Analysis on Thermal Measuring of Rooftop Farming Garden a Case Study of Julong Residential District in Zhongshan

2013 ◽  
Vol 717 ◽  
pp. 306-311
Author(s):  
Juan Yu Wu ◽  
Ming Xin Liu ◽  
Lei Xiao
Keyword(s):  
Green Roof ◽  
Internal Surface ◽  
Lower Surface ◽  
Urban Neighborhoods ◽  
Metropolitan Regions ◽  
Interior Spaces ◽  
Surface Temperatures ◽  
Rooftop Farming ◽  
Residential District ◽  
Lower Surface Temperature

Nowadays, many urban cities in the world are facing problems of urban heat island and lack of greenery space. Rooftop farming is a strategy for intensifying urban agriculture activities, which can not only improve nutrition and food security in urban neighborhoods, but also reduce the energy consumption of air-condition and ease the power shortage in urban area of metropolitan regions. In this study, a thermal experiment and an index of energy saving analysis were carried out in Zhongshan, Guangdong Province, China in August 2011, measuring external and internal surface temperatures of roofs with and without greening, using the same set of climate parameters. The experiment results show that the green roof with urban farming can contribute to the modulation of air temperature in the interior spaces of building. During the hot days in summer, the external surface temperatures of green roof are lower than the normal flat one. The result also reveals that external surfaces of vegetated green roof system could effectively lower surface temperature by 6 °C and save 18.7% electric power, comparing with the general flat roof of traditional building.

scholarly journals Cement blocks with EVA waste for extensive modular green roof: contribution of the components for thermal insulation

2017 ◽  
Vol 10 (1) ◽  
pp. 92-106 ◽  
Author(s):  
A. B. DE MELO ◽  
T. N. M. MENDONÇA
Keyword(s):  
Thermal Insulation ◽  
Green Roof ◽  
Internal Surface ◽  
Green Roofs ◽  
Additional Contribution ◽  
Surface Temperatures ◽  
Air Temperatures ◽  
Footwear Industry ◽  
Hot And Humid Climates ◽  
Typical Summer

Abstract Green roofs can contribute in many ways to the quality of the environment, being known for reducing the heat transfer to the interior of the buildings. Amongst the available techniques for the execution of this type of covering, the use of light cement blocks which are compatible with the system of extensive modular green roofs is proposed. For the light cement blocks, produced with EVA aggregates (waste from the footwear industry), an additional contribution in the capacity of thermal insulation of the proposed green roof is expected. In the present article, the demonstration of such contribution is intended through measurements carried out in prototypes in hot and humid climates. After characterizing the capacity of thermal insulation of the proposed green roof, with different types of conventional covering as a reference, an additional contribution of the component used in this green roof was identified by making comparisons with measurements collected from another green roof, executed with cement blocks without the presence of the EVA aggregates. In the experiments, external and internal surface temperatures were measured in each of the prototypes' coverings, as well as the air temperatures in the internal and external environments. From the analysis of the data for a typical summer day, it was possible to prove that the proposed green roof presented the lowest temperature ranges, considering the internal air and surface temperatures. The presence of the EVA aggregates in the proposed blocks contributed to the decrease of the internal temperatures.

A Numerical Study of the Development of Convective Motion in a Bottom Heated Square Enclosure Containing Ice and Water

1999 ◽  
Author(s):  
P. H. Oosthuizen
Keyword(s):  
Wall Temperature ◽  
Freezing Point ◽  
Numerical Study ◽  
Convective Motion ◽  
Lower Surface ◽  
Uniform Temperature ◽  
Density Maximum ◽  
Square Enclosure ◽  
Finite Element Procedure ◽  
Lower Surface Temperature

Abstract A numerical study of the steady state flow in a square enclosure with two vertical walls which are adiabatic and with two horizontal isothermal walls has been undertaken. The enclosure contains water and the upper wall is maintained at a uniform temperature that is below the freezing point of water while the lower wall is maintained at a uniform temperature that is above the freezing point of water. The upper portion of the enclosure is thus filled with ice and the lower portion is filled with water. The conditions considered in the present study are such there can be significant natural convection in the water and the effect of the density maximum that exists in the water at approximately 4°C can have a significant effect on this flow. The main aim of the study was to determine how far above 4°C the hot wall temperature can be before significant convective motion develops in the water. The governing equations have been expressed in dimensionless form and solved using a finite element procedure. The effect of the various governing parameters on the mean Nusselt number has mainly been considered and the effect of the lower surface temperature has, in particular, been studied. The results obtained, which indicate that convective motion does not occur until the lower hot wall temperature is well above the maximum density temperature, can be used to determine the actual hot wall temperature at which significant convective motion develops.

