Potential for energy cost savings by utilising alternative temperature control strategies for controlled atmosphere stored apples

Optimal storage conditions for apples are usually defined as those that maximise possible storage duration, but could be redefined as those conditions that result in sufficient preservation whilst minimising energy costs. A review of research on controlled atmosphere (CA) storage suggests that temperature changes in CA have less impact on product deterioration than in air. This paper reviews the underpinning observations of fruit physiology in CA and the possible approaches to reducing energy costs through temperature manipulation. Experimental results indicate that minor increases in temperature during CA storage have little influence on apple quality outcomes across a number of apple cultivars. Calculations for applying a 9 h on 15 h off cycle estimated an approximate 40% of electricity cost savings whilst only incurring a 0.5 °C average fruit temperature swing. These results suggest that opportunities for substantial energy cost savings in controlled atmosphere apple stores exist.

► Potential rewards and risks of load shifting during apple storage are quantified.
► Temperature changes in controlled atmosphere had little impact on apple quality.
► Load shifting in a commercial room resulted in a temperature oscillation of ±1 °C.
►  A 40% energy cost saving may be possible with a 0.5 °C temperature oscillation.
► Load shifting of controlled atmosphere stores to save energy costs seems viable.