Diverting excess generation to immersion heater

[BBE]

As above, I have a Gaia turbine that produces about 26/28,000kw p/a, farm uses about 10k but still have to buy a big proportion of that. Farmhouse is heated by oil. When we're not utilising what's been generated how could it be diverted to a termal store to heat farmhouse? What type of kit would be required? I've a good sparkey but would this require a specialist?

 

[Nearly]

there's an auto switch that you can wire in. Sparky would know.

 

[farmerm]

Probably not too hard to have a your immersion heater on when you have power and thermal storage capacity available in your existing hot water tank? But I guess you a thinking of having a bigger thermal store than topping up your hot water tank by perhaps 10C alone can offer... in which case the immersion would go in a larger thermal storage tank, the heat would be transferred to your existing heating system via a plate heat exchanger with the thermal storage on one side and the return pipe to the boiler on the other... I don't think you would need a pump to circulate the water on the thermal storage side, we don't have one on our biomass system... I guess you might need a thermal control value on the storage side of the heat exchanger that can restrict circulation back into the thermal store else when the thermal storage is colder than your domestic hot water or you will end up using your boiler to heating the thermal store.... when you have you heating/hot water turned on you want your controller to enable your circulation pump but have a thermal switch that means it wont call the boiler whist the boiler is above a given temperature But I am no expert, only the owner of a domestic biomass boiler. There are probably some rules and regs that complicate things

 

[Exfarmer]

It is not specialist work to install an Immersun water heater divert.
however if you really want to harvest the power, you will need a heat store such as a large tank, but this is specialist work. It depends how much you have to spend

 

[f0ster]

there is a device called an iboost, it has a clamp that goes around the meter tails and if any elec is being exported it automatically activates the immersion heater, and stops it when circumstances change.

 

[Bloders]

I use a Watson (now ceased trading) which does the same thing. However, as I have a combi boiler, I use it connected to a 3KW heater. It diverts excess power to the heater which is located in the lounge.

 

[BBE]

It is not specialist work to install an Immersun water heater divert.
however if you really want to harvest the power, you will need a heat store such as a large tank, but this is specialist work. It depends how much you have to spend

there is a device called an iboost, it has a clamp that goes around the meter tails and if any elec is being exported it automatically activates the immersion heater, and stops it when circumstances change.

Thanks. I'll have a look at Immersun & iboost, these sound like what I'm looking for.
Forgot to mention that it's 3 phase, would this make any difference?

 

[Bloders]

Thanks. I'll have a look at Immersun & iboost, these sound like what I'm looking for.
Forgot to mention that it's 3 phase, would this make any difference?

Cant comment about the 3 phase bit, but i read smewhere Immersun had ceased trading.

 

[e3120]

I built my own, heats 1000l buffer off 3 phase endurance. It's only just been turned back on as a decent PPA has been worth more than displacing oil. Even with an 80kW with most exported, the boiler still has to run quite often.

More favourable economics if you're on 50% deemed export.

 

[f0ster]

just looking at the iboost pdf, it requires one iboost per phase,

 

[Lincsman]

I wouldn't bother with the immersion heater other than put it on a simple time switch for when you know there is usually spare power.

I have 2 immersions connected by Solec boxes in a 1500l buffer tank that the biomass boiler heats that is indirectly connected to the house heating system via a heat exchanger, its amazing how two 4kw solar panel systems can heat it on a reasonably sunny day, I suggest you do similar, if for some reason you lose the turbine power you just switch off a pump and the house is back on the old system.

My 2 systems are classed as domestic so I get paid the same whether I use it or export it, which wont be so in your case.

 

[e3120]

I would suggest a system needs to be more dynamic, as it only takes a small amount of import to be accidentally used to defeat the purpose (unless you happen still to have a 'backwards' meter ). Even with a turbine with rated power well in excess of my immersions, they're often stepping up and down as available power varies. I imagine cloud cover having at least as large effects on PV.

 

[BBE]

I built my own, heats 1000l buffer off 3 phase endurance. It's only just been turned back on as a decent PPA has been worth more than displacing oil. Even with an 80kW with most exported, the boiler still has to run quite often.

