Energy Saving in Irrigation Piping System using (UAN 32 ... · Energy Saving in Irrigation Piping...

INTERNATIONAL JOURNAL OF APPLIED ENGINEERING RESEARCH, DINDIGUL Volume 2, No 2, 2011

© Copyright 2010 All rights reserved Integrated Publishing Association

REVIEW ARTICLE ISSN 09764259

318

Energy Saving in Irrigation Piping System using (UAN32) Fertilizer as a Drag Reducing Agent

Abo Elazm.M.M 1 , Kassab.S.Z 2 , Selim.M.M 1 1 Mechanical Engineering Dept, College Of Engineering and Technology,

Arab Academy for Science and Technology, Alexandria, Egypt 2 Mechanical Engineering Dept, Faculty of Engineering,

Alexandria University, Alexandria, Egypt [email protected]

ABSTRACT

In the present study, experiments were carried out on a laboratory circuit to determine the effect of adding fertilizer to the irrigation water as an effective agent to reduce friction. The fertilizer used is Urea Ammonium Nitrate (UAN32). It is a liquid soluble fertilizer used to mix with irrigation water. Several concentrations were used at different Reynolds numbers. The results show that with increasing the UAN32 fertilizer concentration the drag reduction increases till it reaches a maximum value of 6.5% at concentration of 11,000 parts per million, PPM. In addition, as the Reynolds number increases the percentage drag reduction increases in agreement with the wellestablished results in the open literature.

Keywords: Drag reduction; Sprinkler Irrigation, Fertigation.

1. Introduction

The sprinkler and drip are the two most efficient methods of irrigation. Sprinkler method can be applied to all major crops especially closed spaced crops. Among the various factors limiting the extensive use of sprinkler irrigation system, is the high energy requirement. The sprinkler irrigation is operated in turbulent flow condition in the distribution pipes, risers and ejected water jet. Hence, application of turbulent drag reduction phenomenon can be useful in reducing the energy requirement and thereby saving power and fuel requirement, Phukan et al. (2000).

The new irrigation system not only supplies soil with water but also provides agriculture manure to soil, by mixing the irrigation water with soluble manure. This system called fertigation System. The fertigation is the technique of supplying dissolved fertilizer to crops through an irrigation system. Fertigation is now the accepted method of applying most of the crops nutrition, with many growers using liquid soluble fertilizer rather than spreading granular fertilizer and waiting for the rain or sprinklers to wash the fertilizer into the root zone. So, the effectiveness of fertigation is often dependent on the effectiveness of the irrigation system, Selim et al. (2010).

The full advantages of irrigation and fertigation only become evident if the correct irrigation design and management is employed to meet plant requirements and to distribute water and fertilizer evenly. Although fertigation appears to be very technical, it offers several benefits, such as:

1. Central distribution of the fertilizer, less labor, no machinery movement and time loss.

mailto:[email protected]




319

2. The farm owner or manager can mix the correct formulation, and then allow unskilled employees to switch on or off the fertigation system.

3. Saves fertilizer since the fertilizer is injected as and when the plants need it there is no loss. For example using traditional techniques, the rain or a heavy irrigation could wash the fertilizer away from the root zone.

4. Using controlled fustigation reduces the chance of over fertilizing, and subsequent fertilizer loss to river systems.

On the other hand, it is well known that the addition of a minute amount of polymer to a turbulent Newtonian fluid flow can result in a large reduction of the frictional drag in pipes and channels. Although this effect has been known for almost more than half a century, the physical mechanism that causes this drag reduction has still not been clearly identified, Den Toonder et al. (1997). In pipe flows, for example, the drag can be reduced by up to 80 % by adding just a few parts per million (PPM) of polymer. This phenomenon leads to the possibility of increased capacities and faster shipping in pipelines. The discovery of this phenomenon of turbulent drag reduction by polymer additives is generally ascribed to Toms (1949).

