Cooling a Greenhouse - Aquaponics

[M Cosmo]

I would like to start an active discussion on Cooling the Aquaponic Greenhouse. NO LIMITS

This discussion will have no limits to the creative ideas and crazy ideas that may bear fruit or inspire those creative juices in our minds. 

With this much Passive solar mass - WATER - we could open up the cooling of this mass to the night sky. So we would insulate the water in the day to avoid gain and expose or use active solar night cooling. Maybe even an heating - cooling exchanger.

Solar Chimney - I can think of 2 ways to use the solar chimney design. Simplified - Imagine a  metal Flat Black 3ft+ Diameter vertical Tube (could be flat) 10+ ft high. It would have a cone shape at the bottom and vented at the top and bottom. This would create a heat convection flow to pull air from the bottom (connected to the greenhouse) out the top.  A passive exhaust fan.  Version 2 - Put a horizontal wind generator in the tube and get some power from it. 

Geothermal - Tubes in the ground to capture the ground temp to lower the Air temp in the Greenhouse. 

Ok more even more exotic ideas later. 

OM OM OM  in other words  - Happy Trails 

[Scott]

I have been grappling with this problem for while now. I am seriously looking for a Geo-Thermic solution. I live in Orlando so humidity makes many of the normal Evaporative Cooling solutions unusable or at the best very inefficient.

[John Wroten]

OK, I am just getting started with my greenhouse. I built it this summer and have been on line with it for about 2 months. I use to think I was getting my feet wet, but now I think I am drowning. Heat, cool? When I built it I went by some fools idea from Wisconsin (I should have know better) of digging down 3 feet and placing 4 inch sewer pipe from end to end of the house. Put a pipe every one foot verticaly and every 2 feet horizonialy, then blow air through the tubes. Who knows? Just being on line for 2 months, I juess I wasn't able to warm the ground as much as possible. Now the air coming from the ground is 60 degrees.

When I built the green house with a 3 foot deep footer, I went out a few feet on each side and placed 180 feet of 3/4 inch pvc and have valves to allow me to run my water from my fish tank through them  to my grow beds. Since it is cold now, I dont use it. I will know more when summer gets here.

I ran 1/2 cpvc pipe to the top of the greenhouse into a 3 foot square insulated box with 100 feet of pipe in the box with it facing the sun. Now the water coming through it is 3 degrees wamer than going in. This helps warm my fish tank.

What I am learning (the hard way) is that  I shouldn't let my temp in the greenhouse get to 110 degree at 6 feet high, and 80 degree at floor level. The cold weather plants dont like this even tho the water is 65 degree.

Anyhow, I am about to harvest my first lettuce shortly, and I know the reward will be worth all my effort.

Anyone that can give me any advice, I would surely welcome it... John

[Bob Campbell]

In the past I have flown by the seat of my pants, and the results were very disappointing, so I am making a serious attempt to learn about thermodynamics.

My goal is to create a spread sheet that will offer a systematic approach, and all the calculations required in the design of a year round thermally balanced aquaponic green house system using solar to accomplish a minimal utility demand.

I have a pretty good math background, but thermodynamics are expressed in so many systems and units that it leaves a lot of room for error when attempting to cross verify the spread sheet formulas. The project still has a long way to go, and I am open to making this a collaborative effort if you find this interesting

My thermodynamic spread sheets are unfinished, but available from my blog.

chicoaquaponic

Bob

 

[John Nicholson]

Bob Campbell said:

In the past I have flown by the seat of my pants, and the results were very disappointing, so I am making a serious attempt to learn about thermodynamics.

My goal is to create a spread sheet that will offer a systematic approach, and all the calculations required in the design of a year round thermally balanced aquaponic green house system using solar to accomplish a minimal utility demand.

I have a pretty good math background, but thermodynamics are expressed in so many systems and units that it leaves a lot of room for error when attempting to cross verify the spread sheet formulas. The project still has a long way to go, and I am open to making this a collaborative effort if you find this interesting

My thermodynamic spread sheets are unfinished, but available from my blog.

chicoaquaponic

Bob

 

[Brad Howard]

Hey John.  How is it going?  I just saw your post from last December and it look like you have a lot going on there.  How is it working out for you now?  Brad

John Wroten said:

OK, I am just getting started with my greenhouse. I built it this summer and have been on line with it for about 2 months. I use to think I was getting my feet wet, but now I think I am drowning. Heat, cool? When I built it I went by some fools idea from Wisconsin (I should have know better) of digging down 3 feet and placing 4 inch sewer pipe from end to end of the house. Put a pipe every one foot verticaly and every 2 feet horizonialy, then blow air through the tubes. Who knows? Just being on line for 2 months, I juess I wasn't able to warm the ground as much as possible. Now the air coming from the ground is 60 degrees.

When I built the green house with a 3 foot deep footer, I went out a few feet on each side and placed 180 feet of 3/4 inch pvc and have valves to allow me to run my water from my fish tank through them  to my grow beds. Since it is cold now, I dont use it. I will know more when summer gets here.

I ran 1/2 cpvc pipe to the top of the greenhouse into a 3 foot square insulated box with 100 feet of pipe in the box with it facing the sun. Now the water coming through it is 3 degrees wamer than going in. This helps warm my fish tank.

What I am learning (the hard way) is that  I shouldn't let my temp in the greenhouse get to 110 degree at 6 feet high, and 80 degree at floor level. The cold weather plants dont like this even tho the water is 65 degree.

Anyhow, I am about to harvest my first lettuce shortly, and I know the reward will be worth all my effort.

Anyone that can give me any advice, I would surely welcome it... John

[Mark Hall]

Probably the passive mass is the most practical. Making beds out of high density materials. Lots of water and perhaps phase change materials.

