• Title/Summary/Keyword: Adsorption chiller

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Cycle Simulation of an Adsorption Chiller Using Silica Gel-water (실리카겔-물계 흡착식 냉동기 사이클 시뮬레이션)

  • Kwon, Oh-Kyung;Yun, Jae-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.2
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    • pp.116-124
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    • 2007
  • An adsorption chiller is expected to have high energy-efficiency in utilizing the waste heat exhausted from a process. The objective of this paper is to investigate the performance of silica gel-water adsorption chiller from the cycle simulation and to provide a guideline for design of the adsorption chiller. The effect of cycle time, inlet temperature and water flow rate on the cooling capacity and COP is quantified during the cycle operation. It is found that the performance of adsorption chiller is more sensitive to the change of inlet water temperature rather than the water flow rate. It is concluded that the COP is 0.57 in the standard conditions(hot water $80^{\circ}C$, cooling water $30^{\circ}C$, chilled water inlet temperatures $14^{\circ}C$ and cycle time 420sec).

A Study on the Efficiency Enhancement of the HT-PEMFC Having Fuel Processing System by Connecting Adsorption Chilling System (흡착식 냉방 시스템을 이용한 수소개질/연료전지 시스템의 효율향상)

  • NASEEM, MUJAHID;KIM, CHUL-MIN;LEE, SANGYONG
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.5
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    • pp.411-417
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    • 2019
  • An adsorption chiller is connected to the fuel processing/fuel cell system to increase the energy efficiency of the system. Since, the minimum temperature of $70^{\circ}C$ is needed to operate the adsorption chiller, HT-PEMFC is used as a heating source and $80^{\circ}C$ hot water in the water tank at the system is supplied to the chiller. Experimentally measured COP of the adsorption chiller was between 0.4-0.5 and the total calcuated efficiency of the connected system was between 60% and 70% comparing to 47% without adsorption chilling system.

Design Effect of Different Components and Economic Evaluation of an Adsorption Chiller on the System Performance

  • Bidyut B. Saha;Shigeru Koyama;K.C. Amanul Alam;Lee, Jong-Boong
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.17-22
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    • 2002
  • A conventional silica gel/water adsorption chiller has been analyzed numerically. A novel non-dimensional mathematical model has been presented to analyze the design effect of different components of an adsorption chiller. The design parameters of this system are characterized by the number of transfer unit, NTU, of different components and the inert material alpha number, ${\alpha}$of different components of the systems. Results show that condenser NTU$\sub$a/ has the most influential effect on the system performance, which is fellowed by absorber NTU$\sub$e/. It is also seen that coefficient of performance (COP) and non-dimensional specific cooling capacity increases with the increase of NTU$\sub$a/ and NTU$\sub$e/, but decreases with the increase of inert material alpha number. A thermo-economic data of the adsorption chiller and some other heat pump systems those are in practical operation are also presented.

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A Numerical Study for the Heat and Mass Transfer in Silica gel/Water Adsorption Chiller's Adsorber (흡착식 냉동기의 흡착탑에서 열 및 물질전달에 관한 수치적 연구)

  • Kwon, Oh-Kyung;Yun, Jae-Ho;Kim, Joung-Ha;Kim, Yong-Chan;Joo, Young-Ju
    • Proceedings of the SAREK Conference
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    • pp.341-346
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    • 2005
  • Nowadays, adsorption chillers have been receiving considerable attentions as they are energy-saving and environmental1y benign systems. A Fin & tube type heat exchanger in which adsorption/desorption take place is required more compact size. The adsorption chiller is expected to have high energy-efficiency in utilizing the waste heat exhausted from a process. The objectives of this paper are to investigate the effect of fin pitch of fin & tube on the adsorption performance and to develop an optimal design fin & tube heat exchanger in the silica gel/water adsorption chiller. Previous study concluded that optimal particle size selected 0.5mm, type HO silica gel, and fundamental heat transfer & mass transfer experiments carried out. From the numerical results, the adsorption rate for the fin pitch 2.5mm is the highest than that for the fin pitch 5mm, 7.5mm and 10mm. Also cooling water & hot water temperature affect the adsorption rate.

