Backyard Aquaponics
A place to discuss aquaponics

As it seems have you.... and that's the point... even continuously pumped systems... can result in pump failure....

And the "u-beaut" pumps... were a reference to someone else...

I remember from my engineering days that turning things on and off exposes them to repeated surges, which can be hard on the circuitry. It's not a guarantee of shortened life span, but it increases the risk of failure.

It's probably like how one person can smoke a pack a day and live to be ninety, while another person smoking the same amount from the same age gets lung cancer and dies at 50. And a third person who never smoked a single cigarette gets hit by a bus and dies at 25.

I have no idea what I just said, but it felt pretty profound while I was saying it.

True continuously run pumps can fail. Both the siphon pumps and the ones you mentioned having the capacitors fail, were on systems that weren't being continuously run so even though I get your point you sort of made the case for me.

Thanks for the clarification regarding the quote. Posting it with my quote made it appear you were referring to me which is why I took offense.

It's been a week or so since I posted anything here. Just wanted to post some updated pics of some modifications and additions I've made to the setup I'm planning.

To the AP system, I've reconfigured the GB's to be independently filled and drained, rather than piped together in series. This will allow me to selectively make some beds F&D and others CF. I've also added a fourth sump tank under each line, so I'm sure there's plenty of sump reserve, no matter how it operates. I've also moved the GB fill supply lines to the inner walkways so they are more accessible.

I've since added several solar components, borrowing from projects I've got planned for the main house anyway. First, there is the addition of a 3'x24' solar space heater collector along the lower southerly wall of the hoophouse. It's a design which I got from my involvement with the SimplySolar group on Yahoo, of which Gary Reysa from BuildItSolar.com is a contributing member. The collector is made from aluminum downspouts painted black and housed in a wooden frame with insulation and glazing. It is stationary at the optimum angle for the winter sun at my latitude (32 degrees from vertical). It is ducted via 4" pvc and airflow is powered by two 4" inline fans in opposing push/pull configuration. The fans can be controlled by simple snap switches or an Arduino board.

Next, is the addtion of a 8'x24' solar thermal hotwater collection system using CPVC piping for the collector material. The collector mounts are designed to allow adjustment for the optimum tilt angle for the four seasons. Thermal storage is provided by 2 IBC's (red tanks) piped together to form one large 550 gallon heat sink. One red IBC has a heat exchanger coil which is plumbed to the CPVC array to form a closed loop for collecting solar heat energy. The 2nd IBC has another heat exchanger coil that is used to heat water to supply a utility sink in the hoophouse. The water supply comes from the remaining two IBC's (blue tanks) under the fishtanks. It is filtered, purified, and pressurized before being split off to hot/cold supply manifolds. The sink and water system will enable outside cleaning of fish and veggies and topping up the AP system as needed, all using rainwater supply and solar power. The solar space heater will heat the greenhouse during the day and the thermal storage tanks will heat it overnite. I also have the possibility of running PEX tubing through the concrete pad to heat the floor using solar, so there are many options available.

There will be five water pumps to run, as well as fish tank aerators and a couple of fans. So, I put in a service panel and a 4 kW PV solar array using Enphase microinverters. This collection of projects, combined with a battery bank array for overnight power, would really make our AP hoophouse completely self-sufficient and off-grid. The large PV solar array is one that I found on the 3D warehouse. However, it's pretty close to what I would build, especially since it uses the Enphase microinverter technology which I really favor. I'm not sure I'd need an array that large just to support the AP, but our home is all-electric, so any overage produced would certainly not go to waste.

I can only post screen pics, as the 3D model is now too large to upload to the warehouse...

Last two pics:

SWEET!

I also see the addition of a utility sink.

I'm beginning to get the impression you don't do *anything* "just a little bit."

If the solar collector can be moved away from the grow house a bit you will collect more heat. The collector is shading the grow house and even though it's not shading the plants, there will be less heat collected over the entire system. '

If it gets really cold where you are, it might also be worth painting some sections of the grow house black eg where the collector shades the grow house. It might pay to paint black the other side as well.

Grow beds will act as heat exchangers so heat in the grow house equals heat in the water.

Also, just a thought on angles. The coldest part of winter might not be the middle of winter, so there might be some value in setting the angle to suit the coldest part. I'm not sure if that's true, it just fell out of my head.


Is that collector glass covered?

I did some experiments with solar collectors, and was a bit surprised to find there wasn't any need to lay pipe over the entire surface. A single pipe at the top running passively as a thermo siphon was enough to suck all the heat from the collector. This only works with a glass lidded collector. If there is no glass, and the pipe is the collector, obviously the more pipe the better.

Apparently, the ground only a few feet down stays at the average yearly temperature for your area. There might be some heat to collect by [burying] some pipes and running a fan to circulate air. I know nothing of this method other than people do it. I think you can also store heat by running air through during the day and then recover it at night.

Yep, thanks for the suggestion!

