On conventional dairy farms, around 50% of the electrical energy demand is used for cooling milk and heating water for cleaning equipment. The widely used circulation cleaning systems require cleaning water to be heated to approx. 80 °C, a process which accounts for at least 20% of dairy farm energy consumption. At the same time, waste heat generated by milk cooling systems is dissipated to the surroundings. This study focuses on circulation cleaning systems, as boiling water systems are rarely used in Switzerland. By recovering heat from the milk cooling system, it is possible to pre-heat the cleaning water to approx. 50–55 °C and shorten the milk cooling time. As regulations require milk to be cooled quickly to maintain its quality, this is particularly useful, especially in summer when ambient temperatures are high. Trials conducted on nine commercial dairy farms have shown that incorporating a heat recovery system (HRS) into the milk cooling system can save around 47% of the electrical energy demand compared with using a conventional electric boiler to heat the cleaning water. The HRS can also shorten the milk cooling time and reduce the electrical energy consumption of the cooling unit by around 14%. However, it is important to ensure that these systems are correctly installed and regularly maintained.
