Backyard Aquaponics Setup

[H W]

I have hopefully designed a system for my backyard using a WGP-95-PW at 4,300 gallon per hour dual outlet pump with 15 PSI from the pump and a 1,500 gallon fish tank with 350 square feet of growbeds and 16 - 5' x 4" vertical towers to feed from the fish tank, the greenhouse is only going to be a 12' x 26' so I will have an external growbed for the summer. I also am going to install an attic heating system for the winter and an underground cooling system for the summer, because I live on the coast in Mississippi and I need to be able to control the water temperature for the fish and the growing medium, I already have all of the computer data I need for the surface and ground temperatures down to 60 inches for a complete year, and I plan on installing two inches of foam insulation on the bottom and around the tank, since the bottom is 48" below ground. At the present time I will have my computerized weather station next week, so I can have the data I need for the heat produced in the attic versus the ground and outside air temperatures to justify my thoughts on using it as the heat source in the winter and it will be here next week. I have been using a temporary setup, but it does not send it to the computer automatically and I need all of the data 24 hours a day to be positive that this will be the best system for winter heat, versus solar only during clear skies and the shorter daylight hours of winter.

I plan on using an index valve for the growbeds and the vertical towers for the second outlet and the first outlet will be electronically controlled by temperature sensors in the fish tank, attic heater and the underground cooler with manual flow adjusters to make sure I get the system balanced on the front end so the water flow is correct and then the electronics can take care of it after that, because the top of the system in the attic will be approximately 16' feet above the height of the pump. The pump has a rated height of 30' and at 16' it should still produce about 1,500 gallons an hour using one outlet, according to the specs. The attic heater and the underground cooler hold a total of 33 gallons of water in each of them and a total surface area of 59 square feet in each as well.

I also intend on installing an air line directly to the pump inlet to introduce air into the outlets for extra aeration in the growbeds and the fish tank itself. But that may be a potential problem for having to push the water up to 16' high at times and potentially air bounding the system, I am going to try this anyway and if it does create a problem, but I think I know how to stop this problem but if I can't, I will just seal the inlet and install it directly to outlet 2 for the growbeds only. 

I am including a schematic of the basic layout of the routing of the piping for each outlet on the pump and I would appreciate any comments that anyone sees why I might have a problem with the way I have the system designed at this point. I have been through so many different iterations of this system over the last 5 months because of different ideas that I scrapped because of the potential problems that I could see might come up, BUT it always helps to have other people, with fresh eyes, different perspectives and different knowledge that can see potential problems that I might have missed or hadn't thought of. So I would appreciate any thoughts on this setup.

H

[TCLynx]

Remember that the indexing valve requires that the flow to it stop and start for it to index.  This is usually done by turning the pump on/off or in some cases if the pump is strong enough for it, using a solenoid valve.  I don't know how a venturi air inlet would affect those.

I don't know if I would put hand valves after the indexing valve.  If you close off an outlet and the pump sends water to it the indexing valve will have an issue and the water is going to try to escape out the "inactive outlets" possibly damaging or imparing the future functioning of the valve.

[H W]

     TC, thank you for taking the time to look at the details of my proposed system, as I have read many of your posts here and in your blog and website, and have been impressed with the breadth of your knowledge in this field. I do not intend on using a solenoid valve in the system as I propose to have a flood and drain type of system, and I definitely had not considered what effect the excess air may have on the indexing unit. 

     The hand valves are not going to be used to cut off any growbeds, the only reason they are there is to help balance the timing for the indexing system, because the individual growbeds are of different sizes and by slowing the water flow to the smaller beds I theoretically can just set the timer for the same amount in each growbed and it should balance itself out.

     But while I have your attention I would also appreciate it if you would look at a design I have considered for my supplementary heating system in the winter months. I had initially decided to use solar and the usual hoses or box system to help with that, but the more I thought about it the more I discounted that option, as the shortest days of the year are all in the winter months and so the efficiency of the unit is not as helpful as i would like it to be then.

     The system that I finally decided on uses the excess heat in the attic of my house, which increases dramatically during the day as the sun shines on the roof, and yet at night is still much warmer than the commensurate outside ambient temperatures because of the excess heat in the house from running a heater to keep us warm and this eventually  rises into the attic, which means I will have a much longer time during the full 24 hour day to be pumping extra heat into the fish tank and the growbeds, and as you have said before, a system also loses heat from the fish tank every time it is pumping water into growbeds that are much cooler than the water in the fish tank, especially when the sun sets in the greenhouse.

