• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.1
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• pp.73-81
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• 1997

In this experimental study, the air cooling radial shape heat exchanger which influences on the COP and the cooling capacity by heat and mass transfer rate in the adsorbent bed was designed and applied to test its performance for adsorption heat pump(AHP). Zeolite-water was used for the adsorbent-adsorbat pair. As a result, the cooling COP and a cycle period of this adsorption heat pump are 0.28 and 2 hours, respectively, on the condition of none heat recovery from the adsorption reactor(absorber). The other results and recommendations are mainly related to improving the heat and mass transfer inside the absorber to reduce a cycle period.

• Proceedings of the SAREK Conference
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• 2005.11a
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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.

• 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.

• Journal of the Korean Solar Energy Society
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• v.33 no.6
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• pp.39-46
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• 2013

This work introduces a simple one-reactor adsorption desalination system that harnesses low temperature heat sources (solar energy, waste heat), which has been experimentally studied to elicit the most suitable design parameters and operating conditions. The design process of the system was divided into three parts to reflect the operating principle of desalination technology with application of adsorption processes. First, the evaporator for the vaporization of saline water was designed, then the reactor for the adsorption and release of the steam, followed by the condenser for condensation of the fresh water. The specific water yield is measured experimentally with respect to the time while controlling parameters such as heat source temperatures, coolant temperatures, system switching and half-cycle operational times. The present system well demonstrates the applicability of silica gel in relation to adsorption technologies that utilize low temperature heat sources ranging from 60 to $80^{\circ}C$, such as solar energy and waste heat.

• Journal of Power System Engineering
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• v.17 no.1
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• pp.71-76
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• 2013

This study is experimentally performed for using the oyster shell as a desiccant in the batch type system. The peltier element(thermoelectric device) is used for absorbing and releasing the adsorption and desorption heat generation. The cooling and heating effects of peltier element exist in this experiment and these effects are generally known phenomena among some references. The increase in electric current induced into peltier element is effectively release the heat generation of adsorption and desorption. Consequently, the non-dimensional adsorption and desorption amount would increase with increase in electric current. However, in the case of adsorption, the increase of induced current into peltier element, the heat of cold side can not release sufficiently. So the heat of hot side of peltier is transferred into the cold side.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.3
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• pp.115-119
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• 2002

An adsorption isotherm on the heterogeneous surface which has spatially periodic adsorption heat distribution was formalized. Usefulness of the formalized adsorption isotherm is discussed with the help of a model calculation. Statistical thermodynamics is used throughout.

• Korean Journal of Materials Research
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• v.27 no.3
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• pp.127-131
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• 2017

Isosteric heat of hydrogen adsorption is one of the most important parameters required to describe solid-state hydrogen storage systems. Typically, it is calculated from adsorption isotherms measured at 77K (liquid N2) and 87K (liquid Ar). This simple calculation, however, results in a high degree of uncertainty due to the small temperature range. Therefore, the original Sievert type setup is upgraded using a heating and cooling device to regulate the wide sample temperature. This upgraded setup allows a wide temperature range for isotherms (77K ~ 117K) providing a minimized uncertainty (error) of measurement for adsorption enthalpy calculation and yielding reliable results. To this end, we measure the isosteric heats of hydrogen adsorption of two prototypical samples: activated carbon and metal-organic frameworks (e.g. MIL-53), and compared the small temperature range (77~87K) to the wide one (77K ~ 117K).

• Carbon letters
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• v.11 no.1
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• pp.34-37
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• 2010

In this work, graphite nanofibers (GNFs) were prepared by ammonia and heat treatment at temperatures up to $1000^{\circ}C$ to improve its $CO_2$ adsorption capacity. The effects of the heat treatment on the textural properties and surface chemistry of the GNFs were investigated by $N_2$ adsorption isotherms, XRD, and elemental analysis. We found that the chemical properties of GNFs were significantly changed after the ammonia treatment. Mainly amine groups were formed on the GNF surfaces such as lactam groups, pyrrole and pyridines. The GNFs treated at $500^{\circ}C$ showed highest $CO_2$ adsorption capacity of 26.9 mg/g at 273 K in this system.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.245-250
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• 2007

Adsorption characteristics of 1,2-dichlorobenzene on the surface of heat treated silica gel were determined by the moment analysis. The heat treatment of the silica gel was performed at temperatures of 150, 500, and $800^{\circ}C$ and pulse-response of 1,2-dichlorobenzene was measured in a gas chromatograph equipped with thermal conductivity detector (TCD) using the packed column. Equilibrium adsorption constants and isosteric heat of adsorption were recorded the highest value at $500^{\circ}C$. This might be due to the increase of interaction between silica surface and 1,2-dichlorobenzene as the decrease of OH concentration and moisture by increase of heating temperature. Axial dispersion coefficient calculated by the moment method was about $0.046{\times}10^{-4}{\sim}1.033{\times}10^{-4}m^2/sec$ and pore diffusivity of heat treated silica gel at $500^{\circ}C$ measured the lowest value. Because heat treating at $800^{\circ}C$ caused the specific surface area to reduce, equilibrium adsorption constants and isosteric heat of adsorption were decreased.

• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.656-660
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• 1991

Heats of moisture adsorption of the sunflower nutmeat products (ground nutmeat, meal, protein concentrate and protein isolate) were determined from their isosteres at temperatures 10, 20 and $30^{\circ}C$. The changes in the heat of adsorption with moisture level were analyzed by Hunter equation. The Hunter equation was valid for representing the relationship between the heat of adsorption and the moisture content for the sunflower nutmeat products, and the accuracy-of-fit increased as protein content of the materials increased. The heat of adsorption decreased as moisture content increased, but increased as protein content increased. The heats of adsorption were 11.8-10.6 kcal/mole for the ground nutmeat at 4-12% moisture (d.b.) and 12.4-11.0 kcal/mole for the protein isolate at 6-20% moisture (d.b.).