Fixed-speed fans in growing rooms

Comments

1. Shivam Vashisth, yamunangar india, 14 июля 2017:

   Dear Maria
   I want to know the CFM for growing room and how to handle the air circulation in growing and how much CFM is needed for room whose length is 70 breadth is 31 feet and height is 19 feet what would the CFM and air change per hour and what would be air change per hour for growing button mushroom..?

2. sayres,gorgan, 18 мая 2015:

   I've small growing botton mushroom farm .my growing room volume is 72 cubic meter (6?4?3 meter).
   my fan (30?30 cm)and (25?25 diameter) is 1600 cubic meter per hour And 2500 RPM.
   can you help my to find out my fan cfm that i need ?and how many time that i need for changes air?
   is there equation for this?what?
   sorry for my english
   

3. Alexander Tsarev, 1 февраля 2014:

   Dear Maria,
   
   First of all, we must find out of this ventilation corresponds with the existing growing rooms. For this one must know the growing area and features (capacity and preassure) of fans. Certainly, you are aware of the growing area in the room and the quantity of the used compost. As for fans, one can calculate their parameters according to the type of a fan, a scroll number, engine power, and a number of its revolutions per minute. If there are probems with any of it, the capacity can be calculated according to the air velocity in the air pipe and the section area of this air pipe. Pressure can be measured with a special device.
   
   According to the growing area, one can calculate how much air is needed for your mushrooms and the intensiveness of moistening in winter. If the fan capacity is more than it required, it can be reduced. The easiest way is to close down the damper at the output.
   
   If you send the growing area in the room, we can calculate all these numbers.
   
   If there is no opportunity to steam compost after using it, it is better to use the sack system. If compost is in briquetas, the use of chemicals for its disinfection can create problems with further utilization of compost. And this is accompanied by doubtful effect of this measure (use of chemicals). Nevertheless, it is possible to put some fast decomposing preparation before unloading. There will be less dust, and the upper layer of compost will be cleaner. Then there goes the most diligent washing of the room and its processing after unloading used compost. If compost is unloaded not through, and workers performing these duties will not run around the complex, communicating with other workers, it will do only good. But, as practice shows, all this does not guarantee the exclusion of accumulating pathogen background in the growing room, and it only lets slow down this accumulation.
   
   Sincerely, Alexander Tsarev

   • Maria, 2 февраля 2014:

     Thank you very much. One spesification: a damper at the output, is this a damper of recirculation? It is just even I shut down all the dampers (fresh and recirculation); air move in the pipe does not change. Thanks.

   • Alexander Tsarev, 3 февраля 2014:

     The decision which damper and how to open or close it, can be taken only according what exactly you want to change. Fresh air affects primarily the quality of this air – level of carbon dioxide and humidity. And recirculation affects the quality of spreading air in the growing room.
     
     Usually I start working with climate from the qulity of spreading air in the growing room. For this a damper of recirculation is used, and a corresponding fan capacity is chosen (with use of a frequency control and a damper control).
     
     The second step is determination of volume of fresh air supply to receive optimum carbon dioxide concentration in the air of the growing room. Humidity and temperature are set up automatically. Optionally, the first two steps also can be automized.
     
     As for dampers for air pipes, their choice is also an important moment. The best variant is aluminium louver dampers with motor drives for operating them. Other variants (especialy round dampers) have problems with tightness.

   • Maria, 3 февраля 2014:

     Thank you.