wiring for future wind energy

baldric

I have this idea that in 3-5 years the cost and efficiency of wind turbines will improve dramatically at which time I would consider installing one. However I am at first fix electrics at this time and I have it in mind to make provisions for an electric heating unit in every room in the house..( as an alternative for oil)...now what I want to do is to leave the appropriate electric cabling at an accessible spot in each room where I might put a future electric heater.

so my questions are

1. should I just forget about it and install a 20mm conduit instead in that location and pull through whatever is need at that later date
2. if SO is 20 mm conduit big enough and would I need 2 conduits for each heating unit and if so how far apart would anyone suggest?
3.If this is a good time to put in wiring....what should it be ? and what tips have you with regard to it.

Thanks for any ideas

baldric

Dardania

Hopefully someone smarter than me will be able to offer an opinion on my plan here, but what I would suggest doing is:

Forget about electrical elements being installed in each room. Instead, use the radiators you are using now, and install a, say, 200 litre buffer vessel for the oil heating system. In this buffer vessel, to supply heat to it, have a coil off the oil boiler (as normal), and 2 x 3kW electric immersion elements. And then plumb the heating circuit off the buffer vessel out to the radiators.

If your radiators are sized for 60 degrees flow and 40 degrees return, it will take approximately 2 hours for 6kW of heat input to heat that body of water from 10 degrees to 60 degrees. This heat input could be done off peak at cheap rate electricity in future when there is no wind and no oil, or over the course of the day when the wind is blowing...

And for now, if your radiators are sized with those flow & returns, you'll be able to optimise the oil boiler to run in consensing mode quite efficiently.

I think 6.4kW is the max electrical input permissable for micro generators, so the numbers stack up. Also, include a 20A RCBO B type in your consumer unit to accept the electrical input.

baldric

its possible that there is no one smarter!! thats sounds like a damn good idea....and the prospect of having both elec rads and original in all rooms was going to make the place look like a train station...so thats a big improvement.

will be interested to see if there is any other take on this....as wind has got to be going to play a big part in the future

cheers

Dardania

It's funny how you always rethink things freshly in the morning

First off - that RCBO should be a 32A double pole - I wasn't allowing enough current flow for a notional 6kW wind generator, and I didn't mention it should be double pole.

next up, the hot water buffer vessel should be in parallel with the oil boiler, to achieve the desired efficiencies with the oil boiler for now...you could just provide valves on the LPHW headed to accept the buffer vessel in future.

And now for what I didn't ask: what is the floor area of the house (to assess your heat requirements)? And have you done the DEAP BER yet?

How are you planning on complying with building regs 2008? You can either do it by 10kWh/m2/year of heat, or 4kWh/m2/year of electrical renewables - maybe you can do that here?

baldric

thanks dardania

btw what does the lp in lphw mean? sorry for ignorance

the house was started a good few years ago, when I had even less sense than I have now and I do a bit for few months each year when I have a few quid floating around.

anyway the house is about 4000 sq feet plus garage ( attached ) so it should be ready when I retire.....its pre 2008 regs so dont need to comply with those.

I have someone doing a rad schedule for me at the moment and the heating is on 2 circuits and one for domestic hot water

2011

Dardania wrote: »

I think 6.4kW is the max electrical input permissable for micro generators, so the numbers stack up. Also, include a 20A RCBO B type in your consumer unit to accept the electrical input.

Interesting post.

I never hear about this limit on micro generation.
I assume you mean 6.4kVA, not 6.4kW?

I am assuming from reading your post that you are not suggesting that the turbine is synchronized with the grid, instead it is simply connected directly to immersion elements to heat water. This makes sense to me as it would dramatically reduce the capital cost of the install. However if this is the case I would think it best to keep both systems electrically separate. This would mean that the RCBO would not be installed in the consumer unit. Perhaps you could clarify, thanks.

2011

baldric wrote: »

btw what does the lp in lphw mean? sorry for ignorance

Low Pressure Hot Water

Dardania

baldric wrote: »

thanks dardania

btw what does the lp in lphw mean? sorry for ignorance

the house was started a good few years ago, when I had even less sense than I have now and I do a bit for few months each year when I have a few quid floating around.

anyway the house is about 4000 sq feet plus garage ( attached ) so it should be ready when I retire.....its pre 2008 regs so dont need to comply with those.

I have someone doing a rad schedule for me at the moment and the heating is on 2 circuits and one for domestic hot water

As 2011 said, Low Pressure Hot Water - basically the water generated by a gas or oil boiler - typically .6 - 1.5 bar at 60 to 80 degrees Celsius flow temperature.