Since Toms’s discovery, the phenomenon has been studied widely, both experimentally and theoretically. Drag reduction here will be defined as any modification to a turbulent fluid flow system that results in a decrease in the normal rate of frictional energy loss and that leaves the resulting flow turbulent. Toms obtained friction reduction up to 50% compared with a pure solvent using a 0.25% solution of poly (methylmethacrylate) in monochlorobenzene. He used tubes of various diameter and observed that (i) drag reduction occurs in turbulent flow; (ii) for a given polymer concentration and Reynolds number, it increases as the pipe diameter is reduced and also (iii) the drag reduction occurs when the wall shear stress exceeds a critical value which later came to be known as ‘onset of drag reduction’. Since then, there has been number of attempts on drag reducing polymers for possible applications in fire extinguishing operations, crude oil transport, oil well operation, sewers and slurry transport.

The positive results obtained in drag reducing phenomenon in above fields of technology have led the research work to try its possible application in sprinkler irrigation system. In sprinkler irrigation system, there are multiple outlets and frictional losses are quite high. The first experiment demonstrating the application of this phenomenon was performed by Union Carbide Corporation (1969). The addition of the polymer increased crop coverage by 215%.

Khalil et al. (2002) study the effects of two kinds of polymer additives on sprinkler performance with several concentrations: a low molecular weight polymer, sodium carboxymethylcellulose, and a high molecular weight polymer, polyacrylamide. The results showed that with polymer additives the radius of throw and the sprinkler flow rate increase. The jet is slightly affected. Polyacrylamide shows better results than sodium carboxymethylcellulose.

In fertigation system, however, large pumping power is required because water has to travel long distance. If the pumping power can be reduced significantly using this drag reduction phenomenon, great energy saving in the system can be obtained and consequently the fertigation system will become more feasible technically and economically, Yoon et al. (2002).




320

In order to obtain a useful and maximum benefit, it is important to find out the most usable fertilizer in recent years. CF Industries (2009) published the data for nitrogen fertilizer production capacities 2009, Fig. 1. From this data, UAN fertilizer is the one that has the highest production capacity.

Figure 1: Nitrogen fertilizer production capacities in 2009

Blasius, Colburn, and Koo equations are used to analyze turbulent flow. They are in the form of a power equation, Chang et al. (2007):

(1)

Where a, b, and n are constants of proportionality that differ from equation to equation. The constants of proportionality are shown in Table 1.

Table 1: Constants for various turbulent equations, Chang et al. (2007)

Equation A b n Range

Blasius 0 0.079 0.25 4000




321

The objective of the present study is to carry an experimental investigation to study the effectiveness of UAN32 fertilizer, the most usable fertilizer in water irrigation systems nowadays, as drag reducing agent. If this happened, it will add another benefit to the fertigation system by reducing energy required for pumping units.

2. Experimental Setup

The experimental setup, shown in Figs. 2 and 3, consists of a 1000 liters collecting tank (9), 200 liters constanthead upper elevated tank (10), a reciprocating piston pump (2) driven by D.C constant speed motor (1), ball valve (6), flow meter (11), and test section (8). The test section has ten pressure taps (7).

The open air type of upper tank (10) was used in the present study. For all tests, the solution level in the upper tank was fixed at 3.55 m above tested pipe axis. This head is sufficient to provide the required flow velocities to create turbulent flow. The test section (8) consists of a PVC pipe of inner diameter, d = 2.54 cm (1 inch) and total length, L = 6 m. About 30 pipe diameters were used as a developing length between the elbow and the first pressure tab. The friction loss measurement in the tested pipe was conducted by means of series of pressure tabs located along the pipe. The distance between any two neighboring tabs is 0.5 m. The pressure distribution along the tested section was measured by piezometer tube at each pressure tab.

For a drag reducer to be wholly effective it is important that it is highly soluble in the solvent. A batch of polymer solution at the required concentration was prepared in the 1000 liters collecting tank (9). The polymer was provided by Abu Qir Fertilizer Company, Alexandria, Egypt, with the name of UAN32. It is a colorless liquid, may be dyed blue, with slight ammonia odor. UAN32 was gently mixed with tab water and stirred properly for 20 to 30 minutes. The polymer solution had to be prepared approximately 24 hours before an experiment was performed to ensure homogeneous concentration. A period of 5 to 10 minutes of stirring was enough before the direct use, Sellin et al. (1982). The uncertainty value of percentage drag reduction, DR%, is ± 1.29%. More details of the followed procedure are given by Selim (2011).

