Circular reasoning (Rolfe's solar energy system)

[johnb80]

Yes, but running a fan heater in the evening rather than fire up the central heating is a strictly small-scale operation, only good for two or at the most three hours.

Electric resistive heating whilst 100% efficient is very power hungry, AC Units are the way to go you would have used less than 1/3 of that energy.

John, I live 760 feet up in the hills at 55 degrees north. Air conditioning isn't even on my radar.

Entirely your choice of course but it's the only efficient way to heat with electricity. All other forms of electric heating only manage 100% efficiency, AC can do it with an apparent 300% plus.

 

[Rolfe]

Well, I was thinking AC was all about cooling and not for me, but it could be something to think about. All advice welcomed. It would be handy to be able to use extra in the battery for warmth on a cool summer evening, without firing up the central heating, but two hours isn't really enough to do it. It was only useful last night because I'd been out and didn't get home and settled in front of the TV until ten.

I'm certainly not switching this house's heating to heat pumps. I didn't know there was a way to heat an individual room with a stand-alone appliance in the way you suggest. I would certainly be interested in using a bit of battery power for evening heating of a single room, but there doesn't seem to be a huge amount to spare.

It's brightening up here quite a lot now and the battery has reached 96% charge despite being depleted somewhat by the car charge earlier. I saw a peak of 7.6 kw in the solar input just before 2 o'clock. I also see the house load shooting up and down which I presume is the Eddi getting in on the act and grabbing power when it's available to heat the water. Really clever, as someone said.

I can see the sun coming out a bit about nine and the battery charging with whatever it can grab over and above the house load. I can see the car charging on the Zappi around about eleven, taking most of its 2 kwh from the battery but grabbing 0.3 kwh from the grid when the battery's discharge parameters were exceeded. The battery then gets back to charging what it can, and then around one-thirty the Eddi starts grabbing what might otherwise have been wasted export to heat the water tank.

The solar output hasn't clipped yet because the battery has never been full, but any minute now.

 

[Archev]

Well, I was thinking AC was all about cooling and not for me, but it could be something to think about. All advice welcomed. It would be handy to be able to use extra in the battery for warmth on a cool summer evening, without firing up the central heating, but two hours isn't really enough to do it. It was only useful last night because I'd been out and didn't get home and settled in front of the TV until ten.

I'm certainly not switching this house's heating to heat pumps. I didn't know there was a way to heat an individual room with a stand-alone appliance in the way you suggest.

Impressive figures there.
Sounds fantastic

I’ve been trying infra red panels lately. Much cheaper than the electric boiler and only heat when I want them.

 

[Rolfe]

One thing that surprised me was just how MUCH power it's taking to heat the water with the immersion heater. I never used it a great deal, because the oil-fired central heating took care of it and the "cost" was just hidden away in the overall oil account. I used to let the boiler run all summer just to handle the water heating, if it wasn't cold enough to need central heating, and didn't notice how much oil it took. But it's a fair old whack of electricity. Which is good, right now, because it would otherwise be exported for £0.00.

 

[Bam Bam]

If youre on IOG thats not the best way to operate, FIT not being available nowadays.

If you are on IOG [sorry - meant Intelligent Flux, which we are on!] you don't get a choice - they choose the import/export levels for your battery. That's the price you pay for getting 28p during the peak, but it also takes the thought out of it for me as Octopus are constantly tweaking the settings and I don't need to do anything.

One thing that surprised me was just how MUCH power it's taking to heat the water with the immersion heater. I never used it a great deal, because the oil-fired central heating took care of it and the "cost" was just hidden away in the overall oil account. I used to let the boiler run all summer just to handle the water heating, if it wasn't cold enough to need central heating, and didn't notice how much oil it took. But it's a fair old whack of electricity. Which is good, right now, because it would otherwise be exported for £0.00.

Yes any kind of heating is massive (as would be cooling in hot countries). Hot water and space heating. We only have electric immersion but you can really see it on the charts. Kettle also but that is very quick!

