The influence of thermal insulation position in building exterior walls on indoor thermal comfort and energy consumption of residential buildings in Chongqing

Purpose From the 2000s onward, construction practices of urban residential buildings in China have shown a material transformation from clay brick to aerated concrete block. Moreover, the consumption of insulating materials for buildings has been increasing due to the new requirements in building energy-saving standards. This transformation and the increased consumption of insulating materials might have a vital impact on a building’s thermal comfort and its associated energy flows. Therefore, the purpose of this paper is to investigate the indoor thermal performance of urban residential buildings built with different materials and further discuss the correlations between indoor thermal comfort and the associated energy input. Design/methodology/approach This study investigated four residential buildings selected from four residential communities located in the cold climate zone of China. The Integrated Environment Solutions program was used to evaluate the thermal comfort levels and to quantify the operational energy consumption of the case study buildings. Additionally, the University of Bath’s Inventory of Carbon and Energy database was used to estimate the embodied energy consumption and CO2 emissions. Findings The study found that materials transition and increasing consumption did not necessarily improve indoor thermal comfort. However, the materials transition has significantly decreased the embodied energy consumption of urban residential buildings. Furthermore, the increased utilization of insulating materials has also decreased the heating and cooling energy consumption. Therefore, overall, the environmental impacts of urban residential buildings have been reduced significantly. Practical implications In the future, residential buildings completed in the 1990s will need regular maintenance, such as adding insulation. Residential buildings completed based on the latest energy-saving requirements should optimize their ventilation design, for example, by increasing the ventilation rate and by reducing solar heat gains in the summer. Originality/value This paper investigates the effects of the materials change on thermal comfort levels and the environmental impacts of urban residential buildings in the cold climate zone of China, as these have not been the focus of many previous studies.

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Effect of insulation on indoor thermal comfort in a detached house with a floor heating system

E3S Web of Conferences ◽

10.1051/e3sconf/201911102049 ◽

2019 ◽

Vol 111 ◽

pp. 02049 ◽

Cited By ~ 1

Author(s):

Qianwen Guo ◽

Ryozo Ooka ◽

Wonseok Oh ◽

Wonjun Choi ◽

Doyun Lee

Keyword(s):

Thermal Comfort ◽

Thermal Insulation ◽

Energy Savings ◽

Residential Buildings ◽

Insulation Material ◽

Indoor Thermal Comfort ◽

Detached House ◽

The Impact ◽

Floor Heating ◽

Floor Temperature

Appropriate insulation materials, with unique physical properties and of moderate thickness, are essential for energy savings in residential buildings. However, the impact of thermal insulation on indoor thermal comfort with floor heating systems has not been studied extensively. In this study, simulations of a typical Japanese detached house were conducted with four different thicknesses of insulation material in the walls, ceiling, and floor to estimate the mean air temperature (MAT), mean radiant temperature (MRT), floor temperature, predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD). The results showed that increasing the thickness of thermal insulation increased the MAT and MRT by 1.4 – 4.0 ℃ and 1.3 – 4.4 ℃, respectively. Moreover, as the thickness of the thermal insulation increased, the floor temperature rose and exhibited smaller fluctuations. Finally, it was found that increasing the thickness of thermal insulation improved the indoor thermal comfort environment, as evidenced by an increase in the PMV from –1.0 to 0.3, and a decrease in the PPD from 25.1% to 9.5%.

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Sodium acetate–urea composite phase change material used in building envelopes for thermal insulation

Building Services Engineering Research and Technology ◽

10.1177/0143624417743491 ◽

2017 ◽

Vol 39 (4) ◽

pp. 475-491 ◽

Cited By ~ 2

Author(s):

Yin Zhang ◽

Xin Wang ◽

Zhiyuan Wei ◽

Yinping Zhang ◽

Ya Feng

Keyword(s):

Energy Consumption ◽

Thermal Comfort ◽

Phase Change ◽

Phase Change Material ◽

Thermal Insulation ◽

Sodium Acetate ◽

Building Envelopes ◽

Indoor Thermal Comfort ◽

Composite Phase Change Material ◽

Change Material

Integrating phase change material with building envelopes is an effective way to reduce cooling or heating loads, improve indoor thermal comfort and save building energy consumption. In this paper, the composite phase change material of sodium acetate and urea is prepared and its thermal–physical properties with different mixing mass ratios are investigated through experiment and T-history method. Moreover, the heat transfer model of building envelopes with phase change material is established and different phase change material locations in external walls for thermal insulation are compared based on integrated uncomfortable degree. The results show that (1) with rising urea mass fraction, both phase change temperature and latent fusion heat (enthalpy) decline; (2) strontium sulfate is an effective nucleating additive to decrease super-cooling degree for such phase change material solidification and (3) to improve indoor thermal comfort, it is preferable to put phase change material in the middle of external walls. Furthermore, the illustrative example of an office building in Chengdu indicates that phase change material insulation can lead to time lag and decrement for indoor air temperature variations. It also indicates that after inserting such phase change material into building external wall, the highest indoor temperature can be decreased by 7℃, leading to 60% cooling energy saving in one typical summer day. This work can provide guidance for building thermal design with phase change materials. Practical application:The studied sodium acetate–urea composite phase change material has been used as energy storage and thermal insulation materials inserted in envelopes for the demonstration project of low/zero energy consumption passive buildings in China.

