Thermal Stores

Coastalwatch

Martyn1981 said:

I guess between cheap rate leccy and PV, you can mostly get by now, or perhaps another week or two into March?
Actually, today was decent for us here, with both A/C units powered all day, so on average, do you expect PV to cover heating and hot water through the Spring, during the daytime?

Yes, that's the case. I perhaps should have explained that we use the term thermal store as opposed to a standard immersion tank for DHW. Two ASHP's cover all our space heating otherwise. We rely totally on the cheap overnight rate for DHW through some of November, all of December & January and some of Feb. PV sees us adequately through the rest of the year.

Our priority has been trying to save the planet as opposed to fractions of pence per kWh.

EcoScruples

I really like the idea of this to replace my oil fired boiler but 40kw doesn't sound like a lot.
We use around 1,000 litres of Kerosene a year so in theory it should work but I'd be very concerned I'd run out of heating capacity in the middle of a cold winter day with no way to heat my home.
I wonder if anyone knows of any of some real life experience of these yet?

Reed_Richards

This thread confuses a generic type of product, a Thermal Store, with a specific product, the "Zero Emission Boiler" https://tepeo.com/thezeb .  This has a maximum charge of 40 kWh (not kW).  I replaced my old kerosene oil boiler with a heat pump.  The oil boiler used about 2,100 litres of oil a year which I calculated to be 59 kWh per day.

In January 2021 my average daily usage by the heat pump was 50 kWh per day whilst my average for the year was 20 kWh per day.  Heat pumps exaggerate the difference between cold and warm weather but I would say that you need a storage capacity of at least twice your average.      

EcoScruples

I worked out I need about 57kw of heating energy per day in the cold months as I only use my boiler for an average of 180 days a year, it tends to be turned off from May through to October.
That's where my concern comes in at the 40kw rating.
I really like the idea of it. My boiler likely has another 10 yo 15 years life yet so this type of unit will likely improve in that time.

Reed_Richards

The most basic type of thermal store is a tank of hot water.  Some use a phase change material instead of water and that takes up less space and is easier to insulate.  As well as an electric coil, you can have copper pipe coils inside a thermal store which allow you various heating options.    

QrizB

Reed_Richards said:

This thread confuses a generic type of product, a Thermal Store, with a specific product, the "Zero Emission Boiler" https://tepeo.com/thezeb .  This has a maximum charge of 40 kWh (not kW).  I replaced my old kerosene oil boiler with a heat pump.  The oil boiler used about 2,100 litres of oil a year which I calculated to be 59 kWh per day.

The Tepeo ZEB seems a neat solution for small all-electric properties where a heat pump isn't a credible option (certain flats, for example).

I have a moderate-sized 3-bed semi and my heat demand in Nov-Mar will often exceed 40kWh/day; January 2021,which wasn't exceptionally cold, averaged over 60kWh/day. I'd either need two ZEBs or a peak-rate electric top-up, neither of which would be economical. Depending on the tariff a heat pump with a COP of 2 (ie. a poor one) could prove cheaper to run than a single ZEB.

I don't know the price of a ZEB (they don't appear to be generally available yet) but if it's similar to a Sunamp heat battery then the installation costs for a two-ZEB system could be similar to a heat pump.

EcoScruples

QrizB said:

Reed_Richards said:

This thread confuses a generic type of product, a Thermal Store, with a specific product, the "Zero Emission Boiler" https://tepeo.com/thezeb .  This has a maximum charge of 40 kWh (not kW).  I replaced my old kerosene oil boiler with a heat pump.  The oil boiler used about 2,100 litres of oil a year which I calculated to be 59 kWh per day.

The Tepeo ZEB seems a neat solution for small all-electric properties where a heat pump isn't a credible option (certain flats, for example).

I have a moderate-sized 3-bed semi and my heat demand in Nov-Mar will often exceed 40kWh/day; January 2021,which wasn't exceptionally cold, averaged over 60kWh/day. I'd either need two ZEBs or a peak-rate electric top-up, neither of which would be economical. Depending on the tariff a heat pump with a COP of 2 (ie. a poor one) could prove cheaper to run than a single ZEB.

I don't know the price of a ZEB (they don't appear to be generally available yet) but if it's similar to a Sunamp heat battery then the installation costs for a two-ZEB system could be similar to a heat pump.

Im sure i saw a price of £5k for the Zeb which is pretty hefty.
The good news is that as gas and oil boilers are phased out then this type of technology will only improve and become cheaper.

I certainly don't fancy shelling out £10k for that long a payback.

Martyn1981

Feel guilty posting this as I think the phase change materials, and Sunamp tech is very clever, but I don't think they can pay for themselves, ever, v's a new high quality hot water tank. I sat in on a sales pitch at my sister's when a salesman was pushing the kit, and we didn't exactly hit it off when I challenged all of his numbers. He suggested saving 1,000kWh's per year in lost energy. I suggested 150-180kWh based on a quality tank, perhaps with a couple of extra jackets added, reducing losses to about 1kWh per day.

He then challenged my lower than 365kWh figure, so I explained that since he was promoting resistive leccy heating for their property (they'd asked for a chat about heatpumps), then water tank losses during the heating months weren't a loss since they would be within the thermal envelope of the property.

He then started to explain about the special German clay in their storage heaters ..... yeah, that 10yr old BS ..... and things went further downhill. 

EcoScruples

Martyn1981 said:

Feel guilty posting this as I think the phase change materials, and Sunamp tech is very clever, but I don't think they can pay for themselves, ever, v's a new high quality hot water tank. I sat in on a sales pitch at my sister's when a salesman was pushing the kit, and we didn't exactly hit it off when I challenged all of his numbers. He suggested saving 1,000kWh's per year in lost energy. I suggested 150-180kWh based on a quality tank, perhaps with a couple of extra jackets added, reducing losses to about 1kWh per day.

He then challenged my lower than 365kWh figure, so I explained that since he was promoting resistive leccy heating for their property (they'd asked for a chat about heatpumps), then water tank losses during the heating months weren't a loss since they would be within the thermal envelope of the property.

He then started to explain about the special German clay in their storage heaters ..... yeah, that 10yr old BS ..... and things went further downhill. 

  you have to love a hard sell approach.
 

Exiled_Tyke

EcoScruples said:

Martyn1981 said:

Feel guilty posting this as I think the phase change materials, and Sunamp tech is very clever, but I don't think they can pay for themselves, ever, v's a new high quality hot water tank. I sat in on a sales pitch at my sister's when a salesman was pushing the kit, and we didn't exactly hit it off when I challenged all of his numbers. He suggested saving 1,000kWh's per year in lost energy. I suggested 150-180kWh based on a quality tank, perhaps with a couple of extra jackets added, reducing losses to about 1kWh per day.

He then challenged my lower than 365kWh figure, so I explained that since he was promoting resistive leccy heating for their property (they'd asked for a chat about heatpumps), then water tank losses during the heating months weren't a loss since they would be within the thermal envelope of the property.

He then started to explain about the special German clay in their storage heaters ..... yeah, that 10yr old BS ..... and things went further downhill. 

  you have to love a hard sell approach.
 

But worry about those taken in by them.  I had EDF try to convince me that an ASHP was going to save money - until I showed them my figures which they couldn't challenge .....