[No longer] Going for a Givenergy 8.2 kWh AC Coupled battery

Coastalwatch

Toogie said:

I’ve been running my 4kWp array through a GivEnergy 3.6kW hybrid inverter very happily since last December too. My GivEnergy 8.2kW battery is on back order and am wondering if it will ever arrive but Glowgreen tells me ‘yes but not when. 

I have an Octopus SEG account giving me 4.1p/kWh for excess solar whilst I have no battery to soak it up but future exporting income is not a primary driver for me. Currently using 50% of generated solar in the home. 

I’m ditching my 20yr old gas boiler in a couple of months for a Tepeo zero emissions electric (ZEB) boiler and I need to acquire enough battery storage -but not too much that the resource will be underused -to top up the ZEB’s 40kW stored energy on the coldest of winter days when solar is unavailable and the cost of Octopus Go day rate (13.45p/kWH for me this year- inevitably more next year) would make the import leckky costs so much more than gas. 

I’m thinking of test running the single battery set-up through the winter to see if I need a second battery- if so, it would have to be the 9.5kW, a replacement for the 8.2kW promised for later this year. 

I’m interested in comments/ suggestions on the above. 

I'm not familiar with the Tepeo product but it would appear to rely entirely on the Octopus Go rate being made permanent in order to compete with gas financially. There is no additional benefit as with ashp's, so for each 1kWh of energy stored you may get 0.8/0.9kWh of heat from each. Something else to consider is that with a 3.6kW hybrid Inverter and the Tepeo drawing 9.3kW's then during daytime hours, should the back up battery be required, it can only supply 3.6 of the 9.3 kW's required thus drawing circa 5.7 kW's from the grid!

I think I would seek some real case consumption figures of what it is capable of delivering both in terms of heat and duration before being convinced. If it is to be used for DHW too this will cause something of a drain so needs consideration also.

Sorry to sound rather negative but the ad paints a glossy emission free scene but suspect the devil will be in the detail with the owner bearing the costs if all is not quite as made out to be.

Magnitio

Toogie said:

I’m ditching my 20yr old gas boiler in a couple of months for a Tepeo zero emissions electric (ZEB) boiler and I need to acquire enough battery storage -but not too much that the resource will be underused -to top up the ZEB’s 40kW stored energy on the coldest of winter days when solar is unavailable and the cost of Octopus Go day rate (13.45p/kWH for me this year- inevitably more next year) would make the import leckky costs so much more than gas. 

I’m thinking of test running the single battery set-up through the winter to see if I need a second battery- if so, it would have to be the 9.5kW, a replacement for the 8.2kW promised for later this year. 

I’m interested in comments/ suggestions on the above. 

I would agree with Coastalwatch. I had a look at the Tepeo boiler and thought it looked an interesting idea, but it is very reliant on there being a big saving in overnight electricity rates. With more overnight usage in the future, especially with EV charging, I think there is a big risk that the differential in rates will reduce or disappear. As others have mentioned, when you need the heating most is during the months of the year when solar production is limited, so you will be buying electricity at the prevailing rate. Having a large battery won't help much with storing excess solar during Winter as there are very few days when this happens.

These "boilers" are a significant purchase and should last for many years; if they came with a 20 year guarantee of cheap overnight electricity then they might make sense.

Toogie

QrizB said:

Toogie said:

I’m ditching my 20yr old gas boiler in a couple of months for a Tepeo zero emissions electric (ZEB) boiler and I need to acquire enough battery storage -but not too much that the resource will be underused -to top up the ZEB’s 40kW stored energy on the coldest of winter days when solar is unavailable and the cost of Octopus Go day rate (13.45p/kWH for me this year- inevitably more next year) would make the import leckky costs so much more than gas. 

...

I’m interested in comments/ suggestions on the above.

Storing electricity to provide heat is an unconventional choice, although (as you've got solar) it won't go unused outside of heating season.

Could you keep your boiler and burn gas in the cold, dark months of the year, at least for the first year or two while you get a feel for how much extra heat you'll need?

Not as unconventional as you might think QrizB:-

This ZEB is a modern night storage heater with a patented heat core, efficient energy conversion and intelligent IoT control employing agile smart tariffs, solcast predictions, etc.
Tepeo claim 9kW of electricity produces 15kW of stored heat energy. Losses within the unit are nil, the usual radiator water pipe losses apply cos it uses the existing arrangement. The heat core can be topped up from empty in 4 hrs (off peak obs.), 

Teeing in with the gas boiler pipe work might be possible but - and I know this sounds glib - my main driver is getting rid of gas from my carbon footprint ASAP.  Reducing the cost of imported leckky from the grid is my next priority that is why I am investing some of my spare capital in home generation and storage although at my age, I’m unlikely to get a ROI . I know from reading this thread that it is dirty energy still but I have confidence in Octopus to continue disrupting the current energy market model with innovation. 

I think we all want similar end results but with perhaps different approaches and that’s exciting and super interesting for us techie geeks, right?  And the data crunching is brill too if you have the time…

QrizB

Toogie said:

Tepeo claim 9kW of electricity produces 15kW of stored heat energy.

