scholarly journals Cooling and Energy-Saving Performance of Different Green Wall Design: A Simulation Study of a Block

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2912 ◽  
Author(s):  
Jiayu Li ◽  
Bohong Zheng ◽  
Wenquan Shen ◽  
Yanfen Xiang ◽  
Xiao Chen ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Energy Saving ◽  
Air Temperature ◽  
Cooling Power ◽  
Wall Surface ◽  
Low Carbon ◽  
Outdoor Air ◽  
Green Wall ◽  
Green Walls ◽  
Wall Surface Temperature

To mitigate the urban heat island (UHI) and release the low carbon potential of green walls, we analyzed the cooling and energy-saving performance of different green wall designs. Envi-met was applied as the main simulation tool, and a pedestrian street named Yuhou Street was selected as the study object. Four designs of walls were summarized and simulated, demonstrating the living wall system (LWS). Super soil had superiority in cooling and energy saving. Outdoor air temperature, indoor air temperature, outside wall surface temperature, and inside wall surface temperature were analyzed. Apart from the outdoor air temperature, the other three temperatures were all significantly affected by the design of green walls. Finally, energy savings in building cavities were determined. The indoor energy saving ratio of the LWS based on super soil reached 19.92%, followed by the LWS based on boxes at 15.37%, and green facades wall at 6.29%. The indoor cooling powers on this typical day showed that the cooling power of the LWS based on super soil was 8267.32 W, followed by the LWS based on boxes at 6381.57 W, and green facades wall at 2610.08 W. The results revealed the difference in cooling and energy-saving performance of different green walls in this typical hot summer area.

scholarly journals Study on Flow and Heat Transfer Characteristics of Supercritical Kerosene in a Round Tube

2020 ◽  
Vol 316 ◽  
pp. 03003
Author(s):  
Feng Gao ◽  
Qian Zhang ◽  
Hongyu Xiao ◽  
Fengli Chen ◽  
Xuefeng Xia
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Inlet Temperature ◽  
Wall Surface ◽  
Heat Transfer Characteristics ◽  
Navier Stokes Equation ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Wall Surface Temperature ◽  
Central Flow

The finite volume discrete solution of the Navier-Stokes equation and the RNG model of the turbulence model are used to numerically simulate the flow and heat transfer characteristics of supercritical kerosene in a circular tube. The results show that as the inlet mass flow increases, the wall surface temperature and the central flow oil temperature gradually decrease, and the pressure loss becomes larger. As the inlet temperature increases, the wall surface temperature and the central flow oil temperature both increase. When the heat flux density is constant, as the pressure increases, the deterioration of heat transfer will be weakened, and increasing the pressure can improve the effect of convection heat transfer.

Simulation and Optimization of Homogeneous Decomposition of Sulfur Trioxide Gas on a Catalytic Surface

2005 ◽  
Author(s):  
Kiran K. Muramalla ◽  
Yitung Chen ◽  
Anthony E. Hechanova
Keyword(s):  
Heat Exchanger ◽  
Numerical Model ◽  
Surface Temperature ◽  
Flow Rate ◽  
Sulfur Trioxide ◽  
Tube Length ◽  
Two Dimensional ◽  
Wall Surface ◽  
Wall Surface Temperature ◽  
Homogeneous Decomposition

This paper deals with the development of a two-dimensional numerical model to predict the wall-catalyzed homogeneous decomposition of sulfur trioxide in a tubular component geometry for the production of hydrogen by the sulfur-iodine thermochemical water splitting cycle, a candidate cycle in the U.S. Department of Energy Nuclear Hydrogen Initiative. The reacting fluid is a mixture of sulfur trioxide gas and water vapor inside the tubes of a heat exchanger. The heat exchanger is made of Incoloy alloy 800H with ALFA-4 coated on the inner walls which acts as a catalyst. Decomposition of sulfur trioxide depends on many different parameters such as wall surface temperature, mole flow rate of the reacting mixture, diameter of the reactor tube, length of the reactor tube, operating pressure and inlet temperature of the reacting mixture. The effects of wall surface temperature, diameter of the reactor tube and mole flow rate on the decomposition of sulfur trioxide were investigated using a two-dimensional numerical model using Computational Fluid Dynamics (CFD) techniques. The preprocessor GAMBIT was used to create a computational mesh and the CFD software package FLUENT 6.2.16 [1] which is based on finite volume methods was used to simulate the problem. Both FLUENT 6.2.16 and Tecplot 10.0 are used to post process the problem.

scholarly journals Microbiome in an Office Building Using a Cooling Trench as an Outdoor Air Duct

2019 ◽  
Vol 111 ◽  
pp. 06045
Author(s):  
Mizuki Niimura ◽  
U Yanagi
Keyword(s):  
Relative Humidity ◽  
Energy Saving ◽  
Air Temperature ◽  
Indoor Air ◽  
Principal Coordinate Analysis ◽  
Office Building ◽  
Metagenomic Analysis ◽  
Outdoor Air ◽  
Energy Saving Technique ◽  
Building Cooling

