scholarly journals EVALUATION OF THERMAL LOAD REDUCTION AND EFFECT TO INDOOR ENVIRONMENT BY HYBRID VENTILATION SYSTEM

2011 ◽  
Vol 76 (660) ◽  
pp. 159-168
Author(s):  
Katsuhiro MIURA ◽  
Yuich TAKEMASA ◽  
Harunori YOSHIDA
Author(s):  
Seyed Ali Keshavarz ◽  
Mazyar Salmanzadeh ◽  
Goodarz Ahmadi

Recently, attention has been given to indoor air quality due to its serious health concerns. Clearly the dispersion of pollutant is directly affected by the airflow patterns. The airflow in indoor environment is the results of a combination of several factors. In the present study, the effects of thermal plume and respiration on the indoor air quality in a ventilated cubicle were investigated using an unsteady computational modeling approach. The person-to-person contaminant transports in a ventilated room with mixing and displacement ventilation systems were studied. The effects of rotational motion of the heated manikins were also analyzed. Simulation results showed that in the cases which rotational motion was included, the human thermal plume and associated particle transport were significantly distorted. The distortion was more noticeable for the displacement ventilation system. Also it was found that the displacement ventilation system lowered the risk of person-to-person transmission in an office space in comparison with the mixing ventilation system. On the other hand the mixing system was shown to be more effective compared to the displacement ventilation in removing the particles and pollutant that entered the room through the inlet air diffuser.


2009 ◽  
Vol 74 (646) ◽  
pp. 1355-1362 ◽  
Author(s):  
Koki KIKUTA ◽  
Masahiro HATANAKA ◽  
Hirofumi HAYAMA ◽  
Masamichi ENAI

Author(s):  
Martin Kovac ◽  
Katarina Kovacova ◽  
Anna Sedlakova

The object of paper is analysis of natural ventilation system in central greenhouse of Botanical garden in Kosice. The greenhouse was refurbished in 2015. The existing greenhouse covering from glass panels was replaced for polycarbonate panels. The ventilation system of central greenhouse is natural and there are used openings in covering (wall, roof). It is combination of thermally and wind driven ventilation. The main aim of contribution is to analyse different modes of natural ventilation during summer period mainly. The important factors that influence efficiency of natural ventilation in greenhouse are location and area of openings, temperature stratification in greenhouse, solar radiation level, wind speed and direction too. If the greenhouse is ventilated naturally only through external windows (roof windows are closed) the efficiency of ventilation is very poor. The defined modes of natural ventilation search the right location and size of opened windows in order to achieve the most efficiency ventilation of indoor environment. For this purpose the progressive dynamic simulation tool DesignBuilder is used where the geometrical and specific calculated model of whole central greenhouse was created.


2019 ◽  
Vol 111 ◽  
pp. 04006
Author(s):  
Henrik N. Knudsen

The purpose of this study was to evaluate house owners’ experience and satisfaction with the first Danish detached low-energy single-family houses, built according to energy class 2015 before these supplementary requirements became standard for all new dwellings. A questionnaire survey was carried out among owners of newly built energy class 2015 houses. The paper presents the house owners answers to questions on their overall satisfaction, their heat consumption, and their satisfaction with the indoor environment (temperature, draught, air quality, noise and daylight). There is a focus on issues related to having a mechanical ventilation system, i.e. satisfaction with the air quality, does the air feel dry in winter, and does the ventilation system make noise and how the airing behaviour is in winter. As many as 370 out of 869 house owners, corresponding to a response rate of 43%, answered the questionnaire. There was an overall satisfaction with the new low-energy houses. More than 90% of the house owners perceived the indoor environment as satisfactory. The energy consumption was as low as expected by 59%, while only 7% answered that it was higher than expected. Compared with previous similar studies, problems with technical installations have decreased. However, there is a need for continued focus on the commissioning of new and not necessarily thoroughly tested, high-performance installations and new designs. Based on the survey a series of recommendations are given that might help to achieve both a low energy consumption and satisfied occupants of new low-energy dwellings.


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