• 한국환경보건학회지
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• 제43권3호
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• pp.185-193
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• 2017

Objectives: An on-site study was conducted in order to quantify indoor exposure levels and the emission rate of particulate matter for domestic poultry buildings. Materials and methods: Three types of poultry building (caged layer house, broiler house, and layer house with manure belt) as classified by mode of manure treatment and ventilation were investigated in this study. Nine sites per each poultry building were selected and visited for measuring exposure levels and emission rate of particulate matter. Total dust and respirable dust among the particulate matter were analyzed based on the weight method. Emission rates were estimated by dividing emission amount, which was calculated through multiplying indoor concentration ($mg/m^3$), by the ventilation rate ($m^3/h$), into indoor area ($m^2$) and number of poultry reared in the poultry building. Results: Mean exposure levels for total dust and respirable dust in the poultry buildings were $3.91({\pm}1.99)mg/m^3$ and $1.99({\pm}0.89)mg/m^3$, respectively. The emission rates of particulate matter in the poultry buildings were estimated as $4.75({\pm}1.22)mg\;head^{-1}h^{-1}$ and $64.39({\pm}24.95)g\;m^{-2}h^{-1}$ for total dust and $0.58({\pm}0.23)mg\;head^{-1}h^{-1}$ and $7.52({\pm}2.51)mg\;m^{-2}h^{-1}$ for respirable dust, respectively. The distribution patterns for total dust and respirable dust were similar regardless of poultry building type. Among poultry buildings, broiler house showed the highest exposure level and emission rate of total dust and respirable dust, followed by layer house with manure belt and caged layer house. Conclusions: The finding that the broiler house showed the highest exposure level and emission rate of particulate matter can be attributed to sawdust utilized as bedding material, which can be dispersed into the air by movements of the chickens. Thus, a work environmental management solution for optimally reducing dust concentrations is necessary for broiler houses.

• 한국기계가공학회지
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• 제21권2호
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• pp.94-100
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• 2022

A study was conducted to significantly increase the heat transfer area by simultaneously burying the excel pipe in the floor and wall of a container house, thereby greatly reducing the initial heating time. In addition, a small hot water boiler suitable for the heating load of a small container house with a maximum area of 6 m² was studied. A wall-mounted hot water boiler was developed as a result of the study. When a hot water boiler is installed outdoors for heating, heat radiation energy is lost in winter from the hot water boiler and hot water pipe due to the low temperature. We propose an approach through which the energy loss was greatly reduced and the temperature of hot water increased in proportion to the operating time. Moreover, as the mass flow rate of the hot water flowing inside the excel pipe increased, the temperature of the hot water decreased. The temperature of the wall and floor surfaces of the container house increased in proportion to the increase in the mass flow rate of hot water flowing inside the excel tube. Natural convection heat transfer was realized from the wall and floor surfaces of the container house, and the heat transfer area was increased by a factor of 3 with respect to heat transfer area limited to the floor by the existing hot water panel. As a result, the initial temperature increase rate was much higher because of the larger heat transfer area.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.33-40
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• 2020

The main aim of the study is to test a house pricing model by combining hedonic and asset-based pricing models. An understanding of the relationship between house pricing and its return (the rental income) helps to establish houses as a significant asset class. The model tested the relationship between house pricing (dependent variable) and the house attributes (independent variables) derived from Freeman's framework of housing attributes. This study uses a large data-set of 1,899 sample of new, high-end houses purchased between 2016 and 2019 collected from the national capital region of India (Delhi-NCR). The algorithm was built in R-Script, and stepwise multiple linear regression was used to analyze the model. The analysis of the model proves that the three significant variables, namely, carpet area, pay-off, and annual maintenance charges explain the price function. Further, the model is statistically fit. The major contribution of the study is to understand the key factors and their influence on the house pricing. The model will be helpful in risk assessment in the housing investment and enhance the chances of investment. Policy-makers can use information about the underlying valuation drivers of the house prices to stabilize the market and also in framing the tax policies.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.671-679
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• 2021

House ownership is considered as one of the important pre-conditions for marriage in China. Given that gender imbalance is a prominent issue in the country, competition for marriage partners might motivate males to look for a house and probably bigger and more expensive house. This is believed to have caused house price hikes in recent years. This study aims to investigate the impact of gender imbalance on house prices using data from 30 provinces in China for the 2000-2017 period. The results based on the generalized method of moments (GMM) estimations show that house price is strongly influenced by gender imbalance. However, there is no evidence to support differential effects across eastern and mid-western regions. One potential reason is that pre-marriage house ownership has become a common culture for the whole community and therefore it does not vary significantly across regions. There are several important policy implications. Firstly, the issues should be addressed by the policymakers at national level and not regional level. Secondly, the government should intervene to bring back gender ratio to its normal level. Finally, the government should limit the number of houses people can buy and increase the supply of houses in the market.

