HIGH COP Heat Pump

[mad-dawg]

HI
I have a project where I need a heat pump system VRF or split with a COP of 6 or more!
The system will only be used for heating.
I have tried the big names and the highest they can offer is COP 5.5 - 5.7
This is with an ambient of 15°C and room 19°C.
I can fiddle with temperature day numbers to get an artificial SCOP but I need a base COP for approval.
Question is;
Does anyone know of a system (without hot water heat recovery etc) that can get to this?
Am I missing something in the selection process that will boost the COP? (e.g oversized evaporator)
Thanks

[install monkey]

what about them gas fired sanyo's ghp?? oops cop of less than 2 but 71kw off a 5a supply-dont know how much gas they guzzle!

[install monkey]

found this on daikins home page -where the cop of 9 comes from i dont know! Daikin’s heat pump and heat recovery systems
Daikin’s highly efficient heat pumps provide either heating or cooling for shops, offices or industrial buildings, while its heat recovery-equipped systems provide simultaneous heating and cooling for offices or industrial buildings, all from a single system.
What is heat recovery?
Heat recovery is achieved by diverting exhaust heat from indoor units in cooling mode to areas requiring heating. Heat recovery in other words helps you reuse the energy available in one or more areas, and dispatch it to other areas in the same building. Heat recovery systems achieve the highest COP levels in the industry (up to 9*), making these systems the champions of energy efficiency.
Wide range on offer
Daikin offers numerous heat pump and heat recovery systems to match your needs. They come in configurations connecting a single outdoor unit (4 to 54 HP) up to 64 indoor units, and supporting no less than 14 different types of indoor units.
* REYQ8P8 50% cooling - 50% heating load.
Conditions: outdoor temperature 11° CDB, indoor temperature: 18° CWB, 22°CDB




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[Greengrocer]

The only Heat Pump system I know of with a published COP of 6+ is a tiny 1.8kW Hitachi High Wall 1:1 split system - SX8 series which ahs a COP=6.36. Fine for an average size bedroom but no much else. The COP of the larger sizes in this range drop below 6 & the largest 3.5kW system has a COP of "only" 4.28.

What's the application & what sort of capacity / size of system do you need?
What's driving the need for a COP of 6+?

I very much doubt whether any Air to Air VRF/VRV system will achieve a COP of 6 in real world conditions unless you frig the numbers & rating points.

Daikin have recently released a heating only VRV Air to Air system (RXHQ) but I don't know what the COP figures are (probably not much better than the std reversible HP or 3 pipe systems).

[taz24]

.

I think that in reality the reason why you can't get manufacturers to publish claims
of COP's in the 6's and 7's is basicaly because those numbers are only atainable
under test conditions with every single know peramiter set exactley correct.

In real life COP's in the high 4's and perhaps low 5's are more to be expected unless
you jiggle the numbers to get the result you want.

Just my opinion.

taz

.

[Greengrocer]

Yep. Just the car manufacturers fuel consumption figures which none of us can replicate in the real world even when we drive like a hearse!
Sounds to me like some "pen pusher" somewhere has plucked a number out of the air which is not attainable - at present.

[taz24]

Yep. Just the car manufacturers fuel consumption figures which none of us can replicate in the real world even when we drive like a hearse!
Sounds to me like some "pen pusher" somewhere has plucked a number out of the air which is not attainable - at present.

I agree with you.

In fact I use the car fuel analogy as an example.

We know car manufacturers say their car will do 55MPG but do we belive them? No we understand
that that is a guide and is only true if all conditions are perfect.

So why do we expect heat pumps to deliver consistantly high COP's???

If you are dealing with Ground sourced heat pumps you can stabalise the COP all year
round because the ground temp is stable. But Air sourced heat pumps have so many
variables as to be impossible to claim COP accurately.

taz

.

