Supplying Water Warmed by Exhaust Heat from Closed Vertical Composting Facility for Dairy Cows

Abstract.

In this research, in order to use the fermentation heat generated by composting to improve the feeding environment of dairy cattle, the exhaust heat from a closed vertical composting device installed in a dairy farm was collected and used to heat water. We constructed a system that supplies hot drinking water and clarified the characteristics of the heat source and water temperature. The target dairy farmer had a herd of 150 dairy cows. Water supplied to the cows was warmed by a heat exchanger that was connected to an exhaust pipe from a closed vertical composting facility (CVCF). The objective of this study was to develop a system that could use the CVCF exhaust to warm water. In total, 5.8 m³ of fresh cow manure was input to the CVCF every day. The temperature of the CVCF exhaust was almost 60 °C with a heat quantity of 3700 MJ/d (42.7 kW equivalent). The temperature of the supplied water could be reached 32.2 °C, which was 23 °C higher than that of raw water. The energy generation rate and heat utilization efficiency of this water warming system were 465 % and 48.3 %, respectively. Our research demonstrates that CVCFs have the ability to adequately supply warm drinking water for cows. Verification of the effect of this supplementary warmed water for cows should be further investigated.