Indoor Thermal Environment In Summer Research Articles

Field Study to Compare and Evaluate Summer Thermal Comfort of School Buildings with Different Moderate Thermal Mass in Their Building Elements

Previous studies show that moderate thermal mass in school building elements can positively impact the winter indoor thermal environment in a temperate climate with mild, humid winters. Based on a field study, this research contributes new physical data of the summer indoor thermal environment of Auckland school buildings with different designs of moderate thermal mass in their building elements to add to the previous winter field-study data and demonstrates that a school building with moderate thermal mass is adequate in a temperate climate with mild, humid winters and warm, dry summers. This field study compared and evaluated the summer indoor thermal environment of classrooms with different moderate thermal mass in their building elements during the summer school term and the summer school holidays. This study found that a classroom with thermal mass in its building elements has 19% to 21% more time in summer than a classroom without any thermal mass in its building elements when indoor air temperatures are within the thermal comfort zone, which was solely impacted by the building’s thermal performance. This study established a suitable research method to analyse the field-study data and identify the differences in the indoor thermal environments of the school buildings with different designs of moderate thermal mass in their building elements.

Experimental and numerical study on thermal performance of phase-change-material cool roofs in summer

Cool roofs can reduce building energy consumption and improve indoor and outdoor thermal environments. A phase change material cool roof (PCMC roof) was proposed in order to reduce roof heat gain in the indoor thermal environment in summer. Indoor thermal and energy environmental parameters in three full-size rooms (ordinary room, PCM room, and PCMC room) were tested from July to September 2022. The heat transfer characteristics and energy saving effect of roofs were investigated by combining experimental analysis with numerical analysis. Compared with the ordinary roof, the PCMC roof decreased external and internal roof surface real-time temperatures up to 30.0 °C and 6.4 °C respectively, and reduced the roof inner surface heat flux of 33.3%-66.7%. Compared with the relevant roof studies, the energy saving and cooling effects are more significant. Then, based on the mathematical model of roof heat transfer, the correlation analysis between seven different elements was carried out to evaluate the energy-saving effect of PCMC roof. This study investigates the PCMC roof from the aspects of roof heat transfer characteristics, influence on indoor thermal environment, energy saving evaluation, etc., which provides a more complete and valuable reference for advancing building roofs.

Influence of tunnel ventilation on the indoor thermal environment of a poultry building in winter

Tunnel ventilation systems are widely used to create thermal environments for poultry buildings in China. However, existing research mainly focuses on the indoor thermal environment in summer and rarely considers the winter season. A field test was conducted in a layer breeder building in Handan City, China to systematically investigate the characteristics and problems of the thermal environment in winter. Forty-two measuring points were set to analyze the indoor air velocity and temperature distributions, and the nonuniformity coefficient and temperature humidity velocity index (THVI) were adopted as the evaluation indices. Furthermore, the exhaust fan layout of tunnel ventilation was explored to improve the indoor thermal environment using a validated computational fluid dynamics (CFD) method. The results show that (1) the indoor air velocity distribution is quite nonuniform with a nonuniformity coefficient of 0.74, the maximum difference of which is as large as 0.62 m/s; (2) the nonuniformity coefficient of indoor air temperature distribution is 0.16, and the maximum temperature difference is as large as 12.9°C; (3) the indoor THVI is below the appropriate range of 18–25, making the thermal comfort zone only 61.4%; (4) separately installing exhaust fans at the front and end walls with the symmetrical locations and sizes can improve the distribution uniformities of indoor air velocity and temperature by 22.0% and 88.3%, respectively. The experimental results and parametric optimization of tunnel ventilation in this study will be beneficial for designing an appropriate thermal environment for poultry buildings during winter. • The non-uniformity coefficient of air velocity in experimental poultry house is 0.74. • The maximum difference of air temperature in experimental poultry house is 12.9 °C. • The thermal comfort zone in experimental poultry house is only 61.4% of entire space. • Separately installing exhaust fans on front and end walls improves the environment.

