No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Airborne Dust Distribution in Tied Cows House With Different Fans Operation Regime
ResearchGate has not been able to resolve any citations for this publication.
The most notable role in the energy usage of rearing-related buildings belongs to barn climate. For animals, one of the most important climate parameter is the temperature of the barn atmosphere. This can be kept in the proper interval by either heating or cooling. Apart from the operation of technological solutions, the need for airing barns must be taken into consideration. This means there are special technical requirements for airing. Also, they can cause significant energy losses. The temperature limit of heating is mainly influenced by the technological temperature related to keeping the animal in question, its acceptable differences, the heat loss of the barn, and the airing requirement. Energy sources applicable to heating can be traditional sources (coal, oil, gas), renewable sources (solar, biomass, wind, water, or geothermal energy), or transformed energy (electricity). As these have specific operation systems, they also mean further challenges in implementing efficient energy usage. The usage of heating energy can either be optimised by the rational usage of the heating system, or machinery explicitly made for reserving energy. Sparing heating energy via recuperative heating exchange may cut costs significantly, which we also proved in this research with actual calculations. However, we have to state that the efficient usage of heat exchangers requires that the internal and external temperatures differ greatly, which has a huge impact on heat recovery performance.
Two naturally-ventilated freestall dairy barns, constructed in the mid-western United States in the mid 1990’s, were recently (spring, 2007) retrofitted into mechanical “cross-flow” ventilation systems to improve cow comfort and performance. The two barns are part of the National Air Emission Monitoring Study (NAEMS), which is measuring gas and particulate emissions from livestock and poultry buildings and associated manure storages. The two, approximately 27-meter-wide barns were converted from natural ventilation to cross-flow ventilation systems by installing a continuous row of belt-driven, 127-cm diameter axial exhaust fans (59 and 66 fans respectively for barns 1 and 2) along one side of each barn. Air enters each barn along the opposite sidewalls. A solid plastic curtain baffle runs the length of both barns from the closed ridge peaks to the top of a row of headlocks along the feed manger to force ventilation air down to cow level. In addition, two rows of water fogging nozzles (1 m spacing) were installed in both barns, one at the sidewall inlets and the other at the bottom of the interior baffle. The fogging nozzles provide evaporative cooling to the incoming and cross ventilating air. The new ventilation systems were able to maintain indoor air below ambient outdoor temperatures in the two dairy barns and provided convective cooling of the cows during warm summer days. Indoor air quality as measured by carbon dioxide and ammonia concentration were well within generally acceptable levels. Milk yield and feed efficiency improved in these two barns during the 4 summer (June – September) months of 2007 compared to the previous three summers (2004-2006) even though 2007 had greater number of days above 30 °C. Additional research is needed to show more statistical evidence of the biological improvements in herd performance from cross-flow ventilation / evaporative cooling systems.
Dust spatial distribution is an important variable to understand the nature of dust transportation and to implement appropriate control strategies. There is a lack of data on dust spatial distribution in mechanically ventilated airspaces because of lack of adequate sampling techniques. In this project, a multi-point sampler was used to measure the dust spatial distribution at different ventilation rates in a mechanically ventilated airspace, which was an isothermal and two-dimensional flow empty room. Dust mass concentration varied as much as 30-fold between the lowest and the highest within the mechanically ventilated airspace. Ventilation rate had a large effect on the dust spatial distribution. Increasing the ventilation rate reduced the overall mean dust concentration when ventilation rates were lower than 56 air changes/h (ACH). When ventilation rates were higher than 56 ACH in this study, the overall mean dust concentration did not change much (<4%) as the ventilation rate increased by 18%. The spatial gradients of dust concentration become relatively lower as the ventilation rate increases. There is a high dust concentration zone in the ventilated airspace, which is important for selecting proper locations for air cleaning devices.
Airborne particles and ammonia were monitored in horse stalls managed under four conditions. Two ventilation rates, high (27 air changes per h) and low (5 air changes per h) and two bedding types, paper and straw, were employed. At both ventilation rates, the number of airborne particles generated while the stalls were mucked out was higher with straw than with paper. Particles were more efficiently cleared at the higher ventilation rate in both the straw and paper stalls. Ammonia measurements reflected an accumulation over time. In the stalls with low ventilation, ammonia levels were significantly higher than in those stalls with high ventilation regardless of bedding type. Management decisions and their relationships to respiratory disorders are discussed.
Relationship Between Farm Machine Requirement and Farm Size
- L Magó
Magó, L.: 2000. Relationship Between Farm Machine
Requirement and Farm Size, Gazdálkodás, Scientific Journal on
Agricultural Economics -English special edition Vol. XLIV. No.
1. p. 66-75.
Economically Reasonable Using of Different Power Machines According to the Farm Sizes
- L Magó
Magó, L.: 2002. Economically Reasonable Using of Different
Power Machines According to the Farm Sizes, Hungarian
Agricultural Engineering, Periodical of the Committee of
Agricultural Engineering of the Hungarian Academy of Sciences,
Vol. 15/2002. p. 79-82.
Numeričko predviđanje strujnog polja pri prirodnoj ventilaciji stočarskih objekata. Poljoprivredna tehnika, god. XXXIII, br. 3
- G Topisirović
- O Ećim-Đurić
Topisirović G, Ećim-Đurić, O.: 2008. Numeričko
predviđanje strujnog polja pri prirodnoj ventilaciji stočarskih
objekata. Poljoprivredna tehnika, god. XXXIII, br. 3. pp. 41 -47.
Poljoprivredni fakultet. Beograd.