EN - How does a pyrgeometer work?

EN - How does a pyrgeometer work?

    

Question
A pyrgeometer was installed.
How does a pyrgeometer work?


 Answer 

A pyrgeometer measures the outgoing longwave radiation also known as heat emission. The pyrgeometer is installed on the weather station and with this measurement the energy loss of the greenhouse to the sky can be determined. The pyrgeometer measures the heat emission in W/m2. With cloudy weather, the upwards and downwards longwave radiation is just about the same. With such weather conditions, objects such as a greenhouse lose less energy due to heat emission and the measurement will be between -50 and 0 W/m2. With clear skies, the downwards longwave radiation is small and a lot of energy is lost due to upwards radiation and the measurement will be between -80 and -150 W/m2.


 
Heat emission is a crucial factor for climate control, because it has a significant direct effect on the energy balance of the greenhouse and an indirect but strong adverse impact on the energy balance of the crop. The temperature of the crop can decrease quickly with the risk of crop condensation which can lead to growth issues or diseases. 


  

Especially, when the incoming radiation or energy from outside drops below the outgoing radiation (breakeven moment) due to heat emission from the greenhouse. In this situation the pyrgeometer can be used to influence curtain controls and close the (energy) curtain (earlier) when there is a lot of heat emission. Would you like to see how the pyrgeometer can be used as an influence to close the curtain (earlier)? Read this article: How to use a pyrgeometer?

There is some maintenance to do:







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