Experimental and Numerical Analysis on Effect of Passive Cooling Methods on an Indoor Thermal Environment Having Floor-Level Windows

Natural ventilation is a common passive cooling method for improving air quality and thermal comfort; however, hot temperatures in summer and safety and privacy issues at night often result in its unideal performance. Therefore, we proposed the use of floor-level windows, mainly combined with microclimate improvement, to improve the indoor thermal environment by enhancing the cooling effect of natural ventilation during summer. Our study area was a house in Machida, Tokyo. We evaluated the effectiveness of our method in improving the indoor thermal environment in summer and performed a numerical simulation, while illustrating the detailed horizontal and vertical distribution of airflow in the house through the floor-level windows. The influence of different window types and opening angles of floor-level windows on ventilation and cooling was determined using the simulation. We found that: (a) natural ventilation-based passive cooling methods reduced semi-outdoor and indoor temperature and increased the humidity; (b) the airflow formed an indoor wind path; south-westerly inflow was from western floor-level windows and the skylight, and the outflow was from northern floor-level windows; and (c) the side hung windows (with an opening angle of 60°) were an ideal option to improve indoor airflow. However, there was no improvement in the passive cooling performance, due to the inflow of warmer outside air.

Evaluating the improvement effect of low-energy strategies on the summer indoor thermal environment and cooling energy consumption in a library building: A case study in a hot-humid and less-windy city of China

Public buildings such as libraries consume a vast amount of cooling energy for maintaining a comfortable and stable indoor environment in summer, especially in the hot-humid climate. This study used a case study approach to discuss the effect of low-energy strategies that can be applied to improve indoor thermal environment and cooling energy consumption of library buildings in hot and humid cities like Nanning City (a southern city, China). The use of cooling window shutters (a shutter with the effects of shading and evaporative cooling) and ceiling fans for generating airflow was considered as applicable energy-saving measures in this study, and a university library was selected as the study building in which the two energy-saving measures were employed. The SET* and annual cooling load before and after the adoption of the proposed measures were quantitatively investigated with a building energy consumption simulation software (DesignBuilder). Simulation results showed that the daytime SET* values can be reduced by 3.0 °C and 4.5 °C respectively on a typical summer day after the use of the cooling shutters and ceiling fans. Moreover, the cooling loads can also be decreased by 8.4% and 16.6% respectively. Particularly, the combination of these two measures enabled the daytime SET* value and annual cooling load lower by 7.0 °C and 60.8% respectively.

Field experiments on the effects of an earth-to-air heat exchanger on the indoor thermal environment in summer and winter for a typical hot-summer and cold-winter region

An earth-to-air heat exchanger (EAHE) is a shallow geothermal energy utilization technology, which can significantly reduce the building energy consumption. This study aims to investigate the effects of an EAHE on the indoor thermal environment in hot-summer and cold-winter regions. A full-scale experiment was conducted for a continuous 24 h period using two identical buildings (with and without an EAHE) exposed to the same outdoor conditions on typical summer and winter days. Experimental results show that the EAHE provides an average outdoor air temperature reduction of 9.12 °C under cooling conditions and increase of 5.53 °C under heating conditions. Moreover, the average outdoor air relative humidity increases by 46.89% and decreases by 27.41% in the cooling and heating conditions, respectively; the corresponding average EAHE coefficients of performance (COP) are 7.03 and 4.26, respectively. Compared to that of the building without EAHE, the average indoor air temperature of the building with EAHE decreases by 5.9 °C in summer and increases by 4.29 °C in winter, and the average walls’ internal surface temperature decreases by approximately 6 °C and increases by approximately 5.8 °C. Moreover, the EAHE system reduces the average building cooling and heating loads by 55.4 and 40.43 W/m2, respectively.

The SPA-TOPSIS-Based Evaluating Approach on Thermal Sensation Model at Different Vane Angles in UFAD–DV System

Under floor air distribution system and displacement ventilation (UFAD–DV) system is used to provide comfortable indoor thermal environment in summer, which largely satisfies overall and local thermal sensation. In UFAD–DV system, the selection of supply vane angle is particularly important to achieve the best thermal comfort. This paper studied thermal sensation of a manikin in sedentary state through the AIRPAK simulations. Firstly, in order to analyze the influence of the local thermal sensation on overall thermal sensation (OTS), the manikin model consisting of five local body parts was constructed. Then, the set pair analysis technique for order preferences by similarity to an ideal solution (SPA-TOPSIS) method was proposed to analyze the overall thermal sensation model and the combination model of overall and local thermal sensation at different supply vane angles. Finally, according to the SPA-TOPSIS analysis, the combination model of overall thermal sensation and local thermal sensation was determined and the best supply vane angle was 10° downward. The PMV and PPD values of each part of the body and overall body were 0.1932, 0.3413, 0.2287, 0.0503, − 0.0992, 0.173 and 5.9721, 7.5005, 6.377, 5.2632, 5.2579, 6.79, respectively. The weight coefficient method was used for the validation of SPA-TOPSIS-based evaluating results with p < 0.05. In addition, the thermal sensation of foot has important impact on thermal sensation, and the ideal integrated thermal sensation of five local body parts and overall body was achieved. The proposed SPA-TOPSIS-based evaluation approach can determine the best supply vane angle, which optimizes the OTS on the premise of satisfying the local thermal sensation.

