• 설비공학논문집
• /
• 제19권11호
• /
• pp.782-788
• /
• 2007

In this paper, the freezing process of the water supply pipe in the exterior wall of an apartment house was analyzed by numerical method. The thickness of the pipe insulation and the percentage of insulation damage were considered as parameters in this paper. In the cases of the 0%, 8% and 20% damaged of the 5mm thickness insulation, the freezing was completed after 13 hours, 10 hours and 7 hours respectively. And in cases of the 10mm thickness insulation, the freezing was completed after 18 hours, 10.5 hours and 8 hours respectively. As a result, it is predicted that the water freezing would occurred when the water supply pipe with 8% or 20% damaged insulation are installed in the exterior wall. However, the water freezing would not occurred when the water supply pipe with 10mm thickness insulation of 0% damage is installed in the exterior wall.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.1503-1506
• /
• 2009

Bubble jet loop heat pipe is a newly devised variation of heat pipe in which heat is effectively transported by the latent heat of evaporation and condensation as well as the heat capacity of circulating working fluid. The circulatory and oscillating motion of the working fluid becomes possible by the motion of bubble jet which is generated at a narrow circular gap. These bubbles are condensed at the condensing section. Bubble jet loop heat pipe makes it possible to carry heat long distances upward and horizontal directions. Because Its structure is a very simple and a low cost, it is available for the floor heating, vinyl house heating, the defrosting of heat pump system and home refrigerator.

• 설비공학논문집
• /
• 제27권4호
• /
• pp.228-232
• /
• 2015

The water supply galvanized steel pipes of apartment buildings in Bucheon city constructed with building permission before 1994 have many problems such as leaks, the water containing rust, and low water pressure due to corrosion. Therefore, this study aims to find a way to renew the water supply pipes under investigation through a survey. As a result, when replacing the galvanized steel pipe with the corrosion-resistant pipe, the water supply system should also be changed from the gravity tank system to the booster pump system and the hygienic water storage tank. It is necessary to redraft the long-term repair plan including the replacement of the water supply system. Also, it is necessary to save the allowance reserve according to the modified long-term repair plan.

• 설비공학논문집
• /
• 제26권5호
• /
• pp.218-223
• /
• 2014

Korea District heating corp. recently give an attention to combine the district heating and supply pipes as a two pipe system that are in the present system separated with room heating and warm water supply pipe, and the two pipe system is commonly applied for heating service in European countries. In the new two pipe system, only one heat source is supplied to a house and partitioned into room heating and warm water supply by household substation. So the effective distribution of supplied heat source in accordance to user intention is very important. This paper presents the development and performance test of three-way proportional control valve for a combined heat source system in district heating. The proposed valve is controlled to partition heat source into two different directions : hot water distributor for space heating and household substation for warm water supply in response to the pressure drops of tap water caused by the user. The performance investigation is shown within 3% of error compared to the theoretical model of the three-way proportional valve and its controllability is verified.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 추계학술대회논문집
• /
• pp.187-192
• /
• 2006

The effect where the multiple sound arrest ing goes mad to the human being does the zone. From like that cotton, this dissertation the both sides flag executed the research regarding a sound arresting reduction in the object in one example. It compared the piping structure which generally is space-time and a specific piping structure and it tested and research and the modeling regarding a sound arresting reduction the simulation which leads and it executed result and comparison of existing it analyzed. The duplication where the reduction effect is bigger the result general VG2 piping structure than escape it did with the fact that it appears the large effect the piping structure which it connects. Also, the straight pipe effect of multiple sound arresting could not go mad with the fact that.

• Journal of Advanced Marine Engineering and Technology
• /
• 제33권4호
• /
• pp.476-483
• /
• 2009

A linear compressor used in a refrigerator has higher energy efficiency than a reciprocating compressor, but its vibration level is still severe than others. The vibration level of linear compressor at the frequency of 60Hz is dominant since it is the exciting frequency of a motor. In this paper, a simulation tool to predict the shell vibration of the linear compressor was developed. The shell and body parts in a compressor were assumed to be 3-dimensional rigid body having both translational and rotational motion, while the reciprocating piston part has only 1-dimensional translational motion. The flexible loop-pipe was modeled by in-house code of finite element method. To verify the developed tool, five cases of different loop-pipe shapes were examined experimentally. The results by the developed tool showed good agreements with those by experiments.

