Evaluation of thermal comfort in an office building served by a liquid desiccant-assisted evaporative cooling air-conditioning system

Cho, Hye-Jin,Jeong, Jae-Weon Elsevier 2018 Energy and buildings Vol.172 No.-

<P><B>Abstract</B></P> <P>The main purpose of this research is to evaluate the thermal-comfort environment in an office building served by a liquid-desiccant and indirect-and-direct evaporative-cooler-assisted 100% outdoor-air system (LD-IDECOAS). This research presents a method for evaluating the thermal environment via a series of energy simulations using the TRNSYS 17 program, integrated with an engineering equation-solver (EES) program. The supply air (SA) temperature is estimated according to the LD-IDECOAS seasonal operation modes proposed in previous research. The indoor-air conditions are estimated under the assumption that the relative humidity of room air was maintained at the set values by auxiliary humidification systems. Then, the predicted mean vote (PMV) values are estimated using the given indoor environment conditions. In this paper, the indoor-air conditions and PMV values for each LD-IDECOAS operation mode are represented. A detailed analysis of the impact of the indoor-air conditions on the PMV is provided in this paper. Furthermore, the simulation results for LD-IDECOAS were compared with those for a conventional variable-air-volume (VAV) system to evaluate the thermal environment in a building served by LD-IDECOAS. The PMV values with LD-IDECOAS showed that the thermal environment in a conditioned space is generally in compliance with ASHRAE Standard 55. Consequently, it is concluded that using LD-IDECOAS in an office building can produce energy savings with an acceptable level of thermal comfort.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The building thermal performance was simulated to evaluate the thermal comfort in an office building served by LD-IDECOAS. </LI> <LI> A PMV method was adopted and the thermal comfort was evaluated by the TRNSYS 17 and EES programs. </LI> <LI> The LD-IDECOAS PMV variation trend was found to be similar to that of the VAV system, and most of the PMV values were in compliance with the recommended PMV range. </LI> <LI> According to the results, LD-IDECOAS could provide satisfactory thermal comfort for occupants in the Korean climate. </LI> </UL> </P>

LC Aligning Properties for Homeotropic Alignment of NLC on the SiO_x Thin Film as Incident Angle of Electron Beam Evaporation Angle

Kim, Jong-Hwan,Kang, Hyung-Ku,Han, Jin-Woo,Kang, Soo-Hee,Kim, Young-Hwan,Hwang, Jeoung-Yeon,Seo, Dae-Shik The Korean Institute of Electrical and Electronic 2006 Transactions on Electrical and Electronic Material Vol.7 No.1

In this study, liquid crystal (LC) aligning properties for homeotropic alignment on the $SiO_x$ thin film by electron beam evaporation method with electron beam system in accordance with the evaporation angles were investigated. Also, the control of pretilt angles homeotropic aligned LC on $SiO_x$ thin film as the function of the evaporation angles were studied. The uniform vertical LC alignment on the $SiO_x$ thin film surfaces with electron beam evaporation was achieved with all of the thin film angle conditions. It is considerated that the LC alignment on the $SiO_x$ thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $SiO_x$ thin film surface created by evaporation. The values of the pretilt angles according to the evaporation angle were from about $0.7^{\circ}$ to about $3.4^{\circ}$. The highest pretilt angles of about $3.4^{\circ}$ in aligned NLC on the $SiO_x$ thin film surfaces by electron beam evaporation were measured under the condition of $45^{\circ}$. Also, good LC alignment states on the treated $SiO_x$ thin film layer by electron beam evaporation were observed at annealing temperature of $250^{\circ}C$. Consequently, the high pretilt angle and the good thermal stability of LC alignment on the $SiO_x$ thin film by electron beam evaporation can be achieved.

