Citrus Growers Forum

JoeReal · Posted: Tue 24 Mar, 2009 6:42 pm

Millet, based on your dimensions, the exhaust fans are doing at least 25K cfm.

829 · Posted: Tue 24 Mar, 2009 6:52 pm

Millet wrote:

My greenhouse is 70-ft. long, 32-ft. wide and 11 feet high. It is heated primarily with a 250,000 BTU Modine heater, that is backed up by a second 200,000 BTU Modine heater. Also the greenhouse has two (rarely ever needed) 125,000 BTU Infrared heaters that are controlled by a pilot light. These can be used when the electric supply fails. However I do have a large generator which is capable of suppling electricity the entire greenhouse and my residence. The greenhouse also has exhaust fans capable of completely exchanging the internal air every one minute. - Millet (1,397-)

I only have a hobby scale.

JoeReal · Posted: Tue 24 Mar, 2009 7:29 pm

829 wrote:

I only have a hobby scale.

Larger greenhouses are more efficient. In my case, I would buy or build a greenhouse that would be at least as large as that of Millet's but my yard is too small. So been holding off the project until the economy recovers and we purchase another nearby property.

Smaller greenhouses tend to lose more heat per unit area than larger greenhouses because the smaller ones have larger surface area to floor area or volume ratio.

bastrees · Posted: Wed 25 Mar, 2009 11:03 am

Joe, The cfm would probably be closer to 19K because the cross-section of the greenhouse in the picture looks like it approaches an ellipse and not a rectangle. Still a lot of air movement! Barbara

bastrees · Posted: Wed 25 Mar, 2009 11:06 am

Oops! I mean half an ellipse! Barbara