solar powered aquaponic systems

[George T]

I'm still planning my system and studying the subject - hope to launch by spring.  We've been without power here in North Florida a couple of times over the years for several days each so I'm thinking of incorporating solar from the outset, 24/7.  Plans are in infancy but I somewhat understand the basic components of panels, charge controller, batteries and inverter.  I don't intend to use solar powered components exactly but rather run the entire system from the batteries/inverter.  As I research pumps and aerators I look for best performance and dependability coupled with low wattage draw.  I haven't thought this through and since we're grid tied, it may make more sense financially just to have enough charged batteries on hand to get through a few days of power outage - I don't know if that is feasible but I believe I can do the math on it once I decide on system size, components, etc.  If you have experience in these matters, please share what worked for you, what didn't and any other thoughts you want to share on the subject.  Thanks and best regards. 

[Mike Konshak]

A\lfred, Its nice to meet you!

I haven't built any greenhouse yet, as I am in the design stages, but from a practical engineer standpoint, the 1st step to keeping the greenhouse warm is to retain the heat it absorbs from the sun and then keep the heat from seeping back out. Passive solar heat is the cheapest way to go (in the long run, and I'll get back to that) but as far as electricity goes, the cheapest you can get is from the grid you are already connected to. You simply cannot generate it any cheaper with renewables, whether it PV's, or wind. It takes 20 years to get a payback and that's with all the subsidies. In the case of my cabin, the grid was just too far away.

Anyway, burning natural gas directly is a cheaper way to heat, as electricity has to get generated by the burning of natural gas or coal, or nuclear, so there is added inefficiencies in the conversion, except with nuclear.

 

I think you should look at redesigning the green house to use passive heating, by insulating the sides and roof that is not exposed to direct sun, and incorporate a wall of thermal mass (water drums) that will collect heat in the day and radiate it back in the green house at night. The wavelength of the radiated heat will bounce around the interior, as your greenhouse will become a heat trap. Of course you need to seal air leaks as well. You can also add additional layers of glazing with air gaps to improve the R value of the clear parts of the greenhouse.

 

To add additional heat, using solar hot water panels to bring more heat into the floor of the greenhouse, but that will require an investment on your part, but these use very small pumps(<50W)  to operate and can be operated on a single PV panel.

My wife and I took a class a week ago at the Denver Botanical Gardens about high altitude growing (year round) and passive greenhouses were shown that used no electricity or fuel burning heaters. (see a couple of my photos on this forum).

I do not think that 70 degrees is a reasonable expectation all year round, but if tomatoes are a constant crop than maybe you have to. The seminar showed us varieties from Siberia that could thrive in lower temperatures

I live in Louisville, so if you want me to come by and brainstorm ideas with you, I can. I'm sure I can learn as much from you about gardening as you can from me about energy. I'm still debating about becoming a grower and all the attention it demands.

 

 

 

 

ALFRED A. ZABAWA JR said:

Hi All,

    l.  I am new at all this just got 3 starter fish last week so please hel I live in North Denver and we have an outside greenhouse made out of PVC and covered 2 X's with Green house poly from American Clay.  It is a 15'W x 25" L x 12' H.  Last winter it got pretty cold in there and I am
trying to see how I can grow in the winter time that is why we put up
the green house we was told put up a green house and grow year round. 
IU want to know if solar or heat or both is the way to go.  Right now
our electric bill is about $50.00 a month.  I have a 638 gal tank with 2
4 x 8 x 2x4 sides we have a water fall effect to get the water back to
the tank so I don't need aerator or stones.  So I run a 1 hp pump with
4-250watt heater that I was told with an amber temp of 35 degree it
would keep the green house at 70 degree.  But as you all know that
living in Colo., unless you have some type of heat in your outside green
house it is almost impossible to keep it at 35 degree.  I guess what I
am asking is how I can heat my system cheaply (was thinking of wood
burning stove) and also to get off the grid to eliminate the $50.00
monthly electric bill me out.

