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Jon Glanfield
09-03-2011, 07:43 PM
Has anyone heard about Mitsi having to revise their performance figures and or max outputs at low ambients?

Anecdotally apparently their quoted figures are wrong. Due to projects that have gone wrong these have been brought into question and revisions are now required.

I'd be interested to hear if anyone knows about this, I am at 1 of their conferences next week where they are revealing their split and will ask some questions about the above.

Jon

mad fridgie
09-03-2011, 08:04 PM
I know in NZ there has been a lot of issues on how heat pumps are being rated, especilally at lower temps than the standard 7C outdoor ambient. (primarily air to air)
A Kw rating is a snap shot of the duty for one second (Kj/s) so many take this snap shot to show the units performance example 4.2Kw with a relevent COP, whilst other rate theirs on an averaged Kw rating taken over a time scale which includes the defrost. So a similar machine would be rated at 3.5Kw (averaged) with what seems to have a much lower COP. The suppliers who use the first option have a marketting advantage (to hard to expalin the difference to the average joe blow), how ever you tend to get a lot less hassles with those who machines are sized over an average (second method) relating issues of under performance.
I also alot of issues with min, max and nominal ratings. Some machines can only run at max for a fixed time periods, while other can run as long as they want, as long as certain technical limits are maintained. (primarly important when you area to be heated starts from cold), with inverters the nominal ratings are at present speed, to atain max efficiency (for rating only) has little to do with real time efficiency, so many are a little upset that there heating bills are not reduced by as much as expected.

mad fridgie
09-03-2011, 08:24 PM
How many times do you see heat pumps marketted with head lines sales pitches of
" Works to as low as -20C ambient"
" Can heat water upto 65C"
" COPs of upto 6"
" Up to massive *** KW output"
There are so many in the industry who do not know the complexity of the how the statements are produced, how the hell are mum and dad to dicifer the info.
Most of use regardless of what we are buying, understand that there is bit BS around stated claims, but would expect to get something close, to the claim, but with heat pumps (as sorted indicated above), you would be unlikely to get 65C water at -20C ambient, you would not have a great COP and you certainly would not get a massive heat output. It would be nice to see real data that mum and dad could understand, but I am just a dreamer

al
09-03-2011, 08:56 PM
I notice Mitsubishi have always listed a Uk output which is lower than the average figures quoted, marketing is certainly king in this arena!

alec

Bigfreeze
09-03-2011, 09:18 PM
This is why Europe are moving towards SPF's rather than COP. You won't get a grant in Germany unless you fit your unit with a performance monitoring unit and prove your SPF, the level of grant you receive depends on the outcome.

mad fridgie
09-03-2011, 09:37 PM
SPFs??????????????

al
09-03-2011, 09:41 PM
seasonal performance factors i think, supposed to be an average of a years running, not a snapshot?

alec

MikeHolm
10-03-2011, 02:29 AM
Try this one. It's a comparison of a York, Acadia and Mits Slim HPs. I don't think it is a CO2 model but the performance claims and low temperature claims are similar. We use HSPF as well ("H" being heating duh...) but the methodology might be a bit different from the European way of determining SPF. I'll have to look it up.

www.energy.gov.yk.ca/pdf/yukon_airsource_heatpump_mar_2010.pdf

MikeHolm
10-03-2011, 02:30 AM
Speaking of grants, you won't get one here unless it is EnergyStar rated ($$$$$):mad::rolleyes::mad::rolleyes: