Greenhouse build questions

[orion141]

Hi all,

So I am getting closer to deciding upon a potential greenhouse for orchids at my home in Connecticut. Based upon size and money constraints I have been considering the 8x12' gothic arch greenhouse in an 8mm triple wall polycarbonate. I have a few questions regarding heating and cooling.

Gothic arch sells a fan/exhaust system that I will likely purchase. I am also thinking of purchasing the Hot Dawg (modine) 30k BTU propane heater as the primary source of heat (Greenhouse Hot Dawg Heaters| Gothic Arch Greenhouses). Anyone have experience with this heater?

As I will be growing many intermediate temperature orchids I will need cooling for a few months of the year. I was thinking an evaporative cooler would be reasonable here in CT (it does get humid at times, but not like southern regions). I know that some of the folks who grow orchids around here use them successfully. I believe the greenhouse has two 12' inch square vents (one on each end, as per the picture below). Does anyone have thoughts about a relatively simple evaporative cooler that could be used here. Could I use some sort of evaporative cooling pad system with a small pad placed in front of the intake opening so that when the exhaust system kicks on in the summer due to high temperatures it would bring outside air across the cooling pad? For example, something like this: https://www.gothicarchgreenhouses.co...ad_systems.htm

Example 8x12' gothic arch GH from their website:

Thanks in advance!
Orion