• 한국태양에너지학회 논문집
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• 제34권4호
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• pp.31-38
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• 2014

This study makes three apartment building complex an object of analyzing representative building types and energy consumption rate of house holds, and effect of outdoor air cooling. Recently created apatrment complex is composed of very various types of building, plan, and orientation etc. But, it is difficult to remark conclusively that these various types of buildings are designed energy-effectively. Because architects are hard to find useful energy design guideline for decision making. By the preceding study, the present condition and problem about this subject is grasped, apartment building types were examined and representative types were extracted. In this study, energy simulation was conducted, and the effect to outdoor air cooling was analyzed about representative types of the subject apartment complex. It is expected that this analysed results will be basic data for the more integrated study. Research consequence can be summarized as follow: 1) Besides solar gain, household layout of building, orientation, and plan etc. effects compositively on energy consumption rate. 2) The effect of ourdoor air cooling in building of tower type can be improved by arranging households appropriately.

• 한국지열·수열에너지학회논문집
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• 제17권4호
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• pp.68-78
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• 2021

In order to solve the increasing deterioration of the energy shortage problem, ground-source heat pump (GSHP) systems have been widely installed. The control method is a significant component for maintaining the long-term performance and for reducing operation cost of GSHP systems. This paper presents the measurement and analysis results of the cooling performance of a GSHP system using capacity control with outdoor air temperature. For this, we installed monitoring equipments including sensors for measuring temperature, flow rate and power consumption, and then monitored operation parameters from July 9, 2021 to October 2, 2021. From measurement results, we analyze the effect of capacity control with outdoor air temperature on the cooling performance of the system. The average performace factor (PF) of the heat pump was 6.95, while the whole system was 5.54 over the measurement period. Because there was no performance data of the existing GSHP system, it was not possible to directly compare the existing control method and the outdoor air temperature method. However, it is expected that the performance of the entire system will be improved by adjusting the temperature of cold water produced by the heat pump, that is, the temperature of cold water on the load side according to the outside air temperature.

• 설비공학논문집
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• 제13권11호
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• pp.1165-1173
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• 2001

The objectives of this study are to analyze the application of radiant floor cooling and to evaluate the control methods through experiments when the radiant heating system is used for cooling. Through the experiment analysis the control methods such as on/off control, variable flow control and outdoor reset with indoor temperature feedback control are evaluated and compared. The cooling curve (reset ratio) is found for radiant cooling, which shows tole relation between outside air temperature and supply water temperature. Comparison of cooling methods shows that outdoor reset with indoor temperature feedback control is more appropriate than on/off control and variable flow control with regard to prevention of the condensation and thermal comfort.

• 설비공학논문집
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• 제18권2호
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• pp.144-150
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• 2006

The purpose of this study is to predict outlet temperature and humidity through underground pit for the reduction of cooling load and heating load. Commonly, the underground temperature is lower than outdoor in summer but the reverse happens in winter. When the outdoor average air temperature is $25.7^{\circ}C$ during cooling periods, the average outlet air temperature through underground pit is $23.6^{\circ}C$ with 3 m-depth and 60m-length and is $22.2^{\circ}C$ with 3 m-depth and 150 m-length. When the outdoor average air temperature is $4.9^{\circ}C$ during heating periods, the average outlet air temperature through underground pit is $7.7^{\circ}C$ with 3m-depth and 60 m-length and is $10.8^{\circ}C$ with 3 m-depth and 150 m-length. The outlet air temperature is affected by more length than depth of underground pit. The diffusion ratio of outdoor humidity is $-7.7\times10^{-8}kg/s$ in cooling periods and $9.29\times10^{-7}kg/s$ in heating periods.

• 설비공학논문집
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• 제21권5호
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• pp.273-281
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• 2009

In recent semiconductor manufacturing clean rooms, the energy consumption of outdoor air conditioning systems represents about 45% of the total air conditioning load required to maintain a clean room environment. Meanwhile, there is a large amount of exhaust air from a clean room. From an energy conservation point of view, heat recovery from the exhaust air is therefore useful for reducing the outdoor air conditioning load for a clean room. In the present work, an energy-efficient outdoor air conditioning system was proposed to reduce the outdoor air conditioning load by utilizing an air washer to recover heat from the exhaust air. The proposed outdoor air conditioning system consisted mainly of a preheating coil, an air washer, two stage cooling coils, a reheating coil, a humidifier and two heat recovery cooling coils inserted into the air washer and connected to a wet scrubber. It was shown from the lab-scale experiment with outdoor air flow of $1,000\;m^3/h$ that the proposed system was more energy-efficient for the summer and winter operations than an outdoor air conditioning system with a simple air washer.