Transpiration cooling by trees can reduce temps by 5 degrees C. according to TED. I have an idea to pipe air from under the big trees into my greenhouse to cool it. 

[Aquaponik Berater]

  We are in Austria and looking for  solar mass  information to heat in winter....any ideas ?

Building a pit greenhouse  and double glas insulation. 

[Paul Westberg]

Ok, I like it. some new and some theoretical. I am building a greenhouse in Vista, CA that will face south with a east west orientation. Two reasons for this: 1) the lot pretty much dictates it 2) to capture the onshore/offshore winds that naturally occur this close to the ocean. Because we have pretty mild temps and electricity is relatively cheap I was planning on going with fans and a cooler as well as temperature activated vents to try and keep the temps in line. The south wall I am planning a roll up type curtain with a screened backing that will stay closed in winter but open in the warmer months. Heating I am still working on. As the system I am planning will be hybrid and have media beds I can't just heat the water and be safe. From my other greenhouse I learned that the cool air rushing into the media beds when they drain will significantly reduce temps. There must be some moderation of overall temps for success. Time constraints dictate that the heating system be automatic and self regulating so I'll probably end up with some sort of commercial heat system. Not wildly excited about the cost or the fact that all of these I've found are for much larger set ups than mine. C'est la guerre!  Comments?? 

[Aquaponik Berater]

Thank you Bob, great information :)

Bob Campbell said:

In the past I have flown by the seat of my pants, and the results were very disappointing, so I am making a serious attempt to learn about thermodynamics.

My goal is to create a spread sheet that will offer a systematic approach, and all the calculations required in the design of a year round thermally balanced aquaponic green house system using solar to accomplish a minimal utility demand.

I have a pretty good math background, but thermodynamics are expressed in so many systems and units that it leaves a lot of room for error when attempting to cross verify the spread sheet formulas. The project still has a long way to go, and I am open to making this a collaborative effort if you find this interesting

My thermodynamic spread sheets are unfinished, but available from my blog.

chicoaquaponic

Bob

 

[Mark Hall]

What size greenhouse?   Consider having low windows on the south wall that open and close to regulate air flow. Seems like a cleaner design than rolling and unrolling material.Also high windows on the north. If you can stay away from wood in the design you should have a long lasting structure. Your temperatures in Vista are so mild that a passive house might work well. I agree with commercial heat for backup. 

Paul Westberg said:

Ok, I like it. some new and some theoretical. I am building a greenhouse in Vista, CA that will face south with a east west orientation. Two reasons for this: 1) the lot pretty much dictates it 2) to capture the onshore/offshore winds that naturally occur this close to the ocean. Because we have pretty mild temps and electricity is relatively cheap I was planning on going with fans and a cooler as well as temperature activated vents to try and keep the temps in line. The south wall I am planning a roll up type curtain with a screened backing that will stay closed in winter but open in the warmer months. Heating I am still working on. As the system I am planning will be hybrid and have media beds I can't just heat the water and be safe. From my other greenhouse I learned that the cool air rushing into the media beds when they drain will significantly reduce temps. There must be some moderation of overall temps for success. Time constraints dictate that the heating system be automatic and self regulating so I'll probably end up with some sort of commercial heat system. Not wildly excited about the cost or the fact that all of these I've found are for much larger set ups than mine. C'est la guerre!  Comments?? 

[Paul Westberg]

Greenhouse will be 54' long by 15' wide. I really like the self opening solar windows but have not figured a way for that to work with the quanset style greenhouse that this will be. Actually the walls will be vertical to 5' and then curve over. The window idea may just work. Thanks. BTW, most of the structure will be metal; the rest PT lumber. It lasts well here.

Mark Hall said:

What size greenhouse?   Consider having low windows on the south wall that open and close to regulate air flow. Seems like a cleaner design than rolling and unrolling material.Also high windows on the north. If you can stay away from wood in the design you should have a long lasting structure. Your temperatures in Vista are so mild that a passive house might work well. I agree with commercial heat for backup. 

Paul Westberg said:

Ok, I like it. some new and some theoretical. I am building a greenhouse in Vista, CA that will face south with a east west orientation. Two reasons for this: 1) the lot pretty much dictates it 2) to capture the onshore/offshore winds that naturally occur this close to the ocean. Because we have pretty mild temps and electricity is relatively cheap I was planning on going with fans and a cooler as well as temperature activated vents to try and keep the temps in line. The south wall I am planning a roll up type curtain with a screened backing that will stay closed in winter but open in the warmer months. Heating I am still working on. As the system I am planning will be hybrid and have media beds I can't just heat the water and be safe. From my other greenhouse I learned that the cool air rushing into the media beds when they drain will significantly reduce temps. There must be some moderation of overall temps for success. Time constraints dictate that the heating system be automatic and self regulating so I'll probably end up with some sort of commercial heat system. Not wildly excited about the cost or the fact that all of these I've found are for much larger set ups than mine. C'est la guerre!  Comments?? 

[Johnson L Brown]

I live in west central Texas so I can sympathize with you on the heat issue.  I am seriously considering going 4 to 6 feet below grade and only having a glazed roof showing above ground.  the temperatures would be more moderate in my mind at that depth.  I also was thinking of thinking of glazing the inside as well as the outside of the roof to make a space for heating and cooling.  I seems that it would take a lot less effort to heat or cool  that space rather than heat or cool the whole greenhouse. I am hoping that shade cloth and earthen walls would moderate the temperature to maybe something tolerable in the summer and in the winter just heat the space in the roof.  Our freeze line is only about an inch so the earth walls might maintain a warm temperature in the winter.  It's all working perfectly in my imagination but any thoughts on my reasoning would be welcomed.