Naturally ventilated industrial sheds: an investigation about the influence of wind direction in flow rate efficiency in continuous roof vents

Natural ventilation portrays an effective technique for lowering the internal temperature, without spending electricity, and directly contributes to the renewal of indoor air by establishing a healthy environment for workers. Given this, it is usual to have air vent openings located at the top of the roof (continuous roof vents), in addition to those present on the facades of sheds. In naturally ventilated buildings, it is recommended to give due importance to the provision of these openings, since depending on the proposed arrangement, the wind may or may not help in the effectiveness of this strategy. In this work, it is evaluated via computer simulation (EnergyPlus, version 8.7.0), for the climatic conditions of the city of Belo Horizonte/Brazil, the influence of the wind direction in the flow rate of indoor air through the ridge vents, of the longitudinal and transversal type, present in industrial sheds endowed with an internal source of high-intensity heat release. The results obtained show that the flow rate has a symmetrical behavior in the openings of the longitudinal continuous roof vent, that is, when an opening is with the maximum outflow of the internal air, the opening opposite the predominant wind direction is acting as an entry point for the air external. The transverse continuous roof vents are more sensitive about the wind direction since they are positioned perpendicular to the building. The best result found is for the wind situation occurring parallel to the shed, obtaining a reduction in the internal temperature of up to 1°C, an increase in the rate of air changes per hour, in the internal environment, at 1acph, and an increase of up to 10,7% in the volume of air infiltrated into the shed.

Naturally ventilated industrial sheds: an investigation about the influence of wind direction in flow rate efficiency in continuous roof vents

Natural ventilation portrays an effective technique for lowering the internal temperature, without spending electricity, and directly contributes to the renewal of indoor air by establishing a healthy environment for workers. Given this, it is usual to have air vent openings located at the top of the roof (continuous roof vents), in addition to those present on the facades of sheds. In naturally ventilated buildings, it is recommended to give due importance to the provision of these openings, since depending on the proposed arrangement, the wind may or may not help in the effectiveness of this strategy. In this work, it is evaluated via computer simulation (EnergyPlus, version 8.7.0), for the climatic conditions of the city of Belo Horizonte/Brazil, the influence of the wind direction in the flow rate of indoor air through the ridge vents, of the longitudinal and transversal type, present in industrial sheds endowed with an internal source of high-intensity heat release. The results obtained show that the flow rate has a symmetrical behavior in the openings of the longitudinal continuous roof vent, that is, when an opening is with the maximum outflow of the internal air, the opening opposite the predominant wind direction is acting as an entry point for the air external. The transverse continuous roof vents are more sensitive about the wind direction since they are positioned perpendicular to the building. The best result found is for the wind situation occurring parallel to the shed, obtaining a reduction in the internal temperature of up to 1°C, an increase in the rate of air changes per hour, in the internal environment, at 1acph, and an increase of up to 10,7% in the volume of air infiltrated into the shed.

Why Is the Attic Ventilation Disappearing from the Current Urban Houses in the Humid Tropics?

The construction of a townhouse built today no longer has roof vents, compared to colonial buildings as well as traditional architecture scattered in humid tropics. In Indonesia, many buildings are made with a zinc roof, even in North Sulawesi province 92 percent of zinc roofed buildings or metal aluminum. This article has two purposes, the first is to assess the benefits of attic ventilation, especially for zinc roofed buildings and the second is to find out why the ventilation loft is no longer used to present buildings. Research by building two same test cells where one cell has roof vents, and the other cell does not. The test cell with ventilated roofs has the advantage that the interior temperatures are lower on average by 1.2 ∘C than those in a cell without ventilation. Almost all buildings today have a modern and minimalist style where the shape and pattern are delicate and do not allow for roof ventilation; such structures cannot form adequate attic spaces. Based on observation and evaluation, this is the leading cause of the disappearing of attic ventilation. Another thing was caused by efforts to reduce the selling price of a house with consideration of people’s purchasing power. Ignorance from building owners and developers on the benefits of attic ventilation to reduce room temperature and lighting is one of the factors found in this study; even this problem is made worse by architects who often ignore these benefits in their designs. Comprehensive knowledge is needed for the general public and also for architects for the use of roof ventilation which in turn is an effort to achieve thermal comfort and energy savings in the domestic sector

Broiler trailer thermal conditions during cold climate transport

Burlinguette, N. A., Strawford, M. L., Watts, J. M., Classen, H. L., Shand, P. J. and Crowe, T. G. 2012. Broiler trailer thermal conditions during cold climate transport. Can. J. Anim. Sci. 92: 109–122. Thermal environments within broiler transport vehicles are dependent on ambient conditions and, if poorly managed, can be a welfare concern. To effectively manage broiler transport, the environmental conditions throughout vehicles must be understood. Under standard commercial practices, temperature and humidity levels in double-trailer broiler vehicles were examined for a range of ambient temperatures (−24 to 11°C). During warmer ambient conditions (9.8°C) trailer roof vents and side curtains were all open, which resulted in a narrowing of the on-board temperature range (10.3 to 16.7°C). As ambient temperature cooled side curtains and some of the roof vents were closed. This resulted in increasingly variable and more extreme thermal conditions, with heat and moisture accumulated along the midline of the load near the front of the lead trailer and near the back of the rear trailer. At an ambient temperature of −22.1°C trailer temperatures ranged from −20.7 to 21.7°C with an estimated 58.6% of the load volume being exposed to temperatures below 0°C. In addition, the trailer humidity ratio rose 14.0 g kg−1 above ambient and conditions approached saturation (RH>80%) in 55.2% of the load volume. These results support the need to find a means to remove moisture and redistribute heat on broiler trailers during cold ambient conditions.