• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.1
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• pp.48-54
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• 2014

A refrigeration dehumidifier with a recuperative heat exchanger is theoretically analyzed. The recuperative heat exchanger is located between the two air streams from and to the dehumidifying coil, and reduces the sensible heat load in dehumidification process. A simple model is developed to predict performance of the dehumidifier. The model predicts that the recuperative heat exchanger is effective especially in the low humidity condition, where the sensible heat load is relatively large. It is predicted that, by adopting a recuperative heat exchanger, a maximum 30~110% increase in COP is possible for indoor air at $27^{\circ}C$, and 40~60% relative humidity.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.216-221
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• 2007

An experiment was carried out to investigate the effect of a coolant circuit arrangement on the heat transfer and air pressure drop of a fin-tube sensible heat exchanger with the corrugated fin surface. The air inlet temperature was set to $23^{\circ}C$,the relative humidity to 50% and the air inlet flow rate to 20, 22, $25m^3/min$, respectively. while the coolant temperature was set to $7^{\circ}C$, and the coolant mass flow rate to 10, 16, 22kg/min, respectively. Experiment showed that the exchanger having a diameter of 12.7mm with parallel circuit does better performance in sensible heat transfer and air pressure drop than those three of diameter of 12.7mm with a series circuit and that with diameter of 15.88mm with a parallel circuit.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.245-250
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• 2003

In order to control indoor air quality and save energy, it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery. The purpose of this research is to find the performance of paper heat exchanger for exhaust heat recovery, which exchanges latent heat as well as sensible heat. Experimental apparatus comprises heat exchanger model, constant temperature and humidity chamber, fan and measurement systems for temperature, pressure and flow rate. Thermal performance and pressure loss of the paper heat exchanger are measured and compared at various air velocities and outdoor conditions. Experimental results show that paper heat exchanger can recover $50{\sim}70%$ of the enthalpy difference between supply and exhaust air.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.2 no.2
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• pp.85-98
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• 1990

Method of optimum design of a compact sensible plate-fin heat exchanger for the heat recovery of exhaust gas from the air conditioning space was developed in consideration of the econamics of investment cost and profit according to the installation of heat exchanges. In the counterflow heat exchanger, the frontal area was fixed and the length of heat exchanger was optimized in order to maximize the net gain according to the setting of the heat exchanger. In the cross flow heat exchanger, the size of the exchanger was also optimized to maximize the net gain.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.402-407
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• 2008

This study is performed to investigate heat transfer characteristics for thermal performance of fin-and-tube sensible heat exchangers under the low air flowrate according to fin geometry combination and coolant flowrate control. Fins and tubes of samples were separated between front row and rear row. Experiment results are plotted heat transfer rate of each row, heat transfer coefficient and sensible heat ratio against water flowrate control of each row. It is observed that thermal performance can be enhanced by fin geometry combination and water flowrate control of each row under the low air flowrate.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.4
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• pp.17-26
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• 2001

Simulation was conducted using TRNSYS to evaluate the thermal performance of a facility. This facility has a condensing-type heat exchanger which is able to recover the latent energy for the purpose of reducing the heating energy in winter. The boiler and chiller are selected based on the annual peak loads and controlled to maintain the facility at the set temperature of 14~$17^\circ{C}$. Supplied energy by the boiler and recovered energy by the heat exchanger were calculated as a function of number of pass through heat exchanger, kind of fuel and hot water velocity. Simulation results show that about 20% of the total heating load can be recovered by the heat exchanger and the amount of latent heat is increasing with the number of pass. This means that the efficiency of the waste energy recovery system can be increased by using a condensing-type heat exchanger rather than a traditional sensible heat exchanger.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.2
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• pp.131-141
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• 1991

A method of optimum design of an axial rotary sensible heat exchanger for the heat recovery of exhaust gas from the air conditioning space was developed in consideration of economics of investment cost and profit according to the installation of heat exchangers. Leakage rate of exhaust gas was calculated and the correlation for the pressure drop due to leakage of exhaust gas was proposed. Heat transfer between the matrix and exhaust and intake gas was analysed to calculate the effectiveness of heat exchanger, which was used for the optimum design of rotary heat exchanger. The results show that optimum rotational speed increases as the length of rotor increases and there exists optimum NTU which maximizes the gain of total cost according to the installation of rotary heat exchanger.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.12
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• pp.1057-1065
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• 2000

A sizing of sensible and latent energy recovery system with condensing heat exchanger is important to the design of a thermally controlled facilities. The transient system simulation program TRNSYS 14.2/IISiBat has been used to evaluate the energy consumptions of a thermally controlled facilities which consist of boiler, chiller and condensing heat exchanger, The boiler and chiller are selected based on the annual peak loads and controlled to maintain the setting temperature of $14~17^{\circ}C$. Simulation shows that the amount of sensible and latent energy recovered by heat exchanger is almost 20% of total heating load.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.5
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• pp.393-401
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• 2006

The regenerative evaporation water cooler is devised and analysed in this study. The regenerative evaporation water cooler is composed of a sensible heat exchanger to cool the incoming air, followed by a latent heat exchanger to cool the water evaporatively with the cooled air flowing out of the sensible heat exchanger. By linearizing psychrometric characteristics, the heat and mass transfer in the regenerative evaporation water cooler is analyzed theoretically. The results show that the water can be cooled down even lower than the wet-bulb temperature of the inlet air. When the inlet air is $32^{\circ}C$ and 20% in relative humidity, and the inlet temperature of the water is $20^{\circ}C$, the regenerative evaporation water cooler provides a larger cooling capacity than the conventional evaporation water cooler if the effectiveness of the latent heat exchanger is higher than 0.6 and that of the sensible heat exchanger is higher than 0.5.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.10
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• pp.956-964
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• 2005

In order to control indoor air quality and save energy, it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery The purpose of this research is to find the factors affecting the performance of paper heat exchanger for exhaust heat recovery, which can be applied directly to the conventional ventilation unit, air-purifier, and air-conditioning system. In this study, thermal performance and pressure loss of the paper heat exchanger are measured and compared at various operating conditions. The effectiveness of sensible, latent and total heat at the face velocity of 0.75 m/s are $77\%,\;47\%\;and\;57\%$ in the cooling condition and $77\%,\;59\%,\;and\;\%$ in the heating condition, respectively. The effectiveness for sensible heat is only affected by velocity. On the other hand, the effectiveness for latent heat is affected. by temperature and relative humidity.