• 설비공학논문집
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• 제24권11호
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• pp.759-766
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• 2012

To estimate the cooling load for the following day, outdoor temperature and humidity are needed in hourly base. But the meteorological administration forecasts only maximum and minimum temperature. New methodology is proposed for predicting hourly outdoor temperature and humidity by using the forecasted maximum and minimum temperature. The correlations for normalized outdoor temperature and specific humidity has been derived from the weather data for five years at Seoul, Daejeon and Pusan. The correlations for normalized temperature are independent of date, while the correlations for specific humidity are linearly dependent on date. The predicted results show fairly good agreement with the measured data. The prediction program is also developed for hourly outdoor dry bulb temperature, specific humidity, dew point, relative humidity, enthalpy and specific volume.

• 한국지열·수열에너지학회논문집
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• 제7권2호
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• pp.37-42
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• 2011

Dedicated outdoor air(DOA) system which conditions the outdoor air separately is superior to conventional Cooling + reheating system with respect to energy consumption and indoor comfort. Since the sensible and latent load characteristics of indoor and outdoor are different, it is more efficient to treat them separately. In this study, cycle analysis and on-site performance test of DOA system have been conducted. The study shows that DOA requires 50% less equivalent energy than the conventional system. The on-site performance test of a prototype shows that the coefficient of performance(COP) of the DOA system is 37% higher than the conventional system.

• 설비공학논문집
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• 제23권1호
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• pp.8-15
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• 2011

Cooling load reduction was analysed of a ventilation system adopting a regenerative evaporative cooler. The regenerative evaporative cooler is a kind of indirect evaporative cooler which cools the air down to its inlet dewpoint temperature in principle without change in the humidity ratio. The regenerative evaporative cooler was found able to cool the ventilation air to $18{\sim}21^{\circ}C$ when the outdoor condition ranges $25{\sim}35^{\circ}C$ and 0.01~0.02 kg/kg. When the outdoor humidity ratio is lower than 0.018 kg/kg, the regenerative evaporative cooler was found to provide cooling performance enough to compensate the ventilation load completely and to supply additional cooling as well. Energy simulation during the summer was carried out for a typical office building with the ventilation system using the regenerative evaporative cooler. The results showed that the seasonal cooling load can be reduced by about 40% by applying the regenerative evaporative cooler as a ventilation conditioner. The reduction was found to increase as the outdoor temperature increases and the outdoor humidity ratio decreases.

• 대한설비공학회지:설비저널
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• 제35권12호
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• pp.41-48
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• 2006

For the Designing a Dedicated Outdoor Air System with Ceiling Radiant Cooling Panels the concept of a dedicated outdoor air system(DOAS) with parallel sensible cooling was born from the decoupled system concept, which can be summarized as decoupling of ventilation and air-conditioning functions, or decoupling of sensible and latent load functions. First , remove the latent loads from the outside air(OA) intake and generated in spaces using a 100% OA ventilation system(i.e., DOAS). Second, remove the space sensible loads using a parallel mechanical cooling system, such as fan coil units, conventional variable air volume , and ceiling radiant cooling panel(CRCP) independent of the ventilation system.

• 한국태양에너지학회 논문집
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• 제34권3호
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• pp.82-88
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• 2014

Using low outdoor temperature, free cooling system is used in a data center or industrial air-conditioning for energy saving. Because use of IT equipment has increased in some office building recently, there is a growing trend towards using free cooing system. Free cooling system performance is influenced by outdoor temperature. Therefore the performance is different with regions. In this study, performance characteristic of free cooling system is analysed and energy reduction is compared with some regions. Selected regions are 4 cities; including Ulsan analyzed in preceding research, Seoul, ChunCheon and Daejeon. The Aspentech software HYSYS 8.0v was used to conduct the analysis of free cooling system based on temperature per hour of 4 cities in 2013, respectively. The main result is following as. Free cooing system in this study has energy saving effect when outdoor temperature below $7^{\circ}C$. Becuase temperature of Chuncheon is relatively low, using free cooling system can conserve most air-conditioning energy. Energy reduction amount of Seoul is 11%, Chuncheon is 17.5%, Deajeon is 15%, Ulsan is 14%. In case of large scale of air-conditioning, it is reasonable to use free cooling system although the system is used in Seoul.