Go big or go home, right?

Well, I think sometimes my aspirations are much larger than my resources, but you always have to aim a bit higher than your intended target. I've been trying to prepare my family for hard times without obsessing about it negatively. My goal is for our family and home to become as self-sufficient as possible. I just try to come up with the prospective plans and leave the resources and final outcomes to God.

Here's an overhead view with the components geo-located on our property in Google Earth. Very cool to be able to see how everything might fit on the available space. I had to rotate everything to get the right angles, but it seems GE has the size scaling pretty much correct.

re the solar heater being no different than the growhouse - I suspect the black would make a difference. Also the ability to turn it off in summer is a very worthwhile thing.

If you can build it so that you can test it with just 1 pipe running through rather than the full amount of pipes, you might be pleasantly surprised. Especially when the pipe is full of water rather than air, there is a massive transfer of heat.

In my little experiment, I found no difference in operation using one pipe or five. One pipe moving only at thermo siphon pace (ie no pump) moved enough water to cool the glassed box, although in my case I think the fact that I had a small water tank that got up to 30 degrees c meant I was putting 30 degree c water back into the collector on a 10 degrr c day. This meant that the collector temp was around 33 degrees c.

Without the tube flowing, I saw temperatures that would easily make for a slow cooker. From memory it got up to around 70 degrees c.

With a pump pushing cold water through, I'm guessing you could get away with only a few feet of heat exchange pipe inside the collector.

I think the reason people use a lot of pipe is because it's required if there is no cover, and the pipe is actually the collector rather than the heat exchanger. Once you have glass over the top, the box becomes the collector, and the pipe just a heat exchanger. I suspect people improve their design by adding glass, and just leave the collector as it was because it was already built.

It definitely wont hurt to have it, but it might be worth your while to test just the one pipe before you connect up the rest.

Sorry BW, but I'm a bit confused about which solar collector you're referring to. Initially, I thought you were referring to the air space heater collector (made from horizontally placed downspouts) which is only 3' high running along the base of the greenhouse. But now it seems as if you are talking about the solar water heater made from CPVC.

Assuming we're talking about the water heater collector, here's how I understand the physics involved and what I *think* you are suggesting (but I could be way off-base). The CPVC is painted black so it absorbs more solar energy rather than reflecting it away if left in it's native light color. The collection fluid (water or antifreeze in closed loop) must be pumped through the CPVC grid at sufficient volume per minute in order to efficiently capture and exchange the sun's energy into the thermal storage IBC's. Pumped too slowly, and excess heat energy remains in the CPVC material, resulting in a meltdown/stagnation event. Pumped too quickly, and the fluid doesn't remain in contact with the CPVC long enough to transfer heat efficiently, resulting in constant pumping cycles. (I could live with less than 100% efficient, but not meltdown! ) The CPVC collector pipes return to my 550 gallon dual IBC setup where they feed through a large loop of PEX tubing coiled up inside. The heat from the closed collector loop is then exchanged to the cooler water in the IBC's. The pump cycling would be thermostatically controlled by an Arduino or a differential temp controller that compares the fluid temp inside the collector vs the storage tanks.

Now, I will say that if you have less CPVC piping in the collector (i.e. smaller total collector surface area), then it can only result in a lower amount of solar energy being captured because there is less surface area being exposed to the sun's rays and less fluid in the collector at any given time. This is the same factor that PV solar panels experience. The fewer silicon panels you have exposed to the sun, the less m² of collector area you have and the lower the amount of electricity produced. There is a fixed amount of solar energy hitting each m² of the earth's surface. So, I can't see what you are getting at by testing the system using fewer pipes. I'm apparently missing something in the translation somewhere.

The solar space heater is designed specifically to heat and circulate air, whereas the solar water heater is meant to capture heat and store it in water. The space heater would have two blower fans pushing air through the downspouts. It would act like a forced air furnace in your home and it would only operate during the winter months, with the possible exception of using it to vent hot air OUT of the greenhouse in summer. The solar water heater would provide hot water year round, but if the heat from the storage tanks becomes too excessive, then I could simply stop the recirculation pump and cover the collector.

Yes, the water heater collector box will be glazed with polycarbonate sheeting and insulated with 1/2" Dow polyisocyanurate. But there are other considerations which affect the heat capture/transfer to the fluid. One being the method of contact between the CPVC and the surface of the box. If you just had the pipe suspended in the air space within a glass-sealed box it would not efficiently capture much of the solar heat energy. There must be significant direct physical contact of the pipe with surfaces inside the collector box. This is accomplished by covering the polyiso insulation with a sheet of aluminum flashing. The CPVC pipe is then "glued" to the flashing using silicone and everything is painted black. Silicone is probably not the optimal substance for heat transfer, but it's been proven to work well enough. In some cases of well-sealed collectors, too much heat is retained inside the box which led some folks to use the corrugated SunTuff glazing material and not seal it completely, just enough to keep the rain out.