Thermal performance evaluation of low-income buildings based on indoor temperature performance

Lee, Junghun,Kim, Seohoon,Kim, Jonghun,Song, Doosam,Jeong, Hakgeun Elsevier 2018 APPLIED ENERGY Vol.221 No.-

<P><B>Abstract</B></P> <P>In South Korea, about 40,000 buildings of low-income households have been diagnosed and remodeled annually by the Energy Welfare Program, using the normative method. The normative method is based on the heat gain elements of a building. In contrast, the performance-based method is based on the output derived from the thermal performance of each building part. In the normative method, there is no other building in which the input conditions of a building are perfectly matched. Further, cost-effective energy remodeling strategies vary according to the capacity of the diagnosis engineer. In this paper, we analyze the thermal performance of buildings by the performance-based method using indoor temperature, and examine the possibility of a database for the optimal remodeling method. For this, we analyzed more than 2500 simulation cases by combining thermal performance of each building part. The indoor temperature pattern can be similar even when the thermal performance of each building part is different. In buildings with similar indoor temperature patterns, the coefficient of variation of the root mean squared error of energy demand falls within the acceptable error range. Furthermore, changes in energy demand and predicted mean vote are similar when window thermal performance is changed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Indoor temperature pattern can be similar even building conditions are different. </LI> <LI> If similar indoor temperature patterns occur, energy demand is also similar. </LI> <LI> Changes in energy demand are similar when window thermal performance is changed. </LI> <LI> Overall thermal performance of low-income buildings can be diagnosed. </LI> <LI> Databases can store remodeling plans using indoor temperature for future use. </LI> </UL> </P>

PBO/m-aramid 평직물과 SiC 섬유로 제조된 평직물의 3D 유한요소모델 생성 및 열보호 성능 시뮬레이션 연구

심지현,이종혁,지영주,유성훈,배진석 한국섬유공학회 2021 한국섬유공학회지 Vol.58 No.5

In this study, a 3D model of a PBO/m-aramid and SiC fabric was created in a virtual space to evaluate the thermal protection performance of each material used in firefighting suits, and a thermal protection performance simulation study was conducted with an aim to reduce the material development lead time and development cost. To compare the thermal protection performance of the PBO/m-aramid fiber woven fabric, which is the material used for the outer fabric of the existing fire-fighting clothing, and the SiC fiber woven fabric with different fabric densities (high, medium, and low density), a thermal protection performance analysis was conducted for each yarn model after creating the geometry of the fabric model and the finite element model using virtual engineering software. To analyze the thermal protection performance according to the density difference of the SiC fiber woven fabrics, three-dimensional (3D) models of the three types of fabrics with low, medium, and high densities were created. The thermal protection performance analysis compared the thermal protection performance against the radiation heat source exposure of the PBO/m-aramid woven fabrics and the SiC woven fabrics according to density as stated by the KS K ISO 6942 radiant heat protection test method, which is the concrete test standard. A comparison revealed that the thermal protection performance of the SiC material was superior to that of the PBO/m-aramid material, and the high-density woven SiC fabric exhibited the best thermal protection performance.

열관류율[U<SUB>f</SUB>] 1.0 W/㎡·K 이하 커튼월 프레임 개발을 위한 부품 항목 및 성능 영향 연구

박혜영(Park, Hye-Young),박성중(Park, Sung-Jung) 한국건축친환경설비학회 2020 한국건축친환경설비학회 논문집 Vol.14 No.5

Compared to overseas curtain wall products, domestic curtain wall products have a negative thermal performance. To develop curtain wall frame with thermal conductivity 1.0 W/㎡·K or less, it is importance to figure out the thermal performance factors and effects of each part or curtain wall frame. In this work, thermal performance factors such as form and material were classified on 6 parts; aluminium part, gasket, thermal break bar, gasket for setting wimdow, aluminium cover and screw. The thermal performance effect of each part were also calculated according to ISO 12631 and the results were present as a thermal performance improvement rate with in range from the lowest curtain wall thermal transmittance to the highest. The results show that it is thermal break bar which has greatest effect on improving the thermal performance of curtain wall, especially with soft PE foam.

