• 설비공학논문집
• /
• 제16권7호
• /
• pp.630-638
• /
• 2004

Liquid desiccant dehumidification systems have the ability to provide efficient humidity and temperature control while saving the electrical energy requirement for air conditioning as compared to a conventional system. The dehumidifier and the regenerator form the heart of this system. The latent part of the cooling load is overcome using liquid desiccant. The model regenerator has been designed to study the absorption characteristic of the aqueous triethylene glycol (TEG) solution which is in the flow range from 20 to 50 LPM. Also, this system designed that was able to change the height of the regenerator and dehumidifier. Because the effect of performance have different result according the height. The effect of performance factors of the regenerator with inlet solution flow rate, air flow rate, solution concentration, solution temperature, brine temperature, air temperature and inlet air relative humidity have been analyzed. Data obtained are useful for design guidance and performance analysis of the hybrid air conditioning system.

• 설비공학논문집
• /
• 제17권7호
• /
• pp.611-619
• /
• 2005

In a previous work of the authors, the heat and mass transfer in a desiccant rotor was analyzed theoretically through linearization assumptions and four dimensionless parameter groups dominating the dehumidification process were arranged. In this work is verified whether the four dimensionless parameters also play the dominant roles in more realistic situations where the nonlinear factors affect the heat and mass transfer. The results show that the dehumidification characteristics are closely similar to each other as long as the four dimensionless parameters have the same set of values while the rotor configurations and/or the operation conditions are different from each other. The four dimensionless parameters are $\Psi,\;\chi,\;\sigma$ and N, where $\Psi$ implies the average gradient of relative humidity lines in the psychrometric chart, $\chi$ the heat capacity of the rotor and $\sigma$ the sorption capacity of the rotor, and N implies the number of transfer unit.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
• /
• pp.155-161
• /
• 2009

Desiccant systems have been proposed as energy saving alternatives to vapor compression air conditioning for handling the latent load. Use of liquid desiccants offers several design and performance advantages over solid desiccants, especially when solar energy is used for regeneration. The liquid desiccants contact the gas inside the packed column and the heat transfer and mass transfer will occur. This proposal is try study the mass transfer and heat transfer inside the packed column of dehumidifier and regenerator systems. And later on, the rates of dehumidification and regeneration that were affected by desiccant flow rates, air temperature and humidity, and desiccant temperature and all that variation will influence the performance of the systems.

• 대한기계학회논문집B
• /
• 제28권5호
• /
• pp.594-603
• /
• 2004

Several desiccant cooling systems have been developed in terms of cost and performance. In this study a fin-tube exchanger has been used for liquid desiccant dehumidification system. This dehumidifier has been designed to study the absorption characteristic of the aqueous triethylene glycol(TEG) solution which has the flow range from 20 to 50 LPM. The dehumidifier performance characteristics of working factor variables such as inlet solution flow rate, air flow rate, solution concentration and brine temperature have been analyzed. This dehumidifier has the ability to provide running while saving the latent heat load of total energy. The result of this experiment can provide useful data for hybrid air conditioning system.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.25-30
• /
• 2003

Several desiccant cooling systems have been developed in terms of cost and performance. In this study a fin-tube exchanger has been used for liquid desiccant dehumidification system. This dehumidifier has been designed to study the absorption characteristic of the aqueous triethylene glycol(TEG) solution which has the flow range from 20 to 50 LPM. The dehumidifier performance characteristic of working factor variables such as inlet solution flow rate, air flow rate, solution concentration, solution temperature, brine temperature, air temperature and inlet air relative humidity has been analyzed. The result of this experiment can provide useful data for hybrid air conditioning system.

• 설비공학논문집
• /
• 제7권3호
• /
• pp.512-520
• /
• 1995

This study investigates the simultanceous heat and mass transfer between a falling desiccant film and air in cross flow at the interface. The application of this work is the optimization of falling film evaporators for use in potential hybrid air conditioning systems. The specific geometry considered is liquid TEG films falling along the vertical cooled surfaces of a channel with air in cross flow. The equations to describe the coupled heat and mass transfer between a falling desiccant film and air in cross flow for a falling film evaporator have been presented and solved numerically. The effects of important design and operating variables on the evaporator performance predicted by the parametric numerical analysis and suggestions for performance improvements of the evaporator are presented.