 

[George T]

Mike, thanks for your input. I'm on the grid and am now thinking along the lines of batteries for backup, rather than solar and batteries. For that matter, I could always start with batteries/inverter for backup and then add solar sometime when the prices are better. Long-term power outages are infrequent here, although it does happen sometimes. Hope to get started soon.
GT

[ALFRED A. ZABAWA JR]

 

l.  I am new at all this just got 3 starter fish last week so please hel I live in North Denver and we have an outside greenhouse made out of PVC and covered 2 X's with Green house poly from American Clay.  It is a 15'W x 25" L x 12' H.  Last winter it got pretty cold in there and I am trying to see how I can grow in the winter time that is why we put up the green house we was told put up a green house and grow year round.  IU want to know if solar or heat or both is the way to go.  Right now our electric bill is about $50.00 a month.  I have a 638 gal tank with 2 4 x 8 x 2x4 sides we have a water fall effect to get the water back to the tank so I don't need aerator or stones.  So I run a 1 hp pump with 4-250watt heater that I was told with an amber temp of 35 degree it would keep the green house at 70 degree.  But as you all know that living in Colo., unless you have some type of heat in your outside green house it is almost impossible to keep it at 35 degree.  I guess what I am asking is how I can heat my system cheaply (was thinking of wood burning stove) and also to get off the grid to eliminate the $50.00 monthly electric bill me out.

Mike Konshak said:

A\lfred, Its nice to meet you!

I haven't built any greenhouse yet, as I am in the design stages, but from a practical engineer standpoint, the 1st step to keeping the greenhouse warm is to retain the heat it absorbs from the sun and then keep the heat from seeping back out. Passive solar heat is the cheapest way to go (in the long run, and I'll get back to that) but as far as electricity goes, the cheapest you can get is from the grid you are already connected to. You simply cannot generate it any cheaper with renewables, whether it PV's, or wind. It takes 20 years to get a payback and that's with all the subsidies. In the case of my cabin, the grid was just too far away.

Anyway, burning natural gas directly is a cheaper way to heat, as electricity has to get generated by the burning of natural gas or coal, or nuclear, so there is added inefficiencies in the conversion, except with nuclear.

 

I think you should look at redesigning the green house to use passive heating, by insulating the sides and roof that is not exposed to direct sun, and incorporate a wall of thermal mass (water drums) that will collect heat in the day and radiate it back in the green house at night. The wavelength of the radiated heat will bounce around the interior, as your greenhouse will become a heat trap. Of course you need to seal air leaks as well. You can also add additional layers of glazing with air gaps to improve the R value of the clear parts of the greenhouse.

 

To add additional heat, using solar hot water panels to bring more heat into the floor of the greenhouse, but that will require an investment on your part, but these use very small pumps(<50W)  to operate and can be operated on a single PV panel.

My wife and I took a class a week ago at the Denver Botanical Gardens about high altitude growing (year round) and passive greenhouses were shown that used no electricity or fuel burning heaters. (see a couple of my photos on this forum).

I do not think that 70 degrees is a reasonable expectation all year round, but if tomatoes are a constant crop than maybe you have to. The seminar showed us varieties from Siberia that could thrive in lower temperatures

I live in Louisville, so if you want me to come by and brainstorm ideas with you, I can. I'm sure I can learn as much from you about gardening as you can from me about energy. I'm still debating about becoming a grower and all the attention it demands.