차량용 램프 내열인자에 대한 해석적 연구

장영기(Youngki Chang),김미로(Miro Kim),안병재(Byungjae Ahn) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

The thermal performance is one of the most important factors in evaluating an automotive lamp, and is not easy for engineer to improve due to the diversified lamp designs. Achieving a better thermal performance in automotive lamps requires that every component consisting of the lamp such as reflector, bezel, lens, etc maintains its shapes and colors without any deforming or fading from the heat transfer of the bulb. It has been a courtesy that its thermal performance has been verified with experiments and CFD after the design is complete. However, the shortening automobile development period and the frequent changes in design corrupt the effectiveness of the test procedure in the thermal performance. In this study, nine factors of thermal performance were chosen and evaluated their effects on thermal performance. Among them, three main factors were studied to attain thermal performance using CFD. On the completion of this study, it is expected that the thermal performance of automotive lamps can be achieved before the stage of the thermal experiment and CFD.

Evaluation of Electrical Heating Performance and Thermal Insulation of Commercial Electrically Heated Inner Suit for a Dry Immersion Suit

김혜림,이선희 한국섬유공학회 2021 한국섬유공학회지 Vol.58 No.2

In this study, the electric heating performance of a smart heated inner suit wasevaluated as basic data for localization of a dry immersion suit being developed abroad toprevent hypothermia, and its thermal insulation capability was analyzed using a thermalmannequin. Accordingly, two types of smart heated inner suits, namely a dry suit (Suit_IN)and a dry immersion suit (Suit_OUT), were selected along with a location for measuringthe thermal insulation in accordance with KS V ISO 15027-3. Then, the surface and innertemperatures of the suits were measured, and the thermal resistance and thermal insulationproperties were analyzed using the mannequin. Upon supplying power, the innertemperature of Suit_IN was approximately 45 °C, with a slightly higher value of about 53 °Cin the stomach area. In addition, it was confirmed that the hand portions had the highesttemperature of approximately 55 °C. After wearing Suit_IN and Suit_OUT, the inner temperatureof the hand part increased by approximately 25 °C compared to wearing onlySuit_IN, whereas the temperatures of the other parts improved by 5-10 °C, thereby improvingthe total heat generation performance. To confirm the thermal insulation of each partfor each sample, measurements were obtained using a thermal mannequin under environmentalconditions similar to the underwater environment in winter. The thermal resistancewas observed to be large in and around the stomach area where power was supplied, andthe thermal resistances of the hand and foot areas were low owing to the presence ofopenings. In addition, the thermal insulation property (Clo) when wearing both Suit_INand Suit_OUT was approximately twice that of wearing only a single suit. Therefore, wearingboth suits would enable maintaining the body temperature and preventing hypothermiain extreme underwater environments.

C-스터드 이격용 클립을 적용한 석고보드 건식벽체 시스템의 단열 및 구조성능 평가

송진희,이혜림,이경국 한국생태환경건축학회 2022 한국생태환경건축학회 논문집 Vol.22 No.2

Purpose: Dry-wall systems, which use gypsum boards and steel C-studs, are widely used because they have many advantages. They are lightweight and have a faster construction period and easy construction. Dry-wall systems should achieved thermal-insulation performance according to their applications, such as a wall indirectly or directly adjacent to the outdoors. In this case, the proper thickness of the thermal insulation is determined in the design stage. However, steel C-studs, which penetrate the insulation layer repeatedly at 450㎜ or 600㎜ for installation of insulation materials and finishing boards, lead to additional heat loss. They also reduce the thermal insulation performance in the field. Thus, in this study, C-studs with separating clips were proposed to reduce the additional heat loss due to C-studs, and their structural and thermal insulation performance was evaluated. Method: To compare typical C-studs and proposed C-stud with separating clips, certified thermal-transmittance tests, according to the KS F 2277 - determination of steady-state thermal transmission properties, were conducted. The first test specimen used typical C-studs and the second used the proposed C-studs. The linear thermal transmittances of each stud were calculated and compared. In addition, a structural analysis of the proposed C-studs was conducted to evaluate the structural stability and find the proper fixing interval of the separating clips. Result: The thermal transmittance of the proposed C-stud dry-wall system is 0.37W/㎡K, which is 28.8% less than that of the typical C-stud dry-wall system, 0.52W/㎡K. The linear thermal transmittances of the typical and proposed studs were 0.117 and 0.061W/mK, respectively.

