Mr Blobby

Thank you @craig. So is it possible to transpose the above diagram to a (200mm) block cavity? If so then the blind box would be inside the cavity supported by the window and the window inside and fastened to the inner leaf (140mm) blockwork?

... or the blind box sits in the cavity with the window within the inner leaf. Which I think makes more sense.

I think its probably easier to install the blind box in a timber frame as the blind box can be fastened to adjacent timber. With a block cavity then I guess the blind box would sit under a steel on the external leaf. The top of the window is of course lower than the top of the blind box so there would be a smaller opening on the inner leaf I think. I need to get my head round the construction detail for this and discuss with my architect 🤔 Anyone done this already ?

Very interesting. Do you have a block cavity build? If so then did the head unit (140mm > 100mm block) fit flush to the external leaf and the window move into the cavity?

Any update on the Warema blinds? Trying to source windows with external venetian blinds is not easy. Internorm are clueless. Has anyone used Gaulhofer/Roma? Any other suppliers?

In the Zhender perforance data the ouput air, after being cooled, is at 100% RH, which kind of makes sense I guess because the air has been cooled. The input air is, if I am reading this correctly, at 80% RH and water temp input is at 7C. That seems a little ambitious, I'm not sure the panasonic ASHP can cool below 10C An enthalpy exchanger is relied upon in the technical data to get the extra moisture in the air to transport the heat. I imagine that otherwise the comfopost heat exchanger wouldn't work so well with dry air. Basically I agree that the comfopost will take some heat out of the air, which will be nice upstairs, but it shouldn't be relied upon as the only means of cooling.

I think it does from what I have read in the manual I don't think Panasonic support this but I would hope that 18C flow to the UFH would be warm enough to avoid condensation on the manifold umnless RH levels were >95%. I looked at the conmfo post data, I don't get how the cooling output relies on 100% humidty ! Coolind demand is ony 500W, but your'e right, there will be parts of the house without blinds that will suffer local overheating. I think I need to speak to my M and E people about using the UFH for cooling.

Sorry to ask again about my heating system but my M and E consultants are not good listeners. They are proposing two MVHR post-heaters/coolers connected to a Panasonic ASHP. The UFH to be used for heating only. I'm OK with the Comfopost post-heater upstairs but they don't want to do UFH cooling downstairs, which seems like a no-brainer to me. The M and E propsal would have 3 zones, CP1, CP2, and UFH. This just seems over-complicated, more expensive, and less efficient. Before I go on, I am very grateful to @Dan F who over the weekend has patiently answered my questions and explained his similar setup (with comfopost but a different ASHP vendor) and how mixed circuits can control flow temps on the different "zones". Before I make an ass of myself by telling my M and E people how to do their job, I just want a sanity check here first because the solution below is so much simpler and more effective than my M and E proposal that I think I must be missing something. From the latest manual it looks like Panasonic support 2 mixed circuits out of the box, with each "zone" having a pump, mixing valve and temp sensor. A single buffer can be set up to be controlled by a temp offset from the heating/cooling circuits flow temps. UK_INSTALLATION_MANUAL_H 2020V11 (002).pdf Here's page 37 from the latest Panasonic manual: So if I were to replace the radiators above with the comfopost, then I can run UFH and comfopost at different flow temps, say 45,25 heating and 10,18 cooling. This is far too simple to set up. Is this the right way to set up my system for UFH and comfopost heating/cooling. Have I missed anything? Has anyone else set up a Panasonic heat pump in a similar way with mixed circuits for heating cooling, and if so, is it really this simple?

Its funny, I think MandE consultants don't get challenged very often. At least mine don't Thinking more about the buffer connection, I can see how a 2-pipe connection is better for heating but would it be better to have a 4 pipe buffer for cooling? My setup will have a large buffer for the UFH and a smaller buffer for the heat/cool through the post heat exchanger in the MVHR. In cooling mode the Zhender comfo-post buffer would be cooled to, say 10C, while the UFH buffer to, say, 18C. Would a 4-pipe connection to the UFH buffer be better for maintaining different cooling temps? My reasoning is that the 10C flow from the ASHP would mix in the buffer before going to the UFH manifold, whereas in a 2-pipe connection it may go to the UFH directly at too low a temperature. From reading other threads I know others like @Dan F have a similar setup with seperate buffers for cooling. I would be really grateful for any advice on setting this up.