LC Aligning Properties for Homeotropic Alignment of NLCon the SiOx Thin Film as Incident Angle of Electron BeamEvaporation Angle

Jong-Hwan Kim,한진우,서대식,김영환,황정연,Hyung-Ku Kang,Soo-Hee Kang 한국전기전자재료학회 2006 Transactions on Electrical and Electronic Material Vol.7 No.1

In this study, liquid crystal (LC) aligning properties for homeotropic alignment on the SiOx thin film by electron beam evaporation method with electron beam system in accordance with the evaporation angles were investigated. Also, the control of pretilt angles homeotropic aligned LC on SiOx thin film as the function of the evaporation angles were studied. The uniform vertical LC alignment on the SiOx thin film surfaces with electron beam evaporation was achieved with all of the thin film angle conditions. It is considerated that the LC alignment on the SiOx thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the SiOx thin film surface created by evaporation. The values of the pretilt angles according to the evaporation angle were from about 0.7 ° to about 3.4 °. The highest pretilt angles of about 3.4 ° in aligned NLC on the SiOx thin film surfaces by electron beam evaporation were measured under the condition of 45 °. Also, good LC alignment states on the treated SiOx thin film layer by electron beam evaporation were observed at annealing temperature of 250 ℃. Consequently, the high pretilt angle and the good thermal stability of LC alignment on the SiOx thin film by electron beam evaporation can be achieved.

Thermal Evaporation법에 의해 제조된 WO₃ 박막과 NiO-WO₃박막의 전기적 특성에 관한 연구

나은영,나동명,박진성,Na Eun-young,Na Dong-myong,Park Jin-seong 한국전기화학회 2005 한국전기화학회지 Vol.8 No.1

본 연구는 $WO_3$ 박막과 $NiO-WO_3$ 박막을 고진공 저항가열식 thermal evaporation 법으로 (100) n형의 실리콘 단결정 기판 위에 증착시켰고, 막의 결정성 증진을 위하여 공기 중 $500^{\circ}C$에서 30분 동안 열처리하였다. 박막의 결정성 및 결정구조를 분석하기 위해서 X선 회절분석기를 사용하였고, 표면 및 단면 관찰을 위해서는 주사전자현미경을 이용하였다. 그리고 화학 조성 결합에너지는 XPS를 이용하였다. 순수 $WO_3$ 박막의 결정 크기는 $500^{\circ}C$에서 30분 동안 공기중 열처리에 의해서 $0.6{\mu}m$로 성장하였고 $WO_3$ 박막의 두께가 증가할수록 거의 변화 없이 일정하였다. 반면, NiO가 첨가된 $WO_3$ 박막 두께별 결정크기는 각각 $0.12{\mu}m,\;0.28{\mu}m,\;0.32{\mu}m$및 $0.43{\mu}m$로 순수 $WO_3$ 박막에 비해 치밀한 표면을 형성하였고, 최대 5배정도 성장이 억제되었다. 가스감도 측정은 대기 중에서의 센서 저항 값을 기준으로 측정가스 저항 값의 비율 $(R_{NOx}/R_{air})$로 가스감도를 나타내었다. 전기적 성질은 MFC로 NOx가스 5ppm을 일정히 유지시켰고, Multimeter로 계측하여 컴퓨터에 자동 계측되는 시스템을 사용하였다. 순수 $WO_3$박막보다는 $NiO-WO_3$ 박막이 우수한 NOx 감도특성을 보였고 센서의 작동온도는 $250^{\circ}C$에서 우수한 감도를 나타내었다. [ $WO_3$ ] and $NiO-WO_3$ thin films were deposited on a Si (100) substrate by using high vacuum thermal evaporation. The effects of various film thicknesses on the surface morphology $WO_3$ and $NiO-WO_3$ thin films were investigated. X-ray diffraction (XRD), Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy(XPS) were employed to characterize the deposited films. The results suggest that as $WO_3$ thin films became thick, their grain grew up to a $0.6{\mu}m$. On the other hand, NiO-doping to $WO_3$ thin films inhibited the grain growth five times less than undoped $WO_3$ thin films. This results show that NiO doping inhibited the grain growing of $WO_3$ thin films. Also, the variation of NOx sensitivity $(R_{NOx}/R_{air})$ to the thickness of $WO_3$ and $NiO-WO_3$ thin films were measured according to the thickness change of thin films and the working temperature of sensor in 5ppm NOx gas. As a result, $NiO-WO_3$ thin films showed more excellent properties than $WO_3$ thin films for NOx sensitivity.

