scholarly journals Analysis of the distribution of temperature and humidity in different variants of external walls made of hemp-lime composite

2017 ◽  
Vol 16 (2) ◽  
pp. 141-151
Author(s):  
Anna Alberska ◽  
Przemysław Brzyski
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Residential Buildings ◽  
Building Structure ◽  
Legal Requirements ◽  
Proper Design ◽  
Building Component ◽  
Main Factors ◽  
Industrial Hemp ◽  
Structure Destruction

Proper design of the building component, which not only meets the legal requirements, but also provides comfort of using of buildings, requires knowledge of the materials and solutions. Since moisture is one of the main factors that can affect the building structure destruction, it is particularly important to be aware of hygrothermal properties of components. And this is the focus of the study. In this paper several variants of external walls were analysed, according to the requirements in terms of: heat transfer coefficient U, the risk of surface and interstitial condensation. Partitions were designed with composite based on shives from industrial hemp and lime binder, which is not yet widely used in Poland. The purpose of the analysis of this material was to prove the validity of using the natural materials in residential buildings.

Numerical Simulation of a Canadian Well With Several Circumferential Rows of Internal Vortex Generators

2021 ◽  
Author(s):  
Nabil Kharoua ◽  
Hamza Semmari ◽  
Houssem Korichi ◽  
Mehdi Haroun
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Residential Buildings ◽  
Vortex Generators ◽  
Ambient Conditions ◽  
Operational Conditions ◽  
Positive Effects ◽  
The Heat Transfer Coefficient

Abstract Canadian Wells exploit the quasi-stable underground temperature throughout the year for cooling and heating applications. This type of heat exchangers is used in residential buildings, agriculture and industry. Implementing Vortex Generators (VGs) is intended to disturb the thermal and dynamic boundary layers developing in the near-wall regions leading to the increase of the heat transfer coefficient. The present work investigates the positive effects of a sequence of several rows of VGs. The commercial code ANSYS FLUENT was used to perform numerical simulations mimicking the variation of the seasonal operational conditions occurring within one year. The ambient conditions were considered for the city of Constantine located in the east of Algeria at an altitude of 600m over the sea level. Sinusoidal functions of time and depth, were used for the yearly variations of the ground and air temperatures. Parallelepiped VGs were considered in this study. The Reynolds number was in the range Re = 14975–42789. The results illustrated a contrasting effect of the Reynolds number on the heat transfer coefficient and the temperature difference between the inlet and outlet of the Canadian Well. In terms of number of VGs rows, the beneficial heat transfer effects were observed till the fifth row only.

Renovation of Multi-Apartment Building in Latvia

2015 ◽  
Vol 725-726 ◽  
pp. 1177-1181 ◽  
Author(s):  
Anatolijs Borodinecs ◽  
Jurgis Zemitis ◽  
Aleksandrs Zajacs ◽  
Jekaterina Nazarova
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Residential Buildings ◽  
Single Layer ◽  
Average Heat Transfer Coefficient ◽  
Heating Season ◽  
Apartment Building ◽  
Total Energy Consumption ◽  
Average Heat ◽  
Apartment Buildings

Residential buildings in Latvia are one of the essential heat consumers during the heating season. The majority of Latvian as well as European residential buildings were constructed within the period from 1965 to 1990. The average heat transfer coefficient of typical homogeneous single layer external wall of Latvian multi apartment building as well as all buildings constructed in USSR is 0.80 till 1.20W/(m2∙K) [1,2]. Paper presents study on multi apartment buildings renovation specifics in Latvia and its influence in total energy consumption.

scholarly journals Indoor environmental assessment method in residential kitchen

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 2055-2065
Author(s):  
Anita Vorosne-Leitner ◽  
Laszlo Kajtar ◽  
Jozsef Nyers
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Energy Consumption ◽  
Transfer Coefficient ◽  
Residential Buildings ◽  
Local Source ◽  
Radiant Heat Transfer ◽  
Main Role ◽  
Monitoring Method ◽  
Gas Stoves

