Sunamp
- Thread starter hard-work
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I was interested to hear his claim that it provided about 75% of his hot water needs.
The interviewer made the mistake of saying "75% off your gas bill" which is untrue and very misleading.
BTW I have solar panels. In summer, my gas usage (conventional boiler plus vented cylinder) averages 0.5 cu.m/day, and the cost of gas 22 pence per day ex VAT. Obviously there would be no saving on Standing Charge.
considering that throughout the year there is enough sun to heat the cylinder on about half the days, I calculate that running an immersion off the cylinder would save me about £40 in gas plus 5% VAT. Looking at the cost of purchase plus installation, and a guess at device life, I can't see that these devices are a paying proposition.
The interviewer made the mistake of saying "75% off your gas bill" which is untrue and very misleading.
BTW I have solar panels. In summer, my gas usage (conventional boiler plus vented cylinder) averages 0.5 cu.m/day, and the cost of gas 22 pence per day ex VAT. Obviously there would be no saving on Standing Charge.
considering that throughout the year there is enough sun to heat the cylinder on about half the days, I calculate that running an immersion off the cylinder would save me about £40 in gas plus 5% VAT. Looking at the cost of purchase plus installation, and a guess at device life, I can't see that these devices are a paying proposition.
They are small and heat DHW instantly. The life is over 55 years, they said that. When the salt heat store is up to temp the electricity from the panels can be used for the rest of the house. That is not the case with water tube solar panels.
You already have an installation. In new installations these make more financial sense. You do not need a large expensive space consuming cylinder with these. It is a matter of comparing different system installation costs and look at the ROI.
You already have an installation. In new installations these make more financial sense. You do not need a large expensive space consuming cylinder with these. It is a matter of comparing different system installation costs and look at the ROI.
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ROI is very poor.
Cost of £2,000 and saving of £40 a year means it takes 50 years to cover the purchase price.
Long before then it will be obsolete or broken.
Putting £2,000 into a savings account, premium bonds, or your pension fund would do better. Or paying off a bit of your mortgage or other debt.
Cost of £2,000 and saving of £40 a year means it takes 50 years to cover the purchase price.
Long before then it will be obsolete or broken.
Putting £2,000 into a savings account, premium bonds, or your pension fund would do better. Or paying off a bit of your mortgage or other debt.
At 8:45 into the video the conversation turns to life time and of the phase change material and how many heat-cool cycles a cartridge will provide.
On a test rig they survived 20,000 cycles. But he could not give an estimated life for the heat stores. Back in the 1970's phase change heat stores were being tried and they seemed to work with good results. But the life time before the materials then available degraded even without temperatuer cycling was considered as being too short for them to be viable. The degredation was inherent in the chemistry of the materials. Temperature cycling accelerated the degredation.
I also recall that some of the chemicals were highly corrosive and would today be considered as hazardous
Maybe there are better more stable materials
.
On a test rig they survived 20,000 cycles. But he could not give an estimated life for the heat stores. Back in the 1970's phase change heat stores were being tried and they seemed to work with good results. But the life time before the materials then available degraded even without temperatuer cycling was considered as being too short for them to be viable. The degredation was inherent in the chemistry of the materials. Temperature cycling accelerated the degredation.
I also recall that some of the chemicals were highly corrosive and would today be considered as hazardous
Maybe there are better more stable materials
.
It does seem that the phase change material, sodium acetate trihydrate, is very low hazard.
source www.clayton.edu/portals/690/.../MSDS%20sodium%20acetate%20trihydrate.pdf
source www.clayton.edu/portals/690/.../MSDS%20sodium%20acetate%20trihydrate.pdf
Reducing your DHW gas bill by 75% is more than £40 saved. It also allows the solar panels to add to the house electric supply when the heat store is full. As I wrote, in a new installation where space is a [problems (they are small) it would make more sense. I do not go with your outright rejection.
The Spanish and Polish have made inter-seasonal, non-water, heat stores. It makes sense in the likes of Spain with high summer sun and cold winters.
Battery storage is now the norm for the grid. A large electric battery bank is being built in Barrow. In Germany they installed used Smart EV batteries in large banks and used them as grid storage to reduce to need for peak power stations (peakers). The batteries are past their EV usage but they were suitable for grid storage in huge banks. Which brings me to the Tesla Powerwall domestic battery.
With a well insulated house it may be worth getting rid of gas altogether - no standing charges and space released as no gas meter.
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This Sunamp unit and a Tesla Powerwall, I can see being suitable for an off the grid home. The Sunamp unit can pre-heat hot water for an LPG combi. LPG is expensive, but you do not use much of it, it becomes cost effective as the LPG equipment is super cheap compared to oil equipment - they are mainly normal NGas boilers with a simple adjustment. You don't need a big expensive to rent LPG tank. All is needed is a few tall LPG bottles.
When the Powerwall battery is being depleted and there is no sun for the PV panels to generate electricity, a back up DC genny can operate. When the Powerwall is full enough and the PV are generating electricity the genny cuts out. It is all in the control system that matters.
When the Powerwall battery is being depleted and there is no sun for the PV panels to generate electricity, a back up DC genny can operate. When the Powerwall is full enough and the PV are generating electricity the genny cuts out. It is all in the control system that matters.
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Since it doesn't reduce your gas bill by 75%, that is irrelevant.
I have no objection to you spending your own money however you want, but please let's not republish false and misleading claims that may trick others into wasting their savings.
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