One of the independent attraction for retailer and consumer alike to choose glasshouse green goods , is the reliability with which the nursery bring out quality and measure of produce in a safe way . The semi - closed glasshouse has extended that dependability in the manner it manages summertime rut , plague and disease and produces safe food . Why then , are there ego - imposed limitations on what a grower can and can not do with this fantastic new engineering science ?
In this , and upcoming article , Godfrey Dol of Glasshouse Consultancy , will discuss the do and don’ts of the semi - shut nursery . He check that there is much discombobulation on how best to grow crop in a semi - shut greenhouse .
Fan speedIt may surprise many that the first ‘ do not ’ , is to put the rooter stop number at 100 % . Intuitively , growers who exchange to semi - closed , finger that fan speed is the same tool as release opening in a conventional greenhouse . If the temperature in the greenhouse is warm , the vents open further . So , it should be the same in a semi - closed nursery where increase fan speed increase the air substitution . This is true , but at high fan speeds there are other dynamics that come into play . Godfrey discusses just a few of them .
The glasshouse is a heat energy computer memory tank?In a semi - closed glasshouse , the pre - cooled air is brought in from the bottom of the glasshouse and rear slowly to the top . A semi - closed greenhouse has far fewer roof blowhole . They are not meant to let air in , rather they allow the air to entrust the glasshouse . As such they act as a blue - insistency relief valve . As the air rise , it warm up up . It is not unusual to have an air temperature of 45 degrees Anders Celsius ( or more ! ) in the ceiling of the nursery while at plant level , the temperature is 25 degrees Celsius .
Increasing the buff speed to 100 % creates enough Sturm und Drang in the glasshouse to bring in blistering aura from the top back down to the tops of the plant . An analogy can be pass with a rut storage tank car where hot and cold-blooded layer maintain separation if the water enter the tank slowly . When the body of water travels too chop-chop into the tank , the separation is broken , and the water is motley . The same is straight for the air in a semi - closed nursery at high fan hurrying .
MomentumAnother serious side force of in high spirits buff hurrying is that it creates a circular motion in the glasshouse . This phenomenon is called impulse ( more about it in a later article by Godfrey ) . For now , it do to say that the rotary question pulls hot , upper level air down to the top of the plants near the mood chamber create a very red-hot climate for the plants in that area . If the hurrying of the fans is higher , the circular motion increase in speed and the area affected by the hot air coming down will be big .
Another important reason for slowing down the devotee is cost . For representative , increase fan speed from 75 % to 100 % , increase the electrical energy price by 50 % .
Please observe that glasshouse producer utilise different fans and fan speeds . It is better to talk in air rally per time of day . Most of the trouble describe above , are avoided if the sports fan speeding does not commute the zephyr in the glasshouse more than 8.5 times per 60 minutes .
Most cultivator will ask how a semi - closed glasshouse can be kept nerveless if the lover amphetamine is significantly reduced . This will be discussed in another mail .
For more entropy : greenhouse Consultancywww.glasshouse-consultancy.com
Godfrey DolLinkedIn[email protected]+81 80 700 94 006
