scholarly journals A Study on the Status and Thermal Environment Improvement of Ceiling-Embedded Indoor Cooling and Heating Unit

Author(s):  
Miae Seong ◽  
Cheolsoo Lim ◽  
Daigon Kim ◽  
Sangkyun Kim ◽  
Jaewna Park

In this study, a basic study was performed to analyze the seasonal temperature status of a research room in the Global Environment Research Building where ceiling-embedded indoor units are installed to study the room temperature status of the building as well as to improve its thermal environment. In addition, a direction for improvement of the indoor thermal environment in the winter was proposed through a CFD (computational fluid dynamics) simulation and was proven by an additional experiment. Through the results of this study, it appeared that if the ceiling-embedded indoor unit was installed in the small indoor space without considering the thermal vulnerability of its perimeter boundary, the air temperature of the upper part was greatly different from that of the bottom part in the winter. Hence, in this study, as a means to improve it, convectors were installed to minimize the effect of the external thermal environment and angle-controllable air flowing fans were installed to mitigate the stratification distribution. With such result, it was intended to present the essential data for improvement of the thermal environment as well as conservation of heating energy in the winter for buildings by reviewing the use of the ceiling-embedded indoor unit in the future.

2021 ◽  
Vol 13 (19) ◽  
pp. 10651
Author(s):  
Miae Seong ◽  
Cheolsoo Lim ◽  
Jaehyun Lim ◽  
Jaewan Park

In this study, a basic study was performed to analyze the seasonal temperature status of a research room in the Global Environment Research Building, where ceiling-embedded indoor units are installed to study the room temperature status of the building, as well as to improve its thermal environment. In addition, a direction for improvement of the indoor thermal environment in the winter was proposed through a CFD (computational fluid dynamics) simulation and was proven by an additional experiment. Through the results of this study, it appeared that if the ceiling-embedded indoor unit was installed in the small indoor space without considering the thermal vulnerability of its perimeter boundary, the air temperature of the upper part was greatly different from that of the bottom part in the winter. Based on the PMV measurement result, the case that used both FCUs and convectors showed 1.33, the biggest maximum and minimum difference, and the case that used all FCUs, convectors and circulating fans showed 0.68, the smallest maximum and minimum difference. Therefore, it was considered that the operating method suggested in the room used in this study would improve not only the temperature stratification but also the thermal comfort. Hence, in this study, as a means to improve the stratification, convectors were installed to minimize the effect of the external thermal environment, and angle-controllable air flowing fans were installed to mitigate the stratification distribution. With such a result, it was intended to present essential data for the improvement of the thermal environment, as well as the conservation of heating energy in the winter, by reviewing the use of the ceiling-embedded indoor units in the future.


2019 ◽  
Vol 11 (22) ◽  
pp. 6471 ◽  
Author(s):  
Rui ◽  
Zhang ◽  
Shi ◽  
Pan ◽  
Chen ◽  
...  

Despite their high energy consumption, rural residential houses in the hot summer and cold winter (HSCW) zone still have a generally poor indoor thermal environment. The objective of this study was to understand the current status of the indoor thermal environment for rural residential houses in the HSCW zone and analyze its cause in order to develop some strategies for improvement through passive design of the building envelope. Face-to-face questionnaires and interviews, air-tightness testing, and temperature and humidity monitoring were conducted to understand the building envelope, energy consumption, and indoor thermal environment. Then, some passive design strategies were simulated, including the application of functional interior materials such as hygroscopic and phase change materials. An overall passive design for the building envelope can increase the room temperature by 3.6 °C, reduce the indoor relative humidity by 12% in the winter, and reduce the room temperature by 4.4 °C in the summer. In addition, the annual energy-saving rate can reach ~35%.


Author(s):  
Wei Bing ◽  
Jiang Lu ◽  
Li Li ◽  
Zhiwei Wang

Nowadays the capillary plane HVAC terminal system as an advanced terminal air conditioning system is being widely used. It has many advantages such as thermal comfort, energy conservation and saving indoor space etc. In this paper, with the example of a typical residential room where the capillary plane HVAC terminal system is installed, the indoor thermal environment is simulated and the influence of different capillary mat placement modes is analyzed, three operating modes in summer and winter are simulated by using the method of CFD, and the corresponding temperature fields are presented. Based on the simulation results, the temperature fields are appraised from the view of thermal comfort. These will be good references to the design and application of the capillary plane HVAC terminal system.


Solar Energy ◽  
2006 ◽  
Author(s):  
Bing Wei ◽  
Yuefen Gao ◽  
Xiangning Wang ◽  
Zhiwei Wang ◽  
Li Li

In most emporiums with atrium the phenomena of vertical temperature nonuniformity are very severe, especially in winter. In this paper with an example of emporium with atrium the actual data are measured and by using the method of CFD simulation the indoor thermal environment of the atrium and surrounding area are simulated. The three-dimensional flow fields are studied, the temperature and velocity fields under different air flow organization modes are gained, the effect of the atrium to the whole building is discussed and the corresponding correction method to the indoor space loads, especially the space loads in the upper and lower stories are proposed. The results above will be good references for the design of the emporiums with atrium. The use of the correction method will help to obtain a comfortable and stable indoor thermal environment, and also will be good to the building energy conservation.


Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2776
Author(s):  
Xin Ye ◽  
Jun Lu ◽  
Tao Zhang ◽  
Yupeng Wang ◽  
Hiroatsu Fukuda

Space cooling is currently the fastest-growing end-user in buildings. The global warming trend combined with increased population and economic development will lead to accelerated growth in space cooling in the future, especially in China. The hot summer and cold winter (HSCW) zone is the most densely populated and economically developed region in China, but with the worst indoor thermal environment. Relatively few studies have been conducted on the actual measurements in the optimization of insulation design under typical intermittent cooling modes in this region. This case study was conducted in Chengdu—the two residences selected were identical in design, but the south bedroom of the case study residence had interior insulation (inside insulation on all opaque interior surfaces of a space) retrofitted in the bedroom area in 2017. In August 2019, a comparative on-site measurement was done to investigate the effect of the retrofit work under three typical intermittent cooling patterns in the real-life scenario. The experimental result shows that interior insulation provides a significant improvement in energy-saving and the indoor thermal environment. The average energy savings in daily cooling energy consumption of the south bedroom is 42.09%, with the maximum reaching 48.91%. In the bedroom with interior insulation retrofit, the indoor temperature is closer to the set temperature and the vertical temperature difference is smaller during the cooling period; when the air conditioner is off, the room remains a comfortable temperature for a slightly longer time.


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