Increased consumer demand for fresh fruit throughout the year has created a need for long term storage. Long term storage of fruit uses more energy than fresh market products, thus increasing production cost. Pacific Northwest energy costs and more competition for markets has made energy conservation an important factor to be considered by the fruit industry. A BASICA computer program, RLSIM, was developed to predict the transient refrigeration load throughout the storage season in apple and pear cold storage warehouses. RLSIM accurately predicted the seasonal and component refrigeration system energy demand curves during the 1985-1986 cold storage season. The results also indicated that the largest single energy use component is the continuous operation of evaporator fans. Simulation of a six hours on and six hours off fan cycling technique indicated a reduction of 23.75 percent could be achieved in overall refrigeration system energy use in the cold storage warehouse. Cold storage warehouse management can be improved by using the results of RLSIM. Fan cycling schemes could be properly employed without risk of increasing fruit temperature. Recommendations were made to update research in areas of cooling and respiration rates of various fruits in both controlled atmosphere and common storage. / Graduation date: 1988