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Numerical Analysis of the Heat and Mass Transfer in a Fin Tube Type Adsorber (핀튜브형 흡착탑에서 열 및 물질전달 수치해석)

  • Kwon, Oh Kyung;Chung, Jae Dong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.8
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    • pp.457-463
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    • 2013
  • Nowadays, adsorption chillers have been receiving considerable attention, as they are energy saving and environmentally benign systems. A fin tube type heat exchanger in which adsorption/desorption takes place is required with more compact size. The adsorption chiller is expected to have high energy efficiency in utilizing the waste heat exhausted from a process. The objectives of this paper are to scrutinize the effect of design parameters on the adsorption performance, especially the fin pitch of the fin tube, and to develop an optimal design fin tube heat exchanger in a silica gel/water adsorption chiller. From the numerical results, the fin pitch of 2.5 mm shows the highest adsorption rate, compared to other fin pitches, such as 5 mm, 7.5 mm and 10mm. Also, the adsorption rate is affected by the cooling water and hot water temperature.

An Experimental Study of Adsorption Chiller using Silica gel-Water (실리카겔-물계 흡착식 냉동기에 관한 실험적 연구)

  • Kwon, Oh-Kyung;Yun, Jae-Ho;Kim, Joung-Ha
    • Proceedings of the SAREK Conference
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    • pp.1119-1124
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    • 2006
  • The objectives of this paper are to investigate the performance of silica gel-water adsorption refrigeration system with heat recovery process from the system experiment. This system can be driven by waste heat at near ambient temperature from $60^{\circ}C$ to $90^{\circ}C$. The cooling capacity and coefficient of performance(COP) were measured from various experimental conditions. An experimental results revealed the influence of operating temperatures(hot, cooling and chilled water), water flow rates, and adsorption-desorption cycle times on cooling capacity and COP. Under the standard conditions of $80^{\circ}C$ hot water, $25^{\circ}C$ cooling water, $14^{\circ}C$ chilled water inlet temperatures and 420sec cycle time, a cooling capacity of 1.14kW and a COP for cooling of 0.55 can be achieved.

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An Experimental Study on the Heat and Mass Transfer of Adsorption Chiller (흡착식 냉동기의 열 및 물질전달에 관한 실험적 연구)

  • Kwon Oh-Kyung;Yun Jae-Ho;Joo Young-Ju;Kim Yong-Chan;Kim Joung-Ha
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.8
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    • pp.746-753
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    • 2005
  • Adsorption chillers have been receiving considerable attentions as they are energy-saving and environmentally benign systems. In order to evaluate adsorption rates, experiments were performed in the batch type adsorption apparatus. Three types of silica gels were investigated under an assortment of experimental conditions that are representatives of the actual operating environments in the adsorber of adsorption chillers. Experimental results revealed the effects of silica gel particle size, bed temperature, and fin pitch of fin tube on the adsorption rate. The $0.25\~1.18mm$ particle size of silica gel with high adsorption rate was selected as a suitable adsorbent. The measured adsorption rate became bigger with decreasing particle size. From the comparison of adsorption rate, it is found that the fin tube has about $21\%$ higher value than that of the bare tube. The effect of heat and mass flux is found to be more significant in the fin tube than in the bare tube.

Validity of Inter-Particle Models for the Mass-Transfer Kinetics of a Fin-Tube-Type Adsorption Bed (핀-튜브형 흡착탑 해석시 입자간 물질전달 모델의 타당성 검증)

  • Ahn, Sang Hyeok;Hong, Sang Woo;Kwon, Oh Kyung;Chung, Jae Dong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.12
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    • pp.660-667
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    • 2013
  • This study presents a numerical investigation of the heat and mass transfer kinetics of a fin-tube-type adsorption bed using a two-dimensional numerical model with silica-gel and water as the adsorbent and refrigerant pair. The performance is strongly affected by the heat and mass transfer in the adsorption bed, but the details of the mass transfer kinetics remain unclear. The validity of inter-particle models used to simulate mass-transfer kinetics were examined, such as a constant pressure model and non-constant pressure model, and the valid ranges of the diffusion ratio for each model are proposed. The COP and SCP have been numerically calculated as the performance indexes according to the diffusion ratio. The constant pressure model, which is commonly used in previous research, was found to be valid only in a limited range of diffusion ratio.