[S_Line]

If speccing a VRV you could use a heat recovery VRV system, would be inpossible to work out though.
If a server room requires cooling and a open plan reception requires heating, COPs would be really high ? i would presume.

Speccing a system with 15 degrees ambient is just not in the real world
When ambient gets down to 0 which it certainly does, COPs drop like a lead balloon.

[Greengrocer]

I agree with you.

In fact I use the car fuel analogy as an example.

We know car manufacturers say their car will do 55MPG but do we belive them? No we understand
that that is a guide and is only true if all conditions are perfect.

So why do we expect heat pumps to deliver consistantly high COP's???

If you are dealing with Ground sourced heat pumps you can stabalise the COP all year
round because the ground temp is stable. But Air sourced heat pumps have so many
variables as to be impossible to claim COP accurately.

taz

.

Talking of ground source heat pumps take a look at this video - a system with a COP of 15 to 20!!
I haven't watched it in detail yet & it seems to be conveniently "light" on detail however, the one thing that stood out was that this system does not use a compressor. Begs the question what are they using as the motive force & what refrigerants etc etc. http://www.youtube.com/watch?v=i_ZwxXIa0fI
It's probably no good for the OP's application but interesting none the less.

[Bigfreeze]

Talking of ground source heat pumps take a look at this video - a system with a COP of 15 to 20!!
I haven't watched it in detail yet & it seems to be conveniently "light" on detail however, the one thing that stood out was that this system does not use a compressor. Begs the question what are they using as the motive force & what refrigerants etc etc. http://www.youtube.com/watch?v=i_ZwxXIa0fI
It's probably no good for the OP's application but interesting none the less.

Evaporating at 51.4C from 300m of ground loops!!! who's that guy trying to fool. What a load of twaddle. Only if the loops are laid in a geothermal Spring!!!

[mad fridgie]

Evaporating at 51.4C from 300m of ground loops!!! who's that guy trying to fool. What a load of twaddle. Only if the loops are laid in a geothermal Spring!!!
love it, I think they invented jet refrigeration, no thats not right, I am sure Noahs son invented it, when he was bored on the ark. But he was very proud!
So if i read this right, and i may be wrong, he is trying to cool ground that is well above 50C, with ground that is say 25C, water at 18C and air close to 0C.
I have just invented a refrigeration system that will achieve the same results with a COP of 1,000000000000000000000000000000000000000000000000000000000000000. and a bit more
I think I will call it a "HEAT PIPE" original.

[mikeref]

Nah he's warming the ground and the temps 38 something degrees 18 cm below the snow:confused: and all this done without a compressor. And, Mad, there are too many zero's without the comma's. The flow meter has one screw missing in his vid and it's hard to read figures. Pretty much lost concentration then. ZZZZZZzzzzzz...

[Bigfreeze]

And the snow is happilly sitting away on 50 degree earth. I want to visit this magical land!!

[mikeref]

What's that movie of make believe?? Cronicals of Narnia or something. why am i surprised that this guy's project is in some shed out-back of no-where. Where does the 51*c temperature come from in that enviroment?

[MikeHolm]

It's a CIA black box technology and the originator met an untimely demise under questionable circumstances. These guys are obviously imposters.

[MikeHolm]

They might even be aliens

[stanleyzhao]

HI
I have a project where I need a heat pump system VRF or split with a COP of 6 or more!
The system will only be used for heating.
I have tried the big names and the highest they can offer is COP 5.5 - 5.7
This is with an ambient of 15°C and room 19°C.
I can fiddle with temperature day numbers to get an artificial SCOP but I need a base COP for approval.
Question is;
Does anyone know of a system (without hot water heat recovery etc) that can get to this?
Am I missing something in the selection process that will boost the COP? (e.g oversized evaporator)
Thanks
COP of 6 or more is definitely possible for ground source heat pumps (GSHPs). If it's a air source heat pump (http://www.waveheatpump.com) (ASHP), the COP should be 4-5 in the ambient of 20C or so.