• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.263-268
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• 2009

The current focus of domestic car industry is moving from technological development to reducing greenhouse gas. This study investigates and measures the HVAC system and indoor air condition of highway buses, which is conducted to develop a HVAC system using natural energy in the future. The measurements show that thermal balance is not fulfilled because heating sources are randomly placed, and relative humidity is in the 20 percent range both in HVAC and non-HVAC systems, which is far below 40%, or the highest thermal comfort level. CO2 concentration was found to be an average of 1500 ppm, but not more than 2522 ppm with 15 persons on board, and with 29 persons on board, an average of 2053 ppm, but not more than 3066 ppm, both of which far exceed allowed CO2 concentration level, or 1000 ppm. Generally, highway buses drop by rest stops and open doors for 15 to 20 minutes for getting in fresh air. But its air improvement effect is temporary, and it exacerbates indoor air condition.

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.41-48
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• 2003

Most of people spends their times in indoor about 85% of a day. Thus, indoor is more serious than outdoor concerned with the health. We discussed comfortableness in a railroad electric rolling stock, and focused on temperature and humidity. Electric rolling stock is one of major public transportation system because of an increasing in population and heavy traffic problems. The passengers are under the influence of indoor air quality such as air temperature, relative humidity and air velocity. Ventilation system in electric rolling stock should be designed for the health and comfort. One of the main aims is to create an acceptable thermal environment without draught problem. The draught sensation increases when the air temperature decreases and the air velocity increases. Airflow in electric rolling stork is turbulent. Temperature and humidity gradients in electric rolling stock have been studied. And, the difference between mean temperature and rotative humidity measured at 0.7, 0.9, 1.2, 1.7m above the floor. It has been found that temperature and relative humidity with large fluctuations caused more draught complaints.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.2
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• pp.190-195
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• 2012

In this study, as a complementary study of the former study on indoor thermal environment in a tower type apartment house at tropical nights, a field measurement was conducted in winter season. Mainly, characteristics of heat storage and heat emission in apartment structures, in this study, were investigated. As results, indoor air temperature was changed in the range of $22.5^{\circ}C{\pm}1.0^{\circ}C$, and followed not the change of outdoor air temperature but the changed pattern of floor surface temperature. Wall surface temperature was unresponsive to the change of floor surface temperature compared with the change of indoor air temperature because wall structure was composed of concrete which has large heat capacity, and was changed in the range of $22.3^{\circ}C{\pm}0.6^{\circ}C$. Heat was stored continuously into the structures of wall and ceiling through the measurement term. and this means that a large heat capacity of the apartment structure acts as a disadvantage in winter season, too. As a total review of the study with the former study, a large heat capacity of the apartment structure acts against indoor thermal comfort in winter season as well as in summer season.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.69-77
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• 2015

The PMV regression analysis was conducted for this model based on a database of the PMV variables. PMV regression model simplification was completed through sensitivity and data analysis. The simplified PMV regression model's and Fanger PMV model was confirmed through MAE and RMSE. And the EMS in EnergyPlus was used to establish a simplified PMV regression analysis-based thermal comfort control. Also, the thermal comfort controls based on simplified PMV model and the Fanger PMV model were applied to the building model, it was confirmed that both controls met the thermal comfort range in more than 90% of cases during the air conditioning period.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2094-2100
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• 2008

The indoor PMV(Predicted Mean Vote) in rolling stock is very important for the enhancement of the amenity and health of passengers. Many researchers have studied it not for train but for building. Thermal comfort in Rolling Stock is function of temperature, relative humidity, air current, radiation temperature, etc. So, in this study, we have performed thermal environment in rolling stock(Electric motor car, Saemaeul, Mugunghwa train), and verified the relation between the PMV from Nov.2007 and Feb.2008. As a result, the average PMV value for each trains are 0.2, -0.3 Electric motor car, 0.5, 0.1, 0.1, 1.1 for Mugunghwa, 0.3, 0.5 for Saemaeul.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.7
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• pp.535-540
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• 2006

This study was performed In evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of Physiological signals under variations in thermal conditions. Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. It was checked whether they had a good sleep before the night of experiment. EEGs were obtained from C3-A2 and C4-A1 electrode sites and EOGs were acquired from LOC (left outer canthus) and ROC (right outer canthus) for REM sleep detection. Sleep stages were classified, then TST (total sleep time), SWS (slow wave sleep) latency and SWS/TST were calculated for the evaluation of sleep efficiencies on thermal conditions. TST was defined as an amount of time from sleep stage 1 to wakeup. SWS latency was from light off time to sleep stage 3 and percentage of SWS over TST was calculated for the evaluation of sleep quality and comfort sleep under thermal conditions. As result, the condition which raise a room temperature provided comfortable sleep.