Subterranean temperature at a depth of 10 m is almost equal to the average outdoor air temperature of the same area. Therefore, if a building cooling trench is used as an outdoor air duct, outdoor air can be cooled in summer and warmed in winter. This energy-saving technique is often used in Japan. However, since the relative humidity in a cooling trench is high, microbe numbers tend to increase in summer. The present study sought to characterize the microbiome status in the cooling trench of such an office building in Japan. Specifically, we performed a metagenomic analysis in which we analyzed DNA directly upon collection from the environment, without intervening cultivation. The results showed the presence of bacteria of the genera Pseudomonas, Lactobacillus, Nesterenkonia, Staphylococcus, Deinococcus, Acinetobacter, Enhydorobacter, and Corynebacterium. Bacteria of the genera Nesterenkonia, Deinococcus, Enhydorobacter, and Corynebacterium predominated on the surface of the trench. Notably, bacteria of the genus Nesterenkonia constituted >50% of the organisms on the surface of the downstream end of the cooling trench. Principal coordinate analysis was used to compare bacterial inhabitants of outdoor air, indoor air from 2nd- and 3rdfloor offices, and the region downstream of the cooling trench. The results suggested that the microbiome of air in this cooling trench influenced indoor air within the building.

scholarly journals Comparing Air Temperature and Humidity in a Vestibule without and with Green Wall

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 633
Author(s):  
Zuzana Poorova ◽  
Mohammed Salem Alhosni ◽  
Peter Kapalo ◽  
Zuzana Vranayova
Keyword(s):  
Air Temperature ◽  
Doctoral Study ◽  
Green Wall ◽  
Temperature And Humidity ◽  
Living Wall ◽  
Green Walls ◽  
Technical University

The paper is a part of ongoing doctoral study focusing on interior green walls and their qualities. The paper describes living wall built in entrance hall in the laboratory of Technical University of Košice, its construction, irrigation and vegetation; the most important segments of every living wall. The research deals with effect of green wall on air temperature and humidity in the room and compares it with air temperature and humidity in the room without green wall.

Effect of Passive Green Wall Modules on Air Temperature and Humidity

2018 ◽  
Author(s):  
Peter Abdo ◽  
B. P. Huynh
Keyword(s):  
Air Quality ◽  
Air Temperature ◽  
Ambient Conditions ◽  
Closed Chamber ◽  
Green Wall ◽  
Active Systems ◽  
Temperature And Humidity ◽  
Air Layers ◽  
Insulation Effect ◽  
Green Walls

Green walls are bio-filters developed to enhance air quality. Often, these walls form the base from which plants are grown; and the plant-wall system helps to remove both gaseous and particulate air pollutants. Green walls can be found indoors or outdoors and they are classified as passive or active systems. Their benefits include temperature reduction, improvement of air quality and reduction of air pollution, oxygen production as well as the social and psychological wellbeing. They can produce changes in the ambient conditions (temperature and humidity) of the air layers around them which create an interesting insulation effect. The effect of passive green wall modules on the air temperature and on humidity is investigated in this work. A closed chamber made of acrylic sheets is used to monitor the temperature and humidity variation caused by a green wall module placed at its center. Temperature and humidity are measured at different locations inside the chamber during operation for different modules with different plant species.

Optimization of energy saving with adaptive setpoint temperatures by calculating the prevailing mean outdoor air temperature

2020 ◽  
Vol 170 ◽  
pp. 106612 ◽  
Author(s):  
David Bienvenido-Huertas ◽  
Daniel Sánchez-García ◽  
Alexis Pérez-Fargallo ◽  
Carlos Rubio-Bellido
Keyword(s):  
Energy Saving ◽  
Air Temperature ◽  
Outdoor Air

scholarly journals Analyzing impact of sensor coupling on measurement representativeness of wall surface temperature

2021 ◽  
Author(s):  
Sadaf Mansour
Keyword(s):  
Surface Temperature ◽  
Temperature Difference ◽  
Indoor Air ◽  
Internal Surface ◽  
Thermal Coupling ◽  
Wall Surface ◽  
Surrounding Environment ◽  
Wall Assembly ◽  
The Impact ◽  
Wall Surface Temperature

Poor thermal-coupling between sensor and surface is one of the most important factors causing inaccuracy in measurement. Different methods had been suggested by scientists to solve this issue. Embedding the sensor into an object was one of these methods. The goal of these simulations was to assess the impact of sensor coupling on measurement representativeness of wall surface temperature. For this purpose, a cylindrically-shaped sensor was embedded into the internal surface of the wall assembly. The levels of tightness varied from 10% to 90%, which corresponded respectively from very loose to very tight conditions. Also, in this process the impact of other factors such size and materiality of the sensors’ accuracy were evaluated and discussed briefly. In this study, the results proved that as the sensor decoupled more from the surrounding environment, more accurate data was generated from it. Also, the results from the simulations signified the importance of the temperature difference between the wall surface and the indoor air temperature. The temperature difference had a direct relationship with sensor accuracy and measurement representativeness, where smaller temperature difference was associated with higher accuracy.

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