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- Greenhouse Gardening (https://www.orchidboard.com/community/greenhouse-gardening/)

- - Small greenhouse on the terrace (https://www.orchidboard.com/community/greenhouse-gardening/61532-greenhouse-terrace.html)

Your setup is very much like mine. Mine is on a second floor terrace and I also use a high pressure fog system for humidity/cooling.

I use this controller to modulate exhaust fan speed according to temperature:
Phason MTC-4C Modulating Temperature Control - TekSupply

In combination with the humidity controlled fog system they do very well at holding the temperature near the fan speed controller's temperature setpoint.

I am also using one of the common, mechanical humidity on/off controllers and I am not happy with its sensitivity. I have purchased this electronic humidity sensor/controller:
http://www.omega.com/Temperature/pdf/RHCN-3.pdf
I have done some preliminary testing but I was using a 9v battery to power it which gives only marginal operating voltage and current. I need to hook it to the auxillary 24 v output available on the variable speed motor controller that I use with my high pressure fog system pump. I expect that I may also have to place the humidity probe inside a box with baffles and use a small fan to draw air through.

Quote:

Originally Posted by DavidCampen (Post 515275)

thanks for info.
regarding your exhaust fan speed controler, I do not like only 6F fixed between idle and maximum. my maximum is quite high 1 air change in 1 minute. very close to hurricane :). it is fine if you want to decrease humidity in minute, but if outside temp is over 90F a lot of hot and dry air will come inside and I think misting system will not be able to cool and rise humid efficiency. I would like something which could be configured more precisely. Also I would like to shut down exhaust vents below some minimum point.
I have found these two controlers. REB-4 or REB-5 Auto from soler&palau
Soler & Palau Sistemas de Ventilacin, S.L.U. - Innovating solutions (more details in catalogue)
I am still waiting from supplier for detailed manuals.

Humidity controler looks fine. I will keep it in mind.

What is your temperature in GH on hot sunny days? Do you have direct sun to GH?

Yes, that the fan controller only has a 6degF span is a deficiency, I would have like more like 10degC.

I do not have full sun from the south so I do not get full solar influx. Also, where I live, when it is hot the outside humdity will usually be 30-40%RH so evaporative cooling is very effective for me. My greenhouse has an interior volume of about 55 cubic meters and my exhaust fan can pull about 30 cubic meters per minute. On a very hot day I will be putting 25 - 30 liters per hour of RO water into the fogging system to maintain humidity.

I bring intake air in through temperature controlled roof vents. Because of this I also need strong circulating fans when the exhaust fan and fog are running at maximum performance. I want to tie the speed of some of my circulating fans to the speed of the exhaust fan so that they will run faster as the exhaust fan speed increases.

On a hot and sunny day I can keep the greenhouse temperature at least 5degC below the outside air temperature.

what an engineering feat!! most excellent job!! your orchids look so happy, i know you are thrilled with it, specially since you can watch it constantly from the living room....wow!!!!

Quote:

Originally Posted by dounoharm (Post 515301)

what an engineering feat!! most excellent job!! your orchids look so happy, i know you are thrilled with it, specially since you can watch it constantly from the living room....wow!!!!

:agree: that's just superb!!!!!!!!!!!!!!!!!!!!!!

Very impressive! Good job.

Super!
love looking at your photos of your whole set up and your lovely plants! Please do keep posting!

That's a wonderful greenhouse and from your plant pictures, it seems to be doing the job its intended to do!

All of it looks great! So much fun.