A。Simulation Result

Entering all information in regards to the load needs to be performed to allow HOMER to process the calculation。 The required power consumption of the desalination process is constant throughout the year which is 800W。 Thus, there are no variation in the load profile with the load factor is equal to 1。 The total power consumption per day is 19200 Watt-hour per day。 The constraint of the stand-alone power system is the unmet electrical load must not exceed 1% and 100% availability with zero capacity shortage。 Considering that PV modules are free maintenance and each 140W costs about $850 which the capital cost may reach $ 1500 including the installation cost for 140W PV modules。 Then, the replacement cost after 20 years is $1200。 In this design, no tracking system is used which the tilt angle of the PV modules is 6。4° which is the same with the latitude angle。

This simulation use Surrette S460 with nominal voltage of 6V, nominal capacity of 460 Ah and 2 batteries are selected to meet the requirement of 12 voltage systems。 The cost of each battery  may  cost  about  $500,  with  replacement  cost about

$300 and operation & maintenance cost about 2% of  the whole system which is $20 per year。 Entering all these data into HOMER generated series of result to be taken into consideration。 HOMER lists all possible optimum matches for the stand alone power system in the order of cost。 Then, HOMER will categorize the simulated results into the most optimal selection as shown in Fig。 6。

Fig。 6。  Optimal result simulated by HOMER。

An initial capital cost of $225,000 which comes from PV module represents 89。6% of total investment of initial capital cost of $251,000。 The replacement cost and the operating as well as the maintenance cost are also considered in this analysis。 The total cost of the project for the life span of 25 years is $287,498 with deduction of $13,576 from salvageable equipment  and  materials。  The  cost  of  electricity  (COE)  is

$3。243/kWh。 However, the electrical assessment may determine whether this economical saving is viable。 From this setup, it has 0% unmet electric load and no capacity shortage。 Thus, this option can operate the desalination process adequately。 The monthly statistic of battery bank state of charge has reached 80% and above discharge rate for 73% throughout the year which is shown in Fig。 7。 This will increase the life span of the battery bank。

Fig。 7。  Annual frequency histogram for battery state of charge (SOC)。

B。

Experimental Result

Due to fluctuation of solar insolation, the experimental setup was prepared to obtain result for desalination system to verify functionality of the desalination system。 The experimental setup consists two panels of 75W monocrystalline silicon photovoltaic panel, 2000W inverter with charger and batteries of 12 V 200Ah。

Fig。 8。 The experimental setup for desalination system

Fig。 8 shows the experimental setup that was prepared to determine the functionality of the desalination system。 The results obtained are tabulated in Table VI which is shown that the desalination can provide fresh drinking water referring to Table VII。 The pH level for the desalinated water is natural and its salt level is decreased to 0 means that the salt level is nearly non-existed。 The salt level base measurement is stated in Table VIII。

TABLE VI。 RESULT OF SOLAR POWERED DEVICE FOR DESALINATION SYSTEM

Time Solar Radiation

(W/m2) Solar panel output

( W ) Battery Load

( V1 ) Inverter Output