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Solar Panels UK - is it worth it?
- Thread starter jdwuk
- Start date
If AC, I'd suggest not.
With DC, the numbers will depend on 4mm v 6mm etc.
However, I ran my 4mm up and down the trusses and down the outside wall ( in two runs of 20mm conduit) into my comms cupboard.
I'd say a run of under 50ft.
You can, of course, expect some losses but the solar is FOC...and not all PVs are equally efficient.
Would be interesting to see what the Inlet / Outlet temperature differences are on a really cold (or hot) day on MVHR in a somewhat leaky house.
I can't get my head around comparing a draughty house (allowing in external air) or MVHR in a leaky house (forcing air in under pressure, such that, presumably?, more of it will leak out than if the house did not have MVHR)
Will supply some stats once we have them - just inlet and outlet needed? These details still only available in our attic as LAN connection is still on back order, but happy to a couple of point samples in the mean time. We have spray foam sealing on top and bottom, and cavity and exterior EPS on the walls, but it's in no way passiv rated, and one of the old extensions turns out to be less well sealed than I though.
My thinking is, if the MVHR is designed and set up well balanced, then that's the path of least resistance for air. In the absence of any external influence/wind it should be near fully effective. As it gets windier drafts will play a bigger part and effectiveness reduces. But with no wind, the default will be for it to work almost to spec. Hence comment on exposure mattering - we are in relatively sheltered suburbia on the east coast, so I hope to get away with it (while still working on air tightness). But someone on the moors in Yorkshire permanently battered by a howling gale, air tightness will matter more.
Are you not better talking to the guys on the ground? Mine were pretty flexible, up to and including adding an extra panel on the day and letting me spec cable routes?
If they need a trench they will not want to get involved, unless you dig/organise that for them I imagine?
RedMod3
Member
I have 4 ceiling cassettes and one wall unit, it's a Toshiba Daiseikai and it is very quiet and 1m above my head. One cassette is in the lounge and the other 3 are in the long hall. Other than the lounge and main bedroom, no rooms have their own heaters or coolers as they are not needed.
Toshiba RAS-10PKVPG-E/RAS-10PAVPG-E 2.5kW 9,000btu R32 Heat Pump Daiseikai High Wall Mounted Inverter System
Toshiba RAS-10PKVPG-E/RAS-10PAVPG-E 2.5kW 9,000btu R32 Heat Pump Daiseikai High Wall Mounted Inverter System
www.airconditioningworld.co.uk
RedMod3
Member
I can set the speed of the inlet and outlet fans, and the inlet fans on the MVHR system are 2% higher than the outlet to give the property a very slightly higher pressure inside.
RedMod3
Member
No, MVHR systems have separate fans for blowing in air and sucking out air. There isn't just one fan to blow it in.
WannabeOwner
Well-Known Member
I'll be very interested to see if you get the advertised heat recovery. I'm going on what my Passive Haus consultant told me about [my somewhat compromised] air tightness, but it was enough years ago that I may have lost some details.
Good point, next time I have opportunity I'll re-ask my chap how the physics is impacted in a house that isn't air tight
phil4
Member
It's all possible. I've got inverter in the loft, mains in the middle of the house at ground level and batteries in the garage. So AC Cables running from Loft to ground floor that needed floors lifting etc, and cables running through the roof of the garage. Runs of 20+ m from house to garage via loft etc.
all good. we found the solution - it will routed around the house but only on the neighbors drive side. will be tucked behind gutter so good option
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RedMod3
Member
I suspect not having an airtight house doesn't make much difference with a slightly positive air pressure inside. I do notice that is a window is slightly open, it is very much easier to close either the front or back door.
PITA
Model 3 Performance
Our MVHR system is a hybrid.
Upstairs, is a Blauberg centralised system which has seperate ducting for room inlet, and seperate ducting for room outlet.
But...
Downstairs is a Blauberg deCentralised system, which has a seperate wall fan in each room. These seperate wall fans communicate with each other (Bluetooth) to synchronise airflow between the rooms. So as an example, for 70 secinds some might blow while others suck... and then switch around to balance airflow.
This hybrid system helps retrofitting on a decorated home with multiple floors without having ducting.
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The economics of MVHR systems is different to the physics. Practically a MVHR never recovers enough heat to pay for itself in saved heating cost. But a MVHR enables window vents etc to be removed from a building, reducing the uncontrolled ventilation can save the heating costs to make a MVHR economic.
In a well designed and build Passive home, the MVHR can advoid the need for a central heating system hence save a lot of capital costs. This is now less common as LED light builds etc reduces the background heating a house gets from normal living.
Hence I think of MVHR as a quality of life improved due to the improved indoor air quality not as a cost saving method.
In a well designed and build Passive home, the MVHR can advoid the need for a central heating system hence save a lot of capital costs. This is now less common as LED light builds etc reduces the background heating a house gets from normal living.
Hence I think of MVHR as a quality of life improved due to the improved indoor air quality not as a cost saving method.
scdoubleu
Member
now the question is this:
who has Growatt inverter and what is the best settings for it?
My aim is everyone's I believe, priority being:
1) Cover whole house load by Solar.
2) If Solar is not enough - use the battery (during peak time).
3) if there is specific time of day (23:30 - 5:30 when I have the cheapest power and no solar and I charge the car: charge battery.
any advice is appreciated
who has Growatt inverter and what is the best settings for it?
My aim is everyone's I believe, priority being:
1) Cover whole house load by Solar.
2) If Solar is not enough - use the battery (during peak time).
3) if there is specific time of day (23:30 - 5:30 when I have the cheapest power and no solar and I charge the car: charge battery.
any advice is appreciated
Mine is a cheap as chips sofar system but for what it's worthnow the question is this:
who has Growatt inverter and what is the best settings for it?
My aim is everyone's I believe, priority being:
1) Cover whole house load by Solar.
2) If Solar is not enough - use the battery (during peak time).
3) if there is specific time of day (23:30 - 5:30 when I have the cheapest power and no solar and I charge the car: charge battery.
any advice is appreciated
If I haven't enough pv it'll pull from the batteries ( I get a bit from the grid if an iron calls for heat, that'll be due to the inverter getting a bit excited).
I will put the washer- or whatever on etc when the batteries are above 80%, or we are exporting.
The car is charged at 5A....with one short smart charge every now and then.
Whilst I have a 11.30pm start cheap rate start, I now start the battery charge time at 2.30am, with the battery charge limit set at 70%.
In essence we barely pull from the grid.
What really does bug me is that I tend to get 10/40wphr import regardless . Its buttons I know.
