Backyard Aquaponics
A place to discuss aquaponics

I built a duck/rabbit coop uphill and behind my greenhouse. I faced the south roof 45 deg toward the winter sun. The roof is treated plywood, metal roofing, 2x4 furring, and solexx covering. The roof dimensions are 40 feet x 6 feet 4 inches. Yesterday was my first big run. 39F to 50F and the panel stayed 100 to 119 F.

I have a 80F/65F snap switch to turn on a regular sump pump capable of 20 ft head pressure. I use pex line between the plywood and metal roofing under the metal humps. I have 7 runs. I was experiencing a 2 - 4 deg rise across the panel yesterday and my 4000 gallon system rose 2 deg, although a lot of that was due to the 75 deg greenhouse temperature.

I'm roughly experiencing 2 deg rise at 4 gallons a minute, anyone know how to compute that to BTUs?

In and Out Temperature from my Aquaponics System.

Using the information from this site (don't know for certain that they're right just found it from the Internet) - http://www.scegbusiness.com/Article.aspx?userID=351124&articleID=1397)

BTU Collected = Water Volume (lb) x Temperature rise (°F) x 1 Btu/lb°F

A BTU is defined as the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit

Convert GPM to lbs of water for the amount of time that you want to figure the BTU's for. Each gallon weighs 8.34 pounds.

4GPM x 8.34 lbs/Gal = 33.36 lbs of water going through per minute.

BTU/minute = 33.36 x 2°F temp increase x 1 Btu/lb°F = 66.72 BTU increase per minute the panel runs

You'll have to multiply this by the number of minutes it ran to figure the final gain in Btu. I think I have this right but I'm not a 100% certain so have a look at that website

Let us know how it comes out.

Cheers

About 20k BTU in 5 hour run.

Thank you Scotty!

That's great Jason . Makes me want to go out and build a rabbit hutch . Keeping all that nice heat in the system is your next challenge but it's that much heat you didn't have before and that's a good thing. What's your plan for the water in the pipes as it gets colder and the pump doesn't run?

It back feeds when turned off. The supply is piped into the bottom of the header close to the eave and my return comes off the top of the other header near the peak. It drains into one of my fish tanks above the tank for aeration and allows the system to drain to the sump when the sump turns off. When it kicks on you hear all the air coming out of the lines, and when it turns off you hear gurgling for some time. I can also tell by my water level I'm dropping a lot of water. I still want to pipe it underground, and insulate it.

My original plan was to have this up and operational mid summer to heat my water, concrete, ground surrounding my tanks to 85 deg. I think then I would have a large heated mass in which to buffer the winter. So for now, a few deg rise on a sunny day is what I hope for.

As a backup plan, in case you need it, you could use compressed air to blow most of the water out of the lines.

That is an excellent idea. The hose into my fish tank is a very easy target. Thank you!