FullMetalJacket
Well-Known Member
I am bulding a cab and was thinking about humidity and temp...Please help me out..
***FMJ wrote all of the below so feel free to post it anywhere if you think someone may have some valuable input. And I don't mean yes or no, I mean why or why not and some sort of logic to support their stance.***
ThermoElectic Devices:
In laymans terms, thermoelectric devices are basically a small plate that exchanges heat from one side to the other. Most often each side of the plate has heat sinks, one that gets cold and one that gets hot. They use these in small dehumidfiers, some mini-fridges, high end computers, wine coolers etc. These devices are not the most effecient and are less effecient than a compressor commonly found in AC units.
To make these devices as effecient as possible you need to dissipate the heat from the hot side. Fans can be used to do this. The cooler you get the hot side the colder the cold side will get. These devices are cheap, silent(except for a fan to cool hot side), and available in different sizes or wattages. They are also neat because if you change the flow of the current the hot and cold side changes. They are easily controlled with a volage regulator to get precise temps. So accuarte that they are the choice in labratory and scietific research settings for cold plates and cooling/heating chambers.
For more detailed info on what a thermoelectic effect is visit:
Thermoelectric effect - Wikipedia, the free encyclopedia
--
First, the reason I am looking into this technology for cooling and dehumidifying needs is because I want a fully contained cab with complete enviromental control. I have a 36 cu ft flower chamber and a 5000 btu airconditioner and 20 liter dehumidifier are overkill(smallest devices i could find that were quality). They are also loud, very large, expensive, draw a lot of power, and would require a fair amount of work to vent properly while keeping them in the cab. If you refer back to my drawings in my first post you can see how i would se-up my cab if i did use these large items. I would loose stealth though because of the size and noise.
My temps are fine without venting the air in the cab at all due to the cooltube. Temps max at about 91 (with CO2 this is fine) with my cooltube fan running at 75% speed. But my humidity will most likely be an issue. I like my hudidity around 40% or below for flower, especially late flower. Since I live in an area where ambient relative humidity levels are very low, simply exhanging my air hourly would definitely lower my humidity levels into the desire range. But as I stated earlier I would like to have complete control over the enviroment in the cab. Less ventalation equals less noise, odor issues(even though im carbon scrubbing), and CO2 waste. Plus its cool as hell and make the cab usable for scientific research on growing.
--
I would build my own device with parts all found on ebay and I am thinking around $150 total. The challenge is getting the right size/wattage. The cold side would be in the flower chamber and the hot side would be in my utility area. That is very important because like AC the devices in their entirety generate more heat than cold.
I have purchased a 26 watt EVA-DRY dehumidifier that uses this technology and is like 6"L x5"D x"8H. It is 26 watts including the fan and removes approximately 10-14oz of water over a 24 hour peiod according to the manufacturer. I do not think 10 oz in 24 hours is enough but if someone disagrees, please do share. Another problem with it is that it so slightly raise the temps as the air comes in, hits the cold side air sink(removing the humidity) and then passes over the hot side heat sink. Each air sink is approx 2" square inches.
I was thinking going 100W with 1 7" x 4" heat sink on the cold side and one 9"x 5" heat sink on the hot side. If I do a good job of cooling the hot side air sink I would definitely think I could remove 80-100 oz of water in 24 hours. I would think this would be more than enough. Well I stated i would only have the cold side in the flower chamber, i would have a smaller 4"x4" hot side in the chamber to reheat the air after i dehumidified it. This would also enable me to control the heat of the smaller one to use it as a heater, or cut power to it and use the dehumidifier as an "AC" device. All of this wouldn't take up any more space, just the regulation of diiffernt wattages to the TEC(the transfer plate).
I found a few alraedy constructed devices on ebay that can be modified and have more specefic heat measurements if you want to look at them, they are vey informative on how they work as well.
search ebay for "thermoelectric" or...
Huge Swedish ThermoElectric Peltier w/ Heatsink & Fan! - eBay (item 190224036970 end time May-28-08 10:31:40 PDT)
Another device from electronic supplier:
http://www.allelectronics.com/cgi-bi...C_DEVICE_.html
I am not sure these in the above links are large enough to meet my needs but might be. Maybe i can use a few of them. I think making my own would better suit my needs, be more effecient, and save money.
I may not need any additional AC or dehudification at all in my cab but i think building one of these and getting some accurate real world test results in a grow cab would benefit the world of people who grow in small places. Plus it would definitely be a nice addition to my cab.
