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Eirikki
09-29-2016, 09:00 AM
So, i started this project with growing chilli-peppers. :)

I shall make a mini greenhouse, and i have figured out artificial sunlight and ventilation, i am also planning on adjusting the temperature so it can go both above and below the surrounding temperature.

I will try to hold the daytime temp at 70F and the night time at 55F by using peltier eliments.
The greenhouse shall have 24/7 ventilation (except if the humidity gets too low).

The problem is that i dont know how to keep the temperature up while having 24/7 ventilation... :gah:

I have thought of a watercooling based system, where the peltier modules warms/cools a water loop which warms/cools a radiator at the ventilation intake, but its got to be a easier way?

Please help.
Thanks :)

billygoat22
09-29-2016, 08:31 PM
heat recovery ventilator (HRV)

Red Man
09-29-2016, 08:36 PM
I usually see hanging unit heaters in greenhouses. I've also seen boilers for a water loop in the dirt.

Eirikki
09-30-2016, 03:08 AM
I usually see hanging unit heaters in greenhouses. I've also seen boilers for a water loop in the dirt.

As i mentioned its a mini greenhouse (dimensisons(LxWxH): 45x30x40)

I dont think i have room for any of the things you just said

Eirikki
09-30-2016, 03:09 AM
LxWxH in cm

Red Man
09-30-2016, 09:00 AM
Oh, that is mini! What can you fit in there, one pepper plant?

HVAC_Marc
09-30-2016, 04:22 PM
17x11x16" roughly

Peltier heaters? If you're rich enough to run those dont skimp on the rest of the controls. The pull AMPS and you realize they have a COLD side opposite the HOT side, too, right?

Eirikki
10-03-2016, 01:57 AM
17x11x16" roughly

Peltier heaters? If you're rich enough to run those dont skimp on the rest of the controls. The pull AMPS and you realize they have a COLD side opposite the HOT side, too, right?

Yeah i know that, but i cant think of any other cooling solution (minimum 60F)

HVAC_Marc
10-03-2016, 12:01 PM
Yeah i know that, but i cant think of any other cooling solution (minimum 60F)

small aquarium chiller with glycol filled tubing running around inside the mini house

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=28150&cmpid=03cseYY&gclid=CKXmqceEv88CFQqJaQod9jAEgg

Eirikki
10-03-2016, 04:41 PM
Oh, that is mini! What can you fit in there, one pepper plant?

Actually 9, its just for seed to 25cm growth, the rest happens outside, the plant is then more "robust"


small aquarium chiller with glycol filled tubing running around inside the mini house

It whould work... but is a very expensive solution
And i probably should mention that i dont care about the power draw, only the equipment price because i dont pay the electrical bill, i live in a college, and they dont monitor our power draw.

HVAC_Marc
10-03-2016, 06:47 PM
It whould work... but is a very expensive solution
And i probably should mention that i dont care about the power draw, only the equipment price because i dont pay the electrical bill, i live in a college, and they dont monitor our power draw.

Are you stealing the peltiers? they're expensive too, for high wattage versions. And, they will know, when they start blowing breakers and all of a sudden have a MAJOR power increase.

Poodle Head Mikey
10-03-2016, 06:59 PM
Sure.
Put a 50' coil of 1/4" plastic tubing inside a refrigerator.
Put some coils of copper tubing inside the greenhouse.
Connect the two loops together and fill them with water.
Use a small aquarium pump or metering pump or something to circulate the water.
Regulate the greenhouse temperature by adjusting the refrigerator thermostat.

You could do it even cheaper and easier with a 2-3-5 gallon plastic bucket of water in the refrigerator. Drop in a submersible pump and bring the return line back from the greenhouse loop and direct that water back into the bucket.

PHM
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Yeah i know that, but i cant think of any other cooling solution (minimum 60F)

HVAC_Marc
10-03-2016, 07:03 PM
Sure.
Put a 50' coil of 1/4" plastic tubing inside a refrigerator.
Put some coils of copper tubing inside the greenhouse.
Connect the two loops together and fill them with water.
Use a small aquarium pump or metering pump or something to circulate the water.
Regulate the greenhouse temperature by adjusting the refrigerator thermostat.

You could do it even cheaper and easier with a 2-3-5 gallon plastic bucket of water in the refrigerator. Drop in a submersible pump and bring the return line back from the greenhouse loop and direct that water back into the bucket.

PHM
-------

pretty much what i suggested...

my dad did this for a small aquarium. it doesnt work as well as you think it might.

Poodle Head Mikey
10-03-2016, 07:05 PM
Doesn't work well for what reasons? And with what negative factors to it's operation?

PHM
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pretty much what i suggested...

my dad did this for a small aquarium. it doesnt work as well as you think it might.

Eirikki
10-04-2016, 03:57 AM
Sure.
Put a 50' coil of 1/4" plastic tubing inside a refrigerator.
Put some coils of copper tubing inside the greenhouse.
Connect the two loops together and fill them with water.
Use a small aquarium pump or metering pump or something to circulate the water.
Regulate the greenhouse temperature by adjusting the refrigerator thermostat.

You could do it even cheaper and easier with a 2-3-5 gallon plastic bucket of water in the refrigerator. Drop in a submersible pump and bring the return line back from the greenhouse loop and direct that water back into the bucket.

PHM
-------

Yes but then you have to buy a refridgerator...

Eirikki
10-04-2016, 04:44 AM
Whould this solution work?

Eirikki
10-04-2016, 04:45 AM
(The radiator blows air into the greenhouse)

Eirikki
10-04-2016, 04:45 AM
https://s21.postimg.org/ilrwrrutj/hotorcold.png

Eirikki
10-04-2016, 04:46 AM
I would turn on and off the peltier elements to regulate the temp

Poodle Head Mikey
10-04-2016, 11:32 AM
Just take the keg out of the one you already have. <g>

PHM
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Yes but then you have to buy a refridgerator...

HVAC_Marc
10-04-2016, 05:00 PM
Doesn't work well for what reasons? And with what negative factors to it's operation?

PHM
--------

There's not enough heat transfer on the tubing. *MAYBE* if the tubing was frozen in a block of ice but i think that's much more than an average bar fridge can do. My dad tried building a coil loop column with a fan circulator inside the fridge but it just didnt help much. It was for a 10 gallon aquarium with a single halide light above.

The Peltier idea, while interesting, just doesnt have the capacity to do what the OP wants to do. A greenhouse has a massive load and loss. He's not going to have enough circuits to run ALL this electrical load. A basic $3 Peltier is 100 Watts at 12 Volts. That's 8.3 Amps for ONE Peltier unit. He's probably going to need at least 25 units to maintain the temps in the greenhouse. So, how many auto battery starter/jumpers can he run in his dorm room on one circuit? And add to that - pumps, fans, etc. The chiller is a much better solution.