iboost/Eddi vs Immersion timer

[Radian]

31 minutes ago, Miek said:

It was down to the spade connectors on the wiring loom causing a point of high resistance which then produced excess heat ( to the point where the pastic was going brown) and eventually failed.

That type of connector (Lucar) is prone to failure.  Read this for a good rant about them.

[Miek]

48 minutes ago, Radian said:

That type of connector (Lucar) is prone to failure.  Read this for a good rant about them.

Bang on. I didn't know they were called Lucar connectors, thanks for that

[Radian]

I thought it amusing when I asked for a critique of my homebrew pv router on the open energy forums and someone suggested using these:

 

stephenstephen krywenko

23 Jun

 

as critique - i would use surface mount triac. easier fixing when it fail at some point and better heat dissipation. just use push on connectors instead of soldering them on

They do crop up in commercial designs so worth checking first if anyone gets a problem with their diverter.

[MikeSharp01]

2 hours ago, Radian said:

I thought it amusing when I asked for a critique of my homebrew pv router on the open energy forums and someone suggested using these:

Just read that thread and it struck me that you might be able to calibrate 'waste' by synching up your measurements with the meter readings, assuming you have access to your 30 minute IN/OUT readings, over a period of hours or even days just to get a feel for it. It looks like the Joule bucket is not constant for all makes thus challenging assumptions on how your system works but if you could work it out then it's another shareable commodity. Finally it is possible to infer one of two things from the thread: that either commercial units don't care about the occasional mismatch or that they know something you (and the other thread members) don't. I know where I stand on that one.  

[SteamyTea]

@MikeSharp01

How you getting on with making a ESP based pulse logger?

[Radian]

1 minute ago, MikeSharp01 said:

Finally it is possible to infer one of two things from the thread: that either commercial units don't care about the occasional mismatch or that they know something you (and the other thread members) don't. I know where I stand on that one.  

 

Yes, I kind of avoided discussing this topic but tend to agree with Robert.Wall that they probably operate on the assumption of a smaller buffer zone with a bias towards export to avoid even the tiniest bit of unnecessary import. The marketing would have you believe that you're using every last drop of self generation but in reality, due to necessity of having a "one-size-fits-all" product that can cater for different utility meters, they are nowhere near as efficient at doing their job as they could be with proper matching (tuning).

[MikeSharp01]

29 minutes ago, SteamyTea said:

How you getting on with making a ESP based pulse logger?

Well its basically ready, but I have sort of expanded it a bit to make the block do much more than just log the meter but also manage DHT22s and the like. I have not managed to get the RTC working reliably so have switched over to NTP, as @Radian, suggested.  I have sort of written up the first, discover / define (Does/Should), part and am about to start testing the whole system, then I will publish and be damned.

[MikeSharp01]

 

31 minutes ago, MikeSharp01 said:

Well its basically ready,

On the other hand - like too many things I stick my nose into this challenge is expanding greatly and I need to learn to control the levels of detail a bit better. While doing the 'what do / does current systems do.' I hit this problem;  Stepping out from just counting pulses we have energy monitoring and stepping out from that we have energy / cost minimising. When you get out here the path back to pulse counting is obscured by many other factors. So, for instance, we - well some of us, could start to live our lives 12 hours out phase. This would level out demand and flatten prices and I need not worry so much about how much I use. We might extend this idea and in combination with others we can see that living our lives looking ahead based on; the 30 minute import / export tariffs, what our food preferences are, how much sun we are expecting & when and  what's in the fridge the system might work out a good recipe (or small selection of same) and give instructions as to when to cook it. So now in designing my pulse counter I need also to agree how it will fit with all these other futures. Not to mention how to deal with export and the various flashing behaviours of meters from different suppliers when export happens. My head hurts!

