Large systems on Timed Flow

[Kobus Jooste]

Hi all

 

I am currently re-visiting a commercial system dsesign and costing that I did a few years ago.  I am not all that happy with the energy requirements of the system.  As far as I understand, most large systems are based on permanent flow (water pumps and air pumps in the rafts).  I am looking for examples of large systems that can still function on timed flooding of media beds.  I am looking to turn my original HD design into a LD koi system with multiple tanks, gravel beds and rafts.  The rafts will need some aeration, potentially the fish tanks too, but I am trying to scale back on the "allways on" part of the design as much as possible (The original HD design was based on the UVI component ratios and uses 2 kW per hour).  I have not downloaded the larger designs from the Friendlies, thus if they cover something in this range I'll be willing to download the plants to see how similar they are to my concept.  I have the Backyard IBC pdf and have already seen some pretty large systems in there.

 

If anyone else knows of other community-scale systems that are designed around low power consumption I'll be quite interested to learn. 

[the mad german]

Frank I agree, and in a roundabout way pointed that out to TC. I have a friend that has a motor rewind shop and to think in this day and age the formula for the motor rewinding application is almost exactly as it was 40 years to go when considering the electricty to to horsepower conversion work ratio.

Now VFDs are a whole differant ballgame, but then you get into using an analog or binary signal which then needs a pid loop  program to tell it what to do, blah, blah, blah etc.

2KW an hour Kobus?

Wow! Ever thought of using a a gravity fed storage tank mounted up high with a DC solar application to fill it?

 

I would love to play in your sand box if SA wasn't so dang far away.

[Kobus Jooste]

I find this part of the discussion very interesting Frank.  Electronic components have bnever been the focus of my thoughts - only the fact that I did not like how much power they needed.  I also agree with your comments on air bubble characteristics in water aeration (which is why I have not bothered with them in my research or my home system). 

 

What I have been wondering about of late is to look for something mechanical that can operate on the principle of the air lift meets the wind pump.  If we are only lifting a meter in the air (if we design around small height differences to begin with), can pistons be more efficient? A solid tube with a capacity of around half a gallon sucking from the bottom and emptying at the top the same way a wind-driven water pump would do, but you operate the piston with an efficient motor.  If I recall correctly, the Friendly commercial system operated by Green Acre only have to move 12 gallons per minute.  Can a motor-driven piston be more efficient than a pump?  Not calculating the resistive forces of the cylinder, you are only lifting about 2 kg at a time. 

Frank De Block-Burij (hygicell) said:

you should all try and calculate the energy efficiency of your pumps:

I have done so on a regular basis and found that all pumps bar none (found so far) are a shame

that is the result of poor design: all of these (centrifugal) pumps are designed for heads of about 30 m which is far higher than we need (1-2 m)

[Kobus Jooste]

This is an exact replication of what was recommended by UVI for their HD set-up.  It is a large greenhouse, but they recommend .75 kW water circulation and 1.2 kW air agitation.  They have way too much fish for my needs, thus it is possible to scale back.  Because they had such detailed production data, I could use their system best to model electricity consumption, fish food requirements, water use, labour and yield for a business model I worked on. 

the mad german said:

2KW an hour Kobus?

Wow! Ever thought of using a a gravity fed storage tank mounted up high with a DC solar application to fill it?

 

I would love to play in your sand box if SA wasn't so dang far away.

[Frank De Block-Burij (hygicell)]

I would not exclude electronics from my system, quite the contrary:

to control manifolds, pumps and valves

and of course to monitor PH, temperature, DO, flow, alarms (even to your mobile phone) etc...

sooner or later we will come to it all to avoid sleepless nights of worrying

programmable logic controllers (PLC's) or their smaller equivalents (programmable relays) are extremely reliable

I have very good experience with Siemens Logo! (available in 12V version)

back to pumps:

a piston pump is very energy efficient in that is is a positive displacement pump

which means that every movement of the pump positively displaces a certain amount of the medium you wish to pump

piston pumps do that, just like rag pumps or bucket pumps, worm pumps, gear pumps, diaphragm pumps etc... even a propeller pump is a positive displacement pump

if you are interested in pumps, see Russell D. Hoffman's "all about pumps" for glossary and explanation of nearly all existing pumps:

http://www.animatedsoftware.com/pumpglos/pumpglos.htm

warning: don't go to the next link if you are not prepared to be absorbed for at least a few hours of fascinating discovery and learning ;-))):

http://www.animatedsoftware.com./elearning/All%20About%20Pumps/aapu...

sit back, relax, click,read, learn and enjoy (won't be hearing from you for a while, grin)

I encourage you to buy Russell's CD-Rom

Frank

PS using the in my previous post mentioned equation it is easy to calculate the theoretically needed energy to move your water around

you will be amazed at how little this is

but then there is friction and the ensuing heat and sound and wear, all losses

and there is good design to minimise these

or poor design to maximise them

 

 

[the mad german]

Kobus if your serious about a windmill pump I would stick to the piston pump and just cut out the middle man of using air, if you use air then you'll have to design an application when the basic design and principal is already in place by the piston design itself to start the work immediately. Granted it would only be a supplement when the wind blows

Unless your looking at storing huge amounts of compressed air for later work, either way you still have the issue of no-wind days. I'm not sure about the climatic dynamics of your geographic region, But I'm assuming you have lots of sun when I mentioned a solar feed into a storage tank.

[the mad german]

Frank I have to agree with you on the electronics application on a large scale or even semi large scale system.

PLCs can save 1 alot a lot of time and money if setup right and completely automate your system.

A PLC allows the controls to make the corrections for you.

If I had a large scale operation I would definately convert to it. I recently tore out a chemical feed application to some cooling towers that'll work great if I ever go big or bigger.

It controlled the ORP, measured temperature, and controlled the PH with pumps that automatically fed the acid and alkaline solutions to balance the PH,  Plus the pump is a120v  VFD that coverts a 5hp motor/pump to DC so efficiency is through the roof (max amps is only 7). Cooling tower controls and controllers I think fit well into the AP systems if 1 has the experience or the background to utlize them properly they could make life sweet for those constantly struggling or fighting the system with ups and downs of cycling or PH

I love being a pack rat, some people just don't see the value of what they throw out

the mad german

.
Frank De Block-Burij (hygicell) said:

I would not exclude electronics from my system, quite the contrary:

to control manifolds, pumps and valves

and of course to monitor PH, temperature, DO, flow, alarms (even to your mobile phone) etc...

sooner or later we will come to it all to avoid sleepless nights of worrying

programmable logic controllers (PLC's) or their smaller equivalents (programmable relays) are extremely reliable

I have very good experience with Siemens Logo! (available in 12V version)

back to pumps:

a piston pump is very energy efficient in that is is a positive displacement pump

which means that every movement of the pump positively displaces a certain amount of the medium you wish to pump