Nowadays, energy consumption, environmental protection and safety are fundamental issues in design process. In order to reduce energy consumption, buildings become increasingly insulated and air tight. It has controversial effect on indoor environment, therefore, it has become essential to apply an effective ventilation system. This requires detailed design, especially if there is a strong, local source in the space. In residential buildings, gas stoves are significant source of gaseous pollutants and heat load. Indoor environmental assessments have been carried out in order to evaluate the key parameters. The aim of this studies is to develop a new design and monitoring method of residential kitchens with gas stoves. Primary results of laboratory researches indicate that the largest stovetop burner with power of 2.8 kW, has the main role. Significant emissions of NOx have been measured, in an average size kitchen (Vroom = 36 m3) the Hungarian standard NOx concentration level (200 ?g/m3) can be ensured with an exhaust air-flow of 1102 m3/h. With respect of thermal environmental parameters, heat loads of residential gas stoves could be characterized with convective heat transfer coefficient of 4.5 W/m2K and radiant heat transfer coefficient of 5.9 W/m2K. As regards thermal comfort parameters, predicted mean rate index in proved to be applicable in residential kitchens from ?0.3 to +2.0. However draught rating cannot be applied, with respect to the temperature limitations.

scholarly journals Fundamental Properties and Thermal Transferability of Masonry Built by Autoclaved Aerated Concrete Self-Insulation Blocks

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1680 ◽  
Author(s):  
Fenglan Li ◽  
Gonglian Chen ◽  
Yunyun Zhang ◽  
Yongchang Hao ◽  
Zhengkai Si
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Shear Strength ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Residential Buildings ◽  
Fundamental Properties ◽  
Autoclaved Aerated Concrete ◽  
Aerated Concrete ◽  
Insulation Block

This paper performed a detailed study on the fundamental properties and thermal conductivity of autoclaved aerated concrete (AAC) self-insulation block, and the mechanical properties and heat transfer resistance of the AAC self-insulation block masonry. Different kinds of joints and the plastering surface were used to build the masonry specimens. The distinctive feature of the blocks and mortars is the lower thermal conductivity with expected strength. Compared to those with larger thickness of insulation mortar joints, the masonry with thin-layer mortar joints had better compressive performance and lower shear strength. The compressive strength of masonry was related with the block and mortar strengths, the shear strength of masonry along mortar joints was related with the mortar strength. The stress–strain relationship of masonry in compression could be predicted by the similar expression of conventional block masonry. The tested heat transfer coefficient of AAC self-insulation block masonry with thickness of 250 mm without plastering surfaces was (0.558 ± 0.003) W/(m2·K). With the plastering surfaces, the heat transfer coefficient reduced by 4.4% to 8.9%. Good agreements in values of heat transfer coefficient existed by using the test, theoretical computation and ANSYS (ANSYS Inc. Canonsburg, PA, USA) analytical methods. Based on the extensibility analyses, the heat transfer coefficients of AAC self-insultation block masonry with different thickness are proposed. The best thickness is proposed for the outer walls of residential buildings in different cold zone to meet the design requirement of energy conservation.

scholarly journals Research on Energy-Saving Design of Rural Building Wall in Qinba Mountains Based on Uniform Radiation Field

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Qin Zhao ◽  
Xiaona Fan ◽  
Qing Wang ◽  
Guochen Sang ◽  
Yiyun Zhu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Energy Consumption ◽  
Transfer Coefficient ◽  
Energy Saving ◽  
Radiation Field ◽  
Thermal Environment ◽  
Residential Buildings ◽  
South Wall ◽  
Heating Energy Consumption

How to create a healthy and comfortable indoor environment without causing a substantial increase in energy consumption has become a strategic problem that the development of all countries must face and solve. According to the climatic conditions of Qinba Mountains in China, combined with the characteristics of local rural residential buildings and residents’ living habits, the field survey and theoretical analysis were used to study the thermal environment status and the heating energy consumption condition of local rural residential buildings. The thermal design method of walls for the local rural energy-saving buildings based on the indoor uniform radiation field was explored by using the outdoor comprehensive temperature function expressed by the fourth-order harmonic Fourier series as the boundary condition of the wall thermal analysis. ANSYS CFX was adopted to study the suitability of the energy-saving wall structure designed by the above method. The results show that the indoor thermal environment of local rural residential buildings in winter is not ideal and the heating energy consumption is high, but this area has the geographical advantage to develop solar energy buildings. It is proposed that the indoor thermal comfort temperature of local rural residential buildings in winter should not be lower than 14°C. When the internal surface temperature of the external walls in different orientations are equally based on the design principle of uniform radiation field, the heat transfer coefficient of the east wall, the west wall, and the north wall of the local rural residential buildings is 1.13 times, 1.06 times, and 1.14 times of the south wall heat transfer coefficient, respectively. The energy-saving structural wall with KPI porous brick as the main material and the south wall heat transfer coefficient of 0.9 W/(m2·K) is the most suitable energy-saving wall for local rural residential buildings.

