The Optimum Inclination Angle Engineering Essay

The intent of this assignment is to plan a basic grid connected photovoltaic system for my ain house. The system will be installed on the roof and will dwell of a PV array connected through an inverter to AC tonss of the house and to the grid. The analysis of the system operation is given in the following subdivision. Furthermore, the study takes into history the site location and determines any facets that may act upon the design of the system. In add-on, a suited PV faculty and inverter are selected and the computations sing the matching of these constituents are presented, every bit good as for any other equipment in the system that is required to be rated. Finally, the array mounting method is discussed and the system ‘s part to the edifice ‘s burden is estimated.

The information sing the irradiation degrees and the optimal disposition angle for the location of the site are presented in Appendix A.

System Description

The Grid connected system avoids the demand and later the costs for electricity storage in batteries by utilizing the grid as a battery system. The produced electricity is sold to the grid. When the system does n’t bring forth any electricity, power is drawn from the grid. This machine-controlled procedure is performed by a net metering or net charge plan. An advanced or 2nd grid metre is added to maintain path of how much electricity has been sold to the grid.

The Grid Connected PV system design has the undermentioned constituents:

PV Array or Generator: A figure of PV faculties connected in series and/or in parallel giving a DC end product out of the incident irradiance. The orientation and joust of these panels are of import design parametric quantities, every bit good as shadowing from environing obstructors.

Inverter: A power convertor that inverts the DC power from the panels into AC power. The features of the end product signal should fit the electromotive force, frequence and power quality bounds in the supply web.

Tonss: Bases for the web connected contraptions in the edifice that are fed from the inverter, or, instead, from the grid.

Meters: They account the energy being drawn from or fed into the grid.

Grid: A individual or three-phase web managed by a Public Electricity Supplier.

A conventional block diagram of a basic grid connected system is shown in Fig. 1.

Figure 1: Conventional diagram of a basic grid connected PV system ( beginning: [ 6 ] )

The Site

A site visit is required before planing so as to find the of import facets that may act upon the design. These are the solar panel orientation, tilt angle and the solar entree to the site. Obstructions that may happen to shadowing every bit good as other issues that can increase the installing cost should be besides identified. Last but non least, there are installing and statute law criterion policies that have to be taken into history.

For the intent of the undertaking, the house is located in a suburb near Athens, Greece. The belongings has 110m2 roof south confronting with an disposition angle of 30 & A ; deg ; . The mean day-to-day irradiation is 4.944kWh/m2 at the optimal disposition angle 30 & A ; deg ; ( solar informations are presented in Appendix A ) [ 1 ] . The site is characterised by high temperatures in the summer period and clear conditions conditions both in summer and winter periods. A image of the belongings is shown in Figure 2.

Figure 2: Picture of the belongings ( beginning: Google Earth )

Harmonizing to the state ‘s statute law sing PV systems installed on house roofs ; a system should non transcend the capacity of 10kWp.

Another of import facet is that there is adequate infinite under the rooftop that can host the inverter supplying protection against heat, rain and understating the inverter ‘s noise degree under operation.

Design and Installation

PV Module Selection

The selected PV faculty is the Panasonic HIT-H250E01 that generates up to 250Wp end product ( 20.8 % cell efficiency and 18 % faculty efficiency ) . The cell construction comprises a Hetero-junction with Intrinsic Thin-layer ( HIT ) and is composed of a thin mono-crystalline Si wafer surrounded by ultra-thin formless Si beds. [ 2 ]

The ground for taking this faculty is due to its high temperature operation ability, the higher care efficiency compared to other conventional crystalline Si solar cells.