If they are literally claiming that, they're snake oil salesmen and you should run a mile.

ed110220

QrizB said:

Toogie said:

Tepeo claim 9kW of electricity produces 15kW of stored heat energy.

If they are literally claiming that, they're snake oil salesmen and you should run a mile.

Yeah, unless it has some sort of heat pump that is physically impossible. More likely that they are being a little creative with their description and mean the equivalent cost saving through using cheaper off peak electricity. Pretty dubious I think.

2nd_time_buyer

ed110220 said:

QrizB said:

Toogie said:

Tepeo claim 9kW of electricity produces 15kW of stored heat energy.

If they are literally claiming that, they're snake oil salesmen and you should run a mile.

Yeah, unless it has some sort of heat pump that is physically impossible. More likely that they are being a little creative with their description and mean the equivalent cost saving through using cheaper off peak electricity. Pretty dubious I think.

This is quoted in their brochure (on page 6):

https://drive.google.com/file/d/1T1TS-RQhHnBYV5KgPm-dgAaXog0wHl_k/view?usp=sharing

However, this is presumably maximum power input versus maximum power output. Not energy in versus energy out.

Page 11 correctly identifies the efficiency at 100% 

Mildly misleading to say the least

Petriix

QrizB said:

Toogie said:

Tepeo claim 9kW of electricity produces 15kW of stored heat energy.

If they are literally claiming that, they're snake oil salesmen and you should run a mile.

It is, of course, entirely possible to get more heat out than electricity put in by using a heat pump to extract energy from the environment. I'm not sure if that's the case here, but it's not beyond credibility. 

2nd_time_buyer

Toogie said:

QrizB said:

Toogie said:

I’m ditching my 20yr old gas boiler in a couple of months for a Tepeo zero emissions electric (ZEB) boiler and I need to acquire enough battery storage -but not too much that the resource will be underused -to top up the ZEB’s 40kW stored energy on the coldest of winter days when solar is unavailable and the cost of Octopus Go day rate (13.45p/kWH for me this year- inevitably more next year) would make the import leckky costs so much more than gas. 

...

I’m interested in comments/ suggestions on the above.

Storing electricity to provide heat is an unconventional choice, although (as you've got solar) it won't go unused outside of heating season.

Could you keep your boiler and burn gas in the cold, dark months of the year, at least for the first year or two while you get a feel for how much extra heat you'll need?

Not as unconventional as you might think QrizB:-

This ZEB is a modern night storage heater with a patented heat core, efficient energy conversion and intelligent IoT control employing agile smart tariffs, solcast predictions, etc.
Tepeo claim 9kW of electricity produces 15kW of stored heat energy. Losses within the unit are nil, the usual radiator water pipe losses apply cos it uses the existing arrangement. The heat core can be topped up from empty in 4 hrs (off peak obs.), 

Teeing in with the gas boiler pipe work might be possible but - and I know this sounds glib - my main driver is getting rid of gas from my carbon footprint ASAP.  Reducing the cost of imported leckky from the grid is my next priority that is why I am investing some of my spare capital in home generation and storage although at my age, I’m unlikely to get a ROI . I know from reading this thread that it is dirty energy still but I have confidence in Octopus to continue disrupting the current energy market model with innovation. 

I think we all want similar end results but with perhaps different approaches and that’s exciting and super interesting for us techie geeks, right?  And the data crunching is brill too if you have the time…

A heat pump will be a much more efficient (lower carbon footprint) choice. If you wanted to keep the gas central heating system and transition over, then one or more air-to-air heat pumps would seem to be a better fit as they are around 400% efficient (compared to 100% for the system that you are proposing).

I have recently installed one:

https://forums.moneysavingexpert.com/discussion/6341294/help-sizing-an-air-to-air-heat-pump   

Since then the government has introduced 0% VAT rate on air-to-air heat pump installs.

Even paying full energy cap price for electricity, it is a bit cheaper than gas to run. If you are running it from electricity at the Octopus Go rate or would otherwise be Solar Export rate at around 7p per kwh than it costs around 25% of the price of gas for the same heat output.

Not only would you save a fortune on the running costs, you would only need 25% of the battery storage too, which will save you another fortune.

Solarchaser

The tepeo basically heats concrete, so getting more out than you put in is impossible. 
(Edit. Reading the brochure it's a 9kw input but 15kw output of the stored energy.... not exactly clear)
So too is losses at nil.

I'm beginning to be glad that I was too far away to be in the trial/initial buyers.
I'm instead going with a 500l water tank that I'm gonna insulate the heck out of as my way of using tou and ditching gas.

QrizB

Solarchaser said:

I'm instead going with a 500l water tank that I'm gonna insulate the heck out of as my way of using tou and ditching gas.

I was wondering how big a tank I'd need to do this.

We get through 30kWh of heat on a typical December or January day. If I use the existing radiators they'll work acceptably down to 50C, and I wouldn't want to heat the tank above 85C, so that's 35C of delta-T.

I reckon (OK I used this) I'd need a ~750-litre tank, which is pretty big but not impossible (a cubic metre IBC would give me some headroom).

Wonder if I could tell Mrs QrizB it was a coffee table?