• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.1
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• pp.15-20
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• 2017

The summer climate is very hot and humid in Korea. The humidity is an important factor in determining thermal comfort. Recently, the research for dehumidification device development has been attempted to save energy that is required for the operation of the current dehumidifiers on the market. Existing dehumidification systems have disadvantages such as wasting energy to drive a compressor. Meanwhile, dehumidification systems with membranes can dehumidify humid air without increasing the dry bulb temperature so it doesn't have to consume cooling energy. In this paper, the cooling energy savings was studied when a dehumidification system was applied in a model building instead of a chiller. The sensible heat load was almost the same result, but the latent heat load was decreased by 38.9% and the total heat load was decreased by 8.5%. As a result, electric energy used to drive the compressor in a chiller was saved by applying a membrane air-conditioning system instead.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.4
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• pp.331-340
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• 2004

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we used a model for evaluation of fresh air latent heat load reduction by hygroscopic of air to earth exchange system taking into account coupled heat and moisture transfer of underground double floor space. In conclusion it shows the validity of the proposed method for a design tool and the quantitative effect of the system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.2
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• pp.128-136
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• 2008

It is necessary to estimate the cooling load of the next day for effective control of ice thermal storage system. In this paper, new methodology is proposed to estimate the cooling load using design parameters of building and predicted weather data. Only six input parameters such as sensible heat coefficient and constant, latent heat coefficient and constant, maximum and minimum temperature are necessary to obtain hourly distribution of cooling load for the next day. Two benchmarking buildings(hospital and research institute) are selected to validate the performance of the proposed method, and the estimated cooling loads in hourly and daily bases are calculated and compared with the measured data for E hospital. The estimated results show fairly good agreement with the measured data for both buildings.

• 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.

• 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.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.7 no.1
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• pp.45-50
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• 2011

Hybrid desiccant cooling system(HDCS) consists of desiccant rotor, regenerative evaporative cooler, heat pump and district heating hot water coil. In this study, TRNSYS and EES, dynamic and steady simulation programs were used for studying hybrid desiccant cooling system which is applied to an apartment house from June to August. The results show that power consumption of the hybrid desiccant cooling system is 70 kWh in June, 199 kWh in July and 241 kWh in August. Sensible and latent heats removed by the hybrid desiccant cooling system are 300 kWh, 301 kWh in June, 610 kWh, 858 kWh in July and 719 kWh, 1010 kWh in August. COP of the hybrid desiccant cooling system is 8.6 in June, 7.4 in July and 7.2 in August. COP of the hybrid desiccant cooling system decreases when latent heat load increases. Operation time of the system is 70 hours in June, 190 hours in July and 229 hours in August. Since the cooling load is largest in August, the operation time of August is longest for maintaining the indoor temperature at $26^{\circ}C$. Due to the characteristics of hybrid desiccant cooling system for efficiently handling both sensible and latent loads, this system can handle sensible and latent heat loads efficiently in summer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.9
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• pp.620-627
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• 2010

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we investigated the correlation between outdoor air temperature and outlet air temperature in the system. In conclusion, from the results of the high correlation we proposed a equation of regression for the outlet air temperature in the system by using linear regression analysis.

• Journal of the Korean Society of Industry Convergence
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• v.13 no.3
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• pp.169-181
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• 2010

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we proposed a simplified presumption method for the prediction of cooling and heating performance in the system. In conclusion the proposed method has been verified by comparing with the calculated value of the numerical analysis model by using nonlinear two-dimension hygroscopic question.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.9
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• pp.628-634
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• 2010

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we proposed a simplified presumption method for the prediction of cooling and heating performance in the system. In conclusion the proposed method has been verified by comparing with the calculated value of the numerical analysis model by using nonlinear two-dimension hygroscopic question.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.162-167
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• 2011

Thermal storage plays an important role in building energy saving, which is greatly assisted by the incorporation of latent heat storage in building materials. A phase change material is a substance with a high heat of fusion which, melting and solidifying at a certain temperature, can be storing and releasing large amount of energy. Heat is stored or released when the material changes from solid to liquid. Integration of building materials incorporating PCMs into the building envelope can result in increased efficiency of the built environment. The aim of this research is to identify thermal performance of PCMs impregnated building materials which is applied to interior of building such as gypsum and red clay. In order to analyze thermal performance of phase change materials, test-cell experiments and simulation analysis were carried out. The results show that micro-encapsulated PCM has an effect to maintain a constant indoor temperature using latent heat through the test-cell experiments. PCM wallboard makes it possible to reduce the fluctuation of room temperature and heating and cooling load by using EnergyPlus simulation program. Phase change material can store solar energy directly in buildings. Increasing the heat capacity of a building is capable of improving human comfort by decreasing the frequency of indoor air temperature swings so that the interior air temperature is closer to the desired temperature for a long period of time.