Conforto térmico em instalações para processamento úmido de café

Este estudio tuvo como objetivo evaluar el confort térmico para trabajadores, en tres edificaciones de procesamiento húmedo de café en Colombia, utilizando el índice WBGT, y análisis de temperatura y humedad relativa a través de mapeo. Los límites recomendados del WBGT fueron excedidos en la actividad de abastecimiento de combustible de la secadora en la Edificación 3. Las tres edificaciones presentaron variabilidad higrotérmica espacial debida a la secadora de café, y a problemas con la ventilación, volumen de control y resistencia térmica de materiales en los edificios 2 y 3. Para favorecer la transferencia de calor de la secadora al ambiente exterior, y hacer más homogéneo el ambiente térmico de las edificaciones, se recomienda instalar puentes térmicos alrededor de esta zona, y para hacer más eficiente la evacuación de vapor y calor, aumentar el área de ventilación natural en las edificaciones 2 y 3, e instalar claraboyas de ventilación sobre la secadora

Desempenho de um sistema de resfriamento evaporativo em instalações para suínos em fase de terminação

The thermal environment inside of a finishing phase swine barn has great influence on the success of swine production. This environment can be characterized by the black globe temperature and humidity index (BGHI), that represents the air temperature, humidity, wind speed and radiation. Due to the small number of Brazilian reports on this specific subject, this experiment was performed to verify the effect of one kind of evaporative cooling system on the thermal comfort of the animal in a swine barn, during the 98/99 summer at Patos de Minas, MG, Brazil. Two constructions were used, divided in 36 barns, each one with 15 animals, 110 to 150 days old. Along a side of one barn, four cooling devices were installed, with a ventilation system connected to a sprayer, to form an evaporative cooling system (ECS). The other barn did not have any cooling system being a control unity (COS). The ECS provided an improvement of the environmental thermal conditions, reducing the index of black globe temperature and humidity inside the building, from 83.5 to 82.4, during the critical period of the day (2 p.m.). The ECS provided also an improvement of the food conversion, from 3.27 to 2.88, and a tendency of a substantial weight gain, from 0.97 to 1.02 kg per day.O ambiente térmico no interior das instalações para suínos em fase de terminação tem importância vital para o sucesso da atividade suinícula. Esse ambiente pode ser representado pelo índice de temperatura de globo e umidade (ITGU), que inclui a temperatura, a umidade relativa e a velocidade do ar, e a radiação. Baseado nisto foi desenvolvido um trabalho com o objetivo de avaliar o efeito de um sistema de resfriamento evaporativo no conforto térmico de instalações para suínos em fase de terminação. O experimento foi realizado no período de verão (98/99) no município de Patos de Minas, MG. Foram utilizadas duas instalações divididas em 36 baias. Em cada baia foram alojados 15 animais por um período de 40 dias, com idade média inicial de 110 dias. Na lateral de uma instalação foram instalados quatro equipamentos de resfriamento composto de sistema de ventilação e nebulização, tendo-se o tratamento com resfriamento evaporativo (TRE); na outra instalação não foram utilizados equipamentos de resfriamento, tendo-se o tratamento testemunha (TES). O TRE proporcionou melhoria das condições térmicas ambientais, reduzindo o índice de temperatura de globo e umidade, no período crítico do dia (14h00), de 83,5 para 82,4, no interior da instalação. O TRE também proporcionou melhoria na conversão alimentar dos animais, de 3,27 para 2,88, e uma tendência de maior ganho de peso dos mesmos, de 0,97 para 1,02 kg por dia

Sugarcane bagasse ash as a partial-portland-cementreplacement material

This investigation is focused on the evaluation of the effects of the partial replacement of Portland cement by sugar cane bagasse ash (CBC) in mortars. The main objective wasto find a suitable destination for an agricultural residue generated in an increasing amount in Brazil, as the use of CBC as a mineral admixture in mortars and concretes, contributes to decrease the environmental impact of these materials related to cement production. Experimental techniques were applied both for the CBC characterization and for the evaluation of its use as a mineral admixture in mortars, based on mechanical and physical tests. The results from tests with mortars indicated the viability of the partial substitution of cement by up to 20% of the CBC considered

Thermal comfort in buildings for wet processing of coffee.

This study aimed to assess thermal comfort for workers in three buildings for wet coffee processing in Colombia, using the WBGT index, and temperature and relative humidity analysis through mapping. The limits recommended by the WBGT index were exceeded during the activity of putting fuel in the dryer in Building 3. The three buildings presented spatial hygrothermal variability due to the coffee dryer, as well as problems with ventilation, volume control, and the thermal resistance of materials in Buildings 2 and 3. In order to favor heat transfer from the dryer to the outside environment, and to make the thermal environment of these buildings more homogeneous, it is recommended to install thermal bridges around this area, to make more efficient the evacuation of steam and heat, as well as to increase the natural ventilation area in Buildings 2 and 3, and install ventilation skylights over the dryer

Evaluation of the fertilizer and contamination potential of different broiler litter types subjected to various use cycles

The aim of this study was to evaluate two types of poultry bedding litter (wood shavings and coffee husks) with increasing use cycles, the best time to proceed with composting based on the carbon/nitrogen ratio and the ability to generate ammonia. The results obtained with the present experiment conditions indicated that the litter with wood shavings in the first cycle and the litter with coffee husks in the first and second cycles presented the best behavior in terms of the C/N ratio needed for later use as compost. In regards to the contamination potential, it was found that increasing the number of reutilizations for both the wood-shaving and coffee-husk litters resulted in a greater ammonia emission