The global effectiveness of the UAN32 as drag reducing agent is first investigated. This is performed by measuring the flow head loss through the test section (8). An elevated tank (10) was used to ensure the same input head. A reciprocating (piston) pump (2) was used to raise the solution from the collecting tank (9) to the upper elevated tank (10) to avoid mechanical degradation.

For steady fully developed turbulent pipe flow, the static pressure drop is balanced only by shear stress at the pipe wall. Therefore, the pressure distribution, P , can be calculated directly by measuring the head loss, h , along the pipe axis (xdirection) using piezometer tubes. Therefore, the coefficient of friction, Cf, can be calculated directly by applying Darcy’s equation.

(2)

Where D is the pipe inside diameter, L is the length between pressure tabs, and v is the flow velocity inside the pipe.




322

Figure 2: Schematic diagram of the experimental setup.

Figure 3: General view of the experimental setup

3. Results and Discussions

For the present study, in order to insure the existence of the fully developed flow, the linearity of the wall static pressure drop was checked at the beginning using water only (zero concentration, i.e. 0 PPM). A sample of results is shown in Fig. 4 for the range of Reynolds numbers, RE = 1.5×10 4 to 3.1×10 4 . From this figure, it is clear that, for all Reynolds numbers, the static pressure drop along the pipe wall is linear and consequently the flow is fully developed.




323

In the present study all calculations deal with the coefficient of friction, but the previous equations mentioned in Table.1 sorts the relation between the Fannaing friction factor and Reynolds number. However, the coefficient of friction is four times the Fanning friction factor. Further, the coefficient of friction is shown in Fig. 5. The present results for pure water (zero PPM) are in a good agreement with the Blasius friction law

(3)

This comparison for water results gives confidence to the results of the present experimental setup and work.

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5

Distance from first tapping point (m)

30

20

10

0

35

25

15

5

∆ h(cmW ater)

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5

Pure water (zero PPM)

RE=3.09x10 4 RE=2.87x10 4 RE=2.61x10 4 RE=2.34x10 4 RE=2.1x10 4 RE=1.84x10 4 RE=1.67x10 4 RE=1.50x10 4

Figure 4: Pressure distributions along the test section of pure water at different Reynolds numbers

10000 20000 30000 40000 50000 60000 Reynolds Number, RE

0.02

0.03

0.04

Coefficientoffriction,Cf

Blasius Friction Law

Pure Water

Figure 5: Comparison between the experimental coefficient of friction of pure water (zero PPM) with Blasius friction law at different Reynolds numbers




324

For the case of using fertilizer, i.e. PPM > zero, it is important to use the correct value of the

viscosity in the determination of Reynolds number, . Since the viscosity of each solution concentration may be differ from the viscosity of pure water (zero PPM). The kinematic viscosity of fertilizer solution at the studied concentrations was estimated using the Refutas equation. The calculation is carried out in three steps, Maples (2000).

The first step is to calculate the Viscosity Blending Index (VBI) of each component of the solution using the following equation (known as a Refutas equation)

(4)

Where is the kinematic viscosity in centistokes (cSt). It is important that the kinematic viscosity of each component of the solution be obtained at the same temperature.

The next step is to calculate the VBI of the solution, using this equation:

(5)

Where w is the weight fraction of each component of the solution.

Once the Viscosity Blending Index of a solution has been calculated using equation (5), the final step is to determine the kinematic viscosity of the blend by solving equation (4) for v:

(6)

where VBIsolution is the Viscosity Blending Index of the blend.

0.1 1 10 100 1000 10000 100000 Concentration (PPM)

0.02

0.01

0

0.01

0.02

0.03

∆ν (cSt)

Calculations at temperature of 20 o C ∆ν = (νsolutionνwater)

Figure 6: Variation of kinematic viscosity on solution concentration

http://en.wikipedia.org/wiki/Mass_fraction_(chemistry)




325

The present results of the kinematic viscosity of the solution at the working temperature (the temperature at which all friction loss data were recorded in the present study), i.e. 20 o C, are plotted in Fig. 6, as (Dn ≈ nsolution nwater), against the fertilizer concentration. Figure 6 shows that for concentration up to 100 PPM, the solution and the water have approximately the same viscosity, but above 100 PPM the viscosity of the fertilizer solution is higher than that for water.