[Radian]

1 hour ago, MikeSharp01 said:

 

On the other hand - like too many things I stick my nose into this challenge is expanding greatly and I need to learn to control the levels of detail a bit better. While doing the 'what do / does current systems do.' I hit this problem;  Stepping out from just counting pulses we have energy monitoring and stepping out from that we have energy / cost minimising. When you get out here the path back to pulse counting is obscured by many other factors. So, for instance, we - well some of us, could start to live our lives 12 hours out phase. This would level out demand and flatten prices and I need not worry so much about how much I use. We might extend this idea and in combination with others we can see that living our lives looking ahead based on; the 30 minute import / export tariffs, what our food preferences are, how much sun we are expecting & when and  what's in the fridge the system might work out a good recipe (or small selection of same) and give instructions as to when to cook it. So now in designing my pulse counter I need also to agree how it will fit with all these other futures. Not to mention how to deal with export and the various flashing behaviours of meters from different suppliers when export happens. My head hurts!

 

And you once accused me of over-thinking things (I seem to recall) 🤣

[AliG]

There has been some mention of the efficiency of using gas vs the immersion to heat hot water.

 

My gas consumption is higher than I expected when the heating is off. I have never really got to the bottom of it. I am going to turn the gas hot water heating off for the next 24 hours and compare it to yesterday’s consumption. For most people there wouldn’t be an issue but I have a pool so I can’t separate pool heating from hot water easily. Then I will try using electric heating for a day.

 

I am curious if there are a lot more losses than I expected using gas. The way my system is set up the water seems to get pumped around quite a lot.

 

[MikeSharp01]

1 hour ago, Radian said:

And you once accused me of over-thinking things (I seem to recall) 

Yep - it happens to be one of my biggest challenges, while thinking is not a bad thing it sometimes helps to be shaken out of it, so thanks! 

[Radian]

1 hour ago, AliG said:

For most people there wouldn’t be an issue but I have a pool so I can’t separate pool heating from hot water easily.

Do you have a handle on the daily energy consumption of the pool?

[Wil]

Responding to an earlier question around Solics,

 

I have the solic diverter which is great, but overheats in the electrical cupboard and self-limits the amount it puts into the immersion resulting in occasionally not diverting as much as it could. I need to find a way to move it to somewhere where it doesn’t overheat. Otherwise it’s been excellent and has paid for itself in around 2 years.

 

I also have a Shelly 1PM in parallel (previously a simple timer) so that I can boost the DHW or run it for a couple of hours at E7 to make sure the DHW is in place for the morning. Seemed like the easiest way of diverting but retaining the ability to boost/ timed DHW without pressing the green button on the front of the Solic.

[SteamyTea]

@Radian

As our electronical expert, how easy would it be to hack a cheap timer, like I linked to above, to add a ESPxxxx so that remote control is also possible. Thinking simple override for times of inconsiderate guests/children, or excess PV production.

Edited August 22, 2022 by SteamyTea

[MrMagic]

@SteamyTea Not an answer to your exact question - I use a cheap sonoff to switch a contactor on my storage heater - all "off the shelf", in a little 2 way DIN rail enclosure. Marginally more expensive. Could be used for an immersion also. 6A MCB provides 240v feed to the sonoff. (reflashed with ESPhome for home assistant integration but could be left as is to use the sonoff app. Shelly etc would also work)

 

[SteamyTea]

23 minutes ago, MrMagic said:

in a little 2 way DIN rail enclosure.

I am after an enclosure like that, better get on eBay.

[Radian]

1 hour ago, MrMagic said:

@SteamyTea Not an answer to your exact question - I use a cheap sonoff to switch a contactor on my storage heater - all "off the shelf", in a little 2 way DIN rail enclosure.

Yes, and @SteamyTea the sonoff products are typically (if not exclusively) based on ESP8266 so you have the choice of taking them as they come, or reflashing with one of the various open-source firmwares or rolling your own using micropython, arduino or whatever. The contactor bumps up the switching capacity as in MrMagic's case. 

 

OR you could get a high current relay board + ESP8266 like this one on Ebay

Just needs a 9V or 12V DC PSU

[MikeSharp01]

22 minutes ago, Radian said:

OR you could get a high current relay board + ESP8266 like this one on Ebay

How do they may them so cheap? Wonder if that 3OA relay really is?

 

[AliG]

18 hours ago, Radian said:

Do you have a handle on the daily energy consumption of the pool?

Having turned the hot water off yesterday, the only thing the boiler was doing was heating the pool and pool room, circa 700sq metres.