Panasonic HIT-H250E01 250Wp

Rated Power










Max. Power electromotive force Vmpp


Max. Power current Impp


Open circuit electromotive force Voc


Short circuit current Isc


Temperature coefficient of Power

-0.3 % / & A ; deg ; C

Temperature coefficient of Isc

2.32 mA/ & A ; deg ; C

Temperature coefficient of Voc

-0.108 V/ & A ; deg ; C

Module efficiency

18 %

Cell efficiency

20.8 %



Table 1: Panasonic HIT-H250E01 250Wp faculty specifications [ 2 ] Figure 3: Picture of the faculty

Inverter Selection

The choice of the inverter depends on the energy end product of the array, the matching of the allowable inverter threading constellations with the size of the array in kilowatt and whether the system will utilize one cardinal inverter or multiple, smaller, inverters. Typically inverters are rated at 80-90 % of the array capacity so that high inverter efficiencies are maintained at lower power degrees. This means that really high power degrees are sacrificed since they are out of the scope of operation of the inverter.

The chosen inverter is the SMA SUNNY TRIPOWER STP 8000TL-10. The end product electromotive force is fixed at 230V and 50Hz. The inverter has a high efficiency of 97.5 % and a self-consumption of 1W at dark period. [ 3 ]


Minimum Input Voltage


MPP electromotive force range/ rated input

320V – 800V / 600V

Maximum Input Voltage


Maximum Input Current


Rated Power


Table 2: The SMA Inverter STP 10000TL-10 specifications

Figure 4: The SMA Inverter STP 8000TL-10 [ 3 ]

Module and inverter matching

The array electromotive forces are calculated at assorted conditions, in order to find the lucifer with the input scope of the inverter. Formula ( 1 ) is used for rectifying electromotive force values utilizing the temperature coefficient.

( 1 )

MPP electromotive force at 60 & A ; deg ; C:

The MPP electromotive force at 60 & A ; deg ; C should be higher than the minimal input electromotive force of the inverter. Therefore, minimal figure of faculties in twine:

Voc at -10 & A ; deg ; C:

Voc at -10 & A ; deg ; C should be lower than the maximal input electromotive force of the inverter. Therefore, maximal figure of faculties in twine:

17 Faculties are chosen to be connected in series.

at STC for individual faculty

at STC ( 25 & A ; deg ; C ) for 17 panels connected in series:

MPP electromotive force at STC of the twine should be within input electromotive force scope of the inverter

The MPP electromotive force at STC is really near to the rated input electromotive force of the inverter 600V, intending that the system will run really near to the rated efficiency ( 97.5 % ) .

System maximal current ( Isc at STC ) should be lower than the maximal input current of the inverter. Therefore, maximal figure of faculties in analogue:

The array will dwell of faculties.

Array capacity: .

The array requires an country of

Inverter/Array ratio:

Other System Equipment

Wiring Specification

Safety allowance on current capacity of wiring set at 25 % of the Isc of the array.

Safety allowance on electromotive force capacity of the wiring set at 15 % of the Voc of the twine:

MC4 connections to be used.


The house metre has to be replaced with a 1 that tracks the AC electricity drawn from and supplied to the gird.

Mounting method

There is a figure of systems which already exist in the market for put ining PV systems on to an inclined roof. The belongings has ceramic roof tiles. The tiles are fitted together overlapping one another and are held chiefly by gravitation. The most common manner to mount PV faculties on such a roof is to utilize a climb construction. A simple method is to put in roof hooks/anchors ( Fig.5 ) on to the sub-structure of the roof and so attach the tracks on the maulers ( Fig.6 ) . Then the PV faculties can be easy attached and fixed on the construction ( Fig. 7, 8 ) .Concrete Roof tile hookPantile Roof tile hook

Figure 5: Roof hook [ 4 ] Figure 6: Railing attaching the hook [ 4 ] Figure 7: Repairing PV faculty to a rail. [ 5 ] pv pro on roof mounting system anti larceny

Figure 8: PV faculties attaching the climb system [ 4 ]

The 8.5kWp system consists of 34 faculties ; hence 34 roof mounting kits are required.

System part to the edifice ‘s burden

The 8.5kWp PV system is estimated that can provide an one-year power of:

The edifice ‘s one-year energy ingestion is estimated ( from 12month charging informations ) to be 10200kWh. The PV system can bring forth of that demand ; intending that it will bring forth more than the needed electricity, selling the extra energy to the grid.