Since the concentration of the solution vary depending on soil type, type of crop, and source of water used, several concentrations will be performed. To avoid over fertilizing, the most common used fertilizer concentration is 12% of the total water volume. It is recommended to do not exceed concentrations more than 5% to avoid fertilizer leaching. Consequently, a wide range of concentrations were performed in the present study (500 to12000 PPM), Personal Communications (2010).

Figure 7 shows the pressure distribution of UAN32 fertilizer at several concentrations up to 12,000 PPM at different Reynolds numbers. It shows that for certain concentration, as Reynolds number increases the pressure head drop increases. This is evident for all concentrations. In addition, the pressure head drop is linearly decreases with the increase of the pipe length towards the flow outlet. The trend is in agreement with the wellknown physics for the Newtonian fully developed turbulent flow through pipes.

Figure 8 shows that the effect of UAN32 fertilizer addition is to reduce the friction loss in pipes by reducing the coefficient of friction, for the case of 11,000 PPM (maximum drag reduction case) compared with Pure water (zero PPM) and Blasius friction law. This figure shows clearly that there is a reduction in the coefficient of friction due to adding UAN32 fertilizer to water.

In order to present the obtained data in a useful format for presentation and discussion, it is important to put it in the form of percentage drag reduction, which can be determined as a function of the reduction in the coefficient of friction.

(7)

Where,

Coefficient of friction for fertilizer solution

Coefficient of friction for




326

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5


30

20

10

0

35

25

15

5

∆h(cmWater)

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5

a) Pure water (zero PPM)

RE=3.09x10 4 RE=2.87x10 4 RE=2.61x10 4 RE=2.34x10 4 RE=2.1x10 4 RE=1.84x10 4 RE=1.67x10 4 RE=1.50x10 4

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5


30

20

10

0

35

25

15

5

∆h(cmWater)

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5

b) 5000 PPM RE=3.07x10 4 RE=2.85x10 4 RE=2.6x10 4 RE=2.33x10 4 RE=2.08x10 4

RE=1.83x10 4 RE=1.66x10 4 RE=1.49x10 4

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5


30

20

10

0

35

25

15

5

∆h(cmWater)

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5

c) 7000 PPM RE=3.07x10 4 RE=2.84x10 4

RE=2.6x10 4

RE=2.32x10 4 RE=2.08x10 4 RE=1.82x10 4

RE=1.66x10 4 RE=1.49x10 4

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5


30

20

10

0

35

25

15

5

∆h(cmWater)

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5

d) 10000 PPM RE=3.05x10 4 RE=2.82x10 4 RE=2.58x10 4 RE=2.3x10 4 RE=2.07x10 4

RE=1.81x10 4 RE=1.65x10 4 RE=1.48x10 4

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5


30

20

10

0

35

25

15

5

∆h(cmWater)

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5

e) 11000 PPM RE=3.04x10 4 RE=2.82x10 4 RE=2.57x10 4 RE=2.3x10 4 RE=2.06x10 4

RE=1.81x10 4 RE=1.64x10 4 RE=1.48x10 4

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5


30

20

10

0

35

25

15

5

∆h(cmWater)

0 1 2 3 4 5 0.5 1.5 2.5 3.5 4.5

f) 12000 PPM RE=3.03x10 4 RE=2.81x10 4 RE=2.56x10 4

RE=2.29x10 4

RE=2.06x10 4

RE=1.8x10 4 RE=1.64x10 4 RE=1.47x10 4

Figure 7: Pressure distributions along the test section of UAN32 fertilizer at several concentrations and different RE: a) zero PPM, b) 5000 PPM, c) 7000 PPM, d) 10000 PPM,

e) 11000 PPM, f) 12000 PPM




327

10000 20000 30000 40000 50000 60000 Reynold's Number

(RE)

0.02

0.03

0.04

Coe

fficien

tof fric

tion

(C f )