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Research on the Thermal Environment of Northeast China's Rural Residences

Open House International ◽

10.1108/ohi-01-2017-b0008 ◽

2017 ◽

Vol 42 (1) ◽

pp. 52-57

Author(s):

Cheng Sun ◽

Meng Zhen ◽

Yu Shao

Keyword(s):

Energy Consumption ◽

Thermal Comfort ◽

Energy Saving ◽

Thermal Insulation ◽

Northeast China ◽

Rural Residence ◽

Residential Energy ◽

Residential Energy Consumption ◽

Indoor Thermal Comfort ◽

Rural Residences

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.

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Energy-saving potential of intermittent heating system: Influence of composite phase change wall and optimization strategy

Energy Exploration & Exploitation ◽

10.1177/0144598720969217 ◽

2020 ◽

pp. 014459872096921

Author(s):

Yanru Li ◽

Enshen Long ◽

Lili Zhang ◽

Xiangyu Dong ◽

Suo Wang

Keyword(s):

Energy Consumption ◽

Thermal Comfort ◽

Phase Change ◽

Air Temperature ◽

Indoor Air ◽

Thermal Environment ◽

Optimization Strategy ◽

Indoor Thermal Environment ◽

Indoor Thermal Comfort ◽

Intermittent Heating

In the Yangtze River zone of China, the heating operation in buildings is mainly part-time and part-space, which could affect the indoor thermal comfort while making the thermal process of building envelope different. This paper proposed to integrate phase change material (PCM) to building walls to increase the indoor thermal comfort and attenuate the temperature fluctuations during intermittent heating. The aim of this study is to investigate the influence of this kind of composite phase change wall (composite-PCW) on the indoor thermal environment and energy consumption of intermittent heating, and further develop an optimization strategy of intermittent heating operation by using EnergyPlus simulation. Results show that the indoor air temperature of the building with the composite-PCW was 2–3°C higher than the building with the reference wall (normal foamed concrete wall) during the heating-off process. Moreover, the indoor air temperature was higher than 18°C and the mean radiation temperature was above 20°C in the first 1 h after stopping heating. Under the optimized operation condition of turning off the heating device 1 h in advance, the heat release process of the composite-PCW to the indoor environment could maintain the indoor thermal environment within the comfortable range effectively. The composite-PCW could decrease 4.74% of the yearly heating energy consumption compared with the reference wall. The optimization described can provide useful information and guidance for the energy saving of intermittently heated buildings.

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Determination of Optimum Envelope of Religious Buildings in Terms of Thermal Comfort and Energy Consumption: Mosque Cases

Energies ◽

10.3390/en14206597 ◽

2021 ◽

Vol 14 (20) ◽

pp. 6597

Author(s):

Ahmet Bircan Atmaca ◽

Gülay Zorer Gedik ◽

Andreas Wagner

Keyword(s):

Thermal Properties ◽

Energy Consumption ◽

Thermal Comfort ◽

Thermal Insulation ◽

Energy Savings ◽

Gain Factor ◽

Building Envelope ◽

Comfort Level ◽

Humid Climate ◽

Savings Rate

Mosques are quite different from other building types in terms of occupant type and usage schedule. For this reason, they should be evaluated differently from other building types in terms of thermal comfort and energy consumption. It is difficult and probably not even necessary to create homogeneous thermal comfort in mosques’ entire usage area, which has large volumes and various areas for different activities. Nevertheless, energy consumption should be at a minimum level. In order to ensure that mosques are minimally affected by outdoor climatic changes, the improvement of the properties of the building envelope should have the highest priority. These optimal properties of the building envelope have to be in line with thermal comfort in mosques. The proposed method will be a guide for designers and occupants in the design process of new mosques or the use of existing mosques. The effect of the thermal properties of the building envelope on energy consumption was investigated to ensure optimum energy consumption together with an acceptable thermal comfort level. For this purpose, a parametric simulation study of the mosques was conducted by varying optical and thermal properties of the building envelope for a temperature humid climate zone. The simulation results were analyzed and evaluated according to current standards, and an appropriate envelope was determined. The results show that thermal insulation improvements in the roof dome of buildings with a large volume contributed more to energy savings than in walls and foundations. The use of double or triple glazing in transparent areas is an issue that should be considered together with the solar energy gain factor. Additionally, an increasing thickness of thermal insulation in the building envelope contributed positively to energy savings. However, the energy savings rate decreased after a certain thickness. The proposed building envelope achieved a 33% energy savings compared to the base scenario.

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From Construction to Operation: Achieving Indoor Thermal Comfort via Altering External Walls Specifications in Egypt

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.689.250 ◽

2013 ◽

Vol 689 ◽

pp. 250-253 ◽

Cited By ~ 2

Author(s):

Mohamed M. Mahdy ◽

Marialena Nikolopoulou

Keyword(s):

Energy Consumption ◽

Thermal Comfort ◽

Natural Ventilation ◽

Minimum Energy ◽

Residential Energy ◽

Indoor Thermal Comfort ◽

Minimum Energy Consumption ◽

Different Types ◽

Running Cost ◽

The Cost

The objective of this research is to study the effect of using different material specifications for the external walls on the cost of the energy consumption for achieving internal thermal comfort. We refer to this as operation running cost, which in turn is compared to initial construction cost for each type of the used external walls. In order to achieve this objective, dynamic thermal simulation were carried out for four different types of external walls – commonly used in Egypt – in two different sets of cooling: natural ventilation and mechanical means. Experiments recommend that using the Egyptian Residential Energy Code (EREC) to achieve inner thermal comfort with the minimum energy consumption (consequently the minimum CO2 emissions) and the minimum running cost as well.

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