필름 코팅 유리의 열성능 향상에 관한 연구

최윤정(Choe, Yun-Jeong),조재훈(Jo, Jae-Hun) 한국건축친환경설비학회 2012 한국건축친환경설비학회 학술발표대회 논문집 Vol.2012 No.10

As for a building, heat loss occur most in its windows. Therefore, in this study, this researcher tries to improve thermal performance of glass part of windows that is made from porous materials and features high insulation. This study analyzed the factors affecting thermal performance after surveying calculation method of glass thermal performance which is suggested by ISO, international standard. Next, target thermal performance of windows were selected to calculate the value of glass thermal performance. Lastly, the performance value of each factor affecting thermal performance and glass configuration that satisfy the value of glass thermal performance.

주거건물에서 동일한 열성능을 나타내는 자연 실내온도 범위에 대한 연구

이정훈(Jung-Hun Lee),장철용(Cheol-Yong Jang),송두삼(Doo-Sam Song),김정국(Jeong-Gook Kim),이미진(Mi-Jin Lee),김종태(Jong-Tae Kim),김종훈(Jong-Hun Kim) 대한설비공학회 2016 대한설비공학회 학술발표대회논문집 Vol.2016 No.6

There are amount of research for reducing the energy consumption. However, cause the generalization problem, the optimum value or control strategies couldn’t apply to other buildings which have different input conditions with target building. To solve this, the performance-based method is used and it use the natural indoor temperature. Although there are no building have same indoor temperature pattern, the thermal performance could be similar if it is in the acceptable range. In this study, find out the acceptable error range of indoor temperature which have the similar thermal performance. For this, the window U-value and SHGC of target building were tuned to verify the error rate of heating energy demand using Cv(RMSE) and find out the maximum temperature error range belong to acceptable error range. As a results, it have the same thermal performance if the hourly temperature difference is below the 0.5℃ in year. These paper can be utilized as a preliminary data to categorize the building thermal performance using indoor temperature.

Thermal Performance Sensitivity Analysis for Modeling of Spent Fuel Assembly in Transport System

Kun-ho Chun,Joung-yeul Lee,Seong-ki Lee 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

This study is to investigate fuel cladding temperature in a transport system for the purpose of developing a methodology for evaluating the thermal performance of spent fuel. Detailed temperature analysis in the transport system is important because the degradation mechanism of the fuel cladding is generally sensitive to temperature and temperature history. In such a system, the magnitude of the temperature change is determined by examining the temperature sensitivity of fuel assemblies and system components including fuel cladding temperature, considering the material properties, component specifications, component aging mechanism, and heat transfer mechanism. The sensitivity analysis is performed using heat transfer models by computational fluid dynamics for the horizontal transport system. The heat transfer within the system by convection, conduction and thermal radiation is calculated by thermal-hydraulic analysis code FLUENT. The calculation region is divided into a basket cell and a transport cask. The thermal analysis of the basket cell is for predicting the fuel cladding temperature. And the reason for analyzing the transport cask is to provide the boundary condition for the basket cell by reflecting the external environmental conditions. Here, the basket cell containing the spent fuel assembly is modeled on the homogeneous effective thermal conductivity. The purpose of this analysis is to evaluate fuel cladding temperatures for the following four main items. That is the effect of surface emissivity changes in basket due to the oxide layer of the fuel cladding, the effect of degradation of the canister backfill helium gas, the effect of fuel assembly position in basket cell on fuel cladding and basket temperatures in canister, and the effect of using the homogeneous effective thermal conductivity model instead of the fuel assembly in basket cell. As a result of the analysis, the maximum temperatures in basket cells are evaluated for the above four items. Thermal margins for each item are investigated for thermal performance requirements (e.g., peak clad temperature below 400oC).

열화상 측정장비를 활용한 스틸스터드 형상에 따른 열성능 비교분석

장철용(Cheol-Yong Jang),엄은정(Eun-Jung Um),이나은(Na-Eun Lee) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-

Dry wall using steel stud has the advantage of possibility to install various building, so it used to many buildings inside and outside of the country very rapidly. Though Light gauge steel framed housing offers many advantages to the consumer and the builder, the use of steel studs in wall system cause thermal problems such as thermal performance and pattern staing on walls. The present study has been conducted to observe effect of stud by the shape, and two kind of stud is made for this test to compare thermal performance. The test was conducted by setting those stud on the chamber and heating them. As the results of test and photograping by using TVS, there was temperature gap of each stud, and surface temperature of each section was appeared differently due to shape of stud delaying thermal bridge.