Development of Smart Sensing Devices for Ubiquitous Supervision Of The Cold Chain: Application To Perishable Commodities

Abstract

Wireless sensing technologies allow continuous monitoring of physical parameters that influence the preservation of fruit and vegetables in cold storage, while the smart sensor concept refers to the incorporation of improved prediction capabilities on standard low cost transducers as to enhance quality assurance of stored commodities while reducing in the amount of data to be transmitted. Previous experience of the authors has shown the feasibility of predicting battery shortage due to its effects on measurement oscillations, door opening by means of the instantaneous gradient in temperature and relative humidity, and water loss and condensation on the cargo. In this work, measurements in 3 commercial cold chambers with a variety of horticultural products have been performed, using up to 7 wireless motes from two different manufacturers. The ASABE psychrometric model is used as a base for smart capabilities such as energy consumption estimation is implemented as related to the increase on air enthalpy based on a single Temperature-Relative Humidity sensor. The low cost characteristics of such device encourage the ubiquitous location in the commodities and even the diagnosis of working faults of valves in refrigeration system.