Results 51 to 68 of 68
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11-08-2009, 02:53 PM #51
Re: Mitsubishi ecodan Heatpump Boiler
I would love to know what compressor model these are using.
At a water delivery temp of 80'C, SCT must be >=~80'C, unless pulling a little more from the refrigerant superheat. Even then SCT must be at least 75'C.
Wonder what lifetime testing these folks have to back up their claims. I'd be intrigued.
Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
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11-08-2009, 05:13 PM #52
Re: Mitsubishi ecodan Heatpump Boiler
I'm thinking the more relevant question would be, how do they regulate/limit the heat generated by the compressor motor?
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11-08-2009, 06:44 PM #53
Re: Mitsubishi ecodan Heatpump Boiler
Anything that operates above the trans-critical stage is not going to be good for COP in order to produce 65 to 80 degrees C,granted it will have its market for retro fits which will have marginal efficiency benefits against gas/oil.
We must harness the way we heat our domestic dwellings - low temperatures that the 'normal' energy cycle provides with condensing temps of 40-50 degrees C is the main way forward.
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12-08-2009, 12:57 AM #54
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12-08-2009, 01:21 AM #55
Re: Mitsubishi ecodan Heatpump Boiler
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12-08-2009, 01:25 AM #56
Re: Mitsubishi ecodan Heatpump Boiler
^ Thanks very much, Gary. I'll follow up on their compressor range.
Engineering Specialist - Cuprobraze, Nocolok, CD Technology
Rarefied Technologies ( SE Asia )
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09-03-2010, 10:11 PM #57
Re: Mitsubishi ecodan Heatpump Boiler
I've been looking at the Daikin HT heat pump any one know what SCOP figures. I've been told likely to be around 2, which seems low. Can't get any actual performance details from Daikin, anyone got any experience?
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09-03-2010, 11:42 PM #58
Re: Mitsubishi ecodan Heatpump Boiler
If you e mail technicalhelp@daikin.co.uk with the heading of Daikin Altherma HT information and the nature of the query they will be able to help you.
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10-03-2010, 12:09 AM #59
Re: Mitsubishi ecodan Heatpump Boiler
more likely your not able to supply them with the correct criteria in order to give you an exact SCoP...hence im guessing the figure was quoted by them as worst case scenario.(THEY HAVE SOME VERY GOOD SOFTWARE SO IT IS EASY FOR THEM)
This figure is realistic at worst case up to around 2.5.
And yes you are correct for traditional cycle its not the best, but it does use two compressors utilising R410a & R134a gas as a cascade type system to boost to 80 degrees C.
Although the COP does not on the face of it seem that good, the product is MCS approved unlike alot of those out there that arent, and dont forget the government is now going to PAY people for every kwh they use from an ASHP up to around 7p per KWH up to 23 years of the systems life (dont shoot me if its 6p!)
Hence with the £900 grant plus the above - makes it the most cost effective solution now well above boilers !
hope this helps.
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10-03-2010, 06:26 PM #60
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10-03-2010, 07:37 PM #61
Re: Mitsubishi ecodan Heatpump Boiler
The high temperature units have quite a good COP compared to CO2 units. By the use of 2 compressors it does sound like a lot more energy but if you plot the compression cycle due to the cascade system the heat of compression is lower bringing the discharge pressure and temperature closer to that what a CO2 system will offer which increases the refrigeration effect making the system more efficient.(lower your head pressure and system becomes more efficient). The COP will only depend on what flow temperature you are running the system at!
Just like all of the low temperature systems out there the COP is calculated at 35 degree flow most of the time but people run the system at higher flow temperatures than required reducing the COP and wasting energy.
Daikin UK have a cash back scheme on their Daikin Altherma High temperature units and Daikin Altherma Monobloc units which is extremely attractive!!!
check this out, up to 1800 pounds cash back..
http://www.altherma.co.uk/500-cash-back/default.jsp
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11-03-2010, 01:41 PM #62
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12-03-2010, 12:28 PM #63
Re: Mitsubishi ecodan Heatpump Boiler
This is mentioned in a consultation document going through Parliament at the moment.....far off being accepted, which is just as well, as the proposal is to slap a levy on all our energy bills to pay for it.
Search for the document on line....the front page is attached below
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16-03-2010, 06:09 PM #64
Re: Mitsubishi ecodan Heatpump Boiler
Hi, very interesting thread this, keep it up. My ex-council house is fitted with the regulation baxi back boiler and i've been weighing up my options for a while, my understanding is that mitsi and daikin both have high temp versions, my only worry is that a cascade ashp means two compressors and more parts to fail etc, i wonder how this affects the long term return
also does anyone know how much these things cost GBP ?? that's assuming i can get 'em to sell me one
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26-01-2011, 04:51 PM #65
Re: Mitsubishi ecodan Heatpump Boiler
Hi there we have experienced the same problems could you PM me please
Last edited by frank; 26-01-2011 at 07:04 PM.
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26-01-2011, 04:55 PM #66
Re: Mitsubishi ecodan Heatpump Boiler
do your self a favour stay away from mitsubishi when it comes to air sourse heat pumps PM me and I will explain why
Last edited by frank; 26-01-2011 at 07:05 PM.
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26-01-2011, 05:47 PM #67
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26-01-2011, 05:52 PM #68
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