• Advances in Energy Research
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• v.5 no.4
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• pp.289-304
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• 2017

Large glazed surfaces and windows become common features in modern buildings. The spread of these features was influenced by the dependence of designers on mechanical and artificial systems to provide occupants with thermal and visual comfort. Countries with hot summer and cold winter conditions, like Jordan, require maximum shading from solar radiation in summer, and maximum exposure in winter to reduce cooling and heating loads respectively. The current research aims at designing optimized double-positioned external shading device systems that help to reduce energy consumption in buildings and provide thermal and visual comfort during both hot and cold seasons. Using energy plus, a whole building energy simulation program, and radiance, Lighting Simulation Tool, with DesignBuilder interface, a series of computer simulations for energy consumption and daylighting performance were conducted for offices with south, east, or west windows. The research was based on comparison to determine the best fit characteristics for two positions of adjustable horizontal louvers on south facade or vertical fins on east and west facades for summer and winter conditions. The adjustable shading systems can be applied for new or retrofitted office or housing buildings. The optimized shading devices for summer and winter positions helped to reduce the net annual energy consumption compared to a base case space with no shading device or with curtains and compared to fix shading devices.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.3
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• pp.410-425
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• 1997

Buildings are mostly under part load conditions causing an inefficient system operation in terms of energy consumption. It is critical to operate building air-conditioning system with a scientific or optimal manner which minimizes energy consumption and maintains thermal comfort by matching building sensible and latent loads. Little research has been performed in developing general methodologies for the optimal operation of air-conditioning system. Based on this research motivation, system simulation program was developed by adopting various equipment operating strategies which are energy efficient especially for humidity control in summer. A numerical optimization technique was utilized to search optimal solution for multi-independent variables and then linked to the developed system simulation model within a mam program. The main goal of the study is to provide a systematic framework and guideline for the optimal operation of air-conditioning system focusing on air-side. For given cooling loads and ambient outdoor conditions the optimal operating strategies of a commercial building are determined by minimizing a constrained objective function by a nonlinear programming technique. Desired space setpoint conditions were found through evaluating the trade-offs between comfort and system power consumption. The results show that supply airflow rate and compressor fraction play main roles in the optimization process. It was found that variable setpoint optimization technique could produce lower indoor humidity level demanding less power consumption which will be benefits for building applications of humidity problem.

• Solar Energy
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• v.8 no.1
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• pp.22-32
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• 1988

It is known that the energy consumption and indoor thermal comfort in residential buildings are affected by the thermal performance of building envelopes. The thermal performance of building envelopes varies with their design methods. In this study, the thermal performance changes by the insulating construction types of exterior walls were analyzed, 1) by varing the thickness of the insulation 2) by varing the location of the insulation 3) by varing the location of the plane airspace The analyzed results are presented and the thermal performance evaluating factors were compared and discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.2
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• pp.115-121
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• 2001

Recently, the requirement of healthier and more comfortable environment makes the zoning domain more details. However, it has limitation to satisfy the thermal comfort of an individual because of the effect of the heat generation from the OA machine and partitions in indoor room. In this paper, we certify the validity of task-ambient air-conditioning system that has been developed as a new concept of personal air-conditioning system, and specify design strategies for more efficient task-ambient air-conditioning system with a specification guided by indoor environmental characteristics analyzed through experiment data. In this experiment, we changed the temperature and the quantity of air-flow in task domain to understand characteristic behavior of the thermal environment and investigate the possibility of energy saving. The experiment result is that the environment of the task area depends on the condition of supply air, and though the airflow of the low temperature is supplied with the ambient area, the personal environment and the efficiency of energy saving are improved by controlling the temperature and the quantity of the air shot around the task domain.