A novel solar-powered milk cooling refrigeration unit with cold thermal energy storage for rural application

Abstract

This experimental study analyzed the use of solar photovoltaic energy for operating a novel twin-circuit DC milk chiller without batteries using water-based cold thermal energy storage for different seasons in Chennai, India. HFC-134a and HC-600a were used as refrigerants in the two individual circuits. For each season, the test was conducted continuously for 18 days to analyze the quantity of generated ice that could be utilized to chill 10 L of milk in the morning and in the evening. The average quantity of ice formed per day in the ice bank during monsoon, winter, and summer seasons was found to be 3.61, 19.75, and 27.97 kg, respectively. Thus, it is evident that the use of solar energy with thermal energy storage is effective for operating the milk chilling unit for two seasons, namely winter and summer. However, the system requires an additional power source for continuous operation during the monsoon season. In this study, solar photovoltaic power was observed to be a good choice for chilling milk in the context of global warming and energy consumption. The use of thermal energy storage also allows the initial cost to be reduced.

A comparative study of solar photovoltaic operated milk cooler for realizing the need for load management and starting circuits

“…13 It can be achieved that fresh hot milk is best cooled to 10°C within two hours after milking and to 4°C within three to four hours. 14,15 Therefore, with the temperature of ice below 0°C, ice based cold energy storage method is much more suitable for cooling and keeping milk at 4°C. 16,17 In this work, an ice bank tank (IBT) based SMC with two variable speeds (2000 r/min to 3500 r/min) direct current (DC) compressors is discussed.…”