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Article
Publication date: 3 May 2016

Amos Madhlopa

The purpose of this paper is to investigate a wall-integrated solar chimney for passive ventilation of a building cavity. Ventilation is required to improve the…

Abstract

Purpose

The purpose of this paper is to investigate a wall-integrated solar chimney for passive ventilation of a building cavity. Ventilation is required to improve the circulation of air in the built environment. This can be achieved through natural or forced convection. Natural circulation can be driven by renewable energy, and so it promotes sustainable exploitation of energy resources. Solar energy is one of the promising renewable energy resources.

Design/methodology/approach

The chimney was designed to face the Equator on the wall of a room which required ventilation. Mean monthly daily heating and cooling loads of the room were computed with and without a solar chimney by using hourly meteorological data from nine different weather sites at low, medium and high latitudes. The chimney was implemented with and without airflow control, and simulated by using the ESP-r software.

Findings

Results show that the solar chimney with airflow control marginally reduced the heating load in the building envelope, with a similar effect being exhibited by the chimney with uncontrolled airflow. The cooling load was reduced by the controlled airflow at all the nine sites. In contrast, the uncontrolled airflow increased the cooling load at some sites. In addition, the chimney with airflow control reduced the annual total thermal load at all the sites, while the chimney with uncontrolled airflow raised the total thermal load at some locations.

Originality/value

The performance of solar chimneys designed with and without airflow control systems has been investigated under the same prevailing meteorological conditions at a given site. Findings show that controlling airflow in a solar chimney reduces the total thermal load in the built environment. This information can be applied in different parts of the world.

Details

Journal of Engineering, Design and Technology, vol. 14 no. 2
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 1 March 2017

Cheng Sun, Meng Zhen and Yu Shao

Rural residential energy consumption accounts for 46.6% of total building-related energy consumption of China. In Northeast China, energy consumption for space heating…

Abstract

Rural residential energy consumption accounts for 46.6% of total building-related energy consumption of China. In Northeast China, energy consumption for space heating represents a significant proportion of total rural residential energy consumption and has reached 100 million tce (tons of standard coal equivalent), or more than 60% of total household energy consumption. In terms of energy consumption per square meter of gross floor area, rural residential energy consumption for heating is more than that of cities (20kgce/m2). However, the average indoor temperature of most rural residence is below 10°C, much less than that in cities (18°C). Hence, it is an important task for Chinese energy saving and emission reduction to reduce rural residential energy consumption, while enhancing indoor thermal comfort at the same time.

Restricted by local technology and low economic level, rural residences currently have poor thermal insulation resulting in severe heat loss. This paper reports on research aimed at developing design strategies for improving thermal insulation properties of rural residences with appropriate technology. A field survey was conducted in six counties in severe cold areas of Northeast China, addressing the aspects of indoor and outdoor temperature, humidity, internal and external surface temperature of building envelop enclosure, and so on.

The survey data show the following:

1. Modern (after 2000) brick-cement rural residences perform much better than the traditional adobe clay houses and Tatou houses (a regional type of rural residence in Northeast China – see figure A) in overall thermal performance and indoor thermal comfort;

2. Among the traditional residential house types, adobe clay houses have better heat stability and thermal storage capacity than Tatou houses;

3. Applying an internal or external thermal insulation layer can greatly improve rural residential thermal insulation properties, and is an economical and efficient solution in rural areas;

4. In terms of roofing materials, tiled roofs show much better thermal insulation properties than thatch roofs;

5. Adopting passive solar techniques can form a transition space (greenhouse) against frigid temperatures, resulting in interior temperatures 5.91°C higher than the outside surroundings. It is evident that local passive solar room design offers significant heat preservation effects and lower cost ($12/m2), embodies the ecological wisdom of rural residents, and is therefore important to popularize.

The above experimental results can provide guidance in energy conservation design for both self-built residences and rural residences designed by architects. In addition, the results can also provide experimental data for energy-saving studies for rural residences in China.

Details

Open House International, vol. 42 no. 1
Type: Research Article
ISSN: 0168-2601

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Article
Publication date: 31 January 2020

Maher Dhahri and Hana Aouinet

The purpose of this study is to investigate air flow, temperature distribution and thermal confort in natural ventilation induced by solar chimney for different operating.

Abstract

Purpose

The purpose of this study is to investigate air flow, temperature distribution and thermal confort in natural ventilation induced by solar chimney for different operating.

