scholarly journals Analysis of Thermal Comfort in an Office Space Using Two Typical Ventilation Modes.

2018 ◽  
Vol 3 (8) ◽  
pp. 35
Author(s):  
Chinedum Vincent Okafor ◽  
Kevin Chuks Okolie ◽  
Peter Ogunoh ◽  
Udeagwu Hyginus Oguike
Keyword(s):  
Air Conditioning ◽  
Ventilation System ◽  
Office Building ◽  
Vertical Temperature Gradient ◽  
Displacement Ventilation ◽  
Vertical Temperature ◽  
System A ◽  
Office Space ◽  
Ceiling Height ◽  
Ventilation Modes

This study carried out a comparative study to evaluate the air-conditioning performance of an office space under two typical ventilation modes (displacement and mixing ventilation system). A wall supply diffuser is located at the ceiling height for the mixing ventilation case, whereas, the supply diffuser is at the floor level for the displacement ventilation case. In both cases, the exhaust grill is located at the ceiling. From the result of the simulation, the researchers observed that the displacement ventilation system could have a higher risk of discomfort relating to vertical temperature gradient than when compared to the mixing ventilation case. More so, the simulation result indicates that the temperature distribution in an office building is a function of the type of ventilation system adopted and marginally affected by the diffuser arrangement.

scholarly journals Evaluation of Thermal Behavior of the Skeleton in a Green Building with the Aid of TABS

2019 ◽  
Vol 111 ◽  
pp. 01085
Author(s):  
Hiroshi Muramatsu ◽  
Tatsuo Nobe
Keyword(s):  
Heat Flux ◽  
Thermal Behavior ◽  
Air Conditioning ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Concrete Slab ◽  
Ventilation System ◽  
Office Building ◽  
Air Conditioning System ◽  
Indoor Thermal Environment

In this study, an office building in Japan that incorporates energy-saving features and environmental technologies was investigated. This office building features a green façade, natural ventilation, a concrete slab with no suspended ceilings, and thermo-active building systems. Two airconditioning systems were installed in this building—a ceiling radiation air-conditioning system and a whole floor-blow off air conditioning system. In addition, a natural ventilation system was installed. We surveyed the heat flux of the ceiling surface and indoor thermal environment of this building from 2015 through 2016. The ceiling using the heat storage amount of concrete maintains a constant temperature in the workplace during as well as after office hours. We also performed detailed measurements of the heat flux of the ceiling surface and indoor thermal environment in the summer of 2017. The results showed that the ceiling radiation air-conditioning system provided a stable thermal environment. Furthermore, we report that making use of the thermal behavior of the skeleton improved the operation of the ceiling radiation airconditioning system.

An Experimental Research on Wall Radiant Cooling and Wall-Attached-Jet Air-Conditioning System

2014 ◽  
Vol 501-504 ◽  
pp. 2244-2251 ◽  
Author(s):  
Xiang Lei Kong ◽  
Xin Li Zi ◽  
Long Yun ◽  
Xiao Song Zhang
Keyword(s):  
Indoor Air ◽  
Air Conditioning ◽  
Stable Operation ◽  
Displacement Ventilation ◽  
Vertical Temperature ◽  
Vertical Temperature Profile ◽  
Air Conditioning System ◽  
Radiant Cooling ◽  
Operation Period ◽  
The Subject

Taking the radiant cooling combined with wall-attached-jet air-conditioning system as the subject in a laboratory of Jiangsu university, an experimental study was carried out on pre-dehumidifying period, stable operation period and system shutdown period, along with analysis. The objective is to analyze the pre-dehumidification of the system, indoor air temperature and humidification change, vertical temperature profile and condensation sensitivity. The results show that the hybrid air-conditioning can provide high thermal comfort and avoid condensation effectively, which shows the better performance compared to the system of radiant cooling combined with displacement ventilation to some extent.

CFD Investigation for Indoor Environment of a District Standard Room in Jinan City

2014 ◽  
Vol 548-549 ◽  
pp. 1706-1711
Author(s):  
Dong Yang ◽  
Qing Mei Wen ◽  
Cong Ju Zhang ◽  
Xue Ting Liu ◽  
Shi Jun Wei
Keyword(s):  
Composite System ◽  
Ventilation System ◽  
Simulation Method ◽  
Displacement Ventilation ◽  
Air Velocity ◽  
Vertical Temperature ◽  
Airflow Velocity ◽  
Indoor Airflow ◽  
Radiant Cooling ◽  
Air Speed

This paper introduces the principle and characteristics of roof radiant cooling and displacement ventilation system, using numerical simulation method, the indoor airflow velocity and temperature field of the typical bedroom which uses the composite system in Ji'nan City under the different supply air velocity was calculated. The experimental results show that when the air temperature is 295.15K, to keep the indoor vertical temperature less than 3 °C, air speed should be greater than 0.1m/s and less than or equal to 0.3m/s, to provide reference for the application of roof radiant cooling and displacement ventilation system.

scholarly journals Analysis of the influence of the return position in the vertical temperature gradient in displacement ventilation systems for large halls

2017 ◽  
Vol 140 ◽  
pp. 371-379 ◽  
Author(s):  
Tomas Gil-Lopez ◽  
Miguel A. Galvez-Huerta ◽  
Paul G. O’Donohoe ◽  
Juan Castejon-Navas ◽  
Pedro M. Dieguez-Elizondo
Keyword(s):  
Temperature Gradient ◽  
Vertical Temperature Gradient ◽  
Displacement Ventilation ◽  
Vertical Temperature ◽  
Ventilation Systems