This LPHW is what is piped around the house to feed radiators and the hot water storage cylinder - see the schematic here: http://www.rvr.ie/Advice/Specifiers/Solar_Central_Heating_For_Houses/1_1_1_4_0_1/ for something similar to what I reckon you would use - substitute the solar panels with a wind turbine feeding an electric immersion element. The way you're circuiting it is the right way... What boiler are you using?

The reason I asked for the floor area of your house and the building regs compliance to get a very rough idea of the heat losses from it, and therefore the amount of heat input required to replace the heat lost to the atmosphere.

At 4000sq feet, that's approx. 371 square metres = multiply that by 60W per square metre (a very rough guess, erring on the cautious side) means heat losses of 22kW...

That would suggest at least 4 no. of the Montanas from here: http://www.greenenergytechnologies.ie/dom_t01.asp

If you knew the u values of your house, you should check them against Building Regs Part L 2011 - what you spend on insulation will save having to input heat in the future - maybe get a BER certificate done to check the houses performance while its still be worked on? Is the person sizing your rads able to do a heat loss calculation like this: http://www.plumbingpages.com/featurepages/Heatloss.cfm

2011 wrote: »

Interesting post.

I never hear about this limit on micro generation. Do you mean 6.4kW or 6.4kVA? I am just curious.

I am assuming from reading your post that you are not suggesting that the turbine is synchronized with the grid, instead it is simply connected directly to immersion elements to heat water. This makes sense to me as it would dramatically reduce the capital cost of the install. However if this is the case I would think it best to keep both systems electrically separate. This would mean that the RCBO would not be installed in the consumer unit. Perhaps you could clarify, thanks.

I got the 6.4kW from here: http://www.esb.ie/esbcustomersupply/residential/price-plans/micro-generation-scheme.jsp and it's actually 6kW...don't know how I made that mistake... Regarding power factor (as against 6.4 / 6kVA) it would be in ESB Network's best interests to have unity power factor generators I wouldv'e thought... if you look at the tech documentation here: http://www.esb.ie/esbnetworks/en/downloads/conditions_governing_the_connection_and_operation_of_microgeneration_131106.pdf they allow it to be better than 0.95...

I am presuming the wind turbine is operated in parallel with the mains so that if there is no power, there is still heat available from the mains, and when there is plenty of wind available but no heat (or any other) load, the electricity can be simply exported to the ESB Network. The practice of separating the two power sources is unnecessarily complex in my opinion.

Why would the capital cost increase for connecting to the mains? I've heard it can be horrendous for large scale production, but for micro is it much?

The RCBO should be installed between the micro generator & the electrical load - of the micro generator is connected to the mains then the consumer unit is the handiest, however if its direct to any other load then it will have to be between them...

evosteo

if you combined this wind energy and domestic solar water heating, i reckon it would be possible to supply 80-90% of the heating demand of the household through renewables

thats a very attractive proposition.

i also like the idea of the wind turbines souly suppling the buffer elements,

winter -cold and windy, brilliant idea if you ask me

Dardania

now that you mention the idea of mixing in solar, there is a kind of elegance to your idea!

the hot water demand is constant all year, and solar irradiation is relatively predictable.

and the colder it gets outside from the wind, the more heat is needed, so it should scale nicely together if sized correctly...

2011

Dardania wrote: »

I got the 6.4kW from here: http://www.esb.ie/esbcustomersupply/residential/price-plans/micro-generation-scheme.jsp and it's actually 6kW...don't know how I made that mistake... Regarding power factor (as against 6.4 / 6kVA) it would be in ESB Network's best interests to have unity power factor generators I wouldv'e thought... if you look at the tech documentation here: http://www.esb.ie/esbnetworks/en/downloads/conditions_governing_the_connection_and_operation_of_microgeneration_131106.pdf they allow it to be better than 0.95...

I see that this document refers to kW, so point taken. I normally see generators are rated in kVA, not kW as power factor will depend on the load/generator combination.

I am presuming the wind turbine is operated in parallel with the mains so that if there is no power, there is still heat available from the mains, and when there is plenty of wind available but no heat (or any other) load, the electricity can be simply exported to the ESB Network. The practice of separating the two power sources is unnecessarily complex in my opinion.

I am not saying that this could not or is not done. I thought in your example you were suggesting not to do this. I have worked in plants were they use large generators at peak times in parallel with the ESB supply for "peak shaving". I have also been involved with smaller installations where wind turbines are connected directly to immersion elements at 110VAC (via an RCBO). This saves quite a bit of equipment and installation costs.

Why would the capital cost increase for connecting to the mains? I've heard it can be horrendous for large scale production, but for micro is it much?

