Analytical Study of the Automatic Ventilation System for the Intake of Polluted Air from the Pigsty

The microclimate of a pigsty is determined by the combination of temperature, relative humidity, chemical and mechanical composition of the air, which have a significant impact on animal productivity and must be maintained within strict limits due to the physiological needs and capabilities of animals. An appropriate ventilation system has been created to ensure the removal of air from the pigsty. The purpose of the study is to establish the dependence of the operating parameters of the automatic ventilation system on the air quality in the pigsty, taking into account the permissible concentrations of gases. The developed automatic ventilation system for polluted air intake is located in the middle of the livestock house under the ceiling and consists of a central air duct, to which air intake pipes are connected. Air intake pipes are placed in the middle above each pen where animals are kept. Intake dampers with servomechanisms, temperature, humidity, and air quality sensors are installed at the inlet of the air intake pipes. The outlet of the central air intake duct is connected to the exhaust fan. Intake dampers with servomechanisms and sensors of temperature, humidity, and air quality are connected to the control unit by electrical wires. As a result of analytical studies of the automatic ventilation system for polluted air intake from a pigsty, the conditions for its effective operation have been mathematically substantiated. The developed technique and the algorithm implemented based on the Mathematica software package allows calculating the area of holes that form intake dampers with servomechanisms in the air intake pipes. The distribution of velocities in the air intake pipes and the distribution diagram of the area of holes that form intake dampers with servomechanisms in the air intake pipes are determined taking into account the design and technological parameters of the ventilation system and the distribution of the gas concentration (carbon dioxide, ammonia, and hydrogen sulphide) over the pens

Etude comparée de la ventilation naturelle et automatique à l’aide de tuyaux perforés et du procédé classique de retournements des andains en compostage

Sur la plateforme de compostage de l’ONG ENPRO, pour chaque tas de compost, cinq retournements sont nécessaires en vue d’apporter de l’air pour une bonne décomposition aérobie. Le retournement d’un seul tas de compost nécessite trois ouvriers pour une durée de trois heures. Donc, pour chaque fréquence de retournement, il faut mobiliser dix-sept ouvriers en une journée. Leur prise en charge pour les cinq retournements s’élève à 595000 FCFA. Face à ce coût élevé, la recherche d’alternatives de réduction du nombre d’ouvriers et du temps s’impose. La ventilation naturelle qui consiste à renouveler de l’air par des forces naturelles à travers des ouvertures, se présente comme la technique la plus optimiste. Ainsi, l’objectif de ce travail est d’optimiser la main d’œuvre et le temps accordé aux retournements. Cinq andains sont élaborés dont un standard et les quatre autres à ventilation naturelle. L’étude comparative des critères de maturité et de stabilité a montré des valeurs similaires pour les deux types de compost. Aussi, la ventilation naturelle a permis de réduire le nombre de retournements à deux et le nombre d’ouvriers à dix contre cinq et dix-sept pour le compostage standard puis le coût de prise en charge des ouvriers d’environ 25%.Mots clés : Compostage, retournement des andains, optimisation du temps, ventilation naturelle. English title: Comparative study of natural and automatic ventilation using perforated pipes and the classic method of turning windrows in compostingOn the composting platform of the NGO ENPRO, for each pile of compost, five turns are necessary in order to provide air for good aerobic decomposition. Turning a single compost heap requires three workers for three hours. So, for each turnaround frequency, seventeen workers must be mobilized in one day. Their cost for the five turnarounds amounts to FCFA 595,000. Faced with this high cost, the search for alternatives to reduce the number of workers and time is essential. Natural ventilation, which consists of renewing air by natural forces through openings, is presented as the most optimistic technique. Thus, the objective of this work is to optimize the manpower and the time allocated to turnarounds. Five windrows are produced, one of which is standard and the other four have natural ventilation. The comparative study of the maturity and stability criteria showed similar values for the two types of compost. Also, natural ventilation has reduced the number of turnovers to two and the number of workers to ten against five and seventeen for standard composting and the cost of supporting workers by around 25%. Keywords: composting, windrow turning, time optimization, natural ventilation