Design/methodology/approach

Numerical simulation is performed using a commercial computational fluid dynamics (CFD) package ANSYS CFX software to understand the effects of air temperature, air velocity and solar heat flux on the performance of the solar chimney and thermal comfort. The comfort level was evaluated using the air diffusion performance index (ADPI) according to ASHRAE (55-210). The flow was investigated at inclination angles 45° solar heat flux 550-750 W/m2 and in a solar chimney of 1.4 m length, 0.6 m width and 0.20 m air gab.

Findings

The numerical results from the present simulation were first validated with experimental data, which was used for the thermal comfort indexes calculation. The obtained results of the analysis showed that the used numerical technique could accurately predict air flow and temperature distribution in natural ventilated building using solar chimney; the air temperature, air velocity and solar heat flux have a significant impact on thermal comfort; the temperature of 19°C with velocity of 0.15 m.s−1 gives the best effective draft temperature (EDT) satisfy ASHRAE (55-210) criteria that V = 0.35 m.s−1 and EDT range between −1.7 and 1.1.

Originality/value

In the present paper, air flow, temperature distribution and thermal comfort inside a room equipped with inclined solar chimney were numerically investigated and analyzed. The commercial CFD package (CFX 15) is used. Calculations are carried out in an empty room without any human or mechanical activity and the numerical results are compared with measurement points.

Details

World Journal of Engineering, vol. 17 no. 1
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 18 November 2013

Shiv Lal, S.C. Kaushik and P.K. Bhargava

The ventilation and air-conditioning systems consume the highest energy in the building sector. The proper ventilation in residential buildings through the passive solar

Abstract

Purpose

The ventilation and air-conditioning systems consume the highest energy in the building sector. The proper ventilation in residential buildings through the passive solar systems can substantially reduce the energy consumption in building sector. The paper aims to identify the application of wind shaft as a solar chimney, a passive ventilation system and evaluated the performance of the system.

Design/methodology/approach

The paper investigated the performance of the solar chimney with size, absorber area 9.76 m2 and height 4.57 m, based on experimental data recorded in the city, Kota (25°10N, 75°52E), India. Solar data were recorded using the state of the art weather station situated very closer to the residence. The air velocity and temperatures in the chimney and in the building are recorded in data logger. A simple mathematical model was used for the evaluation of the air change per hour (ACH) in the residential building.

Findings

From the analysis of weather data, it was found that the ambient temperature varies linearly with the solar irradiance. Air change rate of 5.7-7.7 can be achieved from this solar chimney, in peak summer season which is appropriate and meets the ventilation requirement as per BIS (Handbook of Functional Requirements of Buildings – 1987).

Originality/value

The air temperature increases from bottom to top in the solar chimney. The solar irradiance dictates the chimney air temperature, and both are in step with each other. It shows that the solar chimney is working in tune with the solar radiation availability. In peak summer, it provides sufficient ACH to the tune of 3-6. Resulting wind shaft can act effectively as a solar chimney. It is a feasible solution for the ventilation needs and it improves the looks of any residential building.

Details

International Journal of Energy Sector Management, vol. 7 no. 4
Type: Research Article
ISSN: 1750-6220

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Article
Publication date: 14 August 2007

Hiroshi Yoshino, Kenichi Hasegawa and Shin‐ichi Matsumoto

Purpose – The purpose of this paper is to investigate the cooling effect of these features. Japanese traditional buildings have many features, which are effective for…

Abstract

Purpose – The purpose of this paper is to investigate the cooling effect of these features. Japanese traditional buildings have many features, which are effective for cooling the interior of the building. Design/methodology/approach – This paper first of all describes the characteristics of indoor thermal environment and the cooling effect of four traditional buildings, located in the Miyagi Prefecture in the northern area in Japan. The investigated buildings include traditional farmhouses and renovated farmhouses for the improvement of indoor thermal environment. Second, the cooling effect of traditional technologies was studied by the means of computer simulation using a model house, which takes the multi‐zone effects of heat transfer and air flow distribution into consideration. Findings – The paper finds that the cooling technologies of traditional buildings, such as solar shading by thatched roof decreases indoor temperature. The computer simulation revealed that natural ventilation, solar shading by thatched roof and the thermal mass by earthen floor are effective for interior cooling. Practical implications – This paper reveals the cooling effect of traditional technologies quantitatively. From the points of view of energy saving and environment symbiosis based on the understanding of physical principle, it is important to apply these traditional technologies to modern buildings. Originality/value – From the viewpoint of solution of global environmental problems, we can learn a lot from these vernacular technologies inherited from the past. This paper provides valuable information about building based on environmental design methodologies, which promote awareness about sustainable construction.

