Articles
Minimal-data respiration modelling combined with CO2 removal for dual-gas control in modified-atmosphere storage
Article number
1456_33
Pages
251 – 260
Language
English
Abstract
Effective preservation of fruit and vegetables during storage and transport requires maintaining optimal levels of O2, CO2, humidity and temperature.
This study presents a dual gas control system that dynamically balances fresh-produce respiration with controlled ventilation, without the need for gas sensors.
The system is based on predictive process control concepts, powered by a Teensy microcontroller, and uses a thermistor for temperature monitoring, a diffusion tube for air exchange, and two mini blowers, one introducing fresh air into the box, and a second for circulating headspace through a soda-lime reactor to scrub CO2. A logical controller operates the blowers from the outputs of a model that predicts atmosphere compositions from the thermistor readings and blower actions.
An e-paper display also shows the model predictions of the internal atmosphere composition at any given time.
In trials with 30 kg of apples in a 70-L airtight box (temperature varied 5-23°C), the system maintained O2 and CO2 concentrations at 2±0.4% and 3±0.5%, respectively, over 21 days, closely aligning with the 2% setpoints.
This approach offered a moderately precise, cost-effective, gas sensor independent solution for dynamic control of O2 and CO2 during storage and transit.
This study presents a dual gas control system that dynamically balances fresh-produce respiration with controlled ventilation, without the need for gas sensors.
The system is based on predictive process control concepts, powered by a Teensy microcontroller, and uses a thermistor for temperature monitoring, a diffusion tube for air exchange, and two mini blowers, one introducing fresh air into the box, and a second for circulating headspace through a soda-lime reactor to scrub CO2. A logical controller operates the blowers from the outputs of a model that predicts atmosphere compositions from the thermistor readings and blower actions.
An e-paper display also shows the model predictions of the internal atmosphere composition at any given time.
In trials with 30 kg of apples in a 70-L airtight box (temperature varied 5-23°C), the system maintained O2 and CO2 concentrations at 2±0.4% and 3±0.5%, respectively, over 21 days, closely aligning with the 2% setpoints.
This approach offered a moderately precise, cost-effective, gas sensor independent solution for dynamic control of O2 and CO2 during storage and transit.
Authors
Y.B. Kalnar, A. Jalali, C. Weltzien, P.V. Mahajan
Keywords
modified atmosphere, gas control, packaging, modelling
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