.... also, my M&E people are pretty much refusing to design any cooling of the slab, quoting the dreaded condensation argument. Which is bullshit of course at 18C flow temps. (there will be cooling through the Zhender comfo-post add on the MVHR, which I'm ok with, but it does cost an arm and a leg) Should I put my foot down and insist on cooling the slab as well.

Ahhhh, now I get it. The flow remains the same but the pump brings warm water through in the same direction with the ASHP in cooling mode to heat up the frozen bits. In that case the check valve can remain.

Thank you everyone for your very helpful answers. I will go back to my M&E guys and ask them to change to a 2-pipe connection. I'm not sure they get questioned on stuff like this very often! I like the idea of 1 less pump. I think panasonic ASHPs have a pump inside, if so then does that mean no additional pump to the buffer? That's interesting. I thought the defrost cycle sucked warm water from the buffer back into the monoblock. Have I misunderstood how this works? I don't have a copy of the schematic but from memory it includes a second smaller buffer on the cooling circuit. Is there any reason why I can't use the same buffer to simplify things? I'll try and get a copy of the schematic to explain!!

Our M and E guys didn't seem to know much about a 2-pipe connection when I questioned their schematic (with a 4-pipe connection) last week. This is the 2-pipe connection...... From what I have read, a 2-pipe connection is more efficient than a traditional 4-pipe connection. Is that really the case and do members of this forum configure their system this way? Should I ask to change to a 2-pipe connection? Or does it really matter? For background we are aming for passive build with little heat demand. Buffer to sit between ASHP and UFH. Does the flow from ASHP to the buffer need a check valve and if so then are there any defrost cyle issues

Latest Power NI E7 rate is 11.91p My Tesla averages about 270 W/mile Rounding up that's 3 miles for 12p Or 300 miles for £12 Not sure an ICE can beat that yet.

Yes but with long start times the conventional fossil plants can't shutdown overnight and are left running at minimum generation. Their efficiency is terrible, with much higher pollution and cost per MWh. I'm all in favour on renewables but that's the cost of high wind penetration overnight. And that;s why E7 will, I think be around for some time. I hope so anyway because in the winter my EV will be charging. I just hope the price of PV doesn't go through the roof before I get to install it next year.

Here in Ireland windfarms are being curtailed overnight. Free energy is being thrown away. Even at E7 prices it is profitable to supply. The UK (that has a dfifferent energy market) also has several GW lower nightime demand and too much supply. I understand that, intuitively, E7 looks fragile in light of recent price increases but the system needs it. I just don't think it will dissapear anytime soon.

I think you're right, and thank you for pointing this out. Googling around, what you say appears to be bang on, the air flow can move both ways and the ply should be inside the VCL. Looking again at my build-up, however, I'm not sure why there is a need to have the ply on top of the rafters, when the PIR could be attached directly. Maybe architect thinks the OCF between the rafters can't be sprayed against the underside of the insulation. I think I need to chat with my architect about this.

Do you think the VCL in my build-up should be above the ply then? I thought the warm moist air would come from inside the building and so a VCL underneath would potect the ply from condensation. Is that not how it works?

Its part vaulted ceiling upstairs and I like the MVHR and storage in the warm lofted bit. Also running services and light fittings from loft through ceiling is challenging if that is the airtight boundary, is it not?

I'm hoping the VCL under the ply on top of the rafters will stop condensation. Will it not?

No its a cut roof with ridge beam, no trusses.

Thanks @ProDave , that makes a lot of sense to me, and ensures continuity with the membrane that is plastered into the wall. What about insulation between the rafters? Still use OCF between rafters and then membrane under rafters?

We are finalising the construction details for our block cavity passive house and I would really like some feedabck from the group on the roof detail. The warm cut roof will be suspended on a ridge beam, so no trusses or complicated structure in the loft. The architect has suggested open cell foam to provide the air tight layer and insulation. Is this the best approach? What other options are there? For completeness, here is the roof detail: My concern with open cell foam as the airtight barrier is the risk of it not being done well, what then? I dont want to use PIR as insulation between the rafters. Open Cell Foam for air tightness - Yes or No? And if not, why not?

Node red. Very interesting, and not heard of it before so thank you for mentioning it. I have installed the HA add-in and will take a look. You're right of course but we're on a noisy stinky main road hence trying to cool with windows closed if possible. Will be interesting to see how well it works.

A few people (who suspisciously dont use ashp for cooling) warned me to avoid cold floors hence we were plannig to install some fan coils upstairs instead of using the UFH for cooling. Which introduces extra cost and complexity. Am I making a bad deceision here? Should I keep it simple and cool the floor?