Solar Water pumping design

**russ** · 10-18-2011, 12:41 PM

All for free I suppose?

I suggest you start with a local supplier that will provide the engineering for you.

**pradsep4** · 10-18-2011, 01:25 PM

Originally posted by russ

All for free I suppose?

I suggest you start with a local supplier that will provide the engineering for you.

sorry, i am a student and i am doing a project in solar water pumping. i need help to design the pump,motor,inverter,dc-dc converter and pv modules required.?

**Sunking** · 10-18-2011, 01:26 PM

Originally posted by pradsep4

sorry, i am a student

OK great. Now what are some of your ideas. It is your assignment not ours. Tell us what you got and we can critique it. But we are not going to do your work.

**pradsep4** · 10-18-2011, 03:05 PM

Originally posted by Sunking

OK great. Now what are some of your ideas. It is your assignment not ours. Tell us what you got and we can critique it. But we are not going to do your work.

Hydraulic Energy Requirement:
1. Source Capacity(L/Hr) : 5000L/Hr
2. Water Required(L/Day) : 3000L/Day
3. Pumping Time Factor : 1.2
4. Peak Sun(Hrs/day) : 6
5. Pumping rate(L/Hr) : 3000/1.2/6 = 416.67L/Hr
6. Static Level(m) : 2
7. Drawn Down Level(m) : 3
8. Static Lift(m) : 15
9. Discharge head(m) : 0
10. Static Head(m) : 2+3+15= 20m
11. Allowance for Friction : 0.05
12. Total Dynamic Head(m) : (20*0.05)+20= 21m
13. Conversion Factor : 367
14. 14. Hydraulic Energy : (3000*21)/367
: 171.662WH/day
15. Pump System Efficiency : 0.3
16. Array Energy(WH/day) : 171.662/0.3= 572.21WH/day
17. Nominal System Voltage : 24Vdc
18. Ampere-hour load(AH/day) : 572.21/24= 23.842H/day
19. Wire loss Factor : 1.0
20. Battery Efficiency Factor : 1.0
21. Corrected Amp-Hour Load : 23.842AH/day

Design Current and Array tilt
System Location : Coimbatore, Tamilnadu
Insolation Location : Coimbatore, Tamilnadu
Latitude : 11˚1́6˝N
Longitude : 76˚58́2˝E
22. Peak Sun(Hrs/day) : 6Hrs/day
23. Design Current(A) : 23.842/6= 3.974A
System Array Size
24. 24. Module Derate Factor : 0.9
25. 25. Derated Design Current(A) : 3.974/0.9= 4.4156A
26. Rated Module Current(A) :
27. Modules in Parallel : 3.974/
28. Voltage required for load(V) : V
29. Highest Temperature Module Voltage(V) : V
30. Modules in Series : /
31. Total Modules :
32. Rated array Current(A) :Rated Module Current * No. of Modules in parallel
:
33. Rated array Voltage(V) : Rated Module Voltage *No. of Modules in Series
:
34. 34. Array Open Circuit Voltage(V) : Open circuit voltage of module*total modules used
:
Pumped Water And Pumping Rate
35. Pumped Water(L/day) :
36. Pumping Time Factor :
37. Pumping Rate(L/Hr) :

in this design i couldn't understand what the "nominal system voltage" mean? here i have kept it as 24Vdc. but i am not getting the correct design value.

**Sunking** · 10-18-2011, 04:43 PM

Nominal battery voltage is whatever you decide upon like 12, 24, or 48 volts. Battery voltage is chosen based on panel wattage size and cable distances.

**john p** · 10-19-2011, 12:56 AM

My understanding of nominal voltage has always been if it says 24 v then somewhere betwen 20 and 28v.
A 12v "nominal voltage battery is "full" at 14.2v "empty" at 11.6v.
You find most AC electric motors and power supplies are rated to operate on a nominal voltage of 230v but mostly work fine between 220 and 240v.
I dont think it correct to say a nominal voltage is something you pick your self like 12, 24,48v.. It is a figure given to you to work with.

**Sunking** · 10-19-2011, 02:48 PM

Originally posted by john p

My understanding of nominal voltage has always been if it says 24 v then somewhere betwen 20 and 28v.

