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Analytical Modelling of HVAC-IoT Systems with the Aid of UVGI and Solar Energy Harvesting
Published in Deepti Agarwal, Kimmi Verma, Shabana Urooj, Energy Harvesting, 2023
Shafeeq Ahmad, Md. Toufique Alam, Mohammad Bilal, Osama Khan, Mohd Zaheen Khan
To maintain acceptable indoor air conditions and heat comfort, standard ventilation systems must be designed to amalgamate interior-contaminated air by bringing in clean air from the outdoors. In general, ventilation systems are classified into two types based on their working forces: natural ventilation and forced ventilation. The former is generally used as a backup because of difficulty in creating steady wind pressure. In order to fulfil indoor air quality standards, mechanical ventilation regulation is primarily used to improve the pollutant removal process. Suggested mechanical ventilation solutions may vary from standard air supply techniques, like before-hand amalgamation ventilation, displaced ventilation, subsurface air circulation, and individualised ventilation. The removal effectiveness of internal air contaminants relies on the ventilation or circulation pattern in the context of heat and ventilation.
Infection Control Through Environmental Design
Published in AnnaMarie Bliss, Dak Kopec, Architectural Factors for Infection and Disease Control, 2023
Udomiaye Emmanuel, Eze Desy Osondu, Cheche Kalu
Ventilation is the movement of air within a space, often shaped by variance in air pressure. Ventilation is very critical in mitigating nosocomial and other infectious diseases. Ventilation procedures are well defined in terms of air volume per minute per occupant and are based on the hypothesis that occupants and their actions are accountable for most of the contaminants in the conditioned space (Heb, 1997). Ventilation rates for health care facilities are often expressed as room ACH (air change per hour). Peak efficiency for particle removal in the air space occurs between 12–15 ACH (Nath et al., 1994; Hermans & Streifel, 1993; Memarzadeh & Jiang, 2000). Recent studies have shown that an appropriate ventilation rate can effectively decrease the cross-infection risk of airborne infections in health care facilities and public spaces (Zhao, Zuo, Wu, & Huang, 2019; Hua et al., 2010). Natural ventilation can provide a higher ventilation rate than power-driven ventilation in an energy-efficient manner. A study of isolation wards in Chinese hospitals revealed that those with a high percentage of openable openings were found to be better in preventing the plague of SARS among health workers than other available designs (Wang et al., 2003). The ventilation rate requirement – ACH – by the CDC is 12 ACH (Ninomura & Bartley, 2001); the implication is that when the ventilation rate increases, the infection risk would be significantly reduced.
Ventilation performance prediction
Published in Jan L.M. Hensen, Roberto Lamberts, Building Performance Simulation for Design and Operation, 2019
Natural ventilation is the oldest form of ventilation, and it has been used as long as buildings have been constructed. At present, natural ventilation is an interesting alternative to mechanical ventilation even in commercial buildings, due to its potential to reduce building energy consumption and to increase environmental quality such as thermal comfort, ventilation effectiveness, and indoor air quality (CIBSE 2005; Allard 1998). The potential benefits of natural ventilation are not always easy to take advantage of due to dependence on weather conditions and surrounding environment. The local weather conditions, including wind velocity, air temperature, and humidity, have to be suitable for natural ventilation. In addition, in urban environments, local air and noise pollution can dramatically reduce potential for natural ventilation, even if the local weather conditions are favorable. Other considerations in design of natural ventilation have to include fire and safety regulations as well as security issues (Allard 1998). Furthermore, Chapter 20 covers urban-level performance predictions that can be directly used in design considerations of natural ventilation.
Performance analysis of transparent BIPV/T double skin façades integrated with the decision-making algorithm for mixed-mode building ventilation
Published in Architectural Engineering and Design Management, 2023
Prapavee Karunyasopon, Dong Yoon Park, Duc Minh Le, Seongju Chang
Mixed-mode ventilation or hybrid ventilation in buildings utilizes a combination of natural ventilation and a mechanical system (HVAC). In automatic control systems, sensors, and window actuators, along with control algorithms, respond to outdoor and indoor space conditions in real-time. Natural ventilation provides passive cooling or passive heating by introducing fresh air to the cavity or an indoor space. However, there are weather constraints and environmental conditions that must be factored in when applying natural ventilation mode (Chen et al., 2018). Mechanical systems can be shifted to operate when natural ventilation mode is not sufficient or suitable. With its reduction of mechanical fan use, mixed-mode ventilation can create sustainable buildings, diminish energy demand, and save energy costs, while maintaining thermal comfort for occupants (Berkeley, 2018). Even though natural ventilation is a preferable operation mode, not all periods and climates are advantageous for this ventilation strategy. Therefore, the optimum control achieved by the mixed-mode ventilation strategy is needed to maintain an adequate level of indoor air quality and avoid building tendencies to overheat (CIBSE, 2005).
A framework for rapid diagnosis of natural ventilation effect during early design stage using Thermal Autonomy
Published in International Journal of Green Energy, 2023
Liwei Wen, Kyosuke Hiyama, Yu Huang, Xueting Qin
For an evaluation index to be useful, it is important to support appropriate design decision-making on key design elements. Determining envelope insulation conditions is major design task for passive design during the early design stage. The building form significantly affects the driving force of natural ventilation. Furthermore, the operating conditions must also be discussed in the initial design stage to balance the energy-saving effect and thermal comfort. Therefore, this study firstly evaluates the influence of envelope insulation conditions on natural ventilation performance by adopting the proposed metric of Thermal Autonomy. The applicability of Thermal Autonomy in estimating the effect of building form is also examined. Finally, the influence of the operation conditions on natural ventilation performance is evaluated based on the Thermal Autonomy metric.
Evaluation of building arrangement on natural ventilation potential in ideal building arrays
Published in Journal of Asian Architecture and Building Engineering, 2023
Zhong Yawen, Yin Wei, Li Yonghan, Hao Xiaoli, Zhang Shaobo, Han Qiaoyun, Duan Shuangping
For a single building, there are various factors affecting natural ventilation, such as outdoor wind direction and wind speed, building opening area and position, outer surface protrusion, and roughness. Derakhshan and Shaker (2017) explored the effect of the opening aspect ratio on indoor ventilation and observed that when the outdoor wind direction was greater than 45°, the ventilation volume was unrelated to the window size. Mattsson (2004) studied the influence of terrain, surrounding environment, and wind speed on the ventilation rate. For high-rise buildings, Liu et al. (2019) observed that the ventilation is extremely sensitive to the changes in wind conditions, followed by the difference in ventilation mode, window type, and window orientation. Chand, Bhargava, and Krishak (1998) observed that balconies changed the wind-pressure distribution on the windward wall. Lee et al. (2015) observed that the change in the shape of the outer louver had a significant impact on the natural ventilation rate. Ok, Yasa, and Özgunler (2008) suggested that openings located on perpendicular surfaces increase the airflow velocity within courtyards. Kindangen, Krauss, and Depecker (1997) studied the effect of roof shape on indoor ventilation and observed that enhancing negative pressure can promote indoor air circulation. The design of a single building mainly affects indoor ventilation and has less impact on the outdoor wind environment. The outdoor wind environment is mainly affected by local meteorological data and building arrangements.