Details

Management of Environmental Quality: An International Journal, vol. 18 no. 5
Type: Research Article
ISSN: 1477-7835

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Article
Publication date: 20 February 2020

Kamal Pandey and Bhaskar Basu

The rapid urbanization of Indian cities and the population surge in cities has steered a massive demand for energy, thereby increasing the carbon emissions in the…

Abstract

Purpose

The rapid urbanization of Indian cities and the population surge in cities has steered a massive demand for energy, thereby increasing the carbon emissions in the environment. Information and technology advancements, aided by predictive tools, can optimize this energy demand and help reduce harmful carbon emissions. Out of the multiple factors governing the energy consumption and comfort of buildings, indoor room temperature is a critical one, as it envisages the need for regulating the temperature. This paper aims to propose a mathematical model for short-term forecasting of indoor room temperature in the Indian context to optimize energy consumption and reduce carbon emissions in the environment.

Design/methodology/approach

A study is conducted to forecast the indoor room temperature of an Indian corporate building structure, based upon various external environmental factors: temperature and rainfall and internal factors like cooling control, occupancy behavior and building characteristics. Expert insight and principal component analysis are applied for appropriate variables selection. The machine learning approach using Box–Jenkins time series models is used for the forecasting of indoor room temperature.

Findings

ARIMAX model, with lagged forecasted and explanatory variables, is found to be the best-fit model. A predictive short-term hourly temperature forecasting model is developed based upon ARIMAX model, which yields fairly accurate results for data set pertaining to the building conditions and climatic parameters in the Indian context. Results also investigate the relationships between the forecasted and individual explanatory variables, which are validated using theoretical proofs.

Research limitations/implications

The models considered in this research are Box–Jenkins models, which are linear time series models. There are non-linear models, such as artificial neural network models and deep learning models, which can be a part of this study. The study of hybrid models including combined forecasting techniques comprising linear and non-linear methods is another important area for future scope of study. As this study is based on a single corporate entity, the models developed need to be tested further for robustness and reliability.

Practical implications

Forecasting of indoor room temperature provides essential practical information about meeting the in-future energy demand, that is, how much energy resources would be needed to maintain the equilibrium between energy consumption and building comfort. In addition, this forecast provides information about the prospective peak usage of air-conditioning controls within the building indoor control management system through a feedback control loop. The resultant model developed can be adopted for smart buildings within Indian context.

Social implications

This study has been conducted in India, which has seen a rapid surge in population growth and urbanization. Being a developing country, India needs to channelize its energy needs judiciously by minimizing the energy wastage and reducing carbon emissions. This study proposes certain pre-emptive measures that help in minimizing the consumption of available energy resources as well as reducing carbon emissions that have significant impact on the society and environment at large.

Originality/value

A large number of factors affecting the indoor room temperature present a research challenge for model building. The paper statistically identifies the parameters influencing the indoor room temperature forecasting and their relationship with the forecasted model. Considering Indian climatic, geographical and building structure conditions, the paper presents a systematic mathematical model to forecast hourly indoor room temperature for next 120 h with fair degree of accuracy.

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Article
Publication date: 4 May 2012

Kah‐Yoong Chan, Hee‐Joe Phoon, Chee‐Pun Ooi, Wai‐Leong Pang and Sew‐Kin Wong

Power management of a wireless sensor node is important and needs to be designed efficiently without wasting excessive energy. The purpose of this paper is to report on…

Abstract

Purpose

Power management of a wireless sensor node is important and needs to be designed efficiently without wasting excessive energy. The purpose of this paper is to report on the improvement of the power management of a wireless sensor node.

Design/methodology/approach

The design involves the implementation of solar recharging technology with single‐ended primary inductance converter (SEPIC) on a wireless sensor node in order to achieve the improvement in power management.

Findings

The combination of the solar recharging technology with SEPIC converter shows promising results for efficiently supplying the power to the wireless sensor node.

Research limitations/implications

The design idea can be extended for many other electronic sensor applications, which can help to ensure an efficient power management of the sensor nodes.

Originality/value

The proposed design model demonstrates a new idea towards reduction of energy usage for wireless sensor nodes.

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Article
Publication date: 6 February 2017

Huey Tyng Cheong, S. Sivasankaran and M. Bhuvaneswari

The purpose of this paper is to study natural convective flow and heat transfer in a sinusoidally heated wavy porous cavity in the presence of internal heat generation or…

Abstract

Purpose

The purpose of this paper is to study natural convective flow and heat transfer in a sinusoidally heated wavy porous cavity in the presence of internal heat generation or absorption.