John the definition for nominal voltage is:

The voltage given by the manufacturer as the recommended operating voltage of their equipment. If a range (versus a specific voltage) is given, the nominal voltage shall be considered as the midpoint of the range, unless otherwise specified.

In the case and point of a battery:

A reference voltage used to describe batteries, modules, or systems (i.e., a 12-volt or 24-volt battery, module, or system).

**john p** · 10-19-2011, 08:10 PM

Sunking you have only said exactly what I already said.Well you worded it slightly differently but the meaning is exactly the same.
But in your previous post you wrote "Nominal battery voltage is whatever you decide upon like 12, 24, or 48 volts." I still say that is NOT correct you have to use the voltage you have been told to use in the calculation not decide on one yourself..
Your reply would be correct if the person setting the parameters gave you choices.but the person is asking the student to design the system using 24v as the nominal voltage. he cant go changing that any more than he can change any other parameters given to him.

**john p** · 10-19-2011, 08:13 PM

Sunking you have only said exactly what I already said.Well you worded it slightly differently but the meaning is exactly the same.
But in your previous post you wrote "Nominal battery voltage is whatever you decide upon like 12, 24, or 48 volts." I still say that is NOT correct you have to use the voltage you have been told to use in the calculation not decide on one yourself..
Your reply would be correct if the person setting the parameters gave you choices.but the person is asking the student to design the system using 24v as the nominal voltage. he cant go changing that any more than he can change any other parameters given to him.

By definition nominal means you are going to have a range of +or - of the base figure.

**pradsep4** · 10-19-2011, 10:05 PM

Originally posted by john p

Sunking you have only said exactly what I already said.Well you worded it slightly differently but the meaning is exactly the same.
But in your previous post you wrote "Nominal battery voltage is whatever you decide upon like 12, 24, or 48 volts." I still say that is NOT correct you have to use the voltage you have been told to use in the calculation not decide on one yourself..
Your reply would be correct if the person setting the parameters gave you choices.but the person is asking the student to design the system using 24v as the nominal voltage. he cant go changing that any more than he can change any other parameters given to him.

By definition nominal means you are going to have a range of +or - of the base figure.

it's k.. but what is the role of nominal system voltage in design?

**Sunking** · 10-19-2011, 10:55 PM

Originally posted by pradsep4

it's k.. but what is the role of nominal system voltage in design?

Very simple if you are going with a battery system you need to choose 12, 24, 48, or 96 volts.

John is just making fun out of splitting hairs.

**john p** · 10-20-2011, 12:22 AM

I actually thought Sunking and myself had explained every possible aspect of nominal voltage.
but to try again . for most things you cant have and or dont need an exact voltage to make something work.
As already said a nominal 12v lead acid battery is not at all times during its charge or discharge exactly 12v it varies between 11.6 totally discharged to 14.2 fully charged. So if you really wanted to be splitting hairs it should be sold as a 13.8v battery as that is the usual voltage when sold. but if you go asking at a battery store for a 13.8 v lead acid battery for your vehicle you are going to get some strange looks. So you are sold a nominal 12v battery..

**pradsep4** · 10-20-2011, 02:13 AM

Originally posted by john p

I actually thought Sunking and myself had explained every possible aspect of nominal voltage.
but to try again . for most things you cant have and or dont need an exact voltage to make something work.
As already said a nominal 12v lead acid battery is not at all times during its charge or discharge exactly 12v it varies between 11.6 totally discharged to 14.2 fully charged. So if you really wanted to be splitting hairs it should be sold as a 13.8v battery as that is the usual voltage when sold. but if you go asking at a battery store for a 13.8 v lead acid battery for your vehicle you are going to get some strange looks. So you are sold a nominal 12v battery..

ya..but i want the design for batteryless system and i am planning to use dc-dc converter..

**john p** · 10-20-2011, 10:18 AM

well your DC to DC converter will be converting from whatever you are powering it from?? to 24v DC nominal .. some DC to DC converters give very accurate outputs some dont. in your case if it varies betwen 22 and 26 it will not effect a pump motor.
I still dont see how you are not going to be using batteries on the input side of the DC to DC converter, ?????Where you going to get the higher? DC input voltage from for the converter if not from batteries??/

Solar Water pumping design

Solar Water pumping design

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