Study on the Cooling Effect of Window Gardens

Window gardens are known to provide a window view with psychological and physiological benefits, whether they can be used for passive cooling of buildings remains to be investigated. This paper aims to supplement the impact of window gardens on the thermal performance of windows, walls, and even indoor air temperatures, which previous research has ignored. A field experiment was conducted for two classrooms with integrated planting troughs outside the windows, with and without living plants. The indoor air temperature and the interior surface temperature of the two classrooms were measured on a typical hot summer day, with windows closed and air conditioners switched off. The results show that: Window garden with living plants can not only reduce the average temperature of the indoor air by 1.1 ℃, but also reduce the average temperature of the interior surface of the building envelope by 2.8 ℃, the reduction of interior surface temperature is more obvious, which is due to the formation of a cold bridge. Therefore, Window garden can improve the summer indoor thermal environment in hot summer and warm winter area in China.

Performance Evaluation and Optimization of a Building-Integrated Photovoltaic/Thermal Solar Water Heating System for Exterior Shading: A Case Study in South China

Building-integrated photovoltaic/thermal (BIPV/T) systems can produce both electrical and thermal energy through the use of photovoltaic/thermal modules integrated with building envelope. Exterior shading is a common way to improve summer indoor thermal environment of the buildings in low latitudes. This study presents a BIPV/T solar water heating system for exterior shading of residences. In order to evaluate and optimize the system performances, a model was developed to simulate the thermal and electrical production of such system. The simulations for an example system in Guangzhou, a city in South China, were performed to investigate the influences of tank installation height and panel tilt angle on system performances. According to simulation results, the suggested tank installation height is 0.6~0.8 m. The shading coefficient ranges from 0.797 to 0.828 when the tilt angle varies from 14° to 38°. The reduction of panel tilt angle causes a certain improvement of shading performance. The annual auxiliary heat reaches the minimum when the panel tilt angle equals 28°, and the annual electric energy output changes little when the panel tilt angle ranges from 20° to 28°. Comprehensively considering thermal, electrical, and shading performances, the suggested panel tilt angle is 20°~28°. The average thermal and electrical efficiencies are respectively 38.25% and 11.95% when the panel tilt angle ranges from 20° to 28°. The presented system is a promising way to provide hot water, electricity, and exterior shading for residences.

Review of phase change heat storage and night ventilation technology of buildings

Building energy consumption is an important part of total energy consumption in societies; conservation of building operation energy is vital for sustainable development. The use of air conditioning systems to maintain a comfortable summer indoor thermal environment is a common practice in modern buildings, which consumes a large amount of nonrenewable energy and is detrimental to energy efficiency and human health. A passive building energy efficiency strategy is used to enhance the building’s own performance and make complete use of natural energy to create a comfortable indoor thermal environment. Building passive energy conservation strategy is a powerful way to achieve sustainable development, promote economic development, and facilitate environmental protection. Phase change heat storage technology and night ventilation technology are efficient energy saving measures utilized in passive buildings. Phase change heat storage regulates the indoor heat distribution effectively through the phase change period to reduce the peak temperature and increase the lowest temperature in the indoor environment. Furthermore, ventilation during summer nights carries a lot of natural cooling and directly reduces the temperature of the indoor environment. The composite technology that integrates phase change thermal storage and night ventilation can significantly improve the summer indoor environment and reduce cooling energy consumption. The phase change material can absorb extra heat during daytime when indoor environment is hot and release it at night. Simultaneously, night ventilation can remove the heat released by the phase change material and provide cooling capacity to materials, thereby promoting the phase change process. Therefore, this composite technology can reduce the indoor temperature throughout the day. Moreover, the technology uses phase change heat storage to enhance the thermal stability of buildings and to solve the mismatch problem pertaining to the short-term supply of natural cooling resources and whole-day cooling demand of buildings. Alternatively, the technology utilizes night ventilation to fully acquire the natural cooling resources. In this paper, research progress of phase change heat storage and night ventilation cooling technology is reviewed based on the survey of the main field research on phase change heat storage, night ventilation, and composite cooling technology. This paper analyzes the components of the composite cooling technology from the aspects of technical principles, experimental research, energy savings, and cooling effects. The analysis shows that reasonable application of the composite cooling technology can obtain comfortable indoor environments and reduce cooling energy consumption during summer. This paper analyzes the mutual influence relationship between the constituent elements of the composite cooling technology. The technology is affected by various conditions, including climatic conditions, phase change heat storage models, ventilation strategies, etc. Furthermore, there is an urgency to perfect the thermal design standard of these technologies. Finally, the paper presents the prospects for further investigating the composite cooling mechanism and optimizing the thermal design strategy, and indicates the need for further in-depth research in the coupling mechanism of the technology and thermal design methods. This paper could help architects, engineers, and researchers understand these building passive energy saving technologies.

