Solar Panels UK - is it worth it?

[RedMod3]

@PITA/@RedMod3 - do you mind me asking what external compressors you have paired with those and how noisy/big they are? Thanks.

I looked at a relative’s large external Samsung unit recently (air-to-water) - and once I got more than three or four metres away - I was thinking the local road/aircraft noise was louder. The air-to-water setup needed a lot of ‘plant’ in the loft. But I’m suspecting air-to-air plant requirements might be near nought.

(PITA - I remember you mentioning new installs would also need to consider the condensate pump need/siting)

I have a 7.5kW compressor powering 2 ceiling cassettes and one wall unit. Also a 5kW compressor powering 2 wall units. They consume a maximum 1/3 of that power, more like 1/4. Both are Toshiba and outside and both are very quiet and inaudible inside. Went for two compressors in case one failed, so at least one would work. The indoor units and compressors both need condensate pipes, they are invisible in our installs.

 

[RedMod3]

Forgot to add external compressor photos. Our ceiling cassettes have pumps built in so just needed 15mm pipes to drain outside.

Compressors have feelings, I like to keep ours dry.

 

[Avendit]

Forgot to add external compressor photos. Our ceiling cassettes have pumps built in so just needed 15mm pipes to drain outside.

Compressors have feelings, I like to keep ours dry.

Looks like the external units are all almost identical! Ours is bigger, and is a Panasonic unit, but it doesn't look like you can tell the differences between air to air and air to water.

All the plant on our install is a giant HW cylinder and the wet heating system. I'm guessing for the air to air systems you need a different solution for the HW?

 

[PITA]

Forgot to add external compressor photos. Our ceiling cassettes have pumps built in so just needed 15mm pipes to drain outside.

Compressors have feelings, I like to keep ours dry.

Haha nice little shelter there... surprised no solar panels on the roof section

 

[PITA]

All the plant on our install is a giant HW cylinder and the wet heating system. I'm guessing for the air to air systems you need a different solution for the HW?

We kept our Gas Boiler Central Heating system... which also heats our water tank.

We also have a Solar Diverter (Myenergi Eddi) and emersion heater, which also heats our water tank.

Idea being we can heat the house with Gas or Electric.

I didn't shy away from Gas completely, as used very sparingly, it's still OK as a backup.

Most of our heating and cooling throughout the year is Heat Pump. Deep Winter cold days, we use Gas still for a nice hot house.

Eventually, I'll most likely convert to a Air to Water Heat Pump for Central Heating... and similar to @RedMod3 have two Heat Pumps. One Air to Air, and one Air to Water.

 

[RedMod3]

Looks like the external units are all almost identical! Ours is bigger, and is a Panasonic unit, but it doesn't look like you can tell the differences between air to air and air to water.

All the plant on our install is a giant HW cylinder and the wet heating system. I'm guessing for the air to air systems you need a different solution for the HW?

We used to have E7 so we still have our 30 year-old foam covered water cylinder with a top and bottom immersion. Heating water at E7 rates supplemented by an Earthwise solar diverter has been simple and cheap with low maintenance. I swap the immersion element leads over as necessary.

I think the air to water compressors are much bigger and the pipes are larger. Our pipes are 1/4 and 3/8. Also getting rid of storage heaters saved a lot of space.

 

[RedMod3]

Haha nice little shelter there... surprised no solar panels on the roof section

The shelters are north facing, had they been south facing, it might have been a good idea.

 

[exlatccatsa]

Forgot to add external compressor photos. Our ceiling cassettes have pumps built in so just needed 15mm pipes to drain outside.

Compressors have feelings, I like to keep ours dry.

The roof helps with icing, mine doesn't freeze up half as much with the roof on it.

 

[PITA]

The roof helps with icing, mine doesn't freeze up half as much with the roof on it.

... didn't realise that was a 'thing'

The Toshiba Units have a 'de-ice' mode to keep it clear of ice. Ours went through last Winter and didn't have any issues. However it's protected on all sides by 3 sheds. So the wind doesn't really get to it.

 

[phil4]

... didn't realise that was a 'thing'

The Toshiba Units have a 'de-ice' mode to keep it clear of ice. Ours went through last Winter and didn't have any issues. However it's protected on all sides by 3 sheds. So the wind doesn't really get to it.

We've got roof mounted A/C in the office here, it does heating and cooling.

There's nothing worse in the winter than the compressor going into defrost... which results in cold air being blown around the office. Really not nice.

I'm sure things have improved, but I fear even "not blowing warm air" might not be so good when you're trying to warm up a room.

 

[Avendit]

... didn't realise that was a 'thing'

The Toshiba Units have a 'de-ice' mode to keep it clear of ice. Ours went through last Winter and didn't have any issues. However it's protected on all sides by 3 sheds. So the wind doesn't really get to it.

They all do, but they are 'expensive,' or use power without generating heat. @Jeremy Harris (used to be a member, but don't see his account in the @ anymore) did more research than is probably healthy on it: Maximising the COP of an ASHP

 

[hash]

Yes it's likely to be correct assuming they are 380 to 400w panels giving you a 3.8 to 4kW array.
One inverter should be fine, it might be a 3.6kW or 5kW one ( likely to be 3.6kW)
The reason for two inverters, like my order, ( besides 18 panels and 7.2kW) is to take advantage of 4 hour window charging each battery fully, one inverter of the Givenergy type wouldn't achieve this on that 4 hours as max charge rate is 3.6kW.
Also, having two inverters in my scenario enables the house to be supplied with a max demand of 7.2kW if needed.

so with one inverter how much charge will I get into the batteries ? in 4hrs at 5p per hour will I be able to charge the 1 battery fully? or perhaps some in the second one as well?

Thanks

 

[94jdh]

so with one inverter how much charge will I get into the batteries ? in 4hrs at 5p per hour will I be able to charge the 1 battery fully? or perhaps some in the second one as well?

Thanks

Depending on which inverter you were quoted, gen1 max 2.6kW per hour, would give you a max of 10.4kW out of a potential 19kW if both were completely empty.
Gen2 inverter max 3.6kW per hour, would give you a max 14.4kW.
So both generations of the inverter would give you a minimum of one battery fully charged if reliant on cheap rate only.

 

[Liquidv]

Does anybody know if companies install solar panels on top of fibre cement roofs?

 

[Liquidv]

Can anyone recommend any Solar installer companies in the Bexleyheat/Dartford area please?

Thanks

 

[PITA]

Depending on which inverter you were quoted, gen1 max 2.6kW per hour, would give you a max of 10.4kW out of a potential 19kW if both were completely empty.
Gen2 inverter max 3.6kW per hour, would give you a max 14.4kW.
So both generations of the inverter would give you a minimum of one battery fully charged if reliant on cheap rate only.

One of the reasons I chose two Powerwalls was the charge rate capability.

They're really good actually. Charge at 10kW... even with our Car Charging at 7kW as well. Took a screenshot the other day with them at full power before I went to sleep.

Normally they'll throttle back at around 7kW, because that's always enough to get 27kWh stored in 4 hours... but I started the charge late, so they had less 'off-peak' time to do it in.

The 10kW charge rate can be useful if you're limited in some way by time period... or Grid availability, in between scheduled or unscheduled blackouts as an example.

 

[RedMod3]

One of the reasons I chose two Powerwalls was the charge rate capability.

They're really good actually. Charge at 10kW... even with our Car Charging at 7kW as well. Took a screenshot the other day with them at full power before I went to sleep.

Normally they'll throttle back at around 7kW, because that's always enough to get 27kWh stored in 4 hours... but I started the charge late, so they had less 'off-peak' time to do it in.

The 10kW charge rate can be useful if you're limited in some way by time period... or Grid availability, in between scheduled or unscheduled blackouts as an example.

View attachment 798029

I chose two, though the second is yet to be installed, is the 10kW peak draw capability and the opportunity to last double the time at 5p/kWh. We are due to pay 15.9p / KWh in an hours time as one PW is not enough.

 

[94jdh]

One of the reasons I chose two Powerwalls was the charge rate capability.

They're really good actually. Charge at 10kW... even with our Car Charging at 7kW as well. Took a screenshot the other day with them at full power before I went to sleep.

Normally they'll throttle back at around 7kW, because that's always enough to get 27kWh stored in 4 hours... but I started the charge late, so they had less 'off-peak' time to do it in.

The 10kW charge rate can be useful if you're limited in some way by time period... or Grid availability, in between scheduled or unscheduled blackouts as an example.

View attachment 798029

I originally looked at two powerwalls only, but having looked at the alternatives, I could still have a 7.2kW solar array installed with two inverters and two 9.5kW batteries that will still give me a very capable max rate of: around 7.3kW when needed.
That and also savings of a few grand on top.

 

[PITA]

I originally looked at two powerwalls only, but having looked at the alternatives, I could still have a 7.2kW solar array installed with two inverters and two 9.5kW batteries that will still give me a very capable max rate of: around 7.3kW when needed.
That and also savings of a few grand on top.

Really, that sounds good.

How much did you pay for 7.2kWp Solar Array and 19kWh storage batteries?

Cheers

 

[94jdh]

Really, that sounds good.

How much did you pay for 7.2kWp Solar Array and 19kWh storage batteries?

Cheers

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