 

It used 44/45 kWh of gas. The temperature really dropped today to around 13C outside, which I think is around the average for the year. 45kWh a day equates to 16000 for the year which is almost bang in line with what I thought it used. £500 a year before the recent surge in gas prices. £1200 at the current price.

 

On top of this the pool pump uses a bit less than 2000kWh a year of electricity and the dehumidifier uses around 2500kWh. I have altered when they run so that much of the running is overnight at lower prices.

 

So they would have cost around £500 a year also before recent price increases. Around £900 a year on Octopus Intelligent at the moment.

 

I have not thoroughly investigated this before, frankly gas was too cheap to worry about it, I was paying just over 2p a kWh last year.

 

It looks like I use around 45kWh a day of gas for the pool and 40-50kWh a day for hot water. I would guess we use around 4-500l a day which should use 26kWh. Assuming 3kWh a day of standing losses for the tank suggests that the boiler is only around 60-70% efficient heating hot water or heat is being lost somewhere else. I had not really thought about it before, but every part of the heating system is insulated except a low loss header. All the water gets pumped through this from the boiler and it is considerably hotter than any other component in the plant room, it was at around 40C this morning. I am going to wrap it in duct insulation and see if that impacts the pool consumption tomorrow.

 

The other thing is that using the immersion to heat the hot water directly then no pumps would run and the water wouldn't go through the low loss header. Harder to calculate consumption of electricity though, so I will see if I can do that next.

 

If I can reduce the apparent 10kWh a day of disappearing heat that is equivalent to a 5% reduction in my gas bill on its own.

 

The pool heater is off now, so I have turned the hot water back on. It is at 29C at the moment, so I will see how much gas it takes to get back to the normal 55C. My calculator says it should need 15kWh, I think the heat exchanger in the tank is 27kW so it should maybe take half an hour.

 

[AliG]

Have used 16kWh of gas. Temperature at tap increased from 29C to 51C. Suggests about 80% efficiency for the boiler.

 

Have turned the boiler down a bit to make sure it condensing.

 

Will turn off hot water after people have showered and try the same experiment tomorrow.

[Radian]

1 hour ago, AliG said:

Have turned the boiler down a bit to make sure it condensing.

That was going to be my next question - what flow temperature have got the condensing boiler set to? Anything under 60 might upset things as the losses might leave a demand that can't be fulfilled. Bit of a tightrope act.

 

[Radian]

4 hours ago, MikeSharp01 said:

How do they may them so cheap? Wonder if that 3OA relay really is?

 

 

Course it's not but it may live to a ripe old age at  13A. Unlike many chinese 16A relays. The relay looks like it might have the Zettler footprint so could possibly be swapped out for a pukka brand if needs be.

[MikeSharp01]

4 hours ago, AliG said:

circa 700sq metres.

Is it an Olympic size pool - 700m² is 3 tennis courts!

 

[AliG]

50 minutes ago, MikeSharp01 said:

Is it an Olympic size pool - 700m² is 3 tennis courts!

 

Sorry was thinking square feet. Pool room is 10x7 metres. Including the charging room and plant room it is around 84sq metres of heated area. The pool is around 35sq metres.

 

2 hours ago, Radian said:

That was going to be my next question - what flow temperature have got the condensing boiler set to? Anything under 60 might upset things as the losses might leave a demand that can't be fulfilled. Bit of a tightrope act.

Had it set a bit lower until a few weeks ago. A valve actuator broke in the pool heater and the engineer was insistent that it wasn't heating up because the boiler had to be turned up to 70C. Despite the fact it had worked fine for four years.

 

I turned it up and funnily enough it made no difference,  so he eventually replaced the switch, which promptly broke again after about three weeks. So I had to turn it up again so as to not have the same argument. I was told the switch was tested before it was sent out and it was almost impossible that it had broken again. It had!

 

Turned it back to the mid 60s now where it was before.

[Radian]

1 minute ago, AliG said:

Turned it back to the mid 60s now where it was before.

I find 64 is about as low as I dare go if I want the HW at 55. Boiler is a long way from cylinder and the pipes are not particularly well insulated.