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JamesPa
@jamespa
Moderator
Illustrious Member
Joined: Apr 3, 2023
Last seen: Jul 25, 2025
Topics: 16 / Replies: 2638
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RE: Avoid the Heat Pump Villain: Why Low-Loss Headers and Buffers Can Sabotage Your Heat Pump's Efficiency

@tim441 if you want to you can work out roughly how much it's costing by measuring the temperature drop across the buffer flow to flow. The cost is r...

5 months ago
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RE: Avoid the Heat Pump Villain: Why Low-Loss Headers and Buffers Can Sabotage Your Heat Pump's Efficiency

15% or more typically The problem is not loss of energy (which as you say is small) its reduction in flow temperature to the emitters (due to the mi...

5 months ago
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RE: Heat loss calculators and spread sheets

Pretty much that, basically (1) make sure that the fabric model represents the actual fabric and (2) adjust the ACH to fit measured loss. Here is th...

5 months ago
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RE: Fujitsu Waterstage WOYG160LJL Air Source Heat Pump

As long as they follow the weather compensation I wouldn't worry for now, You probably won't want room influence anyway. If they aren't following th...

5 months ago
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RE: Fujitsu Waterstage WOYG160LJL Air Source Heat Pump

3 times per hour is reasonable. Are you sure it isn't doing defrost rather than cycling because of overcapacity?

5 months ago
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RE: Heat loss calculators and spread sheets

@lakey Do you have half hourly or daily readings and what was the heating pattern. Basically my ashp was sized on gas meter readings and the fabric s...

5 months ago
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RE: Twin 10kw Grant Aerona Volumiser Tanks using lots of power

Thats the only logical explanation because for their main function they emphatically dont. Could be, then once he had received them he realised t...

5 months ago
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RE: Heat loss calculators and spread sheets

I remember thats where you started (conservatism in heat loss). What do you actually know in total about heat loss. Do you have any consumption fig...

5 months ago
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RE: Fujitsu Waterstage WOYG160LJL Air Source Heat Pump

Once its running at lowest possible FT you might be able to reassess the operating mode when its mild. Depending on your house, when its mild (which ...

5 months ago
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RE: Heat loss calculators and spread sheets

Fair enough. Obviously you understand that you will take a running cost hit but all designs are a trade off. 45 is often a good compromise for radia...

5 months ago
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RE: Twin 10kw Grant Aerona Volumiser Tanks using lots of power

I still am not sure you get the point of volumiser tanks. They add water volume to the system. They don't need power. Grant and others take the op...

5 months ago
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RE: Heat loss calculators and spread sheets

Are you saying your design flow temperature (at the lowest oat) for the ashp system is 55C? Fans on fancoils do run constantly, but with a decent...

5 months ago
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