joth Posted March 27, 2022 Share Posted March 27, 2022 13 hours ago, Eric said: Sorry to hijack this thread, I have a new build starting soon & never gave any thought to having solar but times are a changing. If you've not yet started the build, put your thoughts into adding more insulation and airtightness. Solar PV can be retrofitted quite easily later in the project. Insulation can't. Link to comment Share on other sites More sharing options...
SteamyTea Posted March 27, 2022 Share Posted March 27, 2022 8 minutes ago, joth said: Solar PV can be retrofitted quite easily later in the project Roof integrated PV can't, and it costs no more than some roof tiling. Link to comment Share on other sites More sharing options...
Thorfun Posted March 27, 2022 Share Posted March 27, 2022 4 minutes ago, SteamyTea said: Roof integrated PV can't, and it costs no more than some roof tiling. and, if aesthetics are important to you, it looks a lot nicer. Link to comment Share on other sites More sharing options...
JohnMo Posted March 27, 2022 Share Posted March 27, 2022 12 hours ago, SteamyTea said: Not in practice. The times when windspeed is low, solar radiation high, along with high air temperatures are very rare, and the solar radiation levels are probably higher than STP for the modules, so they would be over performing anyway. There is a test on the various mounting methods, (found it in the internet by a UK institution) which look at performance of the PV modules over the year in the UK. The difference was so small it was pretty much meaningless. As said only a very small window where the performance gets downgraded. If we lived in Spain it would be different. The further north you are, then even less of an issue. Link to comment Share on other sites More sharing options...
joth Posted March 27, 2022 Share Posted March 27, 2022 1 hour ago, SteamyTea said: Roof integrated PV can't, and it costs no more than some roof tiling. Sure but until the roof structure is up theres still chance to change that. Whereas insulation under floor and in the walls will effect the groundworks so needs deciding far sooner, that's the point. Link to comment Share on other sites More sharing options...
Eric Posted March 27, 2022 Share Posted March 27, 2022 1 hour ago, joth said: If you've not yet started the build, put your thoughts into adding more insulation and airtightness. Solar PV can be retrofitted quite easily later in the project. Insulation can't. We have carried out the groundwork, we are waiting for the kit to be made. Scotframe closed kit, highly insulated. If we were to do it we would want to go for integrated ones. Link to comment Share on other sites More sharing options...
MikeSharp01 Posted March 27, 2022 Share Posted March 27, 2022 1 hour ago, JohnMo said: found it in the internet by a UK institution LINK! Link to comment Share on other sites More sharing options...
JohnMo Posted March 27, 2022 Share Posted March 27, 2022 Here is one report, not sure if it's the one I was looking at. 08_In-roof_Performance_of_PV (1).pdf Link to comment Share on other sites More sharing options...
bobberjob Posted March 27, 2022 Author Share Posted March 27, 2022 So getting back to the question - solar pv is not viable in the winter as an alternative? Link to comment Share on other sites More sharing options...
SteamyTea Posted March 27, 2022 Share Posted March 27, 2022 11 minutes ago, bobberjob said: So getting back to the question - solar pv is not viable in the winter as an alternative? Have you run some scenarios on PVGIS? Link to comment Share on other sites More sharing options...
bobberjob Posted March 28, 2022 Author Share Posted March 28, 2022 Sorry Steamy what is PVGIS please? Link to comment Share on other sites More sharing options...
SteamyTea Posted March 28, 2022 Share Posted March 28, 2022 5 minutes ago, bobberjob said: Sorry Steamy what is PVGIS please? It is probably the best site to assess PV production. This is the link. https://re.jrc.ec.europa.eu/pvg_tools/en/ Not sure if it works on a mobile. Link to comment Share on other sites More sharing options...
Christiano Posted March 29, 2022 Share Posted March 29, 2022 On 27/03/2022 at 21:42, bobberjob said: So getting back to the question - solar pv is not viable in the winter as an alternative? We live in Kent and have 11kW of panels (8.6kW of inverters). On our best days we can generate >60kWh in summer and we generated 45kWh on a perfect day a couple of weeks ago. There are always days in the winter though when we only generate 1.5 and rare days when we don’t even make 1. These often come together so we would need at least double our normal daily usage in battery storage and thinking about it there wouldn’t have been enough in the days leading up to a 2-very-grey-day period to fully charge those batteries. So I would say “no” to your question unless you can provide a significant proportion of your annual consumption for battery storage or maybe if you go to sunnier climes for our winter (wouldn’t that be nice!). Our normal daily usage prior to ASHP was about 24kWh, I think our highest with ASHP was a cold day in late November and we used about 70kWh. Like another poster above, we generate roughly what we use (9mW/year before ASHP) but could only use half of it. It will probably change quite a bit now we have 8kWh battery and ASHP. Link to comment Share on other sites More sharing options...
SteamyTea Posted March 29, 2022 Share Posted March 29, 2022 28 minutes ago, Christiano said: Like another poster above, we generate roughly what we use (9mW/year before ASHP) but could only use half of it. It will probably change quite a bit now we have 8kWh battery and ASHP. I can see the ASHP helping to use up PV generation as that has displaced another energy source. Don't see how a battery makes a great deal of difference, unless you use a lot of energy during hours of darkness. Not as if modern lighting used much (though some in here seem to think they need a kW of LEDs to get them in the mood). A large TV with sound system may burn though a bit, but 8 kWh, probably not. Instantaneous electric showers may help, but even a 10 kW one is pretty pathetic compared to one run off a cylinder. Link to comment Share on other sites More sharing options...
Christiano Posted March 29, 2022 Share Posted March 29, 2022 5 hours ago, SteamyTea said: Don't see how a battery makes a great deal of difference, unless you use a lot of energy during hours of darkness. Before we got the battery I did some analysis and we typically used 8-12kWh outside solar generation hours without the heat pump. We have a pretty high base load, about 500W before battery and heat pump. Link to comment Share on other sites More sharing options...
SteamyTea Posted March 30, 2022 Share Posted March 30, 2022 7 hours ago, Christiano said: We have a pretty high base load, about 500W before battery and heat pump. That would heat my house. Why is it so high? Link to comment Share on other sites More sharing options...
dpmiller Posted March 30, 2022 Share Posted March 30, 2022 1 hour ago, SteamyTea said: That would heat my house. Why is it so high? because they're a normal family? 1 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted March 30, 2022 Share Posted March 30, 2022 4 minutes ago, dpmiller said: because they're a normal family? Yes. I notice that at my Mother's house. Seems to be pulling ~250W constantly. Link to comment Share on other sites More sharing options...
bobberjob Posted March 30, 2022 Author Share Posted March 30, 2022 I filled in the PVGIS which shows summer max of 1200 kWh and winter low of 200 kWh. I’m presuming that this is an average for the month so some days would be higher and some lower. it’s quite complicated but at first glance the simulation shows 20% loss on a 10 kW system. does this fit in with anyone else’s experience? Link to comment Share on other sites More sharing options...
Christiano Posted March 30, 2022 Share Posted March 30, 2022 6 hours ago, SteamyTea said: That would heat my house. Why is it so high? 3 fridges, 3 freezers (don’t ask!), fish tank and fish pond. The battery doing nothing is about 50W and the heat pump uses 150-230W. Link to comment Share on other sites More sharing options...
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