Technical and economic analysis of a pump as a turbine for rural electrification

Figures & data

Figure 1. Location of candidate sites.

Figure 2. Flow duration curve of the three sites.

Table 1. Mean annual flow descending order of Chemoga, Huluka, and Wabi Rivers.

	Chemoga	Huluka	Wabi
M	Mean FDC (m^3/s)	Mean FDC (m^3/s)	Mean FDC (m^3/s)	P
1	55.7301	7.81183	31.476	9.09
2	55.1178	4.67767	29.064	18.181
3	41.1473	3.11443	28.103	27.272
4	40.7447	2.99392	27.414	36.363
5	39.6815	2.68142	26.215	45.454
6	38.7933	2.4951	23.385	54.545
7	38.1926	2.30392	22.96	63.636
8	5.60417	1.9945	20.179	72.727
9	4.29925	1.8975	15.37	81.818
10	3.54725	1.63655	13.52	90.909

Table 2. Calculation of Darcy friction factor (f).

	Methodology
	Moody diagram	Blasius equation	Swamee-Jain equation	Haaland equation
f	0.015	0.026	0.025	0.023

Table 3. Head losses as a function of flow rate.

Q /(m^3/s)	Gross head (m)	Friction loss	Net head (m)
0	27	0	27
0.0013	27	0.4065	26.5934
0.0027	27	1.7041	25.2958
0.0041	27	3.9100	23.0899
0.0055	27	7.0243	19.9756
0.0069	27	11.0468	15.9531
0.0083	27	15.9776	11.0223
0.0097	27	21.8168	5.1831

Figure 3. Performance characteristics of the Piping system.

Table 4. Peak load calculation of power demand.

No.	Appliance	Quantity	Watts in average	Total power (W)	Hours per day	W. hr./day
1	LED bulb	2 × 23 = 46	8.0	368	12 (12-24)	4,416
2	Radio	23	2.5	57.5	17 (1-17)	977.5
3	Phone charger	23	3.0	69.0	14 (1-13)	966
	Sub-total			494.5

Table 5. Net cash in/out outflow.

Year	Cash flow ($)	Year	PV ($)	Year	PV ($)	Year	PV ($)
0	−2241.12	8	2,986.33	16	8,223.93	24	13,461.53
1	−1,596.57	9	3,641.03	17	8,878.63	25	14,116.23
2	−941.87	10	4,295.73	18	9,533.33	26	14,770.93
3	−287.17	11	4,950.43	19	10,188.03	27	15,425.63
4	367.53	12	5,605.13	20	10,842.73	28	16,080.33
5	1,022.23	13	6,259.83	21	11,497.43	29	16,735.03
6	1,676.93	14	6,914.53	22	12,152.13	30	17,389.73
7	2,331.63	15	7,569.23	23	12,806.83

Figure 4. Payback period of the project.

Table 6. Economic feasibility of PAT: Cost and payback analysis.

$\mathrm{I}\mathrm{I}\mathrm{C}\left(\mathrm{\$}\right)$	${\mathrm{M}}_{\mathrm{C}}\left(\mathrm{\$}\right)$	${\mathrm{A}}_{\mathrm{R}}=\left(\mathrm{\$}/\mathrm{y}\mathrm{e}\mathrm{a}\mathrm{r}\right)$	$\mathrm{P}\mathrm{B}\mathrm{P}\left(\mathrm{y}\mathrm{e}\mathrm{a}\mathrm{r}\right)$	Cost of energy ($/kWh)
2,241.12	101.87	654.70	3.42	0.0642

Table 7. Feed per tooth of cutters.

Types of cutters	Slab mill (Helix angle up to 30^0)	Slab mill (Helix angle 30^0 60^0)	Face mill	End mill	Slot mill	Form relieved cutter
Feed per tooth (mm)	0.10–0.25	0.07–0.20	0.12–0.50	0.02–0.25	0.07–0.12	0.07–0.20

Table 8. Cutting speed of different materials.

Material being cut	brass	C.I	Bronze	Mild steel	Hard C steel	Hard alloy steel	Aluminum
S, mpm	45–60	21–30	24–45	21–30	15–18	9–18	15–30

Table 9. Costs and payback period of PAT and cross-flow turbine.

	$\mathrm{I}\mathrm{I}\mathrm{C}\left(\mathrm{\$}\right)$	${\mathrm{A}}_{\mathrm{R}}$  = ($/year)	PBP (year)	Cost of energy ($/kWh)
Initial	2241.12	654.70	3.42	0.0642
Decreasing blade thickness	2285.86	668.35	3.42	0.0642
Blade tip rounding	2266.06	676.53	3.35	0.0623
Blade inlet angle	2266.06	685.06	3.31	0.0611
Blade grooving	2294.29	690.94	3.32	0.0615
Cross-flow turbine	2610.12	432.16	6.04	0.1000

Figure 5. Payback periods for different modification techniques and cross-flow turbine.

Figure 6. Payback period and cost of energy for impeller modification.