In commercial buildings, about 40%-50% of the total electricity consumption is attributed to Heating, Ventilation, and Air Conditioning (HVAC) systems, which places an economic burden on building ...operators. In this paper, we intend to minimize the energy cost of an HVAC system in a multi-zone commercial building with the consideration of random zone occupancy, thermal comfort, and indoor air quality comfort. Due to the existence of unknown thermal dynamics models, parameter uncertainties (e.g., outdoor temperature, electricity price, and number of occupants), spatially and temporally coupled constraints associated with indoor temperature and CO 2 concentration, a large discrete solution space, and a non-convex and non-separable objective function, it is very challenging to achieve the above aim. To this end, the above energy cost minimization problem is reformulated as a Markov game. Then, an HVAC control algorithm is proposed to solve the Markov game based on multi-agent deep reinforcement learning with attention mechanism. The proposed algorithm does not require any prior knowledge of uncertain parameters and can operate without knowing building thermal dynamics models. Simulation results based on real-world traces show the effectiveness, robustness and scalability of the proposed algorithm.
This study fabricated a low-cost activated carbon (AC) adsorbent from readily available bamboo trees to control indoor COsub.2 levels and reduce energy costs associated with sustaining clean indoor ...air. Bamboo is naturally high in potassium content and has narrow fibrous channels that could enhance selective COsub.2 adsorption. The prepared bamboo-based activated carbon (BAC) exhibits predominantly micropores with an average pore size of 0.17 nm and a specific surface area of 984 msup.2/g. Upon amination, amine functionalities, such as pyridine, pyrrole, and quaternary N, were formed on its surface, enhancing its COsub.2 adsorption capacity of 0.98 and 1.80 mmol/g for low-level (3000 ppm) and pure COsub.2 flows at the ambient condition, respectively. In addition, the 0.3% COsub.2/Nsub.2 selectivity (αsub.s,g) of the prepared sorbents revealed a superior affinity of COsub.2 by BAC (8.60) over coconut shell-based adsorbents (1.16–1.38). Furthermore, amination enhanced BAC’s COsub.2αsub.s,g to 13.4. These results exhibit this sustainable approach’s potential capabilities to ensure the control of indoor COsub.2 levels, thereby reducing the cost associated with mechanical ventilation systems. Further research should test the new sorbent’s adsorption properties (isotherm, kinetics, and thermodynamics) for real-life applicability.
The public interest in indoor air quality has rapidly increased in Korean society, and ventilation systems can play an essential role in improving indoor air quality. This study aims to estimate the ...reduction in indoor COsub.2 and radon, which can be effectively mitigated by air exchange, according to the operation of mechanical ventilation in an apartment with the national standard housing size (85 msup.2) and shape in Korea. The time required to meet Korea's mandatory indoor COsub.2 standard (1000 ppm) was 167, 98, 66, and 51 min under air change rates of 0.5, 1.0, 1.5, and 2.0 ACH (air change per hour), respectively. Regarding indoor radon, the removal rate increased with increased ventilation volume, and the minimum concentration level was low and sustained for a prolonged duration. Nonetheless, an air change rate of 0.5 ACH may not offer sufficient ventilation. Additionally, it is imperative to note that indoor radon concentrations tend to escalate swiftly when a mechanical ventilation system is deactivated. Thus, to enhance indoor air quality, it is necessary to reconsider strategies to augment the air change rate and guarantee uninterrupted ventilation.
Environment indoor quality (EIQ) is a significant aspect of the built environment to maintain occupant health, comfort, prosperity and productivity. One of the most critical issues on EIQ is the ...environment of indoor air quality (EIAQ). Indoor air pollution has a big impact on the degradation quality of human life due to harmful chemicals and other toxic materials that it is worsened by ten times than the outdoor air pollution. Environment indoor air quality index (EIAQI) does a crucial role in determining the EIAQ that is good for a healthy human life by combining indoor air quality index (IAQI) and thermal comfort index (TCI). This research presents an EIAQ monitoring and controlling system based on fuzzy logic controller (FLC) to identify, classify and calculate the EIAQI value expressed in four categories: excellent, good, bad and worst. Additionally, the clustering technique is used to categorize the air pollutants according to the similarities characteristics and human health impact. EIAQI values are used as index references to set the control system automatically. The control system is used as a system that can notify the status level and reduce indoor air and thermal comfort pollutants and is in the form of fans, inlet–outlet exhaust, and buzzer and LED. Therefore, these models are an appropriate tool for identifying, classifying, assessing, providing guidance to increase the quality of human life.
This paper investigates the impact of children's recess activity patterns on particulate matter (PM) resuspension in indoor environments, highlighting the complex, multi-dimensional nature of these ...activities and their interaction with environmental parameters. Despite the recognized role of indoor human activity in PM resuspension, research specifically addressing the effects of children's movements has been sparse. Through experimental scenarios that account for the characteristics of student activities, such as movement speed, trajectory, the number of participants, aisle widths, and varying humidity levels, this study uncovers significant differences in PM resuspension rates. It reveals that not only do movement speed and trajectory have a profound impact, but also the interaction between humidity and these factors plays a critical role, especially under lower humidity conditions. Additionally, the study demonstrates how the combination of people density and spatial configurations can significantly influence resuspension rates. The findings offer valuable insights for designing strategies to mitigate particle pollution in classrooms and similar indoor environments.
Display omitted
•The interaction between RH and activity characteristics plays a critical role.•Maintaining appropriate RH levels is beneficial in mitigating adverse health impacts.•The number of individuals significantly affects the resuspension rate of large particles.•Crowded environments lead to elevated particle resuspension rates.
PDF
