The internal rearing environment of livestock houses has become an important issue in the last few years due to the rapid increase in meat consumption. As the number of days of heat waves increase continuously, problems caused by abnormal weather changes steadily occurred. Thus, the main goal of this study is to develop a technology that can automatically calculate heat stress for livestock by considering weather forecast data. Specifically, a web-based heat stress forecasting system for the evaluation of heat stress in broilers was developed. The field experiments were carried out at the selected broiler house to measure and analyze the external weather, the internal environment, and the ventilation flow rate of fans used in tunnel ventilation. The developed model was validated by comparing the field and simulated thermal environment values. Based on a reliable model, Land-Atmosphere Modeling Package (LAMP) weather forecast data was used to show the stress index on the internal rearing environment with a heat stress index suitable for South Korea. When the users input the farm location, structure and equipment, and rearing information, users responded after receiving heat stress from the broiler raised in a mechanically ventilated broiler house.
As the pig industry develops rapidly, various problems are appearing both inside and outside the pig houses. In particular, in the case of pig houses, it is difficult to solve the main problems even if automation and mechanization are applied with ICT technology. The main current issues are: (1) preventing infectious diseases amongst livestock, (2) reducing the emission of harmful gas and odors, (3) improving the growth environment inside the pig house, (4) reducing energy costs, (5) improving the farm management and operating system, and 6) improving the livestock product quality. Air recirculation technology can be applied as a technology that can solve these typical problems in the pig industry. An air-recirculated ventilation system can minimize the inflow of air from outdoors and recycle the internal thermal energy of the pig house. The air-recirculated ventilation system consists of (1) an air scrubber module, (2) external air-mixing module, (3) UV cleaning module, (4) solar heat module, and (5) air-distribution module. First, in this study, the field data were collected to analyze the main problems of the target piglet house for the application of the air-recirculated ventilation system. In addition, a computational fluid dynamics (CFD) model was developed and validated for seasonal aerodynamic analysis. The applicability of the air-recirculated ventilation system was evaluated based on the CFD computed results for various environmental conditions. As a result of evaluating the internal environment according to the ventilation rates and external-air-mixing ratio of the air-recirculated ventilation system, the required ventilation rate and external air-mixing ratio to maintain the proper temperature and gas concentration were determined.
Energy management of a building-integrated rooftop greenhouse (BiRTG) is considered one of the important factors. Accordingly, the interest in energy simulation models has increased. Energy load computed from the simulation model can be used for appropriate capacity calculation and optimal operation of the environmental control system. In particular, because the thermal environment of greenhouses is sensitive to the external weather environment, dynamic energy simulations, such as building energy simulation (BES), play an essential role in understanding the complex mechanisms of heat transfer in greenhouses. Depending on the type and crop density, there is a significant difference in the thermal energy loads of greenhouses. Furthermore, ventilation is also an important factor affecting the energy input of the greenhouse. Therefore, this study aimed to design and validate BES models considering the crop and ventilation characteristics of a naturally ventilated greenhouse before designing and evaluating a BES model for the BiRTG. First, the BES module for the greenhouse and crop models was designed using field-measured data, and the ventilation characteristics were analysed using computational fluid dynamics (CFD). The greenhouse BES model was designed and then validated by comparing air temperature (Ta) and relative humidity (RH) measured at the greenhouse with the BES-computed results of the greenhouse model. The results showed that the average absolute error of Ta was 1.57 °C and RH was 7.7%. The R2 of the designed BES model for Ta and RH were 0.96 and 0.89, respectively. These procedures and sub-modules developed were applied to the energy load calculation of BiRTG.
In this study, the internal environment such as the air temperature, humidity, and wall temperature of the underground utility tunnel, was analyzed. The current status and problems of the air conditioning system were examined by analyzing the capacity of the exhaust fan and the air velocity inside the utility tunnel. The field experiment showed that the utility tunnel has a relative humidity of 95% or higher for most sections during summer. The deviation of the internal air temperature was about 4 ℃ depending on the section, and the dew condensation occurred. However, most of the exhaust fans has a capacity below the standard minimum air velocity of 2.5m•s -1 . In particular, in the section where dew condensation occurred, the air velocity was 0.26 to 0.97 m•s -1 , indicating the presence of stagnant air inside the facility. Therefore, this study attempted to minimize dew condensation by calculating the proper exhaust fan capacity using computational fluid dynamics and installing circulation fans and duct systems in the section where the dew condensation occurred. As a result, when a circulation fan was installed, it was possible to increase the air velocity inside the utility tunnel, and the relative humidity could be reduced by about 78%. By installing a duct, the direct supply of external air or the discharge of internal humid air was simulated for the section where dew condensation occurred. The result showed that the relative humidity could be reduced by about 78% when the duct system was operated in the intake direction. INDEX TERMSCondensation, CFD, Circulation fan, Duct, Ventilation, Underground utility tunnel I. INTRODUCTION A. THE CONCEPT AND CURRENT STATUS OF THE UNDERGROUND UTILITY TUNNELAn underground utility tunnel is a structure that accommodates and supplies two or more types of urban lifelines such as pipelines for electricity, gas, water supply, telecommunication, and sewage. In addition, it is a facility installed underground to improve the aesthetics, preservation of road structures, and smooth flow of traffic, especially in urban areas [1]. If a single pipeline for each electricity, gas, and water is constructed in underground, the increased cost due to construction work and the formation of a complex underground structure network can cause problems in the This article has been accepted for publication in IEEE Access.
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