Analysis of Indoor Thermal Environment Characteristics by Heating Supply Systems in Apartment Houses

Dong woo Cho,Ki hyung Yu 국제온돌학회 2010 International Journal of Ondol Vol.2010 No.-

Recent apartment houses tend to expose the problems of unbalanