My house solar project: What do you think :S

[Willbiker]

Hi All

I would like to invite you to comment on the solar install I am planning for my house. I consume around 10,000 kwh a year due to energy thirsty hobbies and with the crazy new tariffs here in the UK, I decided its time to invest in PV and be a little greener.

Although I have some basic electrical experience and have built a successful off grid solar system for my caravan, I am planning to install the system myself with the help of a builder friend however I have a solar qualified electrician lined up to inspect, connect up and sign off the system.

I would greatly appreciate your opinions on my proposal!

I have a 1960s pitched roof semi detached house which has the rear pitch facing south/east and the front pitch facing north/west. I have calculated the weight of my roof (roughly) and the PV hardware will weight considerably less than 15% of the roof weight so I understand no structural building control sign off is required.

PV:
I am considering going with JA Solar JAM60S10-335/MR BF Half cell panels and using online calculators, I have estimated the following energy generation:
String 1 - South/East, 3.685kw of panels (11x 335w), connected in series, Estimated production per year = 2,617 KHW
String 2 - North/West, 4kw of panels (12x 335w), connected in series, Estimated production per year = 2,662 KHW

Link to panels - https://www.tradesparky.com/solarsp...o-panels/ja-solar-jam60s10-335mr-bf-half-cell

Inverter:
I have purchased a Solis 1P6K-4G 6kw single phase inverter which has an AC limiting feature. According to the manual, each MPPT can accept a 4kw input and an input max voltage of 600v. The AC limiting feature will be set to 3.67kw and an application will be submitted by the Electrician to the grid (UkPowerNetwork) to comply with the rules for inverter installs over 3.67kw. The inverter will be mounted on a block wall in the loft with an AC and DC isolator for the in and out supplies. An armored cable will be run outside from the inverter to the house consumer unit (I don't fancy pulling floors up) where it will feed into a basic electrical meter before feeding into a 32a MCB on the CU. The CT current clamp to control the AC output will be mounted on the live grid supply tail.

Inverter Manual: http://www.durasun.be/Downloads/SOLIS 4G handleiding.pdf

Solar diverter
An Immersun solar diverter will also be installed to divert any unused solar power to my 3kw immersion water heater (and under floor heating in the future). The current clamp will be mounted on the live tail from the grid supply and the diverter will be mounted next to my CU connected to its own 16a MCB.

Here is my system diagram:


What do you think? Have I missed anything critical or calculated anything incorrectly.

Any advice would be greatly appreciated!

Thanks!

 

[Scixxor]

Hello, I would avoid putting panels north-facing if possible. They are much less efficient to the point it's normally not worth facing them north.

 

[Ampster]

If you are in an environment where air source heat pumps are practical I would consider that versus a diversion load. Since they move heat instead of create it they can be as much as five times more efficient than resistive heat. Heat pump water heaters are a good storage medium and can be put on timers. Mine consumes less that a kW an hour. I do not know if they are easy to source in the UK but here in the States they are easy to find.

 

[Welshman]

If you are in an environment where air source heat pumps are practical I would consider that versus a diversion load. Since they move heat instead of create it they can be as much as five times more efficient than resistive heat. Heat pump water heaters are a good storage medium and can be put on timers. Mine consumes less that a kW an hour. I do not know if they are easy to source in the UK but here in the States they are easy to find.

Air source heat pumps in the uk cost at least one and half kidneys……..

 

[Willbiker]

Hello, I would avoid putting panels north-facing if possible. They are much less efficient to the point it's normally not worth facing them north

Hi! Unfortunately I don't have a variety of roofs to pick from only 2. I either go for just the south/east pitch or the North/West pitch also and capture the afternoon/evening Sun. According the online calculators, I should still get 2662kwh. Even if the N/W array achieves 1/3 of a south facing array, it still should generate me at least 1200kwh minimum which In England right now, thats about £500 per year. Approximately a 4 year return on the additional investment.... Seems worth it I think.

 

[Willbiker]

If you are in an environment where air source heat pumps are practical I would consider that versus a diversion load. Since they move heat instead of create it they can be as much as five times more efficient than resistive heat. Heat pump water heaters are a good storage medium and can be put on timers. Mine consumes less that a kW an hour. I do not know if they are easy to source in the UK but here in the States they are easy to find.

I 100% agree! This will be my long term target however on my limited budget, this isnt possible right from the get go. I already have an immersion heater and hot water tank so this will be step one on the road to a greener house