

    The 4-ton Nordyne can dip to 14mbtu at 60F while staying at 30mbtu at 12F. Ultimately that would come at a loss of modulation at low heating/cooling values. A conventional 2-ton is over 25mbtu at 60F.

  9. #9
    Join Date
    Aug 2010
    Location
    Monroe County, PA
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    99
    Quote Originally Posted by DavidNJ View Post
    I didn't realize that is how they did it but it makes sense. Might have worked better if it was multiple compressors though. They rate it at 40mbtu, but don't state the ambient temp. It is rated to -22F, but they don't give its capacity at that temp. They rate the COP as varying from 3.4 to 1.4; since power probably remains constant with 15%, that would imply it loses over half its capacity. It has optional electric resistance heaters up to 17.5kw (60mbtu). It would seem a hot water coil may be a better supplemental solution, although the Zuba may not have a control mechanism for it.

    The 4-ton Nordyne can dip to 14mbtu at 60F while staying at 30mbtu at 12F. Ultimately that would come at a loss of modulation at low heating/cooling values. A conventional 2-ton is over 25mbtu at 60F.
    I would go with a Nordyne if I could afford it, and that's why I'm trying to see if I can approximate the same heating effect by (mis) using an off-the-shelf 2 stage unit (different thread).

    To the Original Poster - I'm not sure where BrockVegas is, but if you're looking for a similar US solution, check out Nordyne/Broan/Fridgidair.

  10. #10
    Join Date
    May 2010
    Location
    New Jersey
    Posts
    1,309
    The question is: what are you trying to achieve? It doesn't look like an air-source heat pump maintains that much capacity in extreme conditions; does it really save operational costs when it is running at a 1.7 COP? If nat gas was $1.50/therm, electric would have to be around 9/kwh.

  11. #11
    Join Date
    Aug 2010
    Location
    Monroe County, PA
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    99
    Quote Originally Posted by IchBinKalt View Post
    Just google it, and you will find the info on it from Mitsubishi... its finding information from other sources that is difficult. But after minutes on here, I have a local guy coming by tomorrow to take a look and quote me a price. He also has some testimonials which help as well...
    Please let us know what you find out after meeting with the contractor, especially if any of the testimonials are available on public reviews websites. I'm assuming you are in Canada though, right?

  12. #12
    Join Date
    Oct 2005
    Location
    Pacific Northwest
    Posts
    2,261
    Not "over sized" but able to ramp up the speed of the compressor in colder weather instead. Big difference.

  13. #13
    Join Date
    Aug 2010
    Location
    Monroe County, PA
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    99
    Quote Originally Posted by crmont View Post
    Not "over sized" but able to ramp up the speed of the compressor in colder weather instead. Big difference.
    From my understanding of DC vs AC motors, the DC motor in this kind of system is not only more efficient, but will likely hold up better over time than the AC motors used in traditional heatpumps.

    I also understand from the above that it is not simply that it is designed for a larger capacity, so it must be either exceeding its capacity or perhaps it simply has a wider operating range than that of a standard AC motor at the lower end of the temperature spectrum? Does the "Ramping Up" involve a higher speed, or is it simply that a higher torque is required to achieve the compression needed lower temps? In either situation, does this mean that they would be going past the rated capability of the motor (or pump itself) to reach the output at lower temps? And would this have any impact on the longevity of either the motor or the pump?

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