Infrared Thermography to Monitor Natural Ventilation during Storage of Potat

S. Geyer, K. Gottschalk

Abstract


A thermographic imaging system is applied as a climate control component in a big potato box store. Traditional temperature sensors distributed in the boxes give product information, i.e. temperatures and relative air humidity values, only for local spots. A thermographic infrared imaging camera system however is able to record a general view over a comparably wide area of the store to detect local differences of surface temperatures in the storage. The project objective is to improve climate control by application of thermography in a free convective ventilated (FCV) box store for potatoes to reduce high temperature differences, which is a typical problem in such types of stores.

It was proved that the FCV principle is working even for huge stores. For stores of that type no cooling or ventilation devices are applied to save energy and finally to protect the environment. Thus, these types of stores are only dependent on ‘natural’ ventilation with ambient (environment) air.

Low temperature differences can be controlled by moving the top and bottom dampers, according to the temperature fluctuations, dependent on outside wind velocity, and can be determined by the thermography system. The visibility of the air movements i.e. directions of flow can be seen by temperature changes. This allows controlling of separate grouped numbers of dampers. Airflow direction and velocity of the outside air can therefore better be involved into control strategies. Anyway, the assumed efficiency of the ‘air-throw ventilation strategy’ (‘cellar-effect’) to cool the whole store by simply opening the top dampers only, could not be verified.

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