• 한국전자통신학회논문지
• /
• 제12권6호
• /
• pp.1151-1158
• /
• 2017

히트파이프 일체형 고효율 난방기는 겨울철 시설원예 내 작물생육에 필수인 난방장치와 배기열 회수기를 일체화하여 배기열이 외부로 배출되기 전 미사용 에너지를 재이용하는 장치이다. 시설원예, 유리온실 등 점검을 통해 우리나라 농업용 난방기의 문제점을 파악하였고, 개선방향을 찾아 시설원예 및 하우스에 맞는 최적화된 농업용 고효율난방기 및 스마트 제어시스템을 제안하였다.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2001년도 학술발표회 발표논문집
• /
• pp.256-260
• /
• 2001

This study was initially performed to investigate current red-pepper drying methods commonly being adopted on red-pepper cultivation farm area. Based on the informations obtained from the field survey, an experiment of red-pepper drying was carried out to verify the actual drying potential of plastic covered solar house similar to the conventional pipe frame greenhouses covered with one or two layer of plastic film. Some results obtained from field survey and drying experiment for red-pepper are summarized as follows; 1. Various patterns of red-pepper drying process were found; 1) complete natural drying with red-pepper exposed in outdoor air, 2) hot air drying by dry chamber only, 3) combination drying by hot air dryer together with plastic covered passive solar house, 4) drying with plastic covered solar house unit. 2. The average air temperatures of outdoor and solar house during drying experiment period were $26.9-30.8\;and\;28.6-33.8^{\circ}C$, respectively, and the maximum air temperatures of those two were $34.2-36.4\;and\;39.8\;-52.3^{\circ}C$, respectively. Horizontal solar intensity during experiment period was $18.49-23.96\;MJ/m^{2}$, and relative humidity of outdoor and experimental solar house were 56 - 66% and 64 - 70%, respectively. 3. The weight of red-pepper during drying experiment period was decreased almost linearly from initial moisture content of 85% to final moisture content of 14%.

• 한국기계가공학회지
• /
• 제9권2호
• /
• pp.6-11
• /
• 2010

For the purpose of reducing the energy consumption in the house heating, the various devices have been developed. One of these is to control the flow in the heat pipe and the flow control valve using shape memory alloy(SMA) spring is proposed in our study. The proposed house heating system is to save the gas consumption and the remote control system is designed for the convenience of using the proposed valve. The developed valve consists of SMA spring, disk, return spring, and regulation handle. The regulation handle is for supplying the additional hot water and is controlled by remote-control-motor. In order to design the remote control system, the Zigbee wireless communication protocol is used. The performance of the proposed valve structure is shown through the experimental result.

• 한국태양에너지학회 논문집
• /
• 제28권5호
• /
• pp.56-64
• /
• 2008

The objective of this study is to develope ground heat exchanger using PHC file used to building foundation, and it's element technology. So we construct PHC ground heat exchanger in the apartment house's PHC foundation and evaluate it's performance. First, we study PHC file type, heat exchanger pipe, grouting materials, and present apartment house's foundation condition for PHC ground heat exchanger and design it's proto type. Second according to grouting materials, we estimate construction convenience, and it's performance. Construction convenience side, PB 22 A pipe and sand grouting with moisture was good for PHC ground heat exchanger elements. Experiment result is very superior. Thermal conductivity B, C type(sand, gravel) was respectively 32.4 W/m$^{\circ}C$, 36.5 W/m$^{\circ}C$, D(concrete) Type 27.8 W/m$^{\circ}C$, E(bentonite) Type 19.6 W/m$^{\circ}C$. Thermal interference for 4 day experiment period in 3.8 m was very small. So PHC file is good for using ground heat exchanger.