Now we have the car that is another big one!

I'm certainly not switching this house's heating to heat pumps. I didn't know there was a way to heat an individual room with a stand-alone appliance in the way you suggest. I would certainly be interested in using a bit of battery power for evening heating of a single room, but there doesn't seem to be a huge amount to spare.

I think we will almost all be switching to heat pumps of one kind or another.

Heating at 300% efficiency is always going to outperform 80-100% efficiency. In a net zero scenario you don't want to be wasting energy on inefficient heating.

 

[Rolfe]

Maybe in the end, but I have a fairly new oil-fired boiler and a new oil tank, and I don't fancy ripping the house apart to make it suitable for changing to a heat pump. Someone else can do that after I'm gone. But I'm not averse to finding out about stand-alone devices to supplement the oil heating, use up spare solar or cheap-rate electricity, and reduce oil use.

 

[johnb80]

Maybe in the end, but I have a fairly new oil-fired boiler and a new oil tank, and I don't fancy ripping the house apart to make it suitable for changing to a heat pump. Someone else can do that after I'm gone. But I'm not averse to finding out about stand-alone devices to supplement the oil heating, use up spare solar or cheap-rate electricity, and reduce oil use.

It's units like this one here in my kitchen, above the TV. It can heat, cool, de-humidify etc. Mega efficient often giving a COP of over 4 (1 kW electrical energy gives you 4 kW heat!). These are made by Mitsubishi, really good quality, very quiet (inaudible on the slowest fan speed), great for those very hot nights.

 

[Rolfe]

It's not the hot nights I'm concerned about, it's the cold ones. We don't do "very hot nights" here. We get chilly evenings after a hot day. I'm interested in heating, not cooling.

 

[johnb80]

It's not the hot nights I'm concerned about, it's the cold ones. We don't do "very hot nights" here. We get chilly evenings after a hot day. I'm interested in heating, not cooling.

Of course, cooling is all part of the system, you dont have to use it. Global warming may change it all!!

 

[Rolfe]

But does it heat? The thing is, I often find myself wanting heating just in the living room and just in the evening, on warm days. Also, I often turn up the thermostat of the central heating in the evening in winter, again to get the living room warmer to sit in. If there was some way of doing that on cheap electricity (or even solar, in the former example) that would be good. Cooling isn't needed, but you keep talking to me about cooling, not heating.

 

[johnb80]

But does it heat? The thing is, I often find myself wanting heating just in the living room and just in the evening, on warm days. Also, I often turn up the thermostat of the central heating in the evening in winter, again to get the living room warmer to sit in. If there was some way of doing that on cheap electricity (or even solar, in the former example) that would be good. Cooling isn't needed, but you keep talking to me about cooling, not heating.

Rolfe, sorry, I obviously didn’t make it clear (I thought I had). YES these systems do both HEAT and COOL. With equal efficiency. What you’re describing as a mode of operation, we’ve been doing for 30+ years.
If you’re passing through Lincolnshire, drop in for a coffee and I’ll show you the system working off battery ?

 

[decrep]

The only thing with A/Cs is they need to be run on a fairly regular basis, it keeps the seals lubricated, or something like that. Other wise they can run out of gas. If you aren't using it thru summer that could happen. But I guess half hour on the odd chilly evening would do the trick.
It's certainly the cheapest, cleanest form of heating, especially if you're running of solar.

 

[Rolfe]

I need to look into it. Yes, it's uncommon to get a long warm spell where you wouldn't want a wee boost in the evening. And if it was only half an hour I wouldn't bother because the fan heater could do it. It's likely to be several hours.

 

[johnb80]

The only thing with A/Cs is they need to be run on a fairly regular basis, it keeps the seals lubricated, or something like that. Other wise they can run out of gas. If you aren't using it thru summer that could happen. But I guess half hour on the odd chilly evening would do the trick.
It's certainly the cheapest, cleanest form of heating, especially if you're running of solar.