Thermal Evaporation 법에 의해 제조된 WO3 박막과 NiO-WO3 박막의 전기적 특성에 관한 연구

나은영,나동명,박진성 한국전기화학회 2005 한국전기화학회지 Vol.8 No.1

WO3 and NiO-WO3 thin films were deposited on a Si (100) substrate by using high vacuum thermal evaporation. The effects of various film thicknesses on the surface morphology WO3 and NiO-WO3 thin films were investigated. X-ray diffraction (XRD), Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the deposited films. The results suggest that as WO3 thin films became thick, certain size of grain grew. On the other hand, their grain grew up to a certain size(?) NiO-dopint to WO3 thin films inhibited the grain growth five times less than undoped WO3 thin films. doping This results show that NiO dope inhibited the grain growth of WO3 thin films. Also, the variation of doping growing NOx sensitivity(RNOx/Rair) to the thickness of WO3 and NiO-WO3 thin films were measured according to the thickness change of thin films and the working temperature of sensor in 5 ppm NOx gas. As a result, NiO-WO3 thin films showed more excellent properties than WO3 thin films for NOx sensitivity.

Thermal Evaporation법으로 제작한 ZnO 나노선의 온도와 산소유량에 따른 성장 특성

오원석,장건익,Oh, Won-Seok,Jang, Gun-Eik 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.8

Zinc oxide (ZnO) nanowires were prepared on Si substrates by a thermal evaporation method at different temperatures and $O_2$ pressure. Microstructural analysis of the obtained ZnO nanowires was performed by using transmission electron microscopy(TEM) and scanning electron microscopy(SEM). Phase analysis was done using X-ray diffraction(XRD). As the deposition temperature and oxygen pressure were increased, the diameter and length of ZnO nanowires had a tendency to increase. Based on TEM and XRD analyses, the nanowires are single crystalline in nature and consist of a single phase. According to the measurements, the ZnO nanowires grown at 1100$^{\circ}C$, Ar 50 sccm, $O_2$ 10 sccm have good properties.

Effect of Refrigerated and Thermal Storage on the Volatile Profile of Commercial Aseptic Korean Soymilk

Hun Kim,Keith R. Cadwallader,Eun-Jeong Jeong,Yong-Jun Cha 한국식품영양과학회 2009 Preventive Nutrition and Food Science Vol.14 No.1

This study determined the effect of refrigerated and thermal storage on the volatile profile of commercial aseptic soymilk. Volatile components in commercial aseptic soymilk stored either under refrigerated (4℃) or thermal (55℃) conditions for 30 days were periodically analyzed by combined solvent-assisted flavor evaporation-gas chromatography-mass spectrometry (SAFE-GC-MS). The concentrations of most of the volatile components, including aldehydes, ketones, alcohols, acids, nitrogen- and sulfur-containing compounds, alkylfurans, furan derivatives and phenolic compounds, were affected to a greater extent by thermal storage compared with refrigerated storage. Profound increases in some volatile compounds with low odor detection thresholds, such as hexanal, octanal, (E)-2-octenal, (E,E)-2,4-decadienal, 1-octen-3-ol, 3-ethyl-2,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, 2-pentylfuran, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, dimethyl trisulfide, guaiacol, 4-vinylguaiacol and 4-vinylphenol, were observed in thermal stored soymilk. The volatile profile changes caused by thermal storage may influence the aroma quality of thermal-stored aseptic soymilk.

Effect of Refrigerated and Thermal Storage on the Volatile Profile of Commercial Aseptic Korean Soymilk

Kim, Hun,Cadwallader, Keith R.,Jeong, Eun-Jeong,Cha, Yong-Jun The Korean Society of Food Science and Nutrition 2009 Preventive Nutrition and Food Science Vol.14 No.1

This study determined the effect of refrigerated and thermal storage on the volatile profile of commercial aseptic soymilk. Volatile components in commercial aseptic soymilk stored either under refrigerated ($4^{\circ}C$) or thermal ($55^{\circ}C$) conditions for 30 days were periodically analyzed by combined solvent-assisted flavor evaporation-gas chromatography-mass spectrometry (SAFE-GC-MS). The concentrations of most of the volatile components, including aldehydes, ketones, alcohols, acids, nitrogen- and sulfur-containing compounds, alkylfurans, furan derivatives and phenolic compounds, were affected to a greater extent by thermal storage compared with refrigerated storage. Profound increases in some volatile compounds with low odor detection thresholds, such as hexanal, octanal, (E)-2-octenal, (E,E)-2,4-decadienal, 1-octen-3-ol, 3-ethyl-2,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, 2-pentylfuran, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, dimethyl trisulfide, guaiacol, 4-vinylguaiacol and 4-vinylphenol, were observed in thermal stored soymilk. The volatile profile changes caused by thermal storage may influence the aroma quality of thermal-stored aseptic soymilk.