• 한국산학기술학회논문지
• /
• 제19권5호
• /
• pp.27-34
• /
• 2018

최근 들어 공기의 제습에 액체 제습제를 사용하는 방법이 각광을 받고 있다. LiCl과 LiBr은 우수한 열물성으로 인하여 액체 제습 시스템에 널리 사용되고 있다. 본 연구에서는 LiCl과 LiBr 수용액을 사용하여 상용 Celdek 소자의 제습 성능을 실험하였다. 실험은 입구 건습구 온도를 $35^{\circ}C/28^{\circ}C$로 유지하고 전방 풍속을 2.0 m/s에서 4.0 m/s로 변화시키며 수행되었다. 수용액의 입구 온도와 농도는 $20^{\circ}C$, 50%, 수용액의 순환량은 50 kg/h로 유지하였다. 실험 결과 제습량은 풍속이 증가할수록 증가하였다. 또한 LiCl의 제습 성능은 LiBr보다 평균 27% 크게 나타났다. 이는 LiCl의 포화 절대 습도가 LiBr의 포화 절대습도보다 작기 때문이다. 반면 LiBr의 압력 손실은 LiCl보다 평균 12% 크게 나타났다. 한편 LiCl 과 LiBr의 Sherwood 수는 비교적 잘 일치하였다. 이로부터 제습제가 Sherwood 수에 미치는 영향은 미미함을 알 수 있다. 기존 상관식들은 본 실험의 Sherwood 수를 현저히 높게 예측하였다.

• 수산해양교육연구
• /
• 제26권5호
• /
• pp.1083-1089
• /
• 2014

The aims of this study are to find out the possibility of the charcoal as a desiccant. The only humidity control under high temperature and high humidity environment can be provided to the thermal comfort at indoor environment. Functionality of charcoal is known to be deodorization, antiseptic effect, filtering effect and humidity control. But research related to humidity control in the country not yet. Thus, the dehumidification capacity of the charcoal experimental results to see the results were as follows : 1) Entering the experimental humidification is 148.02 g/h, 161.05 g/h and 243.2 g/h when air velocity was changed 1.5 m/s, 1.7 m/s and 2.0 m/s. 2) When the basis weight of the charcoal 2.0 m/s air velocity to obtain the largest number of adsorption capacity. 3) Dru bulb temperature and dew point temperature ware measured at front and rear of the charcoal. Absolute humidity is calculated from the measured Dry bulb temperature and dew point temperature. The quantity of dehumidification is calculated from absolute humidity is the largest 129.6 g/h at the air velocity 2.0 m/s.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.645-649
• /
• 2009

Liquid desiccant cooling technology can supply cooling by using waste heat and solar heat which are hard to use effectively. For compact and efficient design of a dehumidifier, it is important to sustain sufficient heat and mass transfer surface area for water vapor diffusion from air to liquid desiccant on heat exchanger. In this study, the plate type heat exchanger is adopted which has extended surface, and hydrophilic coating and porous layer coating are adopted to enhance surface wettedness. PP(polypropylene) plate is coated by porous layer and PET(polyethylene terephthalate) non-woven fabric is coated by hydrophilic polymer. These coated surfaces have porous structure, so that falling liquid film spreads widely on the coated surface foaming thin liquid film by capillary force. The temperature of liquid desiccant increases during dehumidification process by latent heat absorption, which leads to loss of dehumidification capacity. Liquid desiccant is cooled by cooling water flowing in plate heat exchanger. On the plate side, the liquid desiccant can be cooled by internal cooling. However the liquid desiccant on extended surface should be moved and cooled at heat exchanger surface. Optimal mixing and distribution of liquid desiccant between extended surface and plate heat exchanger surface is essential design parameter. The experiment has been conducted to verify effective surface treatment and distribution characteristics by measuring wall side flow rate and visualization test. It is observed that hydrophilic and porous layer coating have excellent wettedness, and the distribution can be regulated by adopting holes on extended surface.

• 설비공학논문집
• /
• 제23권4호
• /
• pp.303-311
• /
• 2011

This study presents a new idea of liquid desiccant dehumidifier with extended surface to improve the compactness. Extended surface is inserted between vertical cooling tubes, and the liquid desiccant flows down along the tube walls and the extended surface as well. Though the extended surface contributes to the increase in the mass transfer area, the effect tends to be limited because less conductive non-metallic materials need to be applied due to the high corrosiveness of liquid desiccant. To analyze the effects of the extended surface insertion, mathematical modelling and numerical integration are performed for the heat and mass transfer in the liquid desiccant dehumidifier. The results show that, though the liquid desiccant on the extended surface is heated due to the moisture absorption, the temperature can be maintained by periodic mixing at the contact points between the tube and the extended surface with the liquid desiccant stream from the tube side at a relatively low temperature. This implies the absorption heat from the extended surface side can be removed effectively by mixing, which leads to a substantial improvement of the dehumidification in the liquid desiccant dehumidifier with extended surface. When the interval of the extended surface, $p_e/L$, is less than 0.1, the dehumidification is shown to increase by more than two times compared with that without extended surface.