By popular demand, this a larger copy of the flow table mentioned in the Open Pipe Flow Measurement Method post.
Small Hydropower & Micro Hydropower
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Q: Can you recommend a Conductivity Meter for Measuring Stream Flow?
— Original Question —
Hydro Turbine - Renewable Energy from Water
Subject: Conductivity meter
From: ‘David’
Date: Mon, July 20, 2009 1:39 am
To: <smallhydroblog@smallhydro.com>
Dear Dorado Vista,
Q: Can you recommend a portable conductivity meter that can assist in the measuring of flow in streams using the salt gulp method. Is there a limit to the maximum flow that can be assessed using this method. I’m interested in flows that range between 50 l/s to 1000 l/s.
Thanks,
David
— A: SmallHydro’s Conductivity Measurement Answer —
From: jess.blog@smallhydro.com
Sent: 21 July 2009 17:34
To: David
Cc: smallhydroblog@smallhydro.com
Subject: RE: Conductivity meter – suggestions.
David,
Take a look at SpecMeters.com for EC or dissolved salt meters.
That particular page has several EC meters that would work. For DoradoVista ranch work we use the “Field Scout” it is sturdy, easy to use and accurate. It will measure both Soils & Water too. There are some more Water specific units and even GPS based ones there too. You are likely just going to need the cheapest water unit you can find.
The dissolved salt pulse method likely has no physical limit, but the practical limit will be defined by your instruments sensitivity and the background of dissolved solids (Electrical Conductivity EC variation), the volume of salt should be just enough to see the distinctive EC increase/decrease pulse.
You will need to use fine ground salt to make sure it dissolves quickly into your brine solution. You also should be careful not to use too much salt as it will affect the biosphere if it is left to concentrate in stagnant pools. Too much salt can take a much longer time to clear out between readings too. Maybe you could try pre dissolving? Most streams carry some salts in them and as such you will need to measure the background Ec and variation as a baseline reference.
Another thing to watch for with this method will be turbulent eddies or swirls in the water streamlines as this will affect the accuracy of your readings. That means you should take several smaller pulses at several different measurement cross-sectional stream-flow positions. This averaging of multiple measurements will make sure your results are free of too much position dependant time measurement error.
Watch for boulders and channel anomalies that will cause these eddies. You will typically want the opposite of what Gold panners want, that is you want swift deep water. Therefore swift deep water outside bends and away from eddies caused by mid channel boulders. Longer measurement distance will cut down on these errors as long as you can clearly measure the distinct EC reading changes.
Would you be Ok with this thread in a post or question later?
Sincerely,
Jess
DoradoVista, Inc.
—
Jess,
Thanks for replying, I will have a look at the link you have sent.
Also more than happy for you to post this thread.
Thanks again,
David
Using PipeFlow®-Expert – For Penstocks & Hydro System Pipelines
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SmallHydro’s Review of -
PipeFlow-Expert with a few Screenshots of Flow & Pressure Calculations
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PipeFlow® Expert - Used to design and analyize Penstocks & Pipes In Hydro Systems.
A number of you readers have commented that you needed a better understanding of your Hydropower penstocks or hydro system pipelines. Some have remarked “that was fast” when a quick and accurate estimate was returned.
In this short review I’m letting you in on my secret, I use PipeFlow-Expert® by Daxesoft to make these initial penstock performance and energy loss design estimates. It is a cycle of trial & re-trial to find the sweet spot for a hydro site. A design spot between power ROI and the sites infrastructure costs. These hydro capital costs include; electric switchgear, turbine and penstock costs, etc. Hint – the penstock and associated hardware are often one of the most expensive components in a hydro system.
Penstocks also can pose a hidden system operational expense in lost hydro energy $ value. When improperly designed, they can also have a long term risk to system integrity and safety issues as well. You can see that it is vital to get the penstock design right as early as you can. Until you get the penstock and hydro turbine design nailed down the whole hydro project is at risk.
For a more detailed and accurate hydropower system penstock analysis I use the same software with a more detailed input model. The design results for this tool are amazing and the tool is quite simple to set up and operate too. Maybe even fun, Ok I can hear you – Now Jess don’t get carried away… ;-)
I’ll just have to post you some videos showing how I use it.
This software has a great graphical interface with tabular data where it makes sense and a great fluid modeling and analysis engine to crank out your solutions on the double. Warnings and quick fix diagnostic pop-ups lead you to suspected areas within your proposed Penstock and pipeline designs that would cause either a very expensive failure or costly rework at a later time. PipeFlow Tools are worth gold to a hydropower system designer or site prospector.
But wait! Before you cart your Penstock over to their site, look at the special offer we have arranged for you first…
These screenshots are just a few of the many Hydro System relevant features of the PipeFlow Expert software. I chose them based on your Hydropower Penstock evaluation needs. For our current SmallHydro PipeFlow tools offer; See our Penstock Tools & Special Offers page.
After getting our special code, visit the PipeFlow site for more details on the different Penstock & Pipeline evaluation tools. I use these tools often while looking at overall Hydroelectric system efficiency and Hydro ROI $ optimization. Note: Make sure you Get your SmallHydro Savings Discount coupon here first
PipeFlow® Expert is by far the Best tool I’ve used of for Penstock Pressure & Flow efficiency evaluations. If your system is simple enough they even carry a less expensive ”Lite” version that will cover just a few pipes, valves and fittings for a real savings.
