Submitted by Maria.Kapsalaki on Mon, 10/28/2013 - 12:29
As compared to mixing ventilation systems, the personalized ventilation system (PV) can help to create a healthy and comfortable working environment with a simultaneous reduction of energy consumption. This latter aspect should be of particular significance for employers and investors who bear responsibility for office space conditions. The parameter which is of paramount interest for this group of people is productivity as it translates into a company’s revenue.
Personalized Ventilation (PV) has been shown to improve inhaled air quality recently. However, it maylead to dissatisfaction such as draft due to personalized air applied locally to the facial region, orstuffiness due to inadequate air supply. This study aims to identify some reasons for the dissatisfactionamong tropically acclimatized people through a systematically experimental design.In this study 24 subjects were subjected to a series of random facial exposure to local air movementeach of 15 minutes duration in a well-controlled indoor air quality chamber.
This paper reports the function and the performance of chair mounted isothermal airflowgenerator system. There were four air outlets on the movable armrests and the air velocity at the body surface of an occupant was adjustable with fan speed controller. The air intakes were installed on the seat and the backrest of the chair. The experiment was carried out with 16 adult persons as the subject and the TSV and CSV were investigated under three different ambient conditions (26, 28, and 30C, 50%RH).
In this paper micro-environment around human body with a personalized ventilation system ina displacement ventilated room was simulated by the standard k-e model. The geometry of thecomputational thermal manikin (CTM) is a real representation of a human body. Detailed analyses of air flow at the facial region and inhaled air quality improvement with personalized ventilation system were carried out with the aid of this complicated CTM.
Thirty human subjects participated in experiments with five different air terminal devices forpersonalized ventilation operating at two levels of room air temperature within the range prescribed instandards for thermal comfort, namely 23C and 26C. The subjects actively used the possibility to change the airflow rate and to adjust the positioning of the air terminal devices in regard to the airflow direction. The individual control provided allowed subjects to maintain thermal neutrality with the systems studied, except one, named Headset at the higher room temperature of 26C.
A personalized ventilation system combined with a seat is introduced in this paper. This kind ofventilation seat is able to provide occupants with improved air quality, individual control and energysavings. A thermal manikin with an artificial lung was used to investigate several fundamental issues on this novel ventilation system. We tested the performances of the eight different air supply nozzles within the flow rate range from 0.1 l/s to 3.0 l/s. The highest pollutant reduction of inhaled air about 80% is achieved by one nozzle named SCN at the flow rate of 3.0 l/s.
The performance of two personalized ventilation systems combined with mixing or displacement ventilation was studied under different conditions in regard to thermal comfort of seated occupants. The cooling performance of personalized ventilation was found to be independent of room air distribution. Differences between the personalized air terminal devices were identified in terms of
the cooling distribution over the manikins body. The personalized ventilation supplying air from the
A distribution of contaminants from floor covering, exhaled air and human bioeffluents was examined in a mock-up of a typical two-person office by means of tracer-gases. The distribution was studied with two types of air terminal device for personalized ventilation combined with displacement ventilation. The results show that the type of personalized ventilation and its use affects the distribution of contaminants to a great extent, as does the type and location of contaminant sources.
Air exhaled by occupants may carry infectious agents and be one way of transmitting respiratory diseases in rooms. The exposure of occupants to exhaled air was examined at two different throw heights of underfloor ventilation combined with two types of personalized ventilation by means of full-scale experiments. The concentration of exhaled air from one occupant was measured in air inhaled by another occupant who used or did not use personalized ventilation.
For the application of personalized (PV) in practice, it is important to recognize its performance under realistic conditions as they apply in rooms. In this paper results of both CFD simulations and laboratory measurements are reported regarding the local ventilation effectiveness with personalized ventilation. It was observed that the personalized air influences only a limited microenvironment at the workstation. Then a new model was proposed to evalate the indoor air quality in the entire space with varied distributions of occupants.