gc100

My Solar quote

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If they just allowed the current deemed/metered export payments for all new installations, without the MCS premium (which adds nothing worthwhile, IMHO) then it would be a bit fairer. 

 

We generate around 6,000 kWh/year, and don't have metered export (although I'd have no problem with an export meter being fitted) so receive the deemed export figure of 50% of generation (as recorded on the generation meter). 

 

Ignoring the FiT subsidy, the 3,000 kWh of deemed export that we receive payment for gives us about £157/year, which seems reasonable to me.  Added to the value of the 3,000 kWh that we generate and use gives a net annual saving of around £600 a year, so not to be sniffed at.  I particularly like being able to charge my car for free for more than half the year.

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What kind of draw (16A/32A) for the EV car is needed?

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39 minutes ago, gc100 said:

What kind of draw (16A/32A) for the EV car is needed?

 

Varies between 6 A and 32 A.  My (home made) charge point can be switched to "solar mode" where it varies the max current available control pilot signal to the car so that the charge rate  tries to match the amount of excess PV generation.  It can't go below 6 A, because that's the minimum that the car will accept.  The unit has a threshold for switch on, so it doesn't start charging the car until PV export exceeds 1500 W.  It then maintains the charge to the car, allowing it to use more power if the PV system is still trying to export to the grid. 

 

It never gets as high as the 32 A maximum in this mode, as maximum from the PV system is only around 25 A or so.  The unit can also be switched to fast charge mode (32 A) if I need to charge the car quickly and am not concerned about using excess PV.  This fast charge mode can also be set on a timer, so that the car fast charges overnight, during the E7 off peak period.

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2 hours ago, scottishjohn said:

If micro generation is going to help save the planet ,then it has to make economic sense or it will never be taken up enough to make sod all difference

I think it does, just that we tend to ignore it.

https://www.bbc.co.uk/sounds/play/m00051lf

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This would seem a good thread to ask this question:-

I have concerns about over-heating due to glass and aspect and solar gain.

Now, if the sun is shining to warm the house would it not be a good idea to run AC from PV array to cool it for free?

Sounds too simple

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9 minutes ago, SlivenClod said:

This would seem a good thread to ask this question:-

I have concerns about over-heating due to glass and aspect and solar gain.

Now, if the sun is shining to warm the house would it not be a good idea to run AC from PV array to cool it for free?

Sounds too simple

 

It's what we do, in fact it's running now as I type this, and is being powered by the excess PV generation.

 

Far better to try and prevent the heat getting in in the first place though, as it takes time to cool things down.

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48 minutes ago, JSHarris said:

 

It's what we do, in fact it's running now as I type this, and is being powered by the excess PV generation.

 

Far better to try and prevent the heat getting in in the first place though, as it takes time to cool things down.

I understand I should be keeping it out, but we love the outdoors and we have fabulous views.

So how do I make best use of the PV generated  power other than AC on the hot days?

PCM heat store, MVHR,  ASHP, ? 

Is it worth having an old fashion immersion heater for DHW?

As you can see I am might confused at the moment and trying to absorb as much info as I can.

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You can still have views, but you can significantly reduce the solar gain coming in through the glass.  We've done this retrospectively, and it's been far less effective and cost more money than it would have done if I'd realised the scale of the problem and designed it out by specifying a better glazing solution.

 

The main issue is that active cooling is relatively slow to respond, as by the time it turns on there is already a fair bit of heat energy stored in the house.  The consequence of this is that the active cooling needs to continue to run for a time after the PV system has stopped generating an excess.  Again, by coincidence, we have this situation right now - PV generation has dropped yet the cooling is still running, and probably will for another hour or two.

 

I'm glad I opted to install cooling, but have repeatedly kicked myself for not having invested more in the relatively large area of glass we have.

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2 hours ago, SlivenClod said:

This would seem a good thread to ask this question:-

I have concerns about over-heating due to glass and aspect and solar gain.

Now, if the sun is shining to warm the house would it not be a good idea to run AC from PV array to cool it for free?

Sounds too simple

 

Deep pockets? Sageglass:

 

 

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It's possible @JSHarris and @SlivenClod are talking past each other here:

 

AC = air conditioning, perhaps.

AC = active cooling, perhaps.

 

I don't think @JSHarris has air conditioning as such (might be wrong - maybe he has a cooler in the MVHR, can't remember). What he does have, though, is an air source heat pump (ASHP) driving the underfloor heating (UFH) which can operate in cooling mode (so UFC???) to drop the ground floor slab temperature a few degrees and thereby cool the house.

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11 minutes ago, Ed Davies said:

It's possible @JSHarris and @SlivenClod are talking past each other here:

 

AC = air conditioning, perhaps.

AC = active cooling, perhaps.

 

I don't think @JSHarris has air conditioning as such (might be wrong - maybe he has a cooler in the MVHR, can't remember). What he does have, though, is an air source heat pump (ASHP) driving the underfloor heating (UFH) which can operate in cooling mode (so UFC???) to drop the ground floor slab temperature a few degrees and thereby cool the house.

 

Yes, we do have an air-to-air heat pump in the MVHR, as well as floor cooling using the UFH and its ASHP in cooling mode. Today it was the MVHR cooling that was on, as the floor cooling has a much slower response, and tends to only be used when we have long periods of warm weather.

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