 

 

 

 

ALFRED A. ZABAWA JR said:

Hi All,

    l.  I am new at all this just got 3 starter fish last week so please hel I live in North Denver and we have an outside greenhouse made out of PVC and covered 2 X's with Green house poly from American Clay.  It is a 15'W x 25" L x 12' H.  Last winter it got pretty cold in there and I am
trying to see how I can grow in the winter time that is why we put up
the green house we was told put up a green house and grow year round. 
IU want to know if solar or heat or both is the way to go.  Right now
our electric bill is about $50.00 a month.  I have a 638 gal tank with 2
4 x 8 x 2x4 sides we have a water fall effect to get the water back to
the tank so I don't need aerator or stones.  So I run a 1 hp pump with
4-250watt heater that I was told with an amber temp of 35 degree it
would keep the green house at 70 degree.  But as you all know that
living in Colo., unless you have some type of heat in your outside green
house it is almost impossible to keep it at 35 degree.  I guess what I
am asking is how I can heat my system cheaply (was thinking of wood
burning stove) and also to get off the grid to eliminate the $50.00
monthly electric bill me out.

 

[K Schreiber]

 

 

 

[K Schreiber]

My concerns are almost identical to yours, except that people in my state have lost power for 1 to 2 weeks after severe winter weather, so I, too, would like to have the pumps & aerators be completely solar powered.  For heat, I plan on building a rocket mass heater - sort of a poor man's masonry stove, very efficient with great thermal mass. 

 

Any help would be appreciated.

[George]

 

A stove can be quite a task master, keeping it fueled.  Possibly you could build up enough heat to get you through the night but I don't know.  Good luck.

K Schreiber said:

For heat, I plan on building a rocket mass heater - sort of a poor man's masonry stove, very efficient with great thermal mass. 

 

Any help would be appreciated.

[K Schreiber]

Long term power outages are almost an annual occurrence here.  We've been lucky that none of them have lasted more than a week - yet.  (We'll see what happens with Irene.)  So that is my primary concern for off grid planning.  The long term power outages are almost always in the winter, so heating with wood is a must, but what do I do during the first 72 hours after a weather disaster when fuel is hard to find or get to.  A rocket mass heater has a lot of thermal mass, so 2 or 3 burns a day should take care of all but the very coldest days.  Pumping and aeration are the big issues.  I read in R. Nelson's book that an airlift pump is very efficient and could address both of those issues.  I've heard hints that airlift pumps don't work.  Anyone have any experience with this?

[TCLynx]

Airlift pumps are usually only really an "efficient" option in situations where a regular water pump would have too much trouble getting fouled or with sediment OR in the aquaculture industry in situations where large air blowers are already running anyway for bio-filteration and fish tank aeration if the lift required is low, water moving can sometimes be done with air without the need for separate power to separate water pumps for each separate system.

 

For small scale backyard type system, I have yet for some one to show me how to move the same amount of water per watt of electricity as you can with a water pump.

[Michael Welber]

It seems to me that utilizing solar power moves aquaponics closer to true sustainability. I have 2 pumps running, each drawing 55 watts of AC power, and am now investigating ways to switch to DC power from a solar panel and use smaller wattage pumps. However, my search has only turned up bilge pumps. Are these the best to use? Or does someone have a better source. The pumps I have are rated at 600 gph and I don't think the bilge pumps hit those numbers. 

[George]

I'm using ac pumps from panels/batteries/inverter/timer and haven't tried 12 volt pumps.  See Mad German - he uses 12 volt.

[Michael Welber]

The value of DC power is a)no inverter b) lower wattage and c)more usable power. The panel will deliver more usable power if it doesn't go through an inverter. Of course I have 2.7 KW on my roof that do go through an inverter but that's of necessity. 

[Raychel A Watkins]

I think solar is the answer except it doesn't work that well when it is totally overcast or raining .  I say this because I have solar water and I have PV for my house.  I can't afford batteries for these systems so if it stays cloudy for long you have could water.  The amount of battery backup then would be crucial.  

Turning to airlifts.  Glen Martinez from Olomana Gardens (not a member here have to work on that)  has shown me an airlift he has made that does push the correct amount of water he says.  He uses just those airlift pumps you buy at aquatic eco system. I plan to try it on a couple of my systems. It passes leaves through it .  I have outdoor systems and leaves can be a problem.