     This is a drawing of the heater system setup in the attic that I have drawn, I also included a radiator at the very top of the system, but I don't intend on installing the radiator until after I see how it performs without it. And I still have to pin down the actual daily variations of the temps in the attic before I decide if I need to do anymore changes to it. I will have one thermometer at 1' from the roof deck and another at 3' from it to see how these temperatures correlate with each other in a 24 hour day.

     Yet the 4" pipe will still move the same 25 gallons per minute through the 4" pipe as the 1 1/4", but it will have 8.5 times longer to heat up the water as it passes through it.

     I would also appreciate any thoughts you might have on this system as well as my replies to you on the actual plumbing for the fish tank and growbeds, and if you see any problems please let me know.

H

[H W]

     I tried to make some changes in the statements above but I lost some of them in the edit. 

     The flood and drain cycles I intend to control by turning on and off the pump, not with a solenoid.

     And the 33 gallons and 59 square feet in the attic heat system does NOT include the radiator water or any surface area it uses for transferring heat, and none of the 1 1/4" piping .that I intend on insulating to and from the fish tank, just the 50' of 4" PVC pipe.

H

[TCLynx]

Plumbing.  So if you are feeding some smaller beds along with bigger beds, a valve to reduce the flow to the smaller bed to be sure both flood in the time required is ok so long as you are not throttling back flow from the pump.  I recommend planning on the pump cycles all being the same time since the valve and timer won't be in communication to know which zone is being pumped to.  When I pump to several small beds with the indexing valve, I mainly just need to make sure each of the beds is getting about even flow and make sure the stand pipes can handle the flow draining down the top of the stand pipe without over flooding the bed when the pump runs for longer than needed (this doesn't hurt anything.)

As to heating.  I really don't have any experience with this method of water heating so I'm not sure what to tell you.  Smaller tubing will actually give you better heat exchange though it won't slow the water down in the same way.  And the fact that you are turning the pump on/off, you will be getting some slowing of the water through the temperature control system.  Be sure you provide a bypass that will open the flow from the pump back into the fish tank when your control valve close off the flow to the heating/cooling so that you are not throttling the pump since suddenly restricting all flow out of the second outlet could damage the pump.

[H W]

TC, thank you so much for your help with this setup, I will try to answer your considerations in the order you presented them.

"Plumbing. So if you are feeding some smaller beds along with bigger beds, a valve to reduce the flow to the smaller bed to be sure both flood in the time required is ok so long as you are not throttling back flow from the pump."

That is exactly why I have been trying to find a dual outlet pump with enough GPM for so long. I will be throttling back the flow to the smaller growbeds so the pump timer will be the same for each growbed. But, since the pump has dual water outlets the excess presssure buildup will just be rerouted to the other outlet at the pump and this should make the back pressure on the pump increase very little because of this. That is what I saw as the beauty of a double outlet pump instead of a single outlet, and why I have been searching for the right one.

"As to heating. I really don't have any experience with this method of water heating so I'm not sure what to tell you. Smaller tubing will actually give you better heat exchange though it won't slow the water down in the same way."

If I tried to use the 1 1/4" piping in the attic it would require 470' to hold the same 33 gallons of water, as well as it would be a nightmare moving around in the attic securing it so the air would have free circulation.

But like you said smaller tubing will give me better heat exchange because the surface area for the 1 1/4" PVC would be a total of 155 square feet instead of just the 59 square feet using the 4" PVC. But since the water is in the 4" over 8 times longer I believe that it will make up for that difference very easily, although I am certainly not qualified to discuss fluid mechanics in any great detail.

My concept from the start of building an aquaponic system has been that by using a dual outlet pump you will actually be pumping pressurized fresh aerated water back into the fish tank anytime the pump is running to fill your growbeds, as I believe this is a much better design than just letting the water from the growbeds fall back into the fish tank at the end of the flood cycle. And this would possibly preclude having to use air blowers or pumps to aerate the water in the fish tank all of the time.

"And the fact that you are turning the pump on/off, you will be getting some slowing of the water through the temperature control system. Be sure you provide a bypass that will open the flow from the pump back into the fish tank when your control valve close off the flow to the heating/cooling so that you are not throttling the pump since suddenly restricting all flow out of the second outlet could damage the pump."

