Design of a low cost, smart and stand-alone PV cold storage system using a domestic split air conditioner

Abstract

To reduce post-harvest losses of food produce and ensure a better return to marginal farmers, a small cold storage has been developed using a domestic split air conditioner. The developed solar-powered cold storage is a low cost, simple and energy-efficient unit. Installation, operation and maintenance costs of the cold storage are also less. The cold storage is integrated with IoT-based sensors for remote monitoring and controlling of temperature and humidity as well as tracking of the stored items. It uses multiple sensors and a microcontroller to maintain and monitor the desired temperature and relative humidity. Average recorded temperature and relative humidity of the cold storage chamber is found to be 6.88 (±0.7) °C and 95 (±1) % respectively. Total cost of the designed 10 t capacity cold storage is around $ 15710 in India including installation charges. This low-cost cold storage can be owned by a group of farmers in the same locality for using it on a sharing basis or it can be owned by a produce trader to store a variety of fruits and vegetables. Using the developed cold storage, total savings to farmers is calculated to be $ 7449 per year. Farmers or traders can save around $ 20.46 in storage rent per tonne per week considering an average 70% utilization of 10 t capacity of the cold storage throughout the year. Further, the cost of cold storage can be recouped from the rent benefits within the first 2.1 year period.