Development of milk cooling system driven by biogas fuel engine

Milking and milk cooling processes, which are considered as the basic processes of a dairy farm, constitute 49% of the total operating cost and cause the most important energy consumption cost of the farm. Today, one of the most effective ways to reduce energy consumption costs is to benefit from renewable energy sources. Therefore, studies to be carried out in this area can provide significant savings in electrical energy consumption as well as encounter all the electricity needs of the farm. Many farms in Turkey leave their animal wastes to nature without using them. This situation causes contamination of underground spring waters, odor and fly formation, etc. cause environmental and health problems. In order to prevent all these problems, the evaluation of animal wastes is of great importance. One of the best evaluation methods of animal wastes is to obtain biogas by decomposition. Within the scope of this thesis, a milk cooling system working with biogas energy obtained from animal wastes has been developed in a dairy farm. The main purpose of the study is to encounter the necessary energy need for the milk cooling process, which is one of the most important processes of a dairy farm, from the bioenergy potential of animal wastes, and in this way, to bring the industry with a highly energy efficient system that obtains all of the energy it consumes from biogas energy. In the biogas reactor developed within the scope of this study, the fermentation process was controlled by keeping the temperature and pressure constant and methane gas was obtained by maintaining the productivity. Filtering processes of carbon dioxide, hydrogen sulfide, etc. gases in the formed methane gas were carried out and stored in a 10 m3 membrane. The driving force generated by the use of the stored biogas in the internal combustion gas engine was transferred to the compressor of the 300-liter milk cooling tank, thereby enabling the cooling process to be performed. The numerical calculations of the system were carried out with the help of a mathematical modeling study developed using the Java language. In experimental studies, it was observed that while 150 liters of milk at 38 °C were cooled to +4 °C in 1 hour and 50 minutes at the first milking, the temperature of 300 liters of milk decreased from 36 ⁰C to 4 ⁰C in an average of 2 hours and 5 minutes at the last milking. In addition, microbial analyzes of the samples taken from the cooled milk were made and it was determined that the average number of colonies formed was 2.1 x 104 colonies/ml (log_10⁡4,32). As a result of the study, it was clearly observed that the milk cooling process with biogas complies with the Turkish Standard TS EN 13732 and significantly reduces the energy consumption of the farm.