Solar power station in Ruse city

Solar power station 21.78 kWp

Increasingly people want to reduce their dependence on energy suppliers. The number of supporters of modern technology, whose dream is to accelerate the movement of mankind to the pure future, signifficantly grows.

One of these enthusiasts has asked us to install a solar power plant on the roof of a farm building. The task was put in the following way: to use the entire roof area as efficiently as possible. For its decision, we have chosen the Panasonic Solar HIT 330 photoelectric modules with high efficiency (19.7%) and low temperature coefficient of change of power (-0.29% / ° C).

Preparation for the installation of a solar power plant

The roof has a one-sided slope with dimensions of 24.5×5.25 meters or ~ 128.6 m2, azimuth 27° (at South = 0°) and angle of inclination 35°. The dimensions of each single module are 1053×1590 mm and the mounting distance between them is about 20 mm.

The technical parameters of the photoelectric modulePanasonic Solar HIT 330

After discussing the possible options with the customer, we focused on the vertical layout of the modules in 3 rows of 22 pieces. Thus the width of the installation will be 22×1,053+21×0.02≈23.59 m and the height 3×1.590+2×0.02=4.81 m. The total solar installation will be 23.59×4.81 m or ~ 113.5 m2, which corresponds to ~ 88% of the roof area.

If we use 66 modules of 330 Watts each, the installed DC power of the solar power plant will be 21.78 kW at peak (kWp).

The house is located near the town of Rousse and before starting work we conducted an analysis of this area to determine the potential of using solar energy.

Solargis data for the region

Insulation for one year
GHI1 405 kW·h/m2
DHI628 kW·h/m2
DNI1 296 kW·h/m2
Average air temperature
Year11.9 °C
January-0.8 °C
July24 °C
Altitude68 m
Tilt of the terrain1.5°
Azimuth on the terrain121° (SE)

The most important type of insulation for photovoltaic systems is GHI — Global Horizontal Irradiation. The GHI of the Solargis data area is 1405 kWh / m2 / year:

Solar Insulation Map for Rousse

PVGIS data for the region

GHI of the region according to PVGIS data — 1480 kWh / m2 / year and is distributed as follows:

Schedule of total yearly insolvency on a horizontal surface

GHI statistics from 2007 to 2016:

GHI statistics for 10 years

Horizon Specificity for Specified Coordinates (South = 0 °):

Line of the horizon and trajectories of the motion of the sunThe blue line shows the trajectory of Sun’s motion in the sky on the day of the winter solstice, December 21, and the red line on the day of the summer solstice, June 21

Preliminary assessment of electricity generation

Taking into account the climate and isolation data, the azimuth and angle of slope of the solar modules as well as the horizon specificity for the site, the annual PVGIS module surface insulation will be 1660 kWh / m2 / year and will be distributed as follows:

Annual insulation of the module surface

With such output data, the 21.78 kWp solar power plant will produce 31.7 MW of electricity per year, which will be distributed as follows:

Annual insulation of the module surfaceThis schedule shows the power output of the solar modules before converting it into AC. No losses in wires and inverters are taken into account here, but the average heat losses associated with solar heating during the warm season are taken into account, and this indicator is signifficantly better for Panasonic Solar than the average for the market.

Installation of the solar modules

Panasonic Solar modules are delivered to the mounting location well packed on two pallets:

Supply of Panasonic Solar photoelectric modules in Rousse, Bulgaria

NENCOM as official distributor of Panasonic Solar offers competitive prices, fast delivery, professional installation and a 25-year warranty of modules.

Supply of solar modules Panasonic HIT 330

We have securely fastened the aluminum profile clips to the wooden beams on the roof:

Mounting of solar power staples

Installation of solar power staples

Placing brackets for photoelectric modules

On the brackets we placed aluminum profiles for mounting the photoelectric modules:

Installation of aluminum profiles for solar power station

Installing aluminum profiles for mounting the photoelectric modules

To join the photovoltaic modules with the shield, we used a special cable from the German company IBC Solar, resistant to temperature spikes and the effects of direct sunlight:

The special cable of IBC Solar for a solar power plant

Laying the solar power cable

We also made lightning protection and earthing of the entire installation:

Earthing of a photoelectric station

Earthing of a solar power station

Installing and inspecting the first solar module Panasonic HIT 330:

Open circuit voltage of the photovoltaic module Panasonic HIT 330

The idle (no load) voltage exactly matches the factory performance — 69.7 B, although the insulation is now considerably less than the «standard» 1000 W / m2. The whole thing is the temperature: the cooler it is, the more efficient the photoelectric modules work on.

The cold not only increases the efficiency of solar modules, but also embellishes them with patterns:

Solar modules in the cold

Photoelectric modules in the cold

Solar modules at negative temperatures

Solar modules during the cold seasonOur efficiency in the cold also proved to be higher :)

We put together 66 modules in 6 strings in 11 pieces. In each string, the modules are connected in series, providing open circuit voltage of about 770 volts:

Solar modules at negative temperatures

Celebrating the last solar module:

Completion of solar power installation

Panasonic Solar modules not only work efficiently but also look great:

Solar power station NENCOM on the roof of a house

Solar power station NENCOM in Rousse

Solar power station NENCOM in Bulgaria

Solar power station NENCOM in Bulgaria

Solar power station NENCOM in Bulgaria

A movie about our work

We have traditionally shot a short video about our work on the site:

The first part of the project is completed. For the second part we buy inverters and lithium-ion energy storage.

See also:


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