0.02

0.03

0.04

Blasius Friction Law

Pure Water 11,000 PPM

Figure 8: Coefficient of friction Versus Reynolds number for Blasius friction law, pure water (zero PPM) and 11,000 PPM of UAN32 fertilizer

From the pressure measurements presented in Fig.7, the percentage drag reduction in the coefficient of friction can be obtained using Eq. 7 and presented in Fig.9. Concentrations of 500 and 1,000 PPM resulted in a drag reduction of only 0.7 % and 1.1 % respectively. However, the percentage drag reduction kept increasing with UAN32 fertilizer concentration increasing till it reaches a value about 6.5 % at a concentration of 11,000 PPM as shown in Fig.9, before starting to decrease as the concentration increase. This figure shows that the maximum percentage drag reduction, DR%, is at 11,000 PPM.

Figure 9: Percentage of drag reduction versus UAN32 concentration at various values of average Reynolds numbers




328

It is worth to mention that the results presented in Fig. 9 are obtained for average Reynolds numbers. This is because as the concentration changes the viscosity of the solution changes (see Fig. 6). Therefore, for the same discharge, Q, and using different concentrations the velocity is constant and the only change in Reynolds number is the viscosity. Table 2 shows the effect of concentration change on the value of Reynolds number.

It is important to note that, Table 2 displays that the maximum percentage Reynolds number difference is less than ±1%.

Table 2: The effect of concentration change on solution viscosity, therefore on RE

Discharge, Q = 37 L/m

Concentration (PPM)

Kinematic viscosity, ν (c.St)

Reynolds number, Re

%RE Difference,

Zero 1 3.0912×10 4 0.99% 1000 1.0015 3.0866×10 4 0.84% 5000 1.006 3.0728×10 4 0.39% 7000 1.0075 3.0682×10 4 0.24% 10000 1.015 3.0455×10 4 0.50% 11000 1.018 3.0366×10 4 0.79% 12000 1.02 3.0306×10 4 0.99% Average Reynolds number 3.0609×10 4 0%

Figure 10: Pressure distributions along the test section at the same average Reynolds number (Reavg = 2.32x10 4 ) for different concentrations

The effect of adding UAN32 fertilizer to water with different concentrations at the same average Reynolds number (REavg = 2.32x10 4 ) is shown in Fig.10. This figure shows that, at




329

the same average Reynolds number, the effect of UAN32 fertilizer is to decrease the friction pressure head loss through the pipe test section. Meanwhile, Fig.11 shows that the same behavior is obtained for other Reynolds numbers.

4. Conclusions

The following concluding remarks are based on the experimental results obtained using UAN32 fertilizer at different concentrations and Reynolds numbers and within the range of the present study.

UAN32 fertilizer can be used not only as a liquid fertilizer but also as a drag reducing agent in irrigation systems. So beside its original benefits, there is an additional benefit of adding it to water through the irrigation system, that is, it will reduce the system consumed power.

UAN32 fertilizer has small effect at low concentrations up to 1000 PPM.The maximum percentage drag reduction for UAN32 fertilizer is between 10,000 and 11,000 PPM. So, if the fertigation system could be sited to pump these concentrations all the time it will give the best power consuming rate.

It is important to mention that adding UAN32 fertilizer to the irrigation water and getting power reduction is a benefit with nearly minimum required cost. This is because the farmer instead of spread the fertilizer over the land without getting any benefit, he can add the fertilizer to the irrigation water and get power reduction.

3.5 4 4.5 Length (m)

7

8

9

Head Lo

ss (c

m water)

a) Q=18 L/min REavg=1.49x10 4

0 PPM 7000 PPM 11000 PPM

3.5 4 4.5 Length (m)

8

9

10

11

b) Q=20 L/min REavg=1.65x10 4

0 PPM 7000 PPM 11000 PPM

[a] [b]

3.5 4 4.5 Length (m)

10

11

12

13

HeadLoss

(cmwater)

c) Q=22 L/min REavg=1.82x10 4

0 PPM 7000 PPM 11000 PPM

3.5 4 4.5 Length (m)

12

13

14

15

16

d) Q=25.1 L/min REavg=2.08x10 4

0 PPM 7000 PPM 11000 PPM

[c] [d]




330

3.5 4 4.5 Length (m)

21

23

25

27

Head Lo

ss (cm water)

e) Q=34.3 L/min REavg=2.84x10 4

0 PPM 7000 PPM 11000 PPM

3.5 4 4.5 Length (m)

24

26

28

30

32

f) Q=37 L/min REavg=3.06x10 4

0 PPM 7000 PPM 11000 PPM

[e] [f] Figure 11: Head loss along pipe length for different concentrations at several average Reynolds

numbers, a) Reavg =14891, b)Reavg=16546, c) Reavg =18200, d) Reavg =20765, e) Reavg =28378, f) Reavg =30609.