Not on domestic Air-conditioning it doesn't. It's just like your refrigerator, no seals involved. The seals you are referring to are on automotive applications, typical where pipes join and more importantly where the compressor shaft passes through the housing to the clutch and aux belt. EV's have sealed compressors and don't have this shaft seal, they do still have seals on the pipes though but the whole system is inherently more reliable than ICE versions.

 

[decrep]

Not on domestic Air-conditioning it doesn't. It's just like your refrigerator, no seals involved. The seals you are referring to are on automotive applications, typical where pipes join and more importantly where the compressor shaft passes through the housing to the clutch and aux belt. EV's have sealed compressors and don't have this shaft seal, they do still have seals on the pipes though but the whole system is inherently more reliable than ICE versions.

Thanks John, that's nice to know, makes sense when you think of it.

 

[Rolfe]

After a few amazingly sunny days I'm now seeing what happens when it's dull. Seeing, not experiencing, because I'm staying with friends on the south coast and watching it all on the app.

It's a nice day here, and my friend, who has 18 panels and no battery, just broke off a conversation saying, "look at that sunshine, I must put the washing on!" (He has a FIT tariff.)

My system is managing to run the empty house and that's about it. Yesterday's sunshine, all of it, only managed to recharge the battery to about 98% from the 72% that was left after it had powered the house for the night. Hot water? Forget it.

Last night the battery went down to 65% running the empty house, and now, one o'clock, it has made it back to 91%. So a wee bit more sun today perhaps. I don't know if I'd have needed anything from the grid if I'd been home using hot water and cooking and watching TV and turning on lights or not. Perhaps not for just a couple of dull days, but eventually. I'll soon find out.

What I will have to find out is how to get the Eddi to deliver hot water when there's no spare sun, or maybe just use the central heating to do it. I'll also have to find out how to charge the battery from the grid overnight.

 

[johnb80]

After a few amazingly sunny days I'm now seeing what happens when it's dull. Seeing, not experiencing, because I'm staying with friends on the south coast and watching it all on the app.

It's a nice day here, and my friend, who has 18 panels and no battery, just broke off a conversation saying, "look at that sunshine, I must put the washing on!" (He has a FIT tariff.)

My system is managing to run the empty house and that's about it. Yesterday's sunshine, all of it, only managed to recharge the battery to about 98% from the 72% that was left after it had powered the house for the night. Hot water? Forget it.

Last night the battery went down to 65% running the empty house, and now, one o'clock, it has made it back to 91%. So a wee bit more sun today perhaps. I don't know if I'd have needed anything from the grid if I'd been home using hot water and cooking and watching TV and turning on lights or not. Perhaps not for just a couple of dull days, but eventually. I'll soon find out.

What I will have to find out is how to get the Eddi to deliver hot water when there's no spare sun, or maybe just use the central heating to do it. I'll also have to find out how to charge the battery from the grid overnight.

With EDDI, simply set a schedule from the APP, dead easy.

Charging your battery from the grid should be straight forward too but I dont know your inverter setup.

 

[Rolfe]

I haven't even got the Eddi app yet! The instruction handbook is still lying on my sofa.

 

[Bam Bam]

I'll also have to find out how to charge the battery from the grid overnight.

The Givenergy app is very intuitive I think.

In the settings you've got import and discharge options. You can set a time to fill up the battery.

Now I'm on intelligent flux I don't need to worry about these - Octopus just changes the settings 20 or so times per day.

Totals?
I think you asked previously how to see your totals over several days or something like that. Also easy to see.

Go to the bar chart icon along the bottom and you can choose what time frame to show bar charts. If you are on a day it shows each hour. If you go for week or month it will show you each day. If you go for annual it shows each month.

For the current total for the day you can look at the bar charts for the day, or just click on the house/solar/battery/grid icon on the 'live' page and it will show the total for that. you can change what this shows in the settings - I've added the 'grid carbon intensity' 'cost' and 'EV' icons (but then I've got the Givenergy Charger so it is integrated).

 

[Rolfe]

Thanks!