A Method to Estimate Real-Time Energy Performance and Carbon Offsets in Residential Buildings

2010 ◽  
Author(s):  
Sergio Escobar ◽  
Jorge E. Gonza´lez ◽  
Adam Wong ◽  
Mark Aschheim
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Real Time ◽  
High Performance ◽  
Residential Buildings ◽  
Thermal Characteristics ◽  
Energy Performance ◽  
Carbon Offsets ◽  
Overall Heat Transfer Coefficient

A method is presented to determine energy performance of residential buildings. The method is based on an extended application of the degree-days basis to determine building thermal performance. The overall heat transfer coefficient and radiation shading factors are extracted from nightime and daytime readings of indoor and outdoor temperatures, solar radiation, and total energy usage of the building. It is shown that the overall heat transfer coefficient (thermal response) UA of the building is linear. Radiation shading factors can be represented as nonlinear functions of time. Application of the method to estimate real-time energy performance and carbon offsets of high performance buildings is discussed. The performance of the building is compared with an equivalent building with standard physical and thermal characteristics.

scholarly journals The effect of different types of window for residential building based on intermittent heating supply

2019 ◽  
Vol 136 ◽  
pp. 03020
Author(s):  
Chenyang Tao ◽  
Nan Li ◽  
Yuchen Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Energy Consumption ◽  
Transfer Coefficient ◽  
Residential Buildings ◽  
Recovery Period ◽  
Residential Building ◽  
Thermal Design ◽  
Intermittent Heating ◽  
Different Types

Aiming to lessen energy consumption and heating cost, this paper analyzes the effect of different types of window for residential building based on intermittent heating supply. The research results show that the type of window with a smaller heat transfer coefficient has higher energy consumption. Otherwise, the rate of temperature rising is slightly affected by the change of window with different heat transfer coefficient and window-to-wall ratio. Based on the economic and technical analysis, through changing the better window, energy-saving ratio can be arrived to 10.4%-16.8% and economic recovery period is 4.4-10.4 years. The research findings can be used for reference to thermal design in new residential buildings and provide improvement of building performance for existing residential buildings.

Evaporation of lignin-lean black liquor

TAPPI Journal ◽  
2015 ◽  
Vol 14 (7) ◽  
pp. 441-450
Author(s):  
HENRIK WALLMO, ◽  
ULF ANDERSSON ◽  
MATHIAS GOURDON ◽  
MARTIN WIMBY
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Black Liquor ◽  
Salt Content ◽  
Solubility Limit ◽  
Lignin Removal ◽  
Kraft Black Liquor ◽  
Black Liquors ◽  
The Heat Transfer Coefficient

Many of the pulp mill biorefinery concepts recently presented include removal of lignin from black liquor. In this work, the aim was to study how the change in liquor chemistry affected the evaporation of kraft black liquor when lignin was removed using the LignoBoost process. Lignin was removed from a softwood kraft black liquor and four different black liquors were studied: one reference black liquor (with no lignin extracted); two ligninlean black liquors with a lignin removal rate of 5.5% and 21%, respectively; and one liquor with maximum lignin removal of 60%. Evaporation tests were carried out at the research evaporator in Chalmers University of Technology. Studied parameters were liquor viscosity, boiling point rise, heat transfer coefficient, scaling propensity, changes in liquor chemical composition, and tube incrustation. It was found that the solubility limit for incrustation changed towards lower dry solids for the lignin-lean black liquors due to an increased salt content. The scaling obtained on the tubes was easily cleaned with thin liquor at 105°C. It was also shown that the liquor viscosity decreased exponentially with increased lignin outtake and hence, the heat transfer coefficient increased with increased lignin outtake. Long term tests, operated about 6 percentage dry solids units above the solubility limit for incrustation for all liquors, showed that the heat transfer coefficient increased from 650 W/m2K for the reference liquor to 1500 W/m2K for the liquor with highest lignin separation degree, 60%.

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