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Author Topic: Advice for a PV newby in Sheffield please :)  (Read 5262 times)
Pressure
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« Reply #75 on: July 25, 2017, 10:47:49 AM »

Many thanks for all the kind words, folks Smiley

Sean, the self-consumption estimate of 67% might be attainable but it's quite a strong assumption. With an ASHP and an Immersun (or similar) I probably can self-consume lots of the generation. 67% is a bit of a stretch.

FWIW I reverse-engineered the forecast model in a spreadsheet and checked what happened if I changed the self-consumption percentage. Payback period wasn't that sensitive to it.

The battery option is a big question. I have not said yes to it yet because even at 2650 the RoI is marginal - but if anyone thinks it's definitely a good idea at that price, do please shout now!

I was so tempted to go 360W just because it's such new, interesting technology but the cost per KW / absolute price (over 10K) was a bit of a stretch.
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M
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« Reply #76 on: July 25, 2017, 12:04:13 PM »

Regarding batts, someone has to jump first, but I'm still of the opinion that costs are just too high. Also prices may well fall faster than any savings, so I'm staying tight for another 2 to 3 years, but have multiple digits crossed.
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Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
Sean
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« Reply #77 on: July 25, 2017, 12:38:32 PM »



Sean, the self-consumption estimate of 67% might be attainable but it's quite a strong assumption. With an ASHP and an Immersun (or similar) I probably can self-consume lots of the generation. 67% is a bit of a stretch.

FWIW I reverse-engineered the forecast model in a spreadsheet and checked what happened if I changed the self-consumption percentage. Payback period wasn't that sensitive to it.



My thoughts were that 67% was low  Smiley

Does that surplus diverter allow for a secondary load ? so if AHSP and HW tank is satisfied you can make use elsewhere, even into a heated towel rail - no thoughts of how it will improve your ROI, just on the basis that if you can, you should.
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Pressure
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« Reply #78 on: July 25, 2017, 01:36:32 PM »

Thanks Sean. I believe the diverter suggested is the Marlec Solar iBoost (https://www.marlec.co.uk/wp-content/uploads/2016/01/Solar-iBoost-Manual-v2.pdf). It looks to me like it deals with just one heater. The Immersun handles three as you probably know. Either way, I *think* I only really have one available - the immersion unit in the ASHP control unit - although I'm a bit hazy about this Smiley.

In other news, the DNO confirmed today that our export limit is 5K, which is nice to have! Though obvs I'd like to use it all.
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M
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« Reply #79 on: July 25, 2017, 02:43:31 PM »

In other news, the DNO confirmed today that our export limit is 5K, which is nice to have! Though obvs I'd like to use it all.

5kW will be fine. Once they are hot (in direct sun) panels will rarely sustain more than 80%, so 6kWp x 80% = 4.8kW. If you had side by side systems with one having 6kW+ of export approval, I'd guess/suggest that there would be little to any difference in annual generation. There's even an argument that in the UK undersizing an inverter about 10-20% is adviseable to boost low generation efficiency.

So no worries, sounds like a great set up.
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Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
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« Reply #80 on: July 25, 2017, 03:11:39 PM »

Thank you very much for your advice M - and to all the kind people on the forum!
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gnarly
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« Reply #81 on: July 25, 2017, 11:22:04 PM »

Did you think any more about the mix of panel directions?  For example all south facing (although that may not quite line up with the house?).

I have south-east facing panels and it is great for morning power but definitely tails off at 3-4pm.  There is only a small contribution to cooking the dinner Sad.  i think a mix of south-east and south-west would be more optimal, keeping a steady supply of solar power with a battery.
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Pressure
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« Reply #82 on: July 26, 2017, 12:47:39 PM »

Yes gnarly - Gavin has adjusted the direction a bit for the different sections of panels.
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Pressure
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« Reply #83 on: August 01, 2017, 08:44:48 AM »

Two words: install day!

Now the day is upon us, here are my last minute fears that add to the drama:

1. The kit is arriving separately from the crew. Our access is quite tight so will the truck be able to get near enough to drop onto our property?

2. Will they be able to get the cable down the existing duct, which is for the ASHP? Gavin thinks so - lets see!

3. Will they be able to connect the Immersun into the ASHP easily? Daikin sounded very confident and Leeds Solar have done it before but it's all new to me!

4. Weather is good this morning but it's looking like there'll be occasional heavy rain this afternoon - I wouldn't fancy being on the roof in a storm.

Excited!
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todthedog
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« Reply #84 on: August 13, 2017, 06:53:30 AM »

All up and working? fingers crossed!
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TheFairway
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« Reply #85 on: August 15, 2017, 08:01:26 AM »

+1

Do say
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3.995kWp SE PV. 5kW Burley Hollywell woodburner. Vent-Axia Sentinel Kinetic Plus MVHR

All posts are my own personal thoughts and opinions and do not represent those of my employer, clients or partners.

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