A Local Dynamic Similarity Model, applicable to dynamic similarity of cross-ventilation, has been applied to outflow openings. Cross-ventilation performance at the openings on the outflow side has been evaluated, and the structure of air flows around the outflow openings has been studied by LES and wind tunnel experiments. It was found that LES reproduces the wind tunnel experiment results fairly well, such as the extensive increase of discharge coefficient in a small region where dimensionless room pressure, PR*, is low.
We have sought to accurately quantify automobile HVAC air flow rates in four passenger vehicles,under a range of different ventilation settings and speeds. We used Sulphur Hexafluoride (SF6) as atracer gas, coupled with a portable doser/sampler system to quantify flow rates and leakage.Results of this work indicate a linear increase in HVAC air flow rate with increasing vehicle speed forall vehicles. Older vehicles were much less airtight than newer vehicles, a likely reflection on improveddesign and reduced door seal deterioration observed in the newer vehicles.
This paper reports on a field investigation of the effect of screening on the induced flow rate in solar chimneys. The solar chimney considered here was a roof solar collector (RSC). It is composed of CPAC monier concrete tiles, an air gap and gypsum board. Two RSC units were integrated into the south-facing roof of a centre single room house of 25 m3 volume. Different types of screening were considered, namely: mosquito net, square net, metal grille and nylon filter.
The author describes how to improve the usual formula to calculate air flow rate through an opened hopper window.Improvements consist in better taking into account the geometry of such windows when estimating their opened area and also in adapting to this type of windows the model used to take into account the influence of wind and of thermal draught.Improved model gives a good comparison with on site measured data from the literature.
The simulation of airflow pattern in an office building in Singapore is based on the environmental conditions and the corresponding ventilation parmeters measured on a typical day. The findings of that study are reported in this paper.
The purpose of the present study was to evaluate the possibility to reproduce heat and air flowcharacteristics in a machine room where high heat generating systems and devices are installed. For this purpose, in an experiment room was air-conditioned by double floor air supply on the assumption that the machine room, data were selected such as air flow rate of the systems and various boundary conditions were elected. Further, double floor supply air flow rate distribution, and heat and air flow distribution in the room were measured.
This research proposes a method for task area wide-cover personal air conditioning thatprevents a human body in the task area from being exposed to a largely irregular thermal environment. A Particle Image Velocimeter (PIV) was used in the research to measure air flow fields for conventional spot cooling and wide-cover personal air-conditioning(PAC) around the human body. The wide-cover type PAC formed a calm air flow field of less than 0.18m/s around the human body, while the spot cooling type PAC formed an air current of 0.3-0.6m/s around the area of the neck.
The present paper evaluates indoor thermal environment, cooling efficiency and energy consumption between a floor-based system and a ceiling-based system using a mock-up model in cooling period. The experimental chamber has a UFAC, underfloor air conditioning system and a ceiling-based system. And the experiments are set with practical internal load conditions including occupants, lighting units, and heat sources (office automation equipment). The following were compared and evaluated;
1) the vertical and horizontal temperature distribution,
A ventilated cavity wall is often proposed in the building envelope design as an alternative to thetraditional wall, mostly due to its ability in reducing the thermal load during the hot season. In order to be recommended as a solution for improving the thermal comfort, a thorough analysis of its performance under all possible scenarios is required. For assessing the thermal performance of the cavity wall, an experimental model has been built and tested at the DECivil of IST.
The paper presents a method of designing thermal comfort conditions in a room with an UnderFloor Air Distribution system (UFAD). A two-phase algorithm is based on: a steady or unsteady heat and mass transfer theory in the first step of computation and thermal comfort calculation in the second step. This method is implemented as the computer program UFAD_NET.