Design of a low cost data acquisition system to monitor the performance of an on-farm bulk milk cooler

Abstract

This study focuses on the design, construction, and testing of a data acquisition system (DAS) to monitor the performance of an on-farm DXBMC as a tool to aid decision making for dairy farmers. Various sensors formed the design of the low cost data acquisition system (DAS) and these comprised of relative humidity and ambient temperature sensor, temperature sensors and a power meter. The study was carried out on an existing dairy farm with an average of 800 cows in milking during peak milking period. Temperature sensors monitored the temperature of the milk delivered to the direct expansion bulk milk cooler (DXBMC) as well as the temperature of the room, the power meter was used to measure the electrical energy consumed by the DXBMC during the cooling process. Findings from the study revealed that the peak season recorded the highest average total energy of 6 898.52 kWh as whereas the off-peak season recorded an average total of 3 771.28 kWh. The annual energy consumption due to milk cooling and storage was 64 336.22 kWh. The energy consumption during cooling of milk was 92.57% with the remaining 7.43% consumed during the storage of milk to maintain it at the set point temperature. During that period the average COP was 2.28 and 1.99 for the AM and PM milking times. On average, the DXBMC cooled 57.33 L/kWh during the off-peak period and increased by 7.7% to 62.13 L/kWh during the peak. The low-cost DAS is simple to use on any dairy farm to provide insight into the operation of the milk cooling system. This allows measures to be taken to enhance performance and save energy where possible.