Optimize Re-circulation of Hyrdoponic System 4

[varun213]

Hi guys, Ive been assigned a project that is not giving me trouble and was hoping I could get some starting points from somebody on here. Here is the the basic description of the project.

The client owns a Storage container about 40' long which is a Complete growing operation going on to grow vegetables and supply them to rural areas that cannot grow leafy greens basically. He reached out to us to for consulting on ONLY the Re circulation portion of his system. It has two pumps and 6 racks that have have plants growing on them. Based off this short description,

what are some ways you can Optimize re-circulation systems? The three Ideas I have are:

1. reduce overall pipe length to minimize frictional losses
2. reduce the overall amount of elbows and tee bends in the system
3. Choose a cheaper pump that can save energy costs

Other than that how would somebody go about this project?

I could really use some tips from anybody that has experience in this area of engineering.

Thank you

 

[HVACMech]

Cheaper pump won't save energy costs... It would save initial capital cost, but will probably increase maintenance cost. Its not clear from the description of the system how it functions, but you should put a VFD on the pump to save energy costs if the pump speed (flow) can be modulated.

 

[IRstuff]

If anything, you want at high reliability pump, given that it probably needs to run continuously. That typically puts you out of the realm of "cheaper."

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[varun213]

thanks, that really helps in narrowing down possible solutions. It does need to run continuously for sure.

I'll try to give the best description possible of the system. Picture a storage container that is about 40' long. Upon entering the storage container is a 6' Reservoir which pumps water through 6 different pipes. There are 6 racks which are laid down along the length of the Container and assembled like a typical shelf. The Pipes then are routed to each rack which has water flowing through them which feed the plant roots. There is a Smaller reservoir at the end of the circuit which has 2 smaller pumps half the size of the main one (from main reservoir) and that I believe pumps the liquid through a return line that goes back to the Main reservoir and repeats the circuit. At beginning of the circuit there is one pipe coming out of the main reservoir and then it splits into 6 different pipes via Fittings and Tee bends. The client has Valves that are placed on each pipe before they go into the reservoir to control flow easily upon entering the storage container.

So far I can only think of re-routing the pipes a bit to reduce as many bends and fittings as possible in the circuit. Other than that would you have any more suggestions based on my description? Pipe is a common PVC plastic material and each of the racks have inlets in them to have water flow through to feed the plants.

 

[hendersdc]

What do you want to optimize the system for?

Production Cost
Production Time
Maintenance Cost
Ease of Field Maintenance
Modularity
Reliability
Efficiency
Aesthetics
Degree of Control/Customization

It sounds like they have an existing design, what do they want it to do/meet that it currently doesn't?

 

[HVACMech]

You have such a small system, "optimizing" it from a mechanical pumping standpoint may not be really possible. You are not going to save any money in pump size by reducing your head because the amount of piping is so short. Sounds like you are wanting to lower the cost of the install altogether. Mechanically I don't think there is much you can do.

 

[varun213]

yea they do have an existing design which works just fine apparently. We are stuck because we dont know where we can make his system any better than it is already.

I would say Efficiency is the the main area of improvement we are looking at. I think by just reducing the bends and elbows in the system if possible by improving Aesthetics can do a lot for his system.
Could you guys throw out any possible ideas that can lower the cost of the system he running already?

 

[HVACMech]

Buy cheaper components...?
From a mechanical efficiency point of view I would guess you will not be able to save anything. Definitely not enough to get you into a different size motor.

 

[LittleInch]

Ask questions about flow. How much do they really need?, how wide does the channel need to be? All flow needs to be paid for in energy. Can you combine all flow into one tank at the base and then use a single pump to pump up to each level? Small pumps are inefficient. Use a bigger single unit.

Does the Dow change over time as the pants grow? Two different sized pumps might be better.

Do all six trays operate at the same flow?

Work out your requirement and challenge all nominal flows or assumptio.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[varun213]

A single pump sounds like a really good idea. The 6 trays are all at the same flow, I can say Taking out bends in the piping system and Using the main reservoir tank with a single pump would really help. I know hydroponic grow operations usually have a sweet spot when it comes to flow rate operations so that will be something I would need to research a bit further.

I'm going to simulate as many possibilities in pipe flow expert software and that can help me narrow down some options.

Thanks again everybody.

 

[LittleInch]

I would go for one tank at the bottom with a float switch to start a pump on/off. Pump to a single tank at the high point with a high level pump off switch.

Pipe straight down with three tees either side and a simple regulating valve to control flow in each layer on each side. Head of water will be constant so once you've got the right flow you shouldn't need to change valve or experiment with sections of small tube to reduce flow - even cheaper and simpler.

Bigger pumps tend to be more efficient so if the size means your pump starts and stops a few time per hour then OK - size your tanks appropriately to cope with that. The duty is quite fixed ( head difference from one tank to the other - 6 feet or so plus some friction losses ) so you can find the most efficient pump and then size your pipe accordingly ( the bigger the better) to reduce losses

You'll need make up water to be added somewhere along the line from time to time.

Power is normally an absolute killer CAPEX cost in remote locations so if you can make it Solar powered all the better.

Good luck and let us know how you get on.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[berkshire]

One thing to bear in mind in grow systems, especially with drip feeders, is the fact that fertilizers are added to the water systems.
These have a tendency to block drippers and increase your head pressure unless preventive maintenance is done on a regular basis.
Now if your concern is only the return lines I cannot help you.
B.E.

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