Good solution for certain locations. How does this retractable system prevent insects from entering the house? The other obvious shortfall is that these would not survive a hurricane of any strength.
If you checkout this web page you will see a video which outlines the 35 years of experience with retractable roof houses. www.cravo.com/en/house-models A stationary or retractable layer of insect net can be installed below the retractable roof for insect control. These retractable roof houses have been hit by 16 hurricanes and cyclones and the structure and roof covering have survived all of them... including 145MPH winds in Puerto Rico
The comment regarding horizontal vs. vertical opening and air exfiltration at 4:50 is unfounded. 2nd law of thermodynamics states: Hot will always move from hotter to cooler and high pressure will move to lower pressure. Everything wants to have equilibrium. I'm an energy inspector, and this is the foundation of our work. Prime example: I stood in my 60 deg. F garage and the temperature outside was 90 deg. F. and windy. The temperature in my attic was over 120 deg. I stood under my attic access located in my cool garage and hot air from the attic was blowing DOWNWARD on me into the cool garage, thus heating the garage. What this man is describing is faulty. House roofs are designed to either have gable (horizontal venting) or vertical (roof top venting). His statement is that horizontal venting is better than vertical venting. This is wrong: The only thing one needs for proper ventilation is a pressure and temperature difference. If the greenhouse has a strong fan and is hotter inside than outside, it will ventilate naturally if there is an opening. Another important factor is the opening of the venting. What is necessary to know is the net free area of the opening that affects only the cubic feet per time air infiltration/exfiltration. Small area = small volume of air change per hour. Large area = large volume of air change per hour.
theoretically what you are saying is agreeable, you forgot to consider outdoor wind direction and velocity which can influence a lot if the ventilation is vertical ventilation, also practically speaking depending up the size of the naturally ventilated greenhouse when plants are continuously transpiring and if the outdoor wind is direction is opposite to the direction of vertical ventilation it affects the air exchange, even if you open the side vents when the plats are bushy air can go through all the way, that's why in a naturally ventilated greenhouse you can the plants are more productive near to side ventilation, in the center of the greenhouse plants will be always week because of poor air circulation, co2 exchange etc...., also retractable roof greenhouses ventilate high and give very good production by using 2 to 3 hp power a day for one hectare, if you want to use a fans for vertical ventilated poly house you may need 70 to 100 hp/hour to atchive 1 air exchange
Statement is not wrong. Rate of exchange with horizontal vs vertical is different due to vent size, and the elimination of flow eddies, which is more about fluid dynamics. In other words, the flow rate is larger and less latent in a full length horizontal vent due to fluid dynamics.
I'm looking to get one of these for commercial orchid growing. Where would I be able to find one and what other names is this kind of greenhouse called?
Have you been working in Photosynthetic Active Radiation changes with the net? Any tropism detected? Thanks for the information, congrats for your work.
That's funny, after criticizing greenhouse because they could need fogging in case of high temperature and low humidity, you then say that a fogging can be installed in Cravo to handle high temp and low humidity. 90% of these arguments are actually in favor of greenhouse...
Question, how does the retractable greenhouse handles rain storms and heavy winds?
Unfortunately, it doesn't. It is fully at the mercy of rainstorms and heavy winds.
very informative, thank you very much for this video
Good solution for certain locations. How does this retractable system prevent insects from entering the house? The other obvious shortfall is that these would not survive a hurricane of any strength.
If you checkout this web page you will see a video which outlines the 35 years of experience with retractable roof houses. www.cravo.com/en/house-models A stationary or retractable layer of insect net can be installed below the retractable roof for insect control. These retractable roof houses have been hit by 16 hurricanes and cyclones and the structure and roof covering have survived all of them... including 145MPH winds in Puerto Rico
Thanks for your comment. Once you go into a retractable cooling house you will understand.
Thank you
In some areas, the energy consumption of greenhouses due to environmental regulation is relatively high, which increases operating costs
The comment regarding horizontal vs. vertical opening and air exfiltration at 4:50 is unfounded. 2nd law of thermodynamics states: Hot will always move from hotter to cooler and high pressure will move to lower pressure. Everything wants to have equilibrium. I'm an energy inspector, and this is the foundation of our work. Prime example: I stood in my 60 deg. F garage and the temperature outside was 90 deg. F. and windy. The temperature in my attic was over 120 deg. I stood under my attic access located in my cool garage and hot air from the attic was blowing DOWNWARD on me into the cool garage, thus heating the garage.
What this man is describing is faulty. House roofs are designed to either have gable (horizontal venting) or vertical (roof top venting). His statement is that horizontal venting is better than vertical venting. This is wrong: The only thing one needs for proper ventilation is a pressure and temperature difference. If the greenhouse has a strong fan and is hotter inside than outside, it will ventilate naturally if there is an opening.
Another important factor is the opening of the venting. What is necessary to know is the net free area of the opening that affects only the cubic feet per time air infiltration/exfiltration. Small area = small volume of air change per hour. Large area = large volume of air change per hour.
theoretically what you are saying is agreeable, you forgot to consider outdoor wind direction and velocity which can influence a lot if the ventilation is vertical ventilation, also practically speaking depending up the size of the naturally ventilated greenhouse when plants are continuously transpiring and if the outdoor wind is direction is opposite to the direction of vertical ventilation it affects the air exchange, even if you open the side vents when the plats are bushy air can go through all the way, that's why in a naturally ventilated greenhouse you can the plants are more productive near to side ventilation, in the center of the greenhouse plants will be always week because of poor air circulation, co2 exchange etc...., also retractable roof greenhouses ventilate high and give very good production by using 2 to 3 hp power a day for one hectare, if you want to use a fans for vertical ventilated poly house you may need 70 to 100 hp/hour to atchive 1 air exchange
I think what he was refering to in 4:50 is that Hot air always rises ESPECIALLY IF RETRACTABLE MEANS AN OPENING OF MORE THAN 50%!!! BOOM SHAKALAKA!!!
Statement is not wrong. Rate of exchange with horizontal vs vertical is different due to vent size, and the elimination of flow eddies, which is more about fluid dynamics.
In other words, the flow rate is larger and less latent in a full length horizontal vent due to fluid dynamics.
I'm looking to get one of these for commercial orchid growing. Where would I be able to find one and what other names is this kind of greenhouse called?
That's exacty what I need here in Colombia! Love it! How can i get in touch?
But with retractable greenhouse, rain water will drop inside, true?
Is it any project of retractoable green house working in India ? If yes , pl share the details & economics.
Have you been working in Photosynthetic Active Radiation changes with the net? Any tropism detected? Thanks for the information, congrats for your work.
Best
You can email us at sales@cravo.com
That's funny, after criticizing greenhouse because they could need fogging in case of high temperature and low humidity, you then say that a fogging can be installed in Cravo to handle high temp and low humidity. 90% of these arguments are actually in favor of greenhouse...
Hlo sir
You can email us at sales@cravo.com