Acknowledgment

The authors would like to acknowledge Abu Qir Fertilizer Co. Alexandria, Egypt, for providing the UAN32 fertilizer used in the present study.

References

1. CF Industries Holdings, Inc. FORM 8K EX99.1 , May 20, 2010

2. Chang, S., DiorioToth, N., Grover, S., Hoang, J. and Wang, A., “Laminar and turbulent flow in pipes: determining the relationship between fanning friction factor and Reynolds number”, Transport Processes Laboratory, pp 63363, 2007.

3. Den Toonder, J.M.J., Hulsen, M.A., Kuiken, G.D.C. and Nieuwstadt, F.T.M., “Drag reduction by polymer additives in aturbulent pipe flow: numerical and laboratory experiments” J. Fluid Mech., 337, pp 193231, 1997.

4. Khalil, M.F., Kassab, S.Z., Elmiligui. A.A., and Naoum, F.A.,”Applications of Drag Reducing Polymers in Sprinkler Irrigation Systems: Sprinkler Head Performance” Trans. ASCE, J. Irrigation and Drainage Engineering, 128, pp. 147152, 2002.

5. Maples, R.E., “Petroleum Refinery Process Economics” (2nd edition) Pennwell Books, Tulsa, Okla, 1993.

6. Patel, V.C. and Head, M.R., “Some observations on skin friction and velocity profiles in fully developed”, J. Fluid Mech., 38, pp.181201, 1969.

7. Personal Communications, 2010, Alexandria University, College of Agriculture, Fertilizing department.




331

8. Phukan, S., Kumar, P., Panda, J., Nayak, B.R., Tiwari, K.N. and Singh, R.P., “Application of drag reducing commercial and purified guar gum for reduction of energy requirement of sprinkler irrigation and percolation rate of the soil” J. Agricultural Water Management, 47, pp. 101–118, 2000.

9. Selim, E.M., ElNeklawy, A.S. and Mosa A.A., “ Humic acid fertigation of drip irrigated cowpea under sandy soil conditions”, AmericanEurasian J. Agric. & Environ, Sci., 5, pp. 538543, 2010.

10. Sellin, R.H., Hoyt, J.J.W., Poliert, J. and Scrivener, O., “The effect of drag reducing additives on fluid flows and their industrial applications part 2: present applications and future proposals” J. Hydraulic Research, 20, pp. 235–292, 1982.

11. Sleem, M.M.,” Energy saving in irrigation piping system using fertilizer”, M.Sc. Thesis, Arab Academy for Science, Technology and Maritime Transport, Alexandria, Egypt, 2011.

12. Toms, B.A., “Some observations on the flow of linear polymer solution through straight tubes at large Reynolds number”, Proc. 1 st Int. Congress on Rheology, 2, pp. 135141, North Holand Publ. Co, 1948.

13. Union Carbide Corporation, “Slippery water cuts friction loss”, J. Fire Eng. 122, pp. 48 49, 1969.

14. Yoon, S.M., Kim, N.J., Kim, C.B., Hur, B.K., “Flow and heat transfer characteristics of drag reduction additives in district heating and cooling systems” J. Ind. Eng. Chem., 8, pp. 564571, 2002.
http://www.informaworld.com/smpp/title~db=all~content=t916282780http://www.informaworld.com/smpp/title~db=all~content=t916282780~tab=issueslist~branches=20

Energy Saving in Irrigation Piping System using (UAN 32 ... · Energy Saving in Irrigation Piping...

Documents

Transcript of Energy Saving in Irrigation Piping System using (UAN 32 ... · Energy Saving in Irrigation Piping...