Photovoltaic modules produce electricity from solar radiation - sunlight.  PV modules consist of a number of semiconductor PV cells connected together to provide a 'standard' voltage of 12V DC. Current and power output will vary with light level peaking in bright sun however they will still produce on grey and overcast days.

 

In comparison to solar thermal installations 'PV' is very expensive however this can be offset.  Subject to conditions, there are government grants available however we, 'JWSolarsolutions' have found that grid tie is proving to be cost effective by the energy supplier purchasing surplus electric at £0.28p (from 1st April 2009)per KWH.

 

 

 

 

 

The project first started in April 2008 where in purchased 6 x BP380 80watt PV panels along with a Mastervolt Soladin 600 inverter. This Inverter was small, easy to install basically being able to plug straight into a power socket. It is of course G83 UK compliant. These panels were placed on my garage facing South (160 degrees). Construction for the mounting frame was made from timber as this was very temporary and they would soon be changed.

 

 

 

 

At this time I changed my electricity supplier to Southern Electricity and applied for an Export Meter. This took about 3 months in total and was pretty straight forward. All G83 installation paper work was completed and a qualified electrician looked over the work and signed off the system. We decided to call the array ‘JWSolar’ with OFGEM. Paperwork was received from E.ON, Central Networks on May 13^th, 2008 giving approval for our Photovoltaic Generator to operate in parallel with Central Networks distribution system. Export meter was fitted at the end of June and we would be paid 18 pence for every KWH Exported from our system.

 

 

Having mastered the concept of Solar PV I decided to purchase the same amount of equipment again bringing the set up to 12 panels and 2 Inverters. The system would then be set up in an East/ West configuration with one Inverter running each array. The above array was dismantled and 6 panels were placed on each side of the garage. The roof angle was around 12 Degrees and output would be lower in the winter but would improve as the summer progressed gaining a little bit of output from the winter. Each side was now 480w each and ran throughout the summer without any problems with an additional 2 panels being added to the arrays, one on both sided bring each side up to 560watts, 1.12KW in total. Due to the positioning of these arrays design software was quoting 720KWH per 1KW install on the West facing roof (250 Degress) and 680KWH per 1KW installed on the East roof (70 Degrees)

 

 

 

Next challenge was to have a look at a Tracker system.

 

I purchased a Lorentz ETA-400 Tracker with 4 x KC130 PV Panels totalling 520watts and another Mastervolt Inverter. A 97mm mounting pool was placed through the Garage roof and inserted into a concrete base. The Tracker frame was mounted and PV panels added to the Tracker and all connected to the Inverter. This Tracker is single Axis but Dual Axis ones can be purchased. The Tracker Follows the sun from the East first thing in the morning and slowly moves throughout the day finally arriving at the West by late afternoon. It returns itself to the central position at the end of the day facing South in direction. The Tracker uses a small PV panel to keep the Voltage as high as possible throughout the day maximising output. The best output I have had from this array is 4.0KWH in any one day as I write this. I have found this very impressive when the best quotes normally promise 4 to 5 times output of your array in the summer. I get almost 8 hours on peak days.

 

Southern Electricity announced that for 6 months from October 1^st, 2008 the Export rate would be £0.20, an increase of £0.02 per KWH.

 

Now extremely busy with Solar Thermal Installs I did not have any spare time until the end of November. At this point I installed 4 x BP4175 Panels totalling 700watts in size along with a SMA Sunny Boy 700 Inverter to run this array. Panels were placed on my porch area which was proved pretty easy due to the height.  I found the SMA Inverter extremely well made, easy to set up and using a Heat Exchanger mounted on the top of the unit rather than a fan to cool the internal parts. Voltage can also be selected using a jumper system internally so different operating voltages can be used.

 

 

 

In March 2009 Southern Electric announced that from April 1^st, 2009 the Export rate would be increased to £0.28 per KWH Exported which was a massive increase. With this in mind it was time to optimise all equipment and some changes would be required. The very impressive 80 Tube Solar Thermal Collectors were repositioned with 2 of them removed to allow room for the PV Array. A frame was then constructed on the South Facing roof to house the panels mounted on the garage. Due to the size of the Arrays the Mastervolt Inverters were replaced with SMA Inverters. 2 rows of 9 x BP380 were installed on the roof, each row connected to a SMA Sunny Boy 700 set at 250 Volts. The frame in future could still house an additional 4 panels in Landscape at the top and another 3 along the Solar Thermal Panels. The roof now was sized at 1440watts and can be increased to 2080watts if required without any major work. Good ventilation was ensured using fixings that left good space between PV Panels and roof. At this point 'Radio Piggy Backed' wireless connection was also added to each of the 3 Inverters and a Sunny Beam Display was added. This device is wireless and communicates with the Inverters every 15 seconds telling the user outputs on each of the arrays and also keeps output records every day for the previous month. This information is downloaded daily and is stored on the SMA Website. It can be viewed by following this link; http://www.sunnyportal.de/Templates/PublicPageOverview.aspx?plant=509158bf-cb83-4dc7-b1fe-d0ef10d9553a&splang=en-GB It shows all daily outputs from the arrays and daily peaks. All days are available from April 09 to view. At this moment in time the info will not show the outputs from the Tracker mounted array, hopefully I will get to sort this out at some point.

 

 

 

The above modifications have completely changed the efficiency of the system and the results have been excellent. The system in total is 2.66KW and uses 4 Inverters. It is important to separate arrays if they face different directions at the voltage is normally determined from the panel which is outputting the lowest amount. Also shading is very important to avoid. A shaded area the size of an A4 sheet on 1 panel can reduce your output by 90% and by using a number of Inverters this can be avoided. DC Cabling should also be kept to a minimum to reduce loses. The figures so far shows that we have produced 1223.23KWH, exporting 940KWH for a 6 month period up to June 30^th, 2009. Export payment so far would be £246.72 and basically our electric bill so far this year is -£162.46 (credit). With everything in place and a good export rate we anticipate an electric bill a £0.00 and a credit of approx £400.00 per year. So far with Solar Thermal and PV we have produced a total of 2374.23KWH YTD (June 2009)

  

JWSolarsolutions can install high quality 'PV' arrays supplying BP or Sharp panels and SMA invertors.  These arrays can be roof or tracker mounted to suit the space available.  If you are interested in this product and would like advise, help or a quotation contact Justin.