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Poor COP with an Ecodan

adam_colwell · 2023-11-28T12:15:14Z

Hi Guys, I'm hoping you may be able to help. I'm getting (I think) poor COP. In November so far I'm getting a cop 2.39, with heating being a cop of 2.71 and DWH being 1.65. My heating is weather compensation with a flow rate which doesn't go higher then 30c at -2 outside and the DWH is set at 45c with it heating back up when it drops by 12c. All rads are fully open upstairs and downstairs we have underfloor heating. Thermostats are set at 23c with room temperature of around 21c downstairs and upstairs of around 20-19c. I've attached pics of my readings and the model.

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Air Source Heat Pumps (ASHPs)

Last Post by Derek M 3 years ago

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Gary

(@gary)

Reputable Member Member

Joined: 4 years ago

Posts: 350

03/12/2023 3:43 pm

@adam_colwell is the unit running or it couldn’t be doing a defrost as the flow and return are the nearly the same. if not check again when it is. It’s only THW1 and 2 you are interested in.

THW5 is the temp of your HW TH7 is the outside temp.

Your flow rate of 14 is low try increasing it to 4 and recheck the flow rate that may improve your COP.

but as you are using a low amount of energy and assuming your house is as warm as you want it to be then I wouldn’t worry

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adam_colwell

(@adam_colwell)

Active Member Member

Joined: 3 years ago

Posts: 21

Topic starter 03/12/2023 3:46 pm

@gary yeah the unit is currently running. So I should wait until it stops and see the temps then?

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Gary

(@gary)

Reputable Member Member

Joined: 4 years ago

Posts: 350

03/12/2023 4:09 pm

@adam_colwell no the unit needs to be running but the temps weren’t any different try again in a bit see if they have changed

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 6 years ago

Posts: 4425

03/12/2023 4:12 pm

@adam_colwell

Let me see now, if everyone had a smaller, well insulated home, would we need all these wind and solar farms, and the vast amount of grid upgrading?

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adam_colwell

(@adam_colwell)

Active Member Member

Joined: 3 years ago

Posts: 21

Topic starter 03/12/2023 4:36 pm

@derek-m sorry, you have lost me. Its all proportional, I'm just trying to make sure my system is running the best it can. I understand people will be using more Kwh then me to heat their home, I'm trying to break it down to Kwh/m2 and reduce that to lowest is possible can be.

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adam_colwell

(@adam_colwell)

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Joined: 3 years ago

Posts: 21

Topic starter 03/12/2023 4:39 pm

@gary I've turned the pump up to 5 and both TW1 and TW2 are currently at 27c

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Derek M

(@derek-m)

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Joined: 6 years ago

Posts: 4425

03/12/2023 4:49 pm

Posted by: @adam_colwell

↑

@derek-m sorry, you have lost me. Its all proportional, I'm just trying to make sure my system is running the best it can. I understand people will be using more Kwh then me to heat their home, I'm trying to break it down to Kwh/m2 and reduce that to lowest is possible can be.

Sorry Adam, my comment wasn't directed at you, I was being facetious as usual.

In other threads we have recently been discussing how much upgrading the electricity grid will require, as people change to Electric Vehicles (EV's) and install heat pumps, solar PV and battery storage, and who will have to pay for this.

I also have to smile when people come on the forum asking why it is costing an arm and a leg to heat their 'mansion' using a heat pump.

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 6 years ago

Posts: 4425

03/12/2023 4:57 pm

Posted by: @adam_colwell

↑

@gary I've turned the pump up to 5 and both TW1 and TW2 are currently at 27c

You need to reduce the pump speed to increase the DT.

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adam_colwell

(@adam_colwell)

Active Member Member

Joined: 3 years ago

Posts: 21

Topic starter 03/12/2023 5:01 pm

@derek-m okay, I've decreased it to 1 and have a flow rate of 10 liters per minute

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adam_colwell

(@adam_colwell)

Active Member Member

Joined: 3 years ago

Posts: 21

Topic starter 03/12/2023 5:03 pm

Right, now I have TW1 at 33c and TW2 at 31c

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Derek M

(@derek-m)

Illustrious Member Member

Joined: 6 years ago

Posts: 4425

03/12/2023 5:32 pm

Posted by: @adam_colwell

↑

Right, now I have TW1 at 33c and TW2 at 31c

You should not worry too much about the DT, if your heat pump is keeping your home warm in an efficient manner. If you have a low flowrate and low DT, then your home must not need a vast amount of thermal energy.

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