**6. Summary**

482 Solar Radiation

When sizing the battery bank, the ampere-hours efficiency (columbic efficiency) of new battery is considered to be 100%. During the charge/discharge cycle of the battery, the battery is charged by receiving an input voltage from the thermocouple system and the same number of voltage is delivered at a lower output voltage. The battery efficiency (battery's voltaic efficiency) is expressed as the ratio of average voltage output to the

The daily load requirements determine the necessary battery bank capacity while the system voltage determines the battery bank voltage and the number of cells to be connected in series. The product of Daily Load (DL) requirement and the number of no-sun days (N)

Total Useable Capacity = DL X N (Ah) The ampere-hours efficiency (columbic efficiency) of new battery is considered to be 100%. The daily load requirement determines the necessary battery bank capacity. The total

An assumption of a lighting programme in poultry house where power is needed for four out of every seven days in a week was made, and the inverse relationship between voltage and amperage was used to determine the average daily current requirement by multiplying current by a factor of 4/7 to yield a net value in Ah, the average daily current required to satisfy the load demand of 5.14Ah as calculated from given relations. An average of 4½ hrs of full sunshine hours per day round the years is taken for a non-critical system. The thermocouple array load capable of generating the required load demand is obtained by

Thermocouple load = average daily current requirement /4.5 (A). When a peak sunshine hour of 4.5 hours/day is required, the thermocouple array designed is capable of generating a measured 1.14A, capable of providing a glow continuously to satisfy the load demand of 5.14Ah. At increased number of sunshine hours above 4 ½ hours,

The conversion efficiency is defined as the ratio of electrical power output and the heat flux

Δ*T* corresponds to the temperature difference between the hot and the cold side of the TEG, *A* is the TEG area and *h* is the overall heat transfer coefficient given by (the ratio of total thermal conductivity (5.4 x 10 -4 W/m2/°C) of the materials of the thermoelectric generators and the thickness (0.015m) of the TEG. The electrical power output (P=174.06 W h). The

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more current generation is possible whereby the battery could be recharged.

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**5.1.2 Battery size requirement and efficiency** 

gives the total useable capacity (TUC) of the battery i.e.

useable capacity (TUC) of the battery is 22.84Ah

dividing the average daily current requirement by 4.5.

**5.1.4 The system conversion efficiency** 

through the entire TEG surface.

**5.1.3 Daily load requirement** 

average input voltage.

The conversion efficiency of the cell is 15%. This is comparable to other solar TEG system efficiency. The research work indicates the possibility of the utilization of asphalt bonded thermocouples to generate enough current for lighting programme in small scale agricultural undertaking such as poultry house illumination. The output voltage across the thermocouple generator can be increased to higher value enough to provide energy for other low thermal processes. Asphalt heat absorber will be a promising solar harvest cell when the surface is polished and made more sensitive to wider photon energy range (1.3- 1.5eV) for increased efficiency.

From the economical point of view, there exists a huge discrepancy between the costs of commercial thermoelectric generators compare with asphalts embedded TEG. The commercial TEG is by a factor of 10 more expensive than the asphalt TEG. The properties of asphalt TEGs are comparable with that of commercial TEG, even though the asphalt TEG used in this study has a smaller area than most commercial TEGs, therefore more asphalt TEGs per unit area can be mounted for increased overall performance at a cheaper price. Further research on antireflection coatings and stacking of different cells with band gaps covering the incident energy of the photons would be a good attempt at achieving higher efficiency.