置換換気方式を導入した食品工場における室内温熱環境の調査研究 : 第1報-夏期・中間期の室内温熱環境の実態調査と省エネルギー効果の試算

置換換気方式を導入した食品工場における室内温熱環境の調査研究 : 第1報-夏期・中間期の室内温熱環境の実態調査と省エネルギー効果の試算

Applying passive cooling measures to a temporary disaster-relief prefabricated house to improve its indoor thermal environment in summer in the subtropics

Temporary prefabricated houses (PHs) can be effective in quickly providing disaster victims with a temporary living place whenever there is a natural disaster. Unfortunately, PHs commonly used for disaster relief purpose do not ensure a thermal comfortable internal conditions for their occupants. In order to search for approaches of improving PH’s thermal environment, a simulation model was firstly developed using Energyplus, and validated by comparing the simulated data with the measured data obtained from a purposely built experimental PH . An analysis on summer heat gain based on the validated model showed that PH’s windows were responsible for the lion’s share of the total heat gain, followed by the roof and east wall. Besides, the effectiveness of applying various passive measures to the PH was studied. The study results suggested that adding a thin movable fabric layer of 0.9 reflectance to the walls and roof, and external window blinds would lead to a very high percentage reduction in unacceptable hours, without however the need to implement all four passive measures, to save the cost of implementation.

Measurement and evaluation of indoor thermal environment in a naturally ventilated industrial building with high temperature heat sources

In this study, indoor thermal environment and workers' perceptions were investigated at four different locations in a naturally ventilated industrial building with high temperature heat sources in summer and winter. The results demonstrated that the differences between the mean radiant temperature and air temperature were between 0.8 °C and 5.3 °C in summer and between 1.6 °C and 11.0 °C in winter, and the average air velocity generally ranged from 0.3 m/s to 1.5 m/s. Moreover, the average wet bulb globe temperature (WBGT) was between 27.3 °C and 29.0 °C in summer and between 5.7 °C and 8.9 °C in winter, which coincided with the workers' perceptions of the thermal environment. The WBGT thus may be one of the potential indices to evaluate the indoor thermal environment in summer and winter. A prediction model for the indoor WBGT using the thermal environmental parameters was developed strictly based on the law of analogy for heat and mass transfer. The predictions agreed quite well with the measured data for WBGT of between 24 °C and 30 °C in summer and 2 °C–10 °C in winter, and the absolute differences between the predicted and measured WBGT were between 0 °C and 1.1 °C with an average of 0.3 °C in summer and between 0 °C and 1.2 °C with an average of 0.5 °C in winter. Therefore, the proposed indoor WBGT prediction model was valid and can be used to determine the acceptable thermal environmental parameters during the design stage for naturally ventilated industrial buildings with high temperature heat sources.

Thermal Performance of a New Type of Phase Change Material Room in Summer and Winter

For lots of areas in the world, the indoor thermal environment is terrible both in summer and in winter. The thermal environment needs to be improved for both the two seasons. A new type of phase change material (PCM) room is proposed in this paper. That is to lay two different kinds of PCM on room envelopes of different orientations. In this paper, the new PCM room and room without PCM are all built. Experiment is done for the two rooms under actual climate condition. Indoor air temperature, wall internal surface temperatures are measured. Results show that the new type of PCM room can improve indoor thermal environment in summer and winter.

