greenhouse Greenhouse coolling on a budget

[SentencedToBurn]

Ok I've moved everything over - the intake is now around the back of the greenhouse and the fan enclosure now sits at the top with a cover I made up just in case there is any condensation drips from the roof. Will hook up the STC-1000 later in the week and will see how efficient this is.
 

 

 

[TylerInNiagara]

How To Set Up a Control System For the Hobby Greenhouse.wmv

https://www.youtube.com/watch?v=kGSlzRMgYwc

 

[Tank]

The guy in the vid must work for the power company
when the greenhouse hits 90F turn on the exhaust fan ($$), then run 1500w to maintain 55F at night (more $$)
 
Paying $$ to blow perfectly good heat into the yard when you may need it at night makes no sense to me.

 

[queequeg152]

The guy in the vid must work for the power company
when the greenhouse hits 90F turn on the exhaust fan ($$), then run 1500w to maintain 55F at night (more $$)
 
Paying $$ to blow perfectly good heat into the yard when you may need it at night makes no sense to me.

 
 
this looks like double thick polycarbonate panel construction to me. you might be surprised how well they insulate.
 
regarding getting rid of excess heat... what is the alternative?  storing heat in water etc like i see people do with bottles etc, is imo an entirely bad idea for a number of reasons.
 
and... Its a tiny ass greenhouse, and hence cannot justify a two stage thermostat, with ridge line vents/ powered fan etc.
 
regarding heating, again small greenhouse, cannot justify a gas system im guessing, and that 1500w is not a static load... its probably like a 10% duty cycle even on colder nights.
 
i would be suprised if this guy is burning more than 10kwh per day.  thats like 30 bucks/month  worth of power down here, tho it could be easily much less as the 10Kwh is an upper estimate.

 

[Tank]

Its a small greenhouse but consider the thermal capacity and temperature of the soil underneath to a depth of 4ft. 
Running 90F air into it for 12 hours would only raise the baseline temperature by a few degrees. The air coming out will be considerably cooler and less humid than the outdoor ambient air which is the best you can do with an exhaust fan.
Roots in relatively warm soil are quite happy with air temperatures much lower than normal.
Water storage takes up space, reduces light and doesnt benefit the roots in the same way.

 

[SentencedToBurn]

I knew that 8 PC Fan panel would come in handy - so far it's just been in the greenhouse moving the air around. Its very weak but good to provide some circulation when the cooling fan isnt on.
 
Now that the night temperatures are dropping down to 16-17C (60-63F) I just picked up a 2nd hand panel heater and mounted it infront of the fans so they are moving the air past it which I'm hoping will heat up the rest of the greenhouse relatively quickly. It's a 425W heater which is designed for a much bigger space so I'm hoping this will be plenty to keep this place warm in winter. It's hooked up to my STC-1000, anything above 29C (84F) and the cooling fan kicks in, and if it gets below 19C (66F) then the panelheater will kick in. Will see how it goes tonight, I don't have a temp logger yet but the thermometer tells me the maximum and the minimum so will be interesting to see how low it drops.