To connect to the ESB network all sorts of conditions have to be met in terms of voltage, frequency, form factor etc. Also both systems (ESB supply and generator) have to be in sync with each other (not out of phase). To comply is not cheap, believe me.

On the other hand, if you have a small wind turbine (this is all you require for 2 x 3kW elements) then these issues are not relevant. If for example you O/P voltage drops below 190VAC and the frequency is only 45Hz it will can still heat water (albeit to a lesser extent), but this would not suitable for connection to the grid.

The RCBO should be installed between the micro generator & the electrical load

Agreed.

- of the micro generator is connected to the mains then the consumer unit is the handiest

Or in something like Emma

Dardania

2011 wrote: »

I see that this document refers to kW, so point taken. I normally see generators are rated in kVA, not kW as power factor will depend on the load/generator combination.



I am not saying that this could not or is not done. I thought in your example you were suggesting not to do this. I have worked in plants were they use large generators at peak times in parallel with the ESB supply for "peak shaving". I have also been involved with smaller installations where wind turbines are connected directly to immersion elements at 110VAC (via an RCBO). This saves quite a bit of equipment and installation costs.



To connect to the ESB network all sorts of conditions have to be met in terms of voltage, frequency, form factor etc. Also both systems (ESB supply and generator) have to be in sync with each other (not out of phase). To comply is not cheap, believe me.

On the other hand, if you have a small wind turbine (this is all you require for 2 x 3kW elements) then these issues are not relevant. If for example you O/P voltage drops below 190VAC and the frequency is only 45Hz it will can still heat water (albeit to a lesser extent), but this would not suitable for connection to the grid.


Agreed.


Or in something like Emma

For small scale energy producers, the synchronization process & guarantee of of correct voltage, frequency etc, is done with G83 modules which can be back at the consumer unit or even integrated into the power producer itself - this is how I've seen it done with CHP units, and I'd imagine that's how it's done with wind turbines. The G83 also has mains voltage detection to open the circuit to the wind producer in the event of a mains failure so that ESB Networks staff don't inadvertently get lifted when they work on the mains side...

In larger scale stuff, G10s play their part - but so far in my career I've only seen them for diesel generators that are not intended to run in parallel for extended times with the mains - I'd bow out of any discussion above that level! I also think that they have to be inspected by ESB Networks prior to energisation, and ESB Networks have 1 member of staff that does this for the entire country, so they are somewhat stretched!

The way to do what you note about using free energy when you have rather than need it is good, and that EMMA device could be very useful in that regard. The other way would be to have a second electric immersion element in your hot water storage cylinder that is connected directly to the wind turbine, and let it operate (thermostatically controlled) autonomously. In this instance however, you would want a smaller electric immersion element & wind turbine, to allow it store heat constantly slowly as it is available... Honestly though I prefer the EMMA with the wind turbine back feeding the mains for export also...

2011

Dardania wrote: »

For small scale energy producers, the synchronization process & guarantee of of correct voltage, frequency etc, is done with G83 modules which can be back at the consumer unit or even integrated into the power producer itself - this is how I've seen it done with CHP units, and I'd imagine that's how it's done with wind turbines.

I would imagine that these are not cheap.

The G83 also has mains voltage detection to open the circuit to the wind producer in the event of a mains failure so that ESB Networks staff don't inadvertently get lifted when they work on the mains side...

Makes sense, I was talking to an ESB employee a while ago that expressed concern about illegal generators connected to the network on the customer side. These would back feed when the ESB supply was switched off!

The way to do what you note about using free energy when you have rather than need it is good, and that EMMA device could be very useful in that regard.

I have not used it, but I had a good chat with a company that sells it. www.coolpower.ie
Again, this is not a cheap device. This would be typical of the large capital cost that I was referring to.

The other way would be to have a second electric immersion element in your hot water storage cylinder that is connected directly to the wind turbine, and let it operate (thermostatically controlled) autonomously.

Yes, the cheap and cheerful route as per my earlier post. Granted, not as good but the install costs considerably less.

In this instance however, you would want a smaller electric immersion element & wind turbine, to allow it store heat constantly slowly as it is available...

+1

Honestly though I prefer the EMMA with the wind turbine back feeding the mains for export also...

A better job for sure, but it will take a long time before a net gain is made financially.

evosteo

its usually the simplest and cheapest methods of doing a job pay off in the long term:rolleyes:

Dardania

evosteo wrote: »

its usually the simplest and cheapest methods of doing a job pay off in the long term:rolleyes:

True that, especially in home installations - not as though all homes are handed over with O&Ms!