More favourable economics if you're on 50% deemed export.

Yes i'm on 50% deemed export.
What switches did you use?

 

[BBE]

I wouldn't bother with the immersion heater other than put it on a simple time switch for when you know there is usually spare power.

I have 2 immersions connected by Solec boxes in a 1500l buffer tank that the biomass boiler heats that is indirectly connected to the house heating system via a heat exchanger, its amazing how two 4kw solar panel systems can heat it on a reasonably sunny day, I suggest you do similar, if for some reason you lose the turbine power you just switch off a pump and the house is back on the old system.

My 2 systems are classed as domestic so I get paid the same whether I use it or export it, which wont be so in your case.

Only problem is that wind is very variable so no consistency of supply to set up a timer.

 

[e3120]

Yes i'm on 50% deemed export.
What switches did you use?

Actual switching is done by the 6 solid state relays at the bottom. These are my biggest bugbear as they don't last, despite heatsinks and cooling fan. Interference from the contactors I tried at first kept resetting the picaxe board at the top, which is the brains of the unit. My import & export info comes from my export meter which closes a pair of contacts every 0.05 kWh. I developed this method after reading about guys that put a light sensor on top of the led on their domestic meters.

Edit: In the 5 minutes since taking the picture, the unit has gone 0, 3, 6, 3, 0, 6, 14, 6kW in the 5-6 m/s breeze.

 

[BBE]

Actual switching is done by the 6 solid state relays at the bottom. These are my biggest bugbear as they don't last, despite heatsinks and cooling fan. Interference from the contactors I tried at first kept resetting the picaxe board at the top, which is the brains of the unit. My import & export info comes from my export meter which closes a pair of contacts every 0.05 kWh. I developed this method after reading about guys that put a light sensor on top of the led on their domestic meters.

Edit: In the 5 minutes since taking the picture, the unit has gone 0, 3, 6, 3, 0, 6, 14, 6kW in the 5-6 m/s breeze.

Proper job ?

 

[Dave645]

As above, I have a Gaia turbine that produces about 26/28,000kw p/a, farm uses about 10k but still have to buy a big proportion of that. Farmhouse is heated by oil. When we're not utilising what's been generated how could it be diverted to a termal store to heat farmhouse? What type of kit would be required? I've a good sparkey but would this require a specialist?

I would look at air source heating as well, and for a way for the system to know your on your own electric rather than mains, thermal stores are ok but the cost of the large well insulated tanks get high fast, and they all suffer from heat losses, directly using the power in the home with say air source heat pumps, may be a long term cheaper solution.

I would also keep an eye on storage like batteries, to reduce your mains usage. it is creeping down in price and there are lots of new stuff popping up all the time. Even if it’s to expensive now that may not be the case in a few years time.

 

[Dave645]

Actual switching is done by the 6 solid state relays at the bottom. These are my biggest bugbear as they don't last, despite heatsinks and cooling fan. Interference from the contactors I tried at first kept resetting the picaxe board at the top, which is the brains of the unit. My import & export info comes from my export meter which closes a pair of contacts every 0.05 kWh. I developed this method after reading about guys that put a light sensor on top of the led on their domestic meters.

Edit: In the 5 minutes since taking the picture, the unit has gone 0, 3, 6, 3, 0, 6, 14, 6kW in the 5-6 m/s breeze.

This is a question about a possible way to reduce the load on your relays, would a relatively small battery storage system as a buffer, be better so the draw is active when the batteries (the relay switches at trigger) are at say 80% full and stops when they are at say 30% empty? The bigger the battery the less often the relays have to trigger. The batteries have other benefits also?

 

[BBE]

I would also keep an eye on storage like batteries, to reduce your mains usage. it is creeping down in price and there are lots of new stuff popping up all the time. Even if it’s to expensive now that may not be the case in a few years time.

Batteries would be the ideal. When I put up the turbine battery technology looked about 2 years off, 6 years later it still seems the same.
Which companies are leading the way with small scale battery storage at the moment?

 

[br jones]

Storage heaters