Sizing and Economic Feasibility of Different Types of Solar Collectors for a Milk Producing Property in the Tropic

To obtain quality milk, several hygiene measures must be taken during the milking process, especially cleaning the milking parlor and equipment using hot water. Thus, the objective of this study was to carry out the sizing and economic feasibility of two solar water-heating systems: flat plate solar collector (FPC) and evacuated tube solar collector (ETC) to clean milking parlors in the interior of Brazil. The sizing and economic feasibility of applicability of this study was carried out for a dairy farm located in the city of Anápolis-GO, Brazil. We calculate the energy produced by the solar collector, the necessary number of collectors, the net present value (NPV) and the time of return (RT) for all systems. The ETC presented higher energy produced per unit area (8590 to 12 979 kJ m-2 day-2) than the FPC (6472 to 8699 kJ m-2 day-2). Furthermore, it presented a total required area around 33.5% lower when compared to the FPC. The system that obtained the lowest total cost was the ETC with approximately US$ 34 441.00. The two systems had positive NPV, and for ETC, this value was 7.2% higher. The return times for FPC and ETC were 3 years and 2 months and 2 years and 10 months, respectively. Both systems have proven their economic viability for heating water from milk producing properties, and may be an option for regions without energy access. In addition, the use of these systems contributes to the reduction of production costs and environmental impacts.