If you will look at the accompanying detail drawing you will see that the main pipe goes directly back to the fish tank for aeration. Detail A and B are electrical controllers handled by the electronic controller to shut the water off from going directly back to the fish tank, it reroutes the water by closing the valve and thus making the water reroute to the attic or underground. If either one of these units fail the water just keeps pumping back into the fish tank, that is my safety net in case of problems. The hand valves are used  to close the entire attic or underground systems from being able to reroute water when I cut the electronic controller off when the weather is perfect and I don't need it, although I am not sure that will ever be the case where I live. Although during the winter I will have the under ground tank shut off all of the time by the hand valve, and the controller will bypass this tank at all times. Although they are not shown in the drawings there are splitters at the attic and underground tank for draining these when appropriate as well as using them as cleanouts for these systems..

I have considered increasing the pipe size from outlet 1 back to the fish tank to a 1 1/2" pipe to handle any excess volume and pressure created by outlet 2, and with your considerations in mind that is exactly what I will do. As the 1 1/2" pipe will handle more than 1/3 more volume than the 1 1/4" pipe, so it will be able to easily handle the extra volume and pressure from outlet 1 being constrained.

Let me thank you again for helping me through the process of redesigning this system so it will be as economical and functional as I can make it. I do have other design ideas for this system and I would appreciate it very much if you would consider helping me with your expertise in these areas as well. Maybe there is a chance we can both increase our knowledge in aquaponics related systems and equipment.

H

[H W]

I finally got my weather station in  February and I set the external unit up in my attic and the internal unit between my inside window and the screen in my carport, and found that this skewed the actual exterior temperature by about a 3 degree increase over what the actual outside temperature was. But the chart listed below shows the actual temperatures recorded by the unit using Cumulus software to record it to my computer directly. So all of the readings shown below should have an extra 3 degrees added to the attic temperatures to compensate for this discrepancy.

The chart shows:         Inside Temp = actual Outside Temperature

                                  Outside Temp = actual Attic Temperature

February 16 -  Cloudy all day but sun seems to be getting through

February 17 -  Cloudy all day but sun seems to be getting through intermittently

February 18 -  Raining hard all day with Tornado and flood watches until the late afternoon

February 19 -  Sun shining all day

February 20 -  Cloudy but sun is shining fairly regularly

February 21 -  Cloudy with sun shining intermittently but regularly

The roof on my house is a light tan color and I have a huge Oak tree, and a smaller one that I am going to cut down, shading the house directly in the southern direction so it keeps the temperature in the attic low until about 2:30 pm, when it maxes out normally, depending on how cloudy it is. I also have two 12" turbines on the roof that I closed off temporarily to do the testing.

As you can see by the picture above the oak tree still is loaded with leaves and covers a major part of the roof area limiting the amount of sun that gets to it, the pictures were taken at 2:50 pm.

The next picture is an aerial shot showing all of the trees in the front, side and back yard and the dimensions of the lot, as well as the position of the sun in January and August, and where I plan to place my greenhouses. If you will look at the following picture you will see that I have trees everyyyywhere on my lot.

I am still studying all of the data from the weather station, but I think I might be better off placing the heat for the fish tank in the greenhouse at the top of the ceiling, but I am definitely not sure about that, because when the temperature gets down to below 30 degrees outside and the sun is not shining very long because of the cloud cover I may not be able to use the heat at all, because the water in my heating system may never get above 60 degrees in the greenhouse. And at 60 degrees tilapia are starting to get into a very bad region for their health.

I believe what I may try is to go ahead and put up my greenhouses and install my heating system in them and see what temperatures I get inside the greenhouse, the only problem I see is that we won't be having very low temperatures outside for the rest of the year so the data will not be near as critical as it needs to be when the temperatures drop below 30 degrees.

I am open to any ideas or suggestions about my options for passive winter heating of the greenhouse and my Tilapia.

H

[larry]

Hay i know i new to post but when i was looking at building my house i read alot about underground heating what it details are during the summer ur water ( like ur cooler lines) would actually transfer heat to the ground around the tank when temperatures drop ur ground would still be warm and transfer heat back to tank. Plus using all those 90°would decrease ur head pressure cause of friction loss (like u would have same problem if using smaller pipe) second u could double ur chiller lines have better pressure to induce ur air injection hope this help. Every penny saved is penny earned !