Analysis of the spatiotemporal temperature fluctuations inside an apple cool store in response to energy use concerns

• Air circulation fans are the major source of heat load during apple cold storage.
• Attempt to reduce energy cost should deliberate on reducing fan operation time.
• The temperature of the apple can be made to fluctuate within limited range.
• It has been demonstrated that fan and refrigeration cycling works to save energy.
• Load shifting of controlled atmosphere stores for saving energy costs seems worthwhile.

Energy cost concerns have led to question the temperature and air flow regimes in cool store facilities. In this paper, a CFD model of the air flow and temperature dynamics inside an apple fruit cool store was developed, validated and used to analyze energy cost saving alternatives. Load shifting was attempted by cycling the temperature set point between 1.2 °C and 0.6 °C following a day/night regime. Discontinuous use of the cooling operation, including 12 h on/12 h off; 10 h on/14 h off; and 8 h on/16 h off, was also investigated. The study showed that the air circulation fan is the major source of heat load. Hence, an attempt to reduce energy cost should first deliberate on reducing the fan operation time. The study developed a generic tool to analyze temperature control options inside an apple cool store in response to energy use concerns.