The Influence of Micro Scale Ratchet Depth on the Motion of Leidenfrost Drop

2015 ◽  
Author(s):  
Jeong Tae Ok ◽  
Sunggook Park
Keyword(s):  
Surface Temperature ◽  
Water Drop ◽  
Lower Surface ◽  
Driving Mechanism ◽  
Entire Surface ◽  
Depth Effect ◽  
Micro Scale ◽  
Temperature Range ◽  
Aspect Ratios ◽  
Surface Temperatures

The influence of ratchet depth on the motion of Leidenfrost water drop was investigated as a continuous effort to reveal the driving mechanism. Continuous directional rebounding behavior of the drop was observed only at below 200°C on both micro ratchets with two different depth-to-period aspect ratios (1:5 and 1:10) and sharp ridges. Overall, the shallow ratchets generated more efficient drop mobility in the entire surface temperature range of 193–299°C due to the increased area between the bottom of the drop and the ratchet surface, caused by the geometrical benefit. However, the depth effect was only critical at relatively lower surface temperatures.

Research on Heat-Transfer Process of the Radiant Ceiling Cooling System

2012 ◽  
Vol 512-515 ◽  
pp. 2171-2174 ◽  
Author(s):  
Quan Ying Yan ◽  
Ran Huo ◽  
Li Li Jin
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Cooling System ◽  
Numerical Models ◽  
Cooling Water ◽  
Lower Surface ◽  
Cooling Capacity ◽  
Heat Transfer Process ◽  
Lower Surface Temperature ◽  
Selection Of

Physical and numerical models of the radiant ceiling cooling system were built and numerically simulated. The results showed that the lower the temperature of cooling water is, the lower surface temperature the ceiling has, and the bigger the cooling capacity is. The bigger the depth of tubes is, the higher the surface temperature and the smaller the cooling capacity. The differences are not evident. The bigger the distance of tubes is, the bigger the surface temperature is and the smaller the cooling capacity is. The diameter of tubes has a few influences on the surface temperature and the cooling capacity. Results in this paper can provide basis and guide for the design of the project, the selection of parameters and the feasibility of the system.

The effect of heating rate on the stability of stationary fluids

1967 ◽  
Vol 29 (2) ◽  
pp. 337-347 ◽  
Author(s):  
I. G. Currie
Keyword(s):  
Rayleigh Number ◽  
Surface Temperature ◽  
Fluid Layer ◽  
Critical Rayleigh Number ◽  
Lower Surface ◽  
Published Data ◽  
Heating Rates ◽  
Lower Surface Temperature ◽  
The Stability ◽  
Horizontal Fluid Layer

A horizontal fluid layer whose lower surface temperature is made to vary with time is considered. The stability analysis for this situation shows that the criterion for the onset of instability in a fluid layer which is being heated from below, depends on both the method and the rate of heating. For a fluid layer with two rigid boundaries, the minimum Rayleigh number corresponding to the onset of instability is found to be 1340. For slower heating rates the critical Rayleigh number increases to a maximum value of 1707·8, while for faster heating rates the critical Rayleigh number increases without limit.Two specific types of heating are investigated in detail, constant flux heating and linearly varying surface temperature. These cases correspond closely to situations for which published data exist. The results are in good qualitative agreement.

scholarly journals Effect of stocking rate and floor types on performance, skin temperature and leucogram in pigs raising

2017 ◽  
pp. 5610-5618
Author(s):  
Diovani Paiano ◽  
Ivan Moreira ◽  
Arley R.B. Quadros ◽  
Natalia Cristina Milani ◽  
Maria Luisa A. Nunes Z ◽  
...  
Keyword(s):  
Skin Temperature ◽  
Lower Surface ◽  
Backfat Thickness ◽  
Cell Immune Response ◽  
Stocking Rate ◽  
Anal Region ◽  
Linear Effect ◽  
Negative Effect ◽  
Lower Surface Temperature ◽  
Pig Performance

Objective. The aim of this study was to evaluate the performance, thermoregulatory characteristics and the leucogram of growing finishing pigs reared in different stocking rates kept on compact floor pens or with shallow pool pens. Material and methods. Thirty-six pigs were used in two steps (total of 72 animals were used). In the first step it was analysed performance pig (daily feed intake, weight gain and feed: gain ratio) and backfat thickness (P2). In the second step, the same analyzes were repeated, in addition, analysis of leucogram and skin temperature was performad in P2 and anal region, at the end of growing and finishing phase. Results. It was evaluated for differences between treatments and stocking. It was not found effect of floor type on growing phase, but the use of shallow pool had a negative effect on the gain and feed: gain ration in the finishing phase. Increasing linear effect on backfat thickness as the stocking rate was reduced, as well as lower surface temperature in the anal region on treatment with shallow pool in the finishing phase. No effect of treatments and type of floor on leucogram pigs. Allowing more space/animal decreased backfat thickness. The use of shallow pool affected negatively the performance in the finishing phase. Conclusions. The shallow pool uses impair the finishing pig performance, despite improving thermolysis, with no effect observed on cell immune response.