Design/methodology/approach

Sinusoidal heating is applied on the vertical left wall of the cavity, whereas the wavy right wall is cooled at a constant temperature. The top and bottom walls are taken to be adiabatic. The Darcy model is adopted for fluid flow through the porous medium in the cavity. The governing equations and boundary conditions are solved using the finite difference method over a range of amplitudes and number of undulations of the wavy wall, Darcy–Rayleigh numbers and internal heat generation/absorption parameters.

Findings

The results are presented in the form of streamlines, isotherms and Nusselt numbers for different values of right wall waviness, Darcy–Rayleigh number and internal heat generation parameter. The flow field and temperature distribution in the cavity are affected by the waviness of the right wall. The wavy nature of the cavity also enhances the heat transfer into the system. The heat transfer rate in the cavity decreases with an increase in the internal heat generation/absorption parameter.

Research limitations/implications

The present investigation is conducted for steady, two-dimensional natural convective flow in a wavy cavity filled with Darcy porous medium. The waviness of the right wall is described by the amplitude and number of undulations with a well-defined mathematical function. An extension of the present study with the effects of cavity inclination and aspect ratio will be the interest for future work.

Practical implications

The study might be useful for the design of solar collectors, room ventilation systems and electronic cooling systems.

Originality/value

This work examines the effects of sinusoidal heating on convective heat transfer in a wavy porous cavity in the presence of internal heat generation or absorption. The study might be useful for the design of solar collectors, room ventilation systems and electronic cooling systems.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 2
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 29 August 2018

Nwakaego Chikaodinaka Onyenokporo and Ekele Thompson Ochedi

The purpose of this paper is to develop a set of affordable retrofit packages that can be applied to existing residential buildings in hot-humid regions to improve…

Abstract

Purpose

The purpose of this paper is to develop a set of affordable retrofit packages that can be applied to existing residential buildings in hot-humid regions to improve occupants’ thermal comfort and reduce energy consumption.

Design/methodology/approach

A critical review of relevant literature to identify passive design strategies for improving thermal comfort and reducing energy consumption in hot-humid climates with focus on the building envelope was conducted in addition to a simulation study of an existing building typology in study area.

Findings

There is enormous potential to reduce energy costs and improve thermal comfort through building retrofit packages which is a recent concept in developing countries, such as Nigeria. Analysing the results of the retrofit interventions using building energy simulation helped in developing affordable retrofit packages which had optimum effect in improving indoor comfort temperature to the neutral temperature specified for hot humid Nigeria and further down to 3°C less than that of the reference building used. The use of passive design strategies to retrofit the building might help homeowners reduce their annual energy consumption by up to 46.3 per cent just by improving the indoor thermal comfort.

Originality/value

In addition to improving thermal comfort and reducing energy consumption, this research identified affordable retrofit packages and considered its cost implications especially to low-income earners who form a larger population of Lagos, Nigeria, as this was not considered by many previous researchers.

Details

International Journal of Building Pathology and Adaptation, vol. 37 no. 3
Type: Research Article
ISSN: 2398-4708

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Article
Publication date: 1 January 2006

Anwar Hossain and Rama Subba Reddy Gorla

To investigate the effect of viscous dissipation on unsteady, combined convective heat transfer to water near its density maximum in a rectangular cavity.

Abstract

Purpose

To investigate the effect of viscous dissipation on unsteady, combined convective heat transfer to water near its density maximum in a rectangular cavity.

Design/methodology/approach

The upwind finite difference scheme along with successive over relaxation iteration technique is used to solve the governing equations for mixed convection flow of water with density maximum inversion in a rectangular cavity.

Findings

The effect of viscous dissipation was to increase the fluid temperature and resulted in the formation of vortex motion near the lower part of the cavity in an opposite direction to the central vortex. An increase in the Eckert number and Reynolds number of the flow resulted in augmented surface heat transfer rates from the top heated surface.

Research limitations/implication

The analysis is valid for unsteady, two dimensional laminar flow. Isothermal conditions are assumed for the top and bottom walls. An extension to unsteady three dimensional flow case is left for future work.

Practical implications

The method is very useful to analyze nuclear reactor thermal/hydraulic loss of coolant transients, energy conservation, ventilation of rooms, solar energy collection, cooling of electronic equipment, dispersion of waste heat in estuaries and crystal growth in liquids.

Originality/value

The results of this study may be of interest to engineers interested in heat transfer augmentation of mixed convection in window cavities.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 16 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

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