An energy efficient hydraulic system to cool manure and reduce ammonia emissions from livestock buildings

摘要

A sustainable hydraulic system is proposed to cool the slurry manure and mitigate the ammonia emissions of livestock buildings, a major source of environmental pollution. In this paper, analytical and numerical methods are used to evaluate the energy efficiency and the mitigation capability of the hydraulic cooling system. Results show that annual primary energy use of only 6.08 kWh per animal can reduce 5.87 kg of ammonia per animal per year. The system is most efficient for manure with less than 12% total solids content. Results also show that the liquid region above the cooling pipes features one-dimensional transient heat transfer formed by unique flow patterns. A simplified analytical model is derived to predict the surface temperature of liquid manure. The analytical solution shows that the manure surface temperature can be reduced by 7.4 and 12 degrees C after 2 and 5 h, respectively. The temperature reduction results in up to 37.3% decrease in ammonia emissions with only 0.8% of the total energy use in livestock buildings. (C) 2019 Elsevier Ltd. All rights reserved.