Experimental evaluation of air distribution in mechanically ventilated residential rooms: Thermal comfort and ventilation effectiveness

2013 ◽  
Vol 60 ◽  
pp. 28-37 ◽  
Author(s):  
R. Tomasi ◽  
M. Krajčík ◽  
A. Simone ◽  
B.W. Olesen
Keyword(s):  
Thermal Comfort ◽  
Experimental Evaluation ◽  
Air Distribution ◽  
Mechanically Ventilated ◽  
Ventilation Effectiveness

scholarly journals Experimental Investigation of Ventilation Performance of Different Air Distribution Systems in an Office Environment—Heating Mode

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1835 ◽  
Author(s):  
Arman Ameen ◽  
Mathias Cehlin ◽  
Ulf Larsson ◽  
Taghi Karimipanah
Keyword(s):  
Thermal Comfort ◽  
Distribution Systems ◽  
Cold Climate ◽  
Air Distribution ◽  
Temperature Pattern ◽  
Office Environment ◽  
Ventilation Effectiveness ◽  
Local Thermal Comfort ◽  
Heating Mode ◽  
Occupied Zone

A vital requirement for all-air ventilation systems are their functionality to operate both in cooling and heating mode. This article experimentally investigates two newly designed air distribution systems, corner impinging jet (CIJV) and hybrid displacement ventilation (HDV) in comparison against a mixing type air distribution system. These three different systems are examined and compared to one another to evaluate their performance based on local thermal comfort and ventilation effectiveness when operating in heating mode. The evaluated test room is an office environment with two workstations. One of the office walls, which has three windows, faces a cold climate chamber. The results show that CIJV and HDV perform similar to a mixing ventilation in terms of ventilation effectiveness close to the workstations. As for local thermal comfort evaluation, the results show a small advantage for CIJV in the occupied zone. Comparing C2-CIJV to C2-CMV the average draught rate (DR) in the occupied zone is 0.3% for C2-CIJV and 5.3% for C2-CMV with the highest difference reaching as high as 10% at the height of 1.7 m. The results indicate that these systems can perform as well as mixing ventilation when used in offices that require moderate heating. The results also show that downdraught from the windows greatly impacts on the overall airflow and temperature pattern in the room.

scholarly journals Numerical Study on Coupled Operation of Stratified Air Distribution System and Natural Ventilation under Multi-Variable Factors in Large Space Buildings

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8130
Author(s):  
Ziwen Dong ◽  
Liting Zhang ◽  
Yongwen Yang ◽  
Qifen Li ◽  
Hao Huang
Keyword(s):  
Thermal Comfort ◽  
Working Conditions ◽  
Distribution System ◽  
Distribution Systems ◽  
Natural Ventilation ◽  
Numerical Study ◽  
Air Distribution ◽  
Large Space ◽  
Air Conditioners ◽  
Air Supply

Stratified air distribution systems are commonly used in large space buildings. The research on the airflow organization of stratified air conditioners is deficient in terms of the analysis of multivariable factors. Moreover, studies on the coupled operation of stratified air conditioners and natural ventilation are few. In this paper, taking a Shanghai Airport Terminal departure hall for the study, air distribution and thermal comfort of the cross-section at a height of 1.6 m are simulated and compared under different working conditions, and the effect of natural ventilation coupling operation is studied. The results show that the air distribution is the most uniform and the thermal comfort is the best (predicted mean vote is 0.428, predicted percentage of dissatisfaction is 15.2%) when the working conditions are 5.9% air supply speed, 11 °C cooling temperature difference and 0° air supply angle. With the coupled operation of natural ventilation, the thermal comfort can be improved from Grade II to Grade I.

scholarly journals CONSTRUCCIÓN DE UNA VIVIENDA SOLAR EN BASE A LAS PROPIEDADES TERMOFISICAS Y EVALUACIÓN EXPERIMENTAL DE SU CONFORT TÉRMICO EN ILAVE

2014 ◽  
Vol 16 (01) ◽  
Author(s):  
ARTURO FLORES CONDORI
Keyword(s):  
Relative Humidity ◽  
Solar Energy ◽  
Thermal Comfort ◽  
Thermophysical Properties ◽  
Experimental Evaluation ◽  
Meteorological Data ◽  
Thermal Inertia ◽  
Living Condition ◽  
Simulation Software ◽  
Experimental Structure