Architecture and Planning Design Strategy of Post-disaster Temporary Settlement with High Building Density——Analysis Based on the Questionnaire in Dujiangyan after Wenchuan Earthquake

After Wenchuan earthquake, there occurred a lot of post-disaster temporary settlements with high building density, which was the first case in our country or in the world. Over 200 victims in Dujiangyan were randomly investigated with questionnaire after they had left temporary settlement areas and had been settled in their permanent houses. It showed that the abominable summer indoor thermal environment was what most interviewees could not bear most, and that the tolerance for the indoor thermal environment related to some objective conditions of subjects’ temporary buildings. Based on the analysis of this relationship, some flaws of architecture and planning design were discovered. Furthermore, in order to improve the summer thermal environment of post-disaster temporary settlement, some strategies were proposed in this paper.

Test Study of the Thermal Environment in Summer of New and Old Two Types of Rural Houses in QiLian Mountain Northern Foothills Area

This study aimed to analyze the summer indoor thermal environment of new and old two types of rural houses in QiLian Mountain northern foothills area. The method of analysis is field testing. The result shows the relationship between indoor thermal environment and envelope materials, location of rooms. In addition, the influence was Quantified in 1~2° C. Finally, advice put forward to promote the indoor thermal environment.

Indoor Thermal Environment Simulation of Xi'an Residential Building in Summer

Natural ventilation is an important role to improve the residential building indoor thermal environment in summer. This paper use Energy Plus to simulate indoor thermal environment and use CFD to simulate indoor air flow for Xi’an residential building, analysis the influence that different ventilation mode for indoor thermal environment factors. Then with the simulated result of PMV-PPD value to estimate indoor thermal comfort. Proved night ventilation is necessary in residential building in Xi’an and effectiveness to improve indoor thermal comfort.

Performance analysis on a residential radiant chilled ceiling system and evaluation on indoor thermal environment in summer: an application

The performance of a residential radiant chilled ceiling system combined with an outdoor air handling unit under steady operating conditions in summer was tested, and the stable operating characteristics of this system were analyzed. Indoor thermal environment parameters of room which employed this system were measured and analyzed and the thermal comfort evaluation of occupants was given. The results show that the composite system works well in summer, which can provide low- and high-temperature chilled water for the air supply terminal and the radiant terminal devices. Good thermal comfort can be achieved in room which employed this system, and no condensation risk occurs when it is applied in hot summer and cold winter zone of China. All the analysis provides a technical support for the popularization of the residential radiant chilled ceiling system combined with an outdoor air handling unit in China, and provides a reference for the further optimization of this system.

A-20 非空調の大空間作業室における熱環境特性に関する研究(その1)夏期の室内環境評価アンケート及び熱環境測定(学術研究)

A-20 非空調の大空間作業室における熱環境特性に関する研究(その1)夏期の室内環境評価アンケート及び熱環境測定(学術研究)

Statistical analyses on summer energy consumption characteristics of residential buildings in some cities of China

The purposes of this paper are to analyse energy consumption characteristics and to find out influence factors of residential energy consumption in summer in typical cities of China. The investigated residences were located in seven cities of five architecture thermotechnical design zones. Questionnaire surveys revealed housing unit characteristics, household characteristics, the possession and utilization of domestic energy consuming appliances and indoor thermal environment in summer. Energy consumption analyses show that summer energy consumption amounts in different cities bear distinct regional characteristics: the household amounts of electricity use are largest in Hongkong, and the values are smaller but still at a high level in Beijing, Shanghai and Changsha, and at the smallest level in Kunming, Harbin and Urumqi, while the difference in gas use is small among these cities. Influence factor analyses show that city locations, housing unit characteristics, the utilization of space coolers and water heaters, household characteristics, and subjective evaluation of indoor thermal environment all contribute to the residential energy consumption in summer when taking all the families in the seven cities as the sample collectivity, while detail analyses for separate cities shows each city has its own characteristics. In Shanghai, the satisfaction rate of thermal environment, the possession and operation of air conditioners and housing unit characteristics greatly affect the summer energy consumption, but the electrical fan is judged as the non-influence factor, while in Urumqi, the possession and operation of electrical fans and the categories of water heaters have remarkable effect, and the influence of housing unit characteristics is also distinct, but the number of air conditioners and their usage contribute little to energy use due to the cool climate.