scholarly journals Operation Testing of an Advanced Personalized Ventilation System

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1596 ◽  
Author(s):  
Csáky ◽  
Kalmár ◽  
Kalmár

Using personalized ventilation systems in office buildings, important energy saving might be obtained, which may improve the indoor air quality and thermal comfort sensation of occupants at the same time. In this paper, the operation testing results of an advanced personalized ventilation system are presented. Eleven different air terminal devices were analyzed. Based on the obtained air velocities and turbulence intensities, one was chosen to perform thermal comfort experiments with subjects. It was shown that, in the case of elevated indoor temperatures, the thermal comfort sensation can be improved considerably. A series of measurements were carried out in order to determine the background noise level and the noise generated by the personalized ventilation system. It was shown that further developments of the air distribution system are needed.

2020 ◽  
pp. 65-74
Author(s):  
Eusébio Conceição ◽  
Mª Inês Conceição ◽  
Mª Manuela Lúcio ◽  
João Gomes ◽  
Hazim Awbi

In this study the numerical simulation of a Heating, Ventilating and Air Conditioning (HVAC) system, based in a personalized ventilation system, installed in an occupied office desk is made. The energy is produced in a Dual Skin Facades (DSF) system installed in the outdoor environment. The personalized ventilation system, placed above and below the writing area, installed in the desk central area. The office desk is occupied by eight virtual manikins. The numerical simulation is made in a winter typical day. This numerical study considers a coupling of a differential numerical model and an integral numerical model. The differential numerical model simulates the Computational Fluids Dynamics (CFD), evaluates the air velocity, air temperature, turbulence intensity and carbon dioxide concentration and calculates the indoor air quality. The integral numerical model simulates the Multi-Node Human Thermo-physiology Model, evaluates the tissue, blood and clothing temperatures distribution and calculates the thermal comfort level. The HVAC system, based on a DSF system, is built using three DSF unities, is equipped with internal venetian blinds. Each one, installed in a virtual chamber, is turned to south. The personalized ventilation system, made with eight upper and eight lower air terminal devices, is installed in the desk central area. On each table top two upper and two lower air terminal devices are considered in the left and right manikin area, while on each side of the table two upper and two lower air terminal devices are placed between the manikins. The office desk is occupied by eight virtual manikins, one sitting on each table top and three sitting on each side of the meeting table. In this numerical study, carried out in winter conditions, the occupants’ clothing level is 1 clo. In these situations a typical activity level of 1.2 met is considered. The evolution of indoor environmental conditions, in the DSF and in the office room, are calculated during a full winter typical day. The thermal comfort, the indoor air quality, the effectiveness for heat removal, the effectiveness for contaminant removal and the Air Distribution Index (ADI), are evaluated. In accordance with the obtained results the thermal comfort levels increase when the air renovation rate increases and the indoor air quality level increases when the air renovation rate increases. However, the ADI is quite constant when the inlet airflow rate increases, because the thermal comfort number decreases when the inlet airflow rate increases and the air quality number increases when the inlet airflow rate increases.


2017 ◽  
Vol 38 (5) ◽  
pp. 505-521 ◽  
Author(s):  
Ferenc Kalmár

In a closed space, appropriate thermal comfort and proper indoor air quality are extremely important in order to obtain the optimal work performance and to avoid health problems of the occupants. Using advanced personalized ventilation systems, different comfort needs can be locally satisfied even in case of warm environments. Thermal sensation and the subjective evaluation of indoor air quality of young and elderly people, men and women respectively, were studied in warm environment using advanced personalized ventilation system combined with total volume ventilation system. Using an advanced personalized ventilation system, 20 m3 h−1 air flow was alternately introduced by three air terminal devices built-in the desk and placed on a horizontal plane at the head level of the sitting subject. Thermal sensation was significantly cooler in case of young women in comparison with the other groups. Odor intensity was evaluated to be significantly lower in case of elderly women in comparison with the other groups. Evaluation of air freshness is in correlation with the general thermal sensation. Variation of the direction of the air velocity vector has a cooling side-effect, which, in warm environments, might be useful in order to improve the thermal comfort sensation. Practical application: From the basic factors that influence the thermal comfort sensation, air velocity is the one and only parameter that must be treated as a vector. The air flow velocity has an important effect on the convective heat quantity released by the human body, but the changes in the air velocity direction have a cooling side-effect. This cooling side-effect should be exploited properly in warm environments by advanced personalized ventilation systems to improve the thermal comfort sensation of the occupants without supplementary energy use.


