greenhouse cooling question

[brit6v]

Hi everyone
I just realized a mistake I made a few minutes ago when I started a thread in the OrchidTalk Members Grow Area -Photo forum. I see now that I should have posted it here intstead (if I haven't made another mistake ???)


We bought a 10'x17'x7' (approx.) kit greenhouse in the Spring and now I'm ready to move my orchids into it but I must first figure out a way to cool it. Our Alabama summer temps are outrageously hot!!! The heat inside the greenhouse is almost unbearable to people, much less orchids!!! During my trial tests, I have had the exaust fan running constantly, another large fan running on high, and also have my 60% aluminet shadecloth overhead. I have understood that we have too much humidity down here for a swamp cooler to work efficiently, and an airconditioner does not seem to be a good option, either. I would very much appreciate it if anyone can help me with advice...or input of any kind.
Vicki

[Brutal_Dreamer]

We have the same trouble here in August. We finally had to install an air conditioner to remove the humidity from the air so that the kool-cell would actually cool the space with cool, moist air.

Not sure what other options you could try.

Good luck, Vicki.

Cheers,
BD

[Ron-NY]

does your greenhouse have a roof vent and a large opening in the wall opposite of the exhaust fan? It could be that your exhaust fan is not powerful enough or that you need a second one.To try to cool a greenhouse can be very expensive with using an air conditioner... High humidity is not a problem for the orchids as long as there is good air movement. What temp does the greenhouse get to when all your systems are running? is 7' the height at the peak or at the sidewalls?

[brit6v]

Hi Ron,
No, I don't have a roof vent. We looked at greenhouses with 1 or more, but decided on this one because we liked the sturdy way it seemed to be built. I have pictures for you. One of the exaust fan in the back of the gh, one of the motorized vents under a bench in the front and one above the door in the front. I also put a floor fan inside (just for testing). Before I move my plants inside, I will put fans on each side above the 2 benches then take the floor fan away (or whatever you suggest). The ceiling height is 7'7" at the peak. Examples of usual mid-(or so) day temps outside are high 90s. A common temp. inside the gh is about 120 with vents open and fan on....sometimes 4 or 5 degrees less. I had a thermometer inside with the highest daily reading of approx. 120. One day when I checked temps, I found that the inside temp had shot up above the 120 mark (needless to say, that broke the thermometer and now I have another one there.)

What do you think about fogging or misting for cooling? We have looked at the the Aquafog 700...and several other sytems on down in price....even down to the $50 or so range?

I would very much appreciate any other advice that you or anyone have for me! Any other questions you need for me to answer to aid in your advice, I'll try my best.
Vicki

does your greenhouse have a roof vent and a large opening in the wall opposite of the exhaust fan? It could be that your exhaust fan is not powerful enough or that you need a second one.To try to cool a greenhouse can be very expensive with using an air conditioner... High humidity is not a problem for the orchids as long as there is good air movement. What temp does the greenhouse get to when all your systems are running? is 7' the height at the peak or at the sidewalls?

[Brutal_Dreamer]

Shade cloth on the sides will also help. (especially the west side)

Cheers,
BD

[Ron-NY]

roof vents passively allows hot air to escape ( hot air rises)...never seen the sidewall peak vents before...I would put in another exhaust fan to the left of the one you have..another vent wouldn't hurt either. the greenhouse I grow in has a ridge vent the whole length of the greenhouse. . Exhaust fans come in different CFM...you need to figure out what capacity you need. I will pm yu with a calculator you can use.

[Hillbilly Bob]

I have 3 fans on a farm fan controller ( Computer) the 1st fan comes on at 72 degrees 320 CFM then as temp rises another 5 degrees a 480 cfm fan comes on and another vent opens thus giving me 800 cfm this does good until about noon. Then when the temp gets 5 degrees higher at which time a 3200 cfm turbo fan kicks in and the other fans shut off to prevent short curcuiting of air. the mist system kicks in at this time .

I was still heating to where I didnt want to be 93-95, I had intake vents that run 1000 cfm 1500cfm and 2000 cfm which I thought would be suffecent but as I experemented I found out that the 3200 cmf turbo could pull more than I was giving it so I went to a screen door and that finally gave the air movement I needed. I also bought a shade cloth at a nearby national store for 28 dollars and have used it even though my roof has uv coating built in. The hottest day here this summer was 98 the GH got to 91 I was happy with that but of course cant quit tinkering so trying for more.

[Bikerdoc5968]

Vicki, I see from your photos you have a SunGlo product. I have the 7' x 15' of the same. Something you may want to do is install additional lighting in the roof, additional outlets at the door end with a switch to operate the lights and cover the intake opening with screen because you will have LOTS of unwanted visitors in short time!!!!! Unfortunately, there is no easy way to cover the top (black) vents to prevent these visitors. While you have a larger GH than I have, you may want to add wire racks at the ends of your GH for additional space. It is available at the big box stores. I also changed the electrical by adding additional breakers and additional outlets on the control board. All very easy to do by yourself. PM me for more stuff. As to the question you asked, I would agree with those who have mentioned misting systems...evaporative cooling is great for the chids!

Another question??? I see they've changed some things on your GH... Didn't it come with redwood benches, and a timer, and a heater, and well, lots of other stuff?????

[brit6v]

Thanks for the info, Ron...and I got the calculator you sent to me...thanks for that, too. I'm going to re-evaluate my air-flow system.
Vicki

roof vents passively allows hot air to escape ( hot air rises)...never seen the sidewall peak vents before...I would put in another exhaust fan to the left of the one you have..another vent wouldn't hurt either. the greenhouse I grow in has a ridge vent the whole length of the greenhouse. . Exhaust fans come in different CFM...you need to figure out what capacity you need. I will pm yu with a calculator you can use.

[brit6v]

Thanks again for your help, Bruce. More shadecloth is certainly on my hopefully-soon-to-do list.
Vicki

Shade cloth on the sides will also help. (especially the west side)

Cheers,
BD