증기 이젝터 위치에 따른 다중효용증발시스템의 설계 및 성능분석

김득원(Deukwon Kim),최상민(Sangmin Choi) 대한설비공학회 2016 설비공학 논문집 Vol.28 No.11

The evaporation of water from an aqueous solution is widely used in the food, desalination, pulp, and chemical industries. Usually, a large amount of energy is consumed in the evaporation process to boil off water due to atmospheric pressure. As a way of improving the energy efficiency of the evaporation process, the combination of multiple effect evaporation and thermal vapor recompression has been proposed and has become a successful technique. In this study, 4 multiple-effect falling film type evaporators for sugar solution are designed and the energy efficiency of the system is analyzed in response to the selection of the steam ejector position. Energy efficiency is increased and vapor is more compressed in the steam ejector as the Thermal Vapor Recompression (TVR) is arranged in the rear part of the evaporator system. A simplified 0-dimensional evaporator model is developed using non-linear equations derived from mass balances, energy balances, and heat transfer equations. Steam economy is calculated to compare the evaporation performance of the 4 proposed evaporators. The entrainment ratio, compression ratio, and expansion ratio are computed to check the ejector performance.

열증착법으로 제조한 NiCr 박막의 미세구조 및 표면산화특성

박진성 조선대학교 에너지.자원신기술연구소 2004 에너지·자원신기술연구소 논문지 Vol.26 No.1

NiCr 합금을 열증발원으로 사용한 thermal evaporation법으로 NiCr 박막을 Al_(2)O_(3)/Si 기판 위에 증착시켰다. 이 때 동일한 량의 NiCr 합금을 1회에 모두 증착하는 방법과, 1/2씩 2회 증착하는 방법으로 NiCr 박막을 각각 증착시켜, 박막의 미세 구조에 따른 막의 특성변화를 고찰하였으며, 열처리 온도에 따른 NiCr 박막의 상 변화, 조성변화 및 미세구조 변화를 XRD, AES 및 FE-SEM으로 각각 분석하였다. 열처리 과정에서 박막내부에 존재하는 Cr 성분이 표면 쪽으로 확산하여 산화됨으로써 Cr 산화층/Ni 층/Cr 산화층의 전형적인 다층구조를 형성함을 알 수 있었으며, 특히, 700℃이상에서는 Ni 층이 Cr 산화층을 통하여 표면 쪽으로 확산됨으로써 표면에 원주형 결정립을 가지는 NiO 층을 형성하였다. 특히 Ni 층이 확산 전의 구조를 유지한 채 표면에 추가적인 NiO 층이 형성되는데, 이는 형성된 Cr 산화층의 확산이 상대적으로 Ni 층에 비하여 어려운데 기인한다. NiCr thin films were fabricated by thermal evaporation method using NiCr alloy as evaporating source. They were deposited by two processes; one-step deposition and two-step deposition. The one-step deposition is the method in which NiCr thin films were once deposited using constant quantity of evaporating source and the two-step deposition is the method in which those were twice deposited using half quantity of evaporating source. NiCr thin films were annealed at various temperatures in air atmosphere in order to investigate effects of annealing conditions on phase, composition, and microstructures of NiCr films. Typical multilayer was formed after annealing in air atmosphere. This results from the diffusion and oxidation of Cr toward surface during annealing. In the case of annealing at 700℃, large columnar grains of NiO were formed on Cr-oxide layer through the diffusion and oxidation of Ni over Cr-oxide layer. Especially, NiO layer was formed additionally on surface, sustaining the underlayer structure with the formation of porous Ni layer.