Photovoltaic Energy Generating System used in the Eco-House

-  Solar Energy and especially the Photovoltaic (PV) generated energy, environmentally it is the most Clean and Green energy as no pollution is created in the process of generating electricity. Solar Energy is clean, renewable (unlike gas, oil and coal) and sustainable, helping to protect our environment.

-  A Photovoltaic (PV) generator consists of an assembly of photovoltaic panels that transform solar radiation into DC electrical energy and can be made up of:

Strings: X number of PV panels connected in series

 Array: group of X strings connected in parallel

Figure 1 Solar Panels combination

-  Large photovoltaic systems can be made up of several arrays, connected to one or more inverters. By maximizing the number of panels inserted into each string, it is possible to reduce the cost and complexity of the connection system of the photovoltaic system.

-  Photovoltaic panels transform energy from the sun into direct current (DC) and direct electrical Voltage. This DC voltage and current are supplied to an Invertor which convert the DC into AC voltage and Current which will supply the Electrical and Electronics home devices.

-  Two types of Solar System are used, one is the Stand Alone Solar System, in which bank of batteries are used in order to generate energy during the night or during non-sunny hours. And the other is Grid Connected Solar System in which the energy generated by the Solar System is exported to the National Grid during the sunny days and no need for the bank of batteries.

-   In accordance with local and national regulations, the power produced can be sold to the grid or credited towards future consumption, so bring­ing about a saving of money.

Figure 2 Solar System operating Diagram

 

-  The complete Grid Connected Solar System is shown in the figure 2

 

-  The number of the solar panels and the invertor capacity are designed according to the Eco House load demand and based on the principle of Zero Energy Balance ,i.e. what the eco house imported energy from the Grid , the Eco House PV generator will export nearly the same amount of energy to the grid.

 

-  The consumed energy per month in MWh and its percentage is shown in figure 3 .

 

Figure 3 Eco House Energy Consumption charts

-  Based on the above Load Demand for the Eco House  a Solar System are designed using a specialized software , the required number of the solar panel is 80 solar panels  each with 250 watt peak generated power ,connected to three phase Inverter  in order to generate a three phase voltage with rated power of 20Kw and total annual energy generated of 38.3 MWh.

 

Figure 4 Connection Diagram for 80 solar panels

-  The connected 80 solar panels and its orientation to fulfill the condition of maximum generated power from the sun is shown in the figure 4

 

Figure 5 Invertor energy meter

-  The Invertor which is used in order to convert the DC Energy in to AC Energy is an advanced one equipped with a very sensitive sensors to detect the grid voltage and compared it with that generated from the solar system, when there is a good synchronization the Invertor output will be connected to the grid and exporting the generated solar energy. Indicating how much energy exported to the grid per day or per month or per any time since the installment of the device. As shown in the figure 5.

 

- It is quite economical in long run. After the initial investment has been recovered, within number of years depending on the national Energy Tariff the energy from the sun is practically free. Solar Energy systems are virtually maintenance free and will last for decades.

Annual income

 

 

Electricity export income

 

 

 

Electricity exported to grid

MWh

38

 

Electricity export rate

$/MWh

26.00

 

Electricity export income

$

995

 

Electricity export escalation rate

%

12.0%

 

 

 

 

- In figure 6 it indicate the cash flow for the solar system , it is clear that within twenty years ,all the energy  generated will be a benefit for the eco house owner and will not be charged by any electricity Bill.

 

 

Figure 6 Eco House Solar System cash flow

 

-  Finally, Table 1 shows the carbon dioxide emission that would have generated if the project is not executed. It is clearly seen that the co2 emission is 32.8 tons/year. This reduction in CO2 emission will be equivalent to 6 cars and light trucks not to be used.

GHG emission reduction summary

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Years of occurrence

Base case
GHG emission

Proposed case
GHG emission

 

 

Gross annual
GHG emission
reduction

Net annual
GHG emission
reduction

 

Power project

tCO2

tCO2

 

 

tCO2

tCO2

 

1 to -1

32.8

0.0

 

 

32.8

 

32.8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Net annual GHG emission reduction

32.8

tCO2

is equivalent to

6.0

Cars & light trucks not used

 

 

 

 

 

 

 

 

 

 

 

Table 1 CO2 emission reduction