<h4 class="text-primary">Resumen</h4><p style="text-align: justify;">El presente artículo consistió en la construcción de una vivienda solar pasivo a base de propiedades termofísicas (Conductividad térmica, calor específico, difusividad térmica y inercia térmica) y desarrollar una evaluación experimental del rendimiento térmico aportado por los elementos constructivos, en una comunidad rural Colloco - Ilave, provisto de adecuado aislamiento térmico en la envolvente (doble pared de adobe, en el cielo raso: paja­carrizo-yeso y en el piso: tierra apisonada-cama de piedra-plástico-paja y totora), ubicación, la orientación y un sistema de acumulación de energía adecuadamente diseñada a base a encapsulado de piedras andesitas porosas y de totora. La distribución de energía calorífica almacenada fue primordial al ambiente dormitorio que esto permite el aprovechamiento de la energía solar para lograr que la temperatura al interior de la vivienda sea más confortable. Se realizó el análisis del comportamiento térmico de la vivienda construida y la vivienda rural típica, para lo cual se tomaron los datos meteorológicos de la zona (temperatura, humedad relativa, velocidad del viento y radiación solar), también se registraron la temperatura y humedad relativa del aire en el ambiente interior y exterior de las viviendas desde 19 de junio al 02 de julio del 2013. Obteniéndose en la vivienda construida las temperaturas máximas y mínimas de 15.85ºC y 11.88ºC respectivamente. Según la evaluación de la vivienda construida se aprecia un incremento de temperatura mínimo de 6.26°C, respecto a la vivienda típica. Para validar estos resultados experimentales, se ha utilizado el programa de simulación térmica EnergyPlus para los datos meteorológicos de la zona (3 868 msnm), comprobándose por el método correlativo, el factor de correlación fue r=0.92575. Este incremento de la temperatura en el interior de la vivienda construida contribuye alcanzar un confort térmico, permitiendo una condición de vida saludable para el poblador rural.</p><p><strong>PALABRAS CLAVE: </strong>* confort térmico * energía solar * propiedades termofísica * simulación térmica</p><h4 class="text-primary">ABSTRACT</h4><p><strong>CONSTRUCTION OF A SOLAR DWELLING BASED ON THERMOPHYSICAL PROPERTIES AND EXPERIMENTAL EVALUATION OF THERMAL COMFORT - ILAVE, PUNO - PERU»</strong></p><p style="text-align: justify;">The present article consists in the construction of a passive solar house based on the study of thermophysical properties (thermal conductivity, specific heat, thermal diffusivity and thermal inertia). We developed an experimental evaluation of the thermal efficiency contributed by different constructive materials, In the rural community of Colloco - Ilave. Once adequate thermal insulation was provided in the enveloping surface (double wall construction of sun-dried adobe brick, a false ceiling with: straw, bamboo and plaster. In the floor: tamped soil, stone bed, plastic, straw and totora reed). Location and position of the solar home in coordination with an energy accumulation system adequately designed with an encapsulation of porous Andesitic stones and Totora reed. Distribution of the stored thermal energy was directed primarily to the main bedroom, this enabled adequate use of solar energy in order to achieve a comfortable temperature within the dwelling. We analyzed the thermal behavior of both this experimental structure and that of a common rural dwelling; taking the interior and exterior meteorological readings found in the two dwelling types. (temperature, relative humidity, wind velocity and solar radiation). Between June 19th and July 2nd, the temperature and relative humidity of the interior of the experimental structure measured a max. of 15.85ºC (60.53ºF) and 11.88ºC (53.384ºF) respectively. According to a general evaluation of the experimental structure, there was a temperature increment of 6.26°C (=¿?ºF) compared to the average temperature of a normal dwelling. In order to confirm these experimental results we used the thermic simulation software EnergyPlus, entering the meteorological data of the area (3,868 meters above sea level=12690.3 ft.) using the correlative method and a correlative factor of r=0.92575. This higher temperature inside of the experimental structure contributes to attaining a thermic comfort allowing for a healthy living condition for the rural inhabitant.</p><p><strong>KEY WORDS: </strong>* thermal comfort * solar energy * thermophysical properties * thermal simulation</p>

Experimental Study of Air Distribution Characteristics in Room of Stratum Ventilation under Two Kinds of Air Change Times

2013 ◽  
Vol 409-410 ◽  
pp. 668-672
Author(s):  
Yong Mei Xu ◽  
Jian Tang ◽  
Jun Han ◽  
Chu Qin Lin
Keyword(s):  
Experimental Study ◽  
Thermal Comfort ◽  
Experimental Studies ◽  
Air Distribution ◽  
Distribution Characteristics ◽  
Breathing Zone ◽  
Wind Speeds ◽  
Pollutant Concentrations ◽  
New Type ◽  
Better Than

Aimed at a new type of ventilation - stratum ventilation, air distributions at a breathing-zone in a model office were measured under kinds of air changes, the measure parameters in the experimental studies included temperatures, wind speeds and pollutant concentrations, based on which the thermal comfort at a breathing-zone were studied. Experimental results show that, the temperature, pollutant concentration and wind speeds in a breathing-zone under 5 times air changes are better than those under 6 times air changes. The calculating results of PMV and PPD indicate that the thermal comfort at a breathing-zone under 5 times air changes is better. The experimental study is instructive for the development of the ventilation.

scholarly journals Operation Testing of an Advanced Personalized Ventilation System

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1596 ◽  
Author(s):  
Csáky ◽  
Kalmár ◽  
Kalmár
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Distribution System ◽  
Noise Level ◽  
Background Noise ◽  
Ventilation System ◽  
Air Distribution ◽  
Personalized Ventilation

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.

Fluid Flow and Heat Transfer Induced by a Window Air Conditioner Unit and Associated Thermal Comfort

2005 ◽  
Author(s):  
Hamza Begdouri ◽  
Luis Rosario ◽  
Muhammad M. Rahman
Keyword(s):  
Thermal Comfort ◽  
Comfort Level ◽  
Cfd Modeling ◽  
Air Distribution ◽  
Air Conditioner ◽  
Surface Areas ◽  
Air Supply ◽  
Office Rooms ◽  
Inlet Angle ◽  
The Impact

This study considers airflow simulations to evaluate the impact of different window air-conditioner locations on the thermal comfort in an office rooms (OR). This paper compares the air distribution for an office room by using computational fluid dynamics (CFD) modeling. The air distribution was modeled for a typical office room window air conditioning unit, air supply from a high pressure on the top and the low pressure exhaust on the bottom considering the existing manufacturing ratios for surface areas. Calculations were done for steady-state conditions including an occupant and a light source. The discharge angle for the supply grill of the AC unit was varied from 20 to 40 degrees. The position of the air conditioner was also varied and studied at 60%, 75% and 90% of the total height of the room. In addition the location of the occupant within the office room was varied. Predictions of the air movement, room temperature, room relative humidity, comfort level, and distribution of contaminants within the office room are shown. Analysis of these simulations is discussed. The positions of the air-conditioner unit, the inlet angle and the occupant position in the office room have shown to have important impacts on air quality and thermal comfort. Results are in good agreement with available experimental data.

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