Of course everything PipeFlow makes has an instant Free download! So you should certainly try it before you buy it with this free limited capability trial version. You’ll need to get our discount offer codes first though, to get your special SmallHydro discount savings applied later if and when you choose buy. Check with PipeFlow for all applicable terms and conditions.
Click on an image or link below to enlarge the details of the screenshot image. There are more od these features and worked examples described on PipeFlow’s site. Just get your SmallHydro Promo Code(s) first!
 Pipe Flow Expert - Systems pipeline & penstock drawing tool details
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Pipe Flow System Drawing Area
Design, build, view and edit your system model with Pipe Flow Expert’s powerful and easy to use interface. The drawing area will let you define tanks, pipes, fittings, valves, pumps, components, flow controls and demands. |
 Hydro Turbine & Pump performace curve graph
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Pump Characteristics & Curve Data
Define a pump as a curve of flow versus head produced or as a fixed flow rate pump. Pumps can be saved and loaded independently to make it easy to copy and duplicate pumps as required. |
 Pipe Flow Expert - Unit selection window - allows custom Hydropower unit settings
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Configure Pipe Flow Units
Choose the units that you want to work in for each field type. The units can all be set to metric or imperial on mass, or can be configured on an item by item basis as required. |
 PipeFlow Expert System Fittings database
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Pipe Size & Materials Database
Choose from a database of standard pipe materials and standard pipe sizes for that material. New pipe material and size data can be added to the database as required. |
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PipeFlow Expert System Fittings database
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Pipe Fittings Database
Choose from our database of fittings information to add fitting information onto pipes. New fittings data can be created by the user and stored in the fittings database. |
Just add water!
SmallHydro,
Jess
“How can we help you connect the drops?”
Your comments & questions are always welcome!
The Original 2 Questions –
Subject: Hydro turbine questions
From: Peter
Date: Wed, July 01, 2009 4:58 amTo: smallhydroblog@smallhydro.com
I have a few questions that I need answers to. I have a seasonal water fall with 38 feet of head. The flow rate varies with the weather.
Q: My first question is why isn’t there a turbine that works on variable speed? As flow increases, the output should increase.
Q: My second question is in your opinion would it be worth investing a small turbine knowing that I may only get 180 days of power.
I hope to build on this site and will be off the grid. I know I will need a hybrid system with solar/possible wind or water. I want the best, but yet the cheapest way to go.Thanks for your time!Pete
My Answers –
Peter,
That’s a great pair of questions about Variable Flow & Speed. There are hydro turbines to solve the variable flow problem, but that is not the same situation as variable speed. The two parameters are related, since an increase in water turbine shaft speed due to pressure changes will cause a proportinate increase in turbine water flow rate for a fixed load. The problem is that variations in turbine RPM will cause generator output frequency to vary too.
For AC generators, transformers and AC motors variable frequency is a very bad thing, it will cause heating and damage insulation, solder and machines. Frequency variation will cause transmission and synchronization problems, leading to brownouts and other problems too.
This varible speed turbine control ability is an area of recent hydroelectric system research. DC alternator designs can tolerate this Hydro turbine generator RPM variation because the final AC power output frequency is defined by the inverter design not the alternator speed (output power will vary though.)
So, let’s look back at the possibility of site flow variation solutions and not hydro generator speed variation;
A: Several variable flow Small & Micro Hydro turbine options exist for you –
A few variable flow Hydro Turbine configurations that come to mind are:
- Multi jet Turgo or Pelton wheels may work but may not be as efficient as they are when that type of turbine is used for higher head >100ft 30m sites. Low head sites favor reaction turbine types.
- A better turbine choice would be crossflow with multiple inlet gates.
- Typical multi gate crossflow uses 2 -3 sections on turbine inlet for 1/3, 2/3, 3/3 or 1/4, 1/2/, 3/4 and 4/4 flow curves respectively.
- You can use other low head variable flow options, Francis with wicket gate, Kaplan with wicket gate >$, etc.
- Propeller and simple PAT (unregulated Francis type) systems operate in a narrow efficiency band or curve, yet if you can put 2 or more of these in parallel you can sequence their inlet valves much like the crossflow. Say that you have a 5 kW and a 10 kW pair of units, now you get a 5, 10, 15 kW range efficiently over a broader range of flows – if the turbine curves overlap effectively.
A: Some things to consider about Site Stream Flow Variability and Availability –
The site with flow variation and some months with zero flow may or may not be economic to set up for hydropower, depending on your Flow Duration Curve or FDC and the overall ROI for your hydropower equipment costs. An FDC is a pareto chart or ordered histogram of a stream’s frequency of flows at a given Q or water flow rate. We’ll cover FDC’s and their creation later in the 12 step Small & Micro Hydropower evaluation process.
Here’s some Additional Questions for you to Answer about your Potential Hydroelectric Site…
1. How much peak, avg vs low flow do you have? (Start with a guess, get an FDC later)
2. You said that you have 38 ft head, is there any storage or just natural falls?
3. Do you have flow data showing avg daily flow for greater than 10-12 years?
FYI – Climate change tends to follow 11 yr sunspot cycles more than anything.
4. Do you have water rights or can you get them?
180 days of 100% flow at your sweet spot may work fine energy wise, if you can punch out enough power. Hybrid solar may help. If you can grid tie, then Hybrid with net metering may work well for you $ ROI wise. If enough power then you can become an Independent Power Producer…
Sincerely,
Jess
DoradoVista, Inc.
PS. Let us know how we can help with your turbine selection. I wanted to let you know that we have some great turbine and water to wire hydropower system sources too depending on what units you are looking for.
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