• Environmental Engineering Research
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• 제23권4호
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• pp.354-363
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• 2018

We examined the levels of brominated flame-retardants (BFRs) including polybrominateddiphenyl ethers (PBDEs), tetrabromobisphenol-A (TBBPA), hexabromocyclododecane (HBCD), and phthalates in indoor dusts in residential houses in Korea, and their distribution patterns depending on building characteristics. Mean concentrations of phthalate esters ($1,825{\mu}g\;g^{-1}$) were significantly higher than that of BFRs (PBDE: $1,332ng\;g^{-1}$, HBCDs: $459ng\;g^{-1}$, and TBBPA: $213ng\;g^{-1}$), indicating more frequent use of phthalate-containing products such as PVC flooring in the Korean houses. PVC flooring house was associated with higher concentrations of DEHP (p = 0.001) and BBP (p = 0.012), indicating that exposure to phthalate was higher in the PVC flooring house. Building age was significantly related with levels of PBDEs especially BDE-47 (p = 0.062), BDE-203 (p = 0.007), DEHP (p = 0.004), and BBP (p = 0.070), respectively, indicating that older buildings can produce higher amounts of PBDEs and phthalates. Our study can provide important information on the sources of BFRs and phthalates in residential houses in Korea.

• 설비공학논문집
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• 제15권6호
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• pp.489-494
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• 2003

"Anmadang" of traditional Korean house is an empty space, surrounded by buildings shaped like the letter, ‘ㅁ’.‘ㅁ’shaped traditional Korean house provides much more comfortable outdoor space for various activities than ‘ㅡ’shaped traditional Korean house. In this paper it has been tried to analyse the dry bulb temperature condition of indoor and outdoor space through measurement of dry bulb temperature in Anmadang, Maru and outdoor space. This paper also analyses the correlation of dry bulb temperature between Anmadang and outdoor space with seasonal variations in traditional Korean houses.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.99-104
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• 2006

Accurate flow rate distribution has been become a very important part for controling of air change rate since the introduction of house ventilation system. An inappropriate selection of fan due to Incorrect prediction of friction loss makes waste energy. The purpose of this study is to recognize applicability of T-Method at house ventilation system by comparing experiment with T-method, The result of this study is as follows Flow rate is small amount in a house, so duct size must be accurate. And duct design with Equal Friction Loss Method presented large error range. Equal friction loss method is not fit to applicate small amount air flow rate. T-Method predicts accurate flow rate comparatively in a house ventilation system. Error range was 3.5%.

• 한국축산시설환경학회지
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• 제14권1호
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• pp.39-46
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• 2008

본 실험은 무창육성 비육돈사에 있어서 여름과 겨울철 환기를 할 때 공기 유입구에서의 공기속도가 환경에 미치는 영향을 조사하고자 CFD를 이용한 모델을 설정하였고, 현장실험을 통한 결과와 CFD 모델의 공기유속 결과를 서로 비교하였다. 공기속도에 있어서 수학적인 모델은 현장실험 결과와 매우 유사하게 나타났다. 환기시스템에서의 공기흐름은 양쪽 측벽 슬롯 판넬을 통하여 공급하였으며 겨울철은 $2{\sim}2.5m/s$ 였고, 여름철은 0.8 m/s 전후였다. 이상의 연구 결과 여름철과 겨울철 모두 해석 Model과 실험 무창육성 비육돈사내 측정 결과 평균 유속은 근소한 차이로 나타나 공기유동 해석 연구에 있어서 CFD 시뮬레이션의 적용으로 합리적인 결과를 도출할 수 있음을 확인하였다.

• 한국농공학회논문집
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• 제59권6호
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• pp.61-71
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• 2017

The tracer gas method has an advantage that can estimate total and local ventilation rate by tracing air flow. However, the field measurement using tracer gas has disadvantages such as danger, inefficiency, and high cost. Therefore, the aim of this study was to evaluate ventilation rate in pig house by using the thermal distribution data rather than tracer gas. Especially, LMA (Local Mean Age), which is an index based on the age of air theory, was used to evaluate the ventilation rate in pig house. Firstly, the field experiment was conducted to measure micro-climate inside pig house, such as the air temperature, $CO_2$ concentration and wind velocity. And then, LMA was calculated based on the decay of $CO_2$ concentration and air temperature, respectively. This study compared between LMA determined by $CO_2$ concentration and air temperature; the average error and root mean square error were 3.76 s and 5.34 s. From these results, it was determined that thermal distribution data could be used for estimation of LMA. Finally, CFD (Computational fluid dynamic) model was validated using LMA and wind velocity. The mesh size was designed to be 0.1 m based on the grid independence test, and the Standard $k-{\omega}$ model was eventually chosen as the proper turbulence model. The developed CFD model was highly appropriate for evaluating the ventilation rate in pig house.

• 한국농공학회지
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• 제19권3호
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• pp.4483-4491
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• 1977

The results obtained are as follows; 1. The variation of the temperature in a vinyl house without heating system is similar to that of air temperature in a day. The difference of maximum temperature and minimum one in a day is 27$^{\circ}C$ which is two times greater than the daily difference of air temperature. 2. When the length of the duct is increased, the high temperature zone is built up in the direction of warm air discharge from the duct, and the low temperature zone is built up in the opposite direction of warm air discharge. But, in case of the duct length is short (0.05 L), the temperature distrubution in a vinyl house become uniform. It is concluded that the shorter length of the duct, the better the distribution of the temperature in a vinyl house is. 3. When the duct is installed at high position, the high temperature zone is built up in the upper zone of the vinyl house and the low temperature zone is built up in the lower zone. And when the position of the duct is low, the rate of temperature variation along the vertical direction become high, and the direct contact of warm air with the plant in the house is occured. It is concluded that the duct should be installed at the position of slightly higher than the plant height. 4. When the fuel consumption rate is fixed at the 101/hr, the lowest temperature warming rate in the vinyl house is 5$^{\circ}C$ without regard to the air temperature.