Has anyone see these used in grow cabs or have knowldge of these in general?
***FMJ wrote all of the below so feel free to post it anywhere if you think someone may have some valuable input. And I don't mean yes or no, I mean why or why not and some sort of logic to support their stance.***
ThermoElectic Devices:
In laymans terms, thermoelectric devices are basically a small plate that exchanges heat from one side to the other. Most often each side of the plate has heat sinks, one that gets cold and one that gets hot. They use these in small dehumidfiers, some mini-fridges, high end computers, wine coolers etc. These devices are not the most effecient and are less effecient than a compressor commonly found in AC units.
To make these devices as effecient as possible you need to dissipate the heat from the hot side. Fans can be used to do this. The cooler you get the hot side the colder the cold side will get. These devices are cheap, silent(except for a fan to cool hot side), and available in different sizes or wattages. They are also neat because if you change the flow of the current the hot and cold side changes. They are easily controlled with a volage regulator to get precise temps. So accuarte that they are the choice in labratory and scietific research settings for cold plates and cooling/heating chambers.
For more detailed info on what a thermoelectic effect is visit:
Thermoelectric effect - Wikipedia, the free encyclopedia
--
First, the reason I am looking into this technology for cooling and dehumidifying needs is because I want a fully contained cab with complete enviromental control. I have a 36 cu ft flower chamber and a 5000 btu airconditioner and 20 liter dehumidifier are overkill(smallest devices i could find that were quality). They are also loud, very large, expensive, draw a lot of power, and would require a fair amount of work to vent properly while keeping them in the cab. If you refer back to my drawings in my first post you can see how i would se-up my cab if i did use these large items. I would loose stealth though because of the size and noise.
My temps are fine without venting the air in the cab at all due to the cooltube. Temps max at about 91 (with CO2 this is fine) with my cooltube fan running at 75% speed. But my humidity will most likely be an issue. I like my hudidity around 40% or below for flower, especially late flower. Since I live in an area where ambient relative humidity levels are very low, simply exhanging my air hourly would definitely lower my humidity levels into the desire range. But as I stated earlier I would like to have complete control over the enviroment in the cab. Less ventalation equals less noise, odor issues(even though im carbon scrubbing), and CO2 waste. Plus its cool as hell and make the cab usable for scientific research on growing.
--
I would build my own device with parts all found on ebay and I am thinking around $150 total. The challenge is getting the right size/wattage. The cold side would be in the flower chamber and the hot side would be in my utility area. That is very important because like AC the devices in their entirety generate more heat than cold.
I have purchased a 26 watt EVA-DRY dehumidifier that uses this technology and is like 6"L x5"D x"8H. It is 26 watts including the fan and removes approximately 10-14oz of water over a 24 hour peiod according to the manufacturer. I do not think 10 oz in 24 hours is enough but if someone disagrees, please do share. Another problem with it is that it so slightly raise the temps as the air comes in, hits the cold side air sink(removing the humidity) and then passes over the hot side heat sink. Each air sink is approx 2" square inches.
I was thinking going 100W with 1 7" x 4" heat sink on the cold side and one 9"x 5" heat sink on the hot side. If I do a good job of cooling the hot side air sink I would definitely think I could remove 80-100 oz of water in 24 hours. I would think this would be more than enough. Well I stated i would only have the cold side in the flower chamber, i would have a smaller 4"x4" hot side in the chamber to reheat the air after i dehumidified it. This would also enable me to control the heat of the smaller one to use it as a heater, or cut power to it and use the dehumidifier as an "AC" device. All of this wouldn't take up any more space, just the regulation of diiffernt wattages to the TEC(the transfer plate).
I found a few alraedy constructed devices on ebay that can be modified and have more specefic heat measurements if you want to look at them, they are vey informative on how they work as well.
search ebay for "thermoelectric" or...
Huge Swedish ThermoElectric Peltier w/ Heatsink & Fan! - eBay (item 190224036970 end time May-28-08 10:31:40 PDT)
Another device from electronic supplier:
http://www.allelectronics.com/cgi-bi...C_DEVICE_.html
I am not sure these in the above links are large enough to meet my needs but might be. Maybe i can use a few of them. I think making my own would better suit my needs, be more effecient, and save money.
I may not need any additional AC or dehudification at all in my cab but i think building one of these and getting some accurate real world test results in a grow cab would benefit the world of people who grow in small places. Plus it would definitely be a nice addition to my cab.
Has anyone see these used in grow cabs or have knowldge of these in general?
