Capital costs
Land and other natural resources that have current alternative uses
Detailed engineering and design
Preparatory installation work
Cost of equipment, raw materials and supplies for construction
Cost of building and auxiliary installation
Engineering and administrative cost during construction
Organization costs
Expenses of running in periods
Operating and maintenance cost
Raw materials and supplies
Energy and Fuels
Labor
Rent and Insurance
Depletion of natural resources
Contingencies
Sunk cost8.2. Solar charge controller sizing
The solar charge controller is typically rated against Amperage and Voltage capacities. Select the solar charge controller to match the voltage of PV array batteries and then identify which types of solar charge controller is right for your application. Make sure that solar charge controller has enough capacity to handle the current from PV array.
For the series charge controller types, the sizing of controller depends on the total PV input current which is delivered to the controller and also depends on PV panel configuration ( series or parallel configuration). According to standard practice, the sizing of solar charge controller is to take the short circuit current (Isc) of the PV array, and multiply it by 1.3 Solar charge controller rating= Total short circuit current of PV array x 1.3
8.3 Solar PV System Sizing
8.3.1 Size the PV Module
Different size of PV modules will produce different amount of power. To find out the sizing of PV module, the total peak watt produced needs. The peak watt (Wp) produced depends on size of the PV module and climate of site location. We have to consider "panel generation factor" which is different in each site location. For Thailand, the panel generation factor is 3.43. To determine the sizing of PV modules, calculate as follows:
Calculate the total watt-peak rating needed for PV modules (for item 1.2) by3.43 to get the total watt-peak rating needed for the PV panels needed to operate the appliances.
Calculate the number of PV panels for the system Divide the answer obtained in item 2.1 by the rated output Watt-peak of the PV modules avaiable to you. Increace any fractional part of result to the next highest full number and that will be the number of PV modules required.
Result of the calculation is the minimum number of PV panels. If more PV modules are installed, the system will perform better and battery life will be improved. If fewer PV modules are used, the system may not work at all during cloudy periods and battery life will be Shortened.
8.3.2 Inverter sizing
An inverter is used in the system where AC power output is needed. The input rating of the inverter should never be lower then the total watt of appliances. The inverter must have the same nominal voltage as your battery.
For stand-alone systems, the inverter must be large enough to handle the total amount of Watts you will be using at one time. The inverter size should be 25-30% bigger then total watts of appliances. In case of appliances and must be added to three inverter capacity to handle surge current during starting.
For grid tie systems or grid connected systems, the input rating of the inverter should be same as PV array rating to allow for safe and efficient operation.
8.3.3 Battery sizing
The battery type recommended for using in solar PV system is deep cycle battery. Deep cycle battery is specifically designed for to be discharge to low energy level and rapid recharged or cycle charged and discharged day after day for years. The battery should be large enough to store sufficient energy to operate the appliances at night and cloudy days. To find out the size of battery, calculate as follows;
Calculate total watt-hours per day used by appliances.
Divide the total watt-hours per day used by 0.85 for battery loss.
Divide the answer obtained in item 4.2 by 0.6 for depth of discharge.
Divide the answer obtained in item 4.3 by the nominal battery voltage.
Multiply the answer obtained in item 4.4 with days of autonomy to get the required Ampere-hour capacity of deep-cycle battery.
Battery Capacity (Ah)= (Total Watt-hours per day used by appliances x Days of autonomy)/
(o.85 x 0.6 x nominal battery voltage)
8.4 Load Determination
To find out the daily average load, a family consists of 4 persons using TV for 5 hours, 6 Led Bulbs for 6 hours, 3 fan for 15 hours daily, Laptop for 1.5 hours. So power requirement of various types of loads are given bellow the table:
Table8.1: Load Determination
Item/loads Rated power
Television 60W
Led Bulbs 6W
Electric Fan 65W
Laptop 70W
Solution:
The daily energy needed for the given family = 5*60+1.5*70+3*15*65+6*6*6 = 3,546 W h
= 3.546 KWh 1 month energy needed for the given family = 3.546*30 =106.38 KWh 1 year energy needed for the given family =3.546*365 =1294.29 KWh 20 year energy needed for the given family = 1294.29*20 = 25885.8 KWh 8.4.1 Cost of power from DESCO ( 3.546 kw-h) (9)
Per Unit Cost of power from DESCO ~ bdt 7 PER UNIT 1 MONTH COST OF POWER FROM DESCO = 106.38*7 = 744.66 Tk 1 year cost of power from DESCO = 1294.29*7 = 9060 Tk
Total cost for 20 Years ( without considering any maintenance cost) = BDT 9060*20 = BDT 181200 Cost of Solar Power System (3.546 Kw-h) (9)
Table 8.2: Cost of Solar Power System
SL. NO. Description of Item BDT
1 Solar Panel, ( 9*100=900W) 54,000
2 Battery (3 or 4, 500A ) 30,000
3 Charge Controller 2,500
4 Wire 3000
5 Panel Mounting 5000
6 Miscellaneous 2000
7 Maintenance Cost ( Labor & Others) 20,000
Total 1,16,500