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. 

[TCLynx]

Well for large scale, to do pure timed pumping you really wind up needing a huge sump capacity.  If you figure using indexing valves you wind up needing less sump capacity but you are running the pump more often to sequence through the beds.  The fact that a larger pump is needed to flood all beds at once means the energy savings is not as much as it might be otherwise.  When you index, you get to use a "medium" size pump between the constant and pure timed but depending on how much grow beds you are talking about, you may still wind up with the pump on quite a bit.  I would say my pumping with the indexing valves (depending on system) is half to 9/10ths of the time.

 

Most of the raft systems are used to having flow all the time but it's not a very big flow.  Well the Friendlies newsletters recommend 5 gallons per minute through the raft beds which isn't a huge amount of pumping, the bio-filtration needs more pumping than that for large systems usually.

 

I don't know the water flow details around the Morningstar fishermen systems but they might be worth a look for you, the water flows through many of their systems don't seem fast.  I don't know how much info they make available online about their systems though.

[Gina Cavaliero]

TC is correct that Friendly style systems recommend a minimum flow of 5 gallons per minute.  We experimented with intermittent flow and it definitely compromised growth rates and also more taxing on the pump.  Our flow rate is at 12gpm and is with a mag drive pump that operates on 120 watts.  We could go with a smaller pump and minimize elec consumption even more, but like the results we are seeing with our current flow.  Over at MSF all of their flow is created with airlift from regenerative blowers and syphon, which does a great job moving the water, however a Sweetwater S21 for example, operates at 570 watts.  Being blowers draw so much more wattage, we prefer to use them soley for aeration and are very diligent about sizing air needs properly and using relief valves to insure the blower isn't working harder than it has too and drawing more wattage.   Utilizing gravity flow and mimimal pumping as an end line return is quite efficient.

[RupertofOZ]

What's your scale differentiation between a "commercial system" and a "community-scale system" Kobus??

[nyfloristics]

Try looking into sequence pumps.  If scaled properly these can be very efficient at a large scale with constant flow.  You can even provide flow to several beds with one pump by using a simple step-down manifold. 

 

[Kobus Jooste]

Rupert, the footprint of a single greenhouse remains 300 m2.  I am using the standard ULMA tunnel from Spain that is typically used here as a baseline to design in.  The difference between "commercial" and "community" is a bit fuzzy I know - meaning different things in different parts of the world.  Over here, the differentiation typically comes with the objectives of the project.

RupertofOZ said:

What's your scale differentiation between a "commercial system" and a "community-scale system" Kobus??

[Kobus Jooste]

Gina, I'm assuming that the flow rate is based on your system's dimentions and not just in general for all friendly AP systems?  Which one of their designs are you operating at the moment?  120 Watt is very nice going.  As you said though, it is the air stones that becomes the issue

Gina Cavaliero said:

TC is correct that Friendly style systems recommend a minimum flow of 5 gallons per minute.  We experimented with intermittent flow and it definitely compromised growth rates and also more taxing on the pump.  Our flow rate is at 12gpm and is with a mag drive pump that operates on 120 watts.  We could go with a smaller pump and minimize elec consumption even more, but like the results we are seeing with our current flow.  Over at MSF all of their flow is created with airlift from regenerative blowers and syphon, which does a great job moving the water, however a Sweetwater S21 for example, operates at 570 watts.  Being blowers draw so much more wattage, we prefer to use them soley for aeration and are very diligent about sizing air needs properly and using relief valves to insure the blower isn't working harder than it has too and drawing more wattage.   Utilizing gravity flow and mimimal pumping as an end line return is quite efficient.

[Gina Cavaliero]

Hey Kobus, actually that flow rate is for all Friendly raft systems, regardless of size.  We are operating a 1024sqft "high density" which means it has the solid settling and fine settling tanks.  However we will be adding another 1024sqft and they will be plumbed in line with the existing system, so the same flow rate will apply and will be one long loop.  Its a tiny little magnetic drive pump.  I love the expression on people's faces when we point it out and tell them that is the only thing moving the water outside of gravity.  Even after seeing it, some still don't believe it.

[Kobus Jooste]

Gina - thanks for the feedback.  My initial work in AP systems research was based on the stuff that I could find scientific papers on - which was quite limited.  I am from a scientific background and wanted information on system yields based on long-term studies.  I must say that I have always liked the Friendly AP designs for simplicity, although I am also a fan of having some gravel beds in there somewhere.  I think I should download their designs and take a closer look.  Their design is close in footprint to my scaled UVI calculations which ends up using far more electricity on the water side.

Gina Cavaliero said:

Hey Kobus, actually that flow rate is for all Friendly raft systems, regardless of size.  We are operating a 1024sqft "high density" which means it has the solid settling and fine settling tanks.  However we will be adding another 1024sqft and they will be plumbed in line with the existing system, so the same flow rate will apply and will be one long loop.  Its a tiny little magnetic drive pump.  I love the expression on people's faces when we point it out and tell them that is the only thing moving the water outside of gravity.  Even after seeing it, some still don't believe it.

[TCLynx]

The Friendlies designs are based on UVI but they went to the drawing board to reduce costs on things like electricity since Hawaii is on some pretty costly electrical rates.  Their commercial package might be worth a look for you, unfortunately I think to get the details you probably have to pay for the plans.

[Gina Cavaliero]

No problem Kobus.  I agree on the gravel beds.  We are actually going to be converting over our first trough where the outflow currently comes off the degas to media.  We think there are multiple benefits to be had there.  We gain higher nutrient levels, although our system is currently cranking at 20+ nitrates right now, but will also be able to eliminate the solids settling, removing the solids and have the benefit of more growing diversity. 

 

Tim at Friendly did some major value engineering of UVI's system.  Like TC said though, you will have to purchase it to get the plans and manual, unless you just come to the training next month after you come to the conference!   It would be a business expense, right?!  I know, I know, but you can't blame a girl for trying!  ;-)

[Kobus Jooste]

I do not mind paying for the plans, and may just be able to slip it into a project rather than having to fork out my own money (what is than in any case - seldom see it!). Our electricity costs have gone up almost 120% since I did my calcs and although my end concept is still similar to UVI, I cannot justify the cost of their configuration.

Gina Cavaliero said:

No problem Kobus.  I agree on the gravel beds.  We are actually going to be converting over our first trough where the outflow currently comes off the degas to media.  We think there are multiple benefits to be had there.  We gain higher nutrient levels, although our system is currently cranking at 20+ nitrates right now, but will also be able to eliminate the solids settling, removing the solids and have the benefit of more growing diversity. 

 

Tim at Friendly did some major value engineering of UVI's system.  Like TC said though, you will have to purchase it to get the plans and manual, unless you just come to the training next month after you come to the conference!   It would be a business expense, right?!  I know, I know, but you can't blame a girl for trying!  ;-)

[Chris Smith]

My commercial system has 640 sqft of trough space and 100 sqft of media beds. My FT has a constant overflow to the media beds. There are 4 media beds and I am developing special valves to direct the water flow to each bed for 15 minutes each. I use a 50w water pump and have two 40w air pumps.

The valves that I am developing work on flow and no pressure which will enable a constant flow system to provide a timed flow to media beds. Each bed has two valves. When the flood valve opens the drain valve closes. When the flood valve closes the drain valve opens allowing the bed to drain very quickly and not tie up excess system water from the sump.