Behavior of Japanese quail in different air velocities and air temperatures

O objetivo deste trabalho foi avaliar o efeito combinado da temperatura e da velocidade do ar no comportamento de codornas japonesas (Coturnix coturnix japonica). Utilizaram-se 216 codornas japonesas na fase inicial de postura. Os comportamentos das aves foram estabelecidos no etograma comportamental (comer, beber, parar, abrir asas/arrepiar, outros). Utilizou-se o delineamento experimental de blocos ao acaso, em arranjo fatorial 4x4, com quatro velocidades do ar (0, 1, 2 e 3 m s-1) e temperaturas do ar (17, 23, 29 e 35°C). O comportamento “parar” foi maior quando as aves foram submetidas a 17°C. À temperatura de 35°C, houve redução significativa (p<0,05) para o comportamento “comer” a 0 m s-1, em comparação às demais velocidades. Os comportamentos das codornas poedeiras são semelhantes no período da manhã e da tarde. As codornas permanecem mais tempo paradas em condições de estresse por frio, a 17°C.The objective of this work was to evaluate the combined effects of air temperature and air velocity on the behavior of Japanese quail (Coturnix coturnix japonica). A total of 216 Japanese quail in their initial laying phase were used. Bird behavior was categorized with an ethogram (eat, drink, stop, open wings/shiver, others). The experimental design was a randomized complete block, in a 4x4 factorial arrangement, with four air velocities (0, 1, 2, and 3 m s-1) and air temperatures (17, 23, 29, and 35°C). The behavior “stop” was greater when the birds were subjected to 17°C. At 35°C, a significant reduction (p<0.05) was observed in the behavior “eat” at 0 m s-1, compared with the other velocities. The behaviors of laying quail are similar in the morning and in the afternoon. Quail remain stopped for a longer time under cold stress conditions, at 17°C

ASPERSÃO DE ÁGUA DE CHUVA ARMAZENADA SOBRE A COBERTURA DE AVIÁRIOS COM TELHAS DE AÇO NA REGIÃO CENTRO OESTE DO BRASIL

Objetivou-se com este trabalho estudar os principais efeitos da aspersão de água de chuva armazenada sobre a cobertura de telhas de aço de instalações comerciais para produção de frangos de corte, na região centro-oeste do Brasil. Foram avaliados variáveis climáticas, temperatura da superfície inferior das telhas, índices zootécnicos e índices de conforto térmico. Adicionalmente, foram avaliados o tempo de funcionamento, o consumo de água e o consumo de energia pelo sistema de resfriamento. O delineamento experimental foi inteiramente casualizado com dois tratamentos e três repetições: Tratamento um - três aviários equipados com sistema de resfriamento interno, modo túnel com pressão negativa, e aspersão de água de chuva armazenada sobre a cobertura de telhas de aço (CA); Tratamento dois - três aviários idênticos aos do tratamento 1 embora, sem aspersão de água sobre a cobertura (SA). O tratamento CA, em média, proporcionou a redução de 19,5°C na temperatura média da superfície interna das telhas no horário mais critico do dia às 15:00h e reduziu a temperatura média do ambiente ao nível das aves em 1,9 °C. Ademais, os índices de conforto térmico no tratamento CA apresentaram valores inferiores durante todo período experimental, houve redução no tempo de funcionamento do segundo grupo de exaustor em 4,8 %, no terceiro grupo em 7,5 % e na bomba de nebulização interna em 9,6 %, reduzindo assim o consumo de energia elétrica, redução na mortalidade, melhoria na conversão alimentar e aumento no ganho de massa corporal média das aves ao abat

Modeling and experimental validation to estimate the energy balance for a poultry house with misting cooling

The aim of this study was to develop and validate a simplified steady state mathematical model to predict temperature distribution in a commercial poultry house equipped with a negative pressure ventilation system and internal misting. The model was validated with data obtained experimentally during the summer. For external temperature conditions of 26, 27, and 29 °C, the best combinations of energy generated by misting (qmisting), ventilation rate (V), global heat loss coefficient for the roof (Ut), and global heat loss coefficient for the wall (Upar) were encountered to maintain the majority of the installation with temperatures within the optimal thermal comfort range for the birds (24 to 29 °C)

Evaluation of different methods for determining ammonia emissions in poultry buildings and their applicability to open facilities

In regions of tropical and subtropical climates, nearly all installations used for intensive broiler chicken production and other animals of economic interest operate as curtain-sided open structures with assisted mechanical ventilation. The lack of ventilation control in these facilities, along with wind direction and velocity effects on ventilation uniformity, complicates calculation of the quantity of gases (ammonia and others) generated by the litter at a given moment. This fact constitutes a pitfall when evaluating the polluting potential of open environments, and when comparisons with data encountered in closed environment facilities used in temperate climates need to be done. All developed countries of Europe and North America already possess methodologies to determine gas emissions in closed installations commonly found in these regions. Therefore, the objective of the present study was to evaluate some specific methodologies used for determining ammonia emissions from broiler houses located in countries of Europe and the United States, and verify the possibility for application of these methodologies to open structures commonly found in Brazil and other countries of South America. A quantitative evaluation showed that the methods with best characteristics for adaptability to the operational conditions and the different types of conditioned environments of buildings with positive pressure or natural ventilation systems were the internal tracer gas, the portable monitoring unit (PMU) and the mobile air emissions monitoring unit (MAEMU). According to the results, model-based approaches that use mass balance and passive diffusion samplers such as the “Ferm Tube” and the Saraz Method for Determination of Ammonia Emissions (SMDAE) proposed by Osorio (2010), can also be adapted to different operational conditions for open buildings