Персонализированная приточная система вентиляции в помещении офисного здания

2019 ◽  
pp. 60-64
Author(s):  
A. Rymarov ◽  
V. Agafonova
Keyword(s):  
Air Flow ◽  
Ventilation System ◽  
Design Feature ◽  
Office Building ◽  
New Materials ◽  
Forced Ventilation ◽  
Office Space ◽  
Small Height ◽  
Urgent Task ◽  
The Individual

Улучшение качества воздуха в рабочей зоне офисных помещений является актуальной задачей. Конструктивная особенность таких помещений заключается в небольшой высоте (порядка 3 м), что затрудняет подачу необходимого объема приточного воздуха, не создавая сквозняков в рабочей зоне. Отмечено, что решение данного вопроса связано с использованием на практике новых материалов и технологий. К их числу относятся текстильные воздуховоды из 100процентного полиэстера с вплетением карбонового волокна. Данный материал обладает прочностью, износостойкостью, минимальным уносом частиц с поверхности. В отличие от стальных оцинкованных воздуховодов в текстильном воздуховоде можно вырезать лазером точные отверстия с оплавленными краями необходимого шага и диаметра. Представлена схема организации персонализированной приточной вентиляции в офисном помещении на основе разработанного воздухораспределительного устройства с микроперфорированным текстильным вкладышем. Данное устройство позволяет регулировать расход воздуха в зависимости от индивидуальной потребности человека вплоть до отключения системы при отсутствии работника. Снижение расхода приточного воздуха способствует повышению энергоэффективности системы вентиляции.Improving the air quality in the working area of the office space is an urgent task. The design feature of such rooms is a small height (about 3 m) that complicates supplying the required volume of induced air without creating drafts in the working area. It is noted that the solution to this issue is associated with the use of new materials and technologies in practice. These include textile ducts made of 100 polyester with carbonic fiber weave. This material possesses strength, wearresistance, minimal ablation of particles from the surface. Unlike steel zinccoated airducts, it is possible to cut with laser precision holes with fused edges of the required pitch and diameter in the textile ducts. A layout of arranging personalized forced ventilation in an office building based on a designed air terminal device with a microperforated textile insert is presented. This device provides for adjusting the air flow depending on the individual needs of the person up to shutting down the system in the absence of an employee. Reducing induced air flow contributes to the energy efficiency of the ventilation system.

scholarly journals Influence of installation of displacement ventilation diffusers above occupied zone on the vertical temperature gradient in simulated office rooms

2019 ◽  
Vol 111 ◽  
pp. 02012
Author(s):  
Panu Mustakallio ◽  
Risto Kosonen ◽  
Mika Ruponen ◽  
Natalia Lastovets
Keyword(s):  
Temperature Gradient ◽  
Internal Heat ◽  
Full Scale ◽  
Vertical Temperature Gradient ◽  
Full Scale Test ◽  
Displacement Ventilation ◽  
Vertical Temperature ◽  
Scale Test ◽  
Office Rooms ◽  
Occupied Zone

Displacement ventilation diffusers are typically installed to the occupied zone, which can limit the utilization of the displacement ventilation. This paper presents the full-scale test results of two simulated office rooms with installation of displacement diffusers near wall, above the occupied zone. Vertical temperature gradients are compared to full-scale tests with installation of displacement diffusers to the occupied zone. The full-scale test setup consisted of two displacement diffusers and ceiling exhaust in wellinsulated room with 20.7 m2 floor area and room heights of 5.1 m and 3.3 m. The internal heat loads simulated situations with 10 occupants (simulated with heated cylinders), fluorescent lighting units, solar load on window surface (heated foils in one wall) without/with direct solar load on floor (heated foil on floor). The installation of displacement ventilation diffusers above occupied zone influenced on the vertical temperature gradient above the occupied zone only slightly. It reduced the vertical temperature gradient in the occupied zone. This confirms the operation of the displacement ventilation with this installation. This can be advantageous due to the smaller temperature stratification in the occupied zone, still the ventilation efficiency can be slightly lower comparing to the typical installation of the displacement diffusers.

Ceiling Radiation and Fresh Air for the Influence of Heating Room Temperature

2014 ◽  
Vol 1055 ◽  
pp. 275-282
Author(s):  
Ying Ning Hu ◽  
Hai Ding ◽  
Shan Shan Hu
Keyword(s):  
Temperature Gradient ◽  
Air Temperature ◽  
Air Conditioning ◽  
Indoor Environment ◽  
Room Temperature ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Air Conditioning System ◽  
Ground Source ◽  
Environment Temperature

This paper focus on the study of Ceiling radiation assist with Ground source heat pump air conditioning system which to analysis the operation characteristic by experiment. By testing the ceiling, all round the room air temperature, air temperature, wall temperature and the floor temperature, research the fresh air temperature have influence on the indoor environment temperature and vertical temperature. At the same time, analyzes radiation plate heat transfer per unit area with the end of the air conditioning water temperature and flow relationship. Experiments show that when the room ceiling radiation + natural air to indoor vertical temperature gradient is the largest, the second is ceiling radiation + no fresh air, indoor vertical temperature gradient is the smallest ceiling radiation + preheat air condition, when the system is stable, 2 meters below the vertical temperature difference about 1°C.

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