Deck pond Construction

[minnowman]

Here are the doors. The plastic is the hinge. A wooden clamp holds the plastic at the top and left side. The doors are screwed shut on the left side. A wood block will hold the flap at the bottom. There is a door in the center at each end for ventilation when necessary. Now I'm waiting for the plastic to come in for the roof. I might make some better doors later.

[SueSTx]

Thanks for showing the doors.

[minnowman]

Between yesterday and today I installed the roof plastic. I clamped one edge of the plastic between two strips of wood and rolled it up. Then I used two ropes to pull the corners across the top. All of the edges are clamped with 1" thick wood and screws 6" apart. Just in time,temps are dropping into the 40s by sat morning.

[SueSTx]

Looks good

[Zoe]

Where did you get the roll of plastic from?  How thick is it?

[Kat]

Impressive! 

[minnowman]

Thanks, Kat
Zoe, The plastic film came from Greenhouse Megastore. It is 21'x 110'x 5mil and cost $160 plus shipping. I havent used this kind before so I don't know how long it will last.

[miguynmkoi]

Great work!  Did you build this all on your own?

[minnowman]

just me

[rdrboone]

Super pond and greenhouse.  You did a magnificent job.

Ruth

[minnowman]

  Anyone who has had a greenhouse knows that it gets very hot inside on a sunny day. Last Winter I was surprised how little of that heat gets into pond water inside. I checked out some solar water heating designs online, but they would have to be very large to heat 5,000 gal. of water. I decided to build a solar greenhouse heat exchanger instead [my own design].
  It is an 8'x7.5' wooden frame with two layers of black plastic over a layer of window screen.  The screen is intended to spread the water into a thin film so that it contacts all of the plastic film. A 1" PVC pipe at the top of the frame with .25" holes every 6" spreads the water across the top. Hot air will transfer its heat to the water through the plastic film. The cooled air will sink and set up a convection current which will bring more hot air into contact. The small submersible pump is on the bottom of the pond on the opposite end so that all of the water in the pond will be heated. A thermostat high in the greenhouse will turn the pump off and on when the air temp changes.
  Thursday's low was 34* f.Today's high was 80 * f. the water in the ponds was 73* f. without the heat exchanger. I'll monitor it as the Winter progresses.

[Michiponder]

I agree with you about the lack of heat transfer from the air to pond water in a greenhouse.   At first in my small greenhouse it only made enough difference to keep the water at a little less than 40F in the dead of winter here in MI.  As the years have gone by I have found that insulating the below ground sides of the pond, raising the sides up about 2 feet and bubbling the water for circulation helped raise the temp several degrees.  A large trickle tower made an even larger difference.  I once used a similar device as yours and while it did do a great job of raising the heat in the pond and was very inexpensive to build there were some drawbacks for me.  The device I used was a pvc pipe with holes drilled at about 4" and had the plastic and heavey screen draped over the pipe suspended by small ropes tied to two slats beneath the pipe.   One drawback was the size of it in  my small greenhouse.   Another was that it blocked a lot of sun.  Space and sunlight are both at a premium here in the cloudy cold state of Michigan.  The reason I discontinued using it though was the fact that pond water is not the cleanest stuff in the world and with my winter fish loads the screen would regularly begin to clog and channel and had to be cleaned often.  This year I am going to experiment with two small sprinkler heads connected to a small pump that will come on when the air temp is above 65F.  By using the bubble type fountain heads and the humidity allready being high in there it will be interesting to see if they pick up more heat from the air than they lose to the cooling effect of evaporation.  Please keep me informed about how your design works.  I am always looking for new ways to improve life for my fish and plants.

Mikel

[Waterbug]

I'm finding this info very useful. I'm thinking my next pond will have tilapia and here in Phoenix it I'm already fairly warm. I hadn't thought about insulating the pond but based on Michiponder experience I will insulate.

For heating water I think I'll use the roof of my house for more of a traditional solar hot water heater. If I get get the pond to mid 80's I can grow tomatoes too. We can't really grow tomatoes here in the summer so that would be nice.

I look forward to reading about the temperatures seen. Thanks.

[minnowman]

Mike, Spraying water into the air definitely does work. I did that several years ago in the minnow greenhouse. In a sealed area the humidity quickly goes to 100 percent and evaporation is not a problem. I don't want any spray on the waterlilies ,so that isn't an option in this case. I've also used a circular shower curtain with water spray inside of it with some success. We'll probably never know exactly how well any of them work without a side by side test. It will just be a judgement call.
Waterbug, Solar water panels with underground storage would heat the ground inside the greenhouse and maintain a more stable temp. You also need to be able to vent excess heat when it's sunny.

[Julles]

Wondering why you put the plastic right up to the pond's edges.  Will you be able to acces the pond, or walk around it?

[minnowman]

There is a door on each end of the greenhouses. The sides can be rolled up part way after removing a few screws. There is a 4' walkway outside of each greenhouse.  The water is only 2' deep in the ponds, so it is easy to walk around inside to maintain the plants. Hopefully this arrangement will keep the plants actively growing until Spring, when I will remove the greenhouses.

[ElvinIshikawa]

  Anyone who has had a greenhouse knows that it gets very hot inside on a sunny day. Last Winter I was surprised how little of that heat gets into pond water inside. I checked out some solar panel heating designs online, but they would have to be very large to heat 5,000 gal. of water. I decided to build a solar greenhouse heat exchanger instead [my own design].
  It is an 8'x7.5' wooden frame with two layers of black plastic over a layer of window screen.  The screen is intended to spread the water into a thin film so that it contacts all of the plastic film. A 1" PVC pipe at the top of the frame with .25" holes every 6" spreads the water across the top. Hot air will transfer its heat to the water through the plastic film. The cooled air will sink and set up a convection current which will bring more hot air into contact. The small submersible pump is on the bottom of the pond on the opposite end so that all of the water in the pond will be heated. A thermostat high in the greenhouse will turn the pump off and on when the air temp changes.
  Thursday's low was 34* f.Today's high was 80 * f. the water in the ponds was 73* f. without the heat exchanger. I'll monitor it as the Winter progresses.

Good one I must say.. Nice innovation..I would love to build similar green house around my home pond very soon.