Lower surface temperature at Bright Ephemeral Feature site on Titan’s north pole

2021 ◽  
Author(s):  
Rajani D. Dhingra ◽  
Donald E. Jennings ◽  
Jason W. Barnes ◽  
Valeria Cottini
Keyword(s):  
Surface Temperature ◽  
Lower Surface ◽  
North Pole ◽  
Lower Surface Temperature

Plasma-assisted ammonia synthesis in a packed-bed dielectric barrier discharge reactor: roles of dielectric constant and thermal conductivity of packing materials

2021 ◽  
Author(s):  
Jin Liu ◽  
Xinbo Zhu ◽  
Xueli Hu ◽  
Xin Tu
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Surface Temperature ◽  
Packed Bed ◽  
Lower Surface ◽  
Active Species ◽  
Dielectric Constants ◽  
Packing Materials ◽  
Specific Input Energy ◽  
Lower Surface Temperature

Abstract In this article, plasma-assisted NH3 syntheses directly from N2 and H2 over packing materials with different dielectric constants (BaTiO3, TiO2 and SiO2) and thermal conductivities (BeO, AlN and Al2O3) at room temperature and atmospheric pressure are reported. The higher dielectric constant and thermal conductivity of packing material are found to be the key parameters in enhancing the NH3 synthesis performance. The NH3 concentration of 1344 ppm is achieved in the presence of BaTiO3, which is 106% higher than that of SiO2, at the specific input energy (SIE) of 5.4 kJ·l−1. The presence of materials with higher dielectric constant, i.e. BaTiO3 and TiO2 in this work, would contribute to the increase of electron energy and energy injected to plasma, which is conductive to the generation of chemically active species by electron-impact reactions. Therefore, the employment of packing materials with higher dielectric constant has proved to be beneficial for NH3 synthesis. Compared to that of Al2O3, the presence of BeO and AlN yields the 31.0% and 16.9% improvement in NH3 concentration, respectively, at the SIE of 5.4 kJ·l−1. The results of IR imaging show the addition of BeO decreases the surface temperature of the packed region by 20.5% to 70.3°C and results in an extension of entropy increment compared to that of Al2O3, at the SIE of 5.4 kJ·l−1. The results indicate that the presence of materials with higher thermal conductivity is beneficial for NH3 synthesis, which has been confirmed by the lower surface temperature and higher entropy increment of the packed region. In addition, when the SIE is higher than the optimal value, further increasing SIE would lead to the decrease of energy efficiency, which would be related to the exacerbation in reverse reaction of NH3 formation reactions.

scholarly journals Effect of moisture buffering on surface temperature variation: study of different indoor cladding materials

2020 ◽  
Vol 172 ◽  
pp. 06002
Author(s):  
Clémence Legros ◽  
Amandine Piot ◽  
Monika Woloszyn ◽  
Mickael Pailha
Keyword(s):  
Surface Temperature ◽  
Building Materials ◽  
Well Being ◽  
Lower Surface ◽  
Comfort Perception ◽  
Lower Surface Temperature ◽  
The Difference ◽  
Materials Used ◽  
Surface Temperature Variation ◽  
Moisture Buffering

The building materials used indoors constantly interact with the environment in which the occupants live. Recent studies have shown that natural materials, such as wood, can improve human well-being. In addition, the building materials facing the indoor air are able to adsorb and desorb water vapour from their surface and exchange it with the surrounding air. This mass exchange comes along with heat exchange, modifying their surface temperature, and thus the indoor environment. Therefore, in this article, we are investigating whether moisture buffering has an impact on comfort. For this purpose, room-scale numerical simulations have been carried out with WUFI Plus, comparing two types of interior cladding materials: painted plasterboards and a raw spruce panelling. The results show a slightly lower surface temperature and air temperature during the summer period when using spruce. A higher hygroscopicity of the spruce than the gypsum can explain this difference in behaviour between the two studied materials. Thus, spruce exchanges more latent heat with the surrounding air. However, only this thermal difference cannot explain the difference in comfort perception between the gypsum and the wood.

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