2021 ◽  
Vol 16 (3) ◽  
pp. 774-793
Author(s):  
Nur Baitul Izati Rasli ◽  
Nor Azam Ramli ◽  
Mohd Rodzi Ismail

This study observed the influence of different ventilation, indoor and outdoor activities (i.e., cooking, praying, sweeping, gathering, and exhaust from motorcycle) between a bungalow house (i.e., stack and cross ventilation applications) and a terrace house (i.e., one-sided ventilation application). We appraised the indoor air quality (IAQ) and thermal comfort. We monitored the indoor air contaminants (i.e., TVOC, CO, CH2O, PM10, O3, and CO2) and specific physical parameters (i.e., T, RH, and AS) for four days in the morning (i.e., 6.00 a.m. – 9.00 a.m.), morning-evening (i.e., 11.00 a.m. – 2.00 p.m.), and evening-night (i.e., 5.00 p.m. – 8.00 p.m.) sessions. The results found that cooking activities are the major activities that contributed to the increase of the TVOC, CO, PM10, O3, and CO2 concentrations in the bungalow and terrace houses. However, IAQ exceeded the Industry Code of Practice on IAQ (ICOP) limit in the terrace house. The bungalow house applies stack and cross ventilation, double area, and a long pathway of indoor air contaminants movements. Besides that, the results indicated that cooking activities worsen the ventilation system because CO2 exceeded the ICOP limit on Day 2 at 74.1 % (evening-night session) and Day 3 at 13.2 % (morning session), 11% (morning-evening session), and 50.1 % (evening-night session). Moreover, the combination of mechanical (i.e., opened all fans) and natural ventilation (i.e., opened all doors, windows, and fans) is the best application in the house without a cooking ventilator with lower indoor air movement. Furthermore, the temperatures exceeding the ICOP limit of 23-26 °C for both bungalow and terrace houses could be lower indoor air movement, which is less than the ICOP limit of 0.15-0.5 m/s and high outdoor air temperature. Therefore, it is prudent to have an efficient ventilation system for acceptable indoor air quality and thermal comfort in the family house.


Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 110
Author(s):  
Nivetha Vadamalraj ◽  
Kishor Zingre ◽  
Subathra Seshadhri ◽  
Pandarasamy Arjunan ◽  
Seshadhri Srinivasan

Maintaining both indoor air quality (IAQ) and thermal comfort in buildings along with optimized energy consumption is a challenging problem. This investigation presents a novel design for hybrid ventilation system enabled by predictive control and soft-sensors to achieve both IAQ and thermal comfort by combining predictive control with demand controlled ventilation (DCV). First, we show that the problem of maintaining IAQ, thermal comfort and optimal energy is a multi-objective optimization problem with competing objectives, and a predictive control approach is required to smartly control the system. This leads to many implementation challenges which are addressed by designing a hybrid ventilation scheme supported by predictive control and soft-sensors. The main idea of the hybrid ventilation system is to achieve thermal comfort by varying the ON/OFF times of the air conditioners to maintain the temperature within user-defined bands using a predictive control and IAQ is maintained using Healthbox 3.0, a DCV device. Furthermore, this study also designs soft-sensors by combining the Internet of Things (IoT)-based sensors with deep-learning tools. The hardware realization of the control and IoT prototype is also discussed. The proposed novel hybrid ventilation system and the soft-sensors are demonstrated in a real research laboratory, i.e., Center for Research in Automatic Control Engineering (C-RACE) located at Kalasalingam University, India. Our results show the perceived benefits of hybrid ventilation, predictive control, and soft-sensors.


2021 ◽  
Vol 203 ◽  
pp. 70-92
Author(s):  
Douaa K. Al Assaad ◽  
Mohamad S. Orabi ◽  
Nesreen K. Ghaddar ◽  
Kamel F. Ghali ◽  
Darine A. Salam ◽  
...  

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