# Homemade heat exchanger ideas



## fishhead (Jul 19, 2006)

Does anyone have plans for a large scale heat exchanger?

A friend has a 36' x 38' building that needs an air heat exchanger. He needs to replace the air several times a day.

I was thinking of something along the lines of a single layer serpentine length of hot water baseboard heater pipe with fins. He could hook a blower up to the pipe for the exhaust and let that create the negative pressure in the building to draw fresh air over the fins of the baseboard heater pipe. The pipe could be housed in styrofoam


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## Ross (May 9, 2002)

What heat source?


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## fishhead (Jul 19, 2006)

I think he's going with propane.


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## Ross (May 9, 2002)

Commercial HRV's are pretty cheap but if you wanted to create a home made one then something along the lines your thinking could work but I wouldn't want to create a negative pressure in the building. You could cause the propane heat source to back draft (kinda depends if it's a one or two pipe system). You still want neutral air pressure. HRV's are typically balanced so no more air goes out than in. A manometor helps get that right. Don't get completely set on finned tube you could use small duct pipe with aluminum rods going right through and sticking into the incoming air stream. Heat moves to cold so it will draw into the cooler incoming air.


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## gobug (Dec 10, 2003)

How high is the ceiling, and what will the building be used for? 

I am guessing that humidity is not real high in MN in the winter, so water in the air may not have to be handled by the unit. 

Building codes may have an impact on which unit must be used, especially if the building use is commercial. 

The best HRV's are only about 80%. 70% is cheaper. Go to ebay for HRV and you will see units and some details that may help you decide what your friend will need.


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## Jerry in MN (Dec 2, 2007)

fishhead said:


> I think he's going with propane.


Would it make sense to preheat the incoming air with solar, something along the lines of SolarWall?


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## fishhead (Jul 19, 2006)

I don't know how high his ceiling is but I'm guessing it's a pole barn.

He's going to raise insect larvae and they give off a lot of ammonia so that's why he needs the air exchange.


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## gobug (Dec 10, 2003)

Very interesting, especially since I was a licensed exterminator. The ant bait most readily accepted by multiple types of ants used silk worm larvae as the food base. It had a strong odor. I can just imagine a large pole barn full of some insect as a movie: Larvaephobia.

It seems like a habitat for insects could be a much smaller controlled space, hence the size of HRV could be one of the smaller units. Ammonia is nasty, probably nothing to mess with. An air to air (HRV) may not be the best choice. It is out of my league. Good luck to your friend.


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