Panasonic aquarea - dual zone cooling @ diff temps possible?

[JohnMo]

23 minutes ago, -rick- said:

 

Ah, trying to make something that wasn't designed for it do cooling. I thought we were talking about things that did support it but the manufacturer didn't recommend.

Not actually come across any GSHP that do cooling out the box, Nebe have a super expensive add on kit for it, but not seen anything else.

 

12 hours ago, SimonD said:

ground source required so much additional plant and complexity, it was ridiculous - e.g. borehole  min 150m deep not ground loop and additional air batteries together with a hydronic design utilising a volumiser and the dhw cylinder to dump excess heat

I suspect all this comes about as they as they not reversible - so instead of adding the functionality to the GSHP box, they add it externally via a load complication. Not really thinking inside the box they are literally thinking outside the box.

[SimonD]

5 minutes ago, JohnMo said:

Nebe have a super expensive add on kit for it, but not seen anything else.

 Nibe is one manufacturer who makes a distinction between active and passive cooling  - they have what they call a 2 pipe system for passive and a 4-pipe system for active. It's the active system that has the expensive add on kit where iirc the passive one is marginal. I can't remember if you can access the schematics openly or whether you've got to be Nibe Pro to access them, but it's all available.

 

Nibe is one manufacturer who doesn't seem to shrug their shoulders regarding cooling but is careful to advise on proper system design.

[SimonD]

1 hour ago, -rick- said:

f you use a GS heat pump to cool a property the heatpump is actively heating the ground during this time. The problems with ground source I thought were more with the ground freezing when you try to pull too much heat from it during winter. Didn't think adding heat to the ground during summer was a big issue comparitively.

 

This is what I thought too. And I thought that using cooling could be advantageous to recharge the soil for the next winter. However, it was explained to me that the ground loop system can't take the quantity of heat dumped into it which therefore reduces the hp cooling capacity. Apparently the borehole solution can take the dumped heat.

 

You don't see the same behaviour with ashp of course because it's dumping the heat to the atmosphere and you're limited to the units ability to transfer the heat. This is why you might employ an air battery such as a fan coil unit to assist the gshp to dump heat outside the ground.

 

Tbh, modelling the thermal behaviour of the ground is beyond my knowledge at the moment, so I'm kind of accepting their wisdom in this until I see some evidence to the contrary.

[SimonD]

2 hours ago, jack said:

I've used underfloor cooling for nearly 10 years (didn't use it the first two or three years after we moved in) with great success and zero issues.

 

Panasonic's UK technical team were hugely supportive while I was trying to get the ASHP working efficiently in UFH mode, but they were very cold (pardon the pun) on the idea of underfloor cooling. I think there's just a strong bias in the undustry against it, probably due to a combination of risk-aversion and ignorance.

 Absolutely. I've just completed an installation with a new ashp and when commissioning the thing I found some new stuff within the control software and some behaviour of the system that wasn't covered anywhere in the manuals. So I made my list of questions, called up technical support and in a tone that suggested they though I was an idiot, they told me that what I was asking either wasn't possible or wasn't implemented - but I played with it anyway and my tests show that what they told me was incorrect. It's not the only time tech support have told me the wrong thing even with Gas boilers and controls.

 

I think the nature of this forum is that we're happy to push the boundaries and take some risks whereas the manufacturers have to cover their backs, just as I do with a system installation.  You know you have to when you try to explain system flow temperature and they look at the thermostat quizzically telling you that it says 21....not 55

[-rick-]

53 minutes ago, SimonD said:

This is what I thought too. And I thought that using cooling could be advantageous to recharge the soil for the next winter. However, it was explained to me that the ground loop system can't take the quantity of heat dumped into it which therefore reduces the hp cooling capacity. Apparently the borehole solution can take the dumped heat.

 

This doesn't really match what I've seen before (though again it's been a while). I suspect this is a case where they are thinking aircon not cooling and designing for the 'cool a hot room down rapidly' type situation with all its other complications.

[SBMS]

14 hours ago, JohnMo said:

is just complexity for the sake of it.

I’m not doing it for the sake of it and I really don’t follow this logic - I don’t know where summers and temperatures will be in ten years - and I don’t know exactly how the house will respond to summer temperatures until I’ve actually built and lived in it. Why the aversion to a proposed system that can do exactly what you suggest (run at above dew point) but also have the capability to run lower for the sake of a mixer valve and temperature sensor? 

 

I can’t understand why future proofing in most contexts is seen as a good thing by self builders but I seem to be proposing heresy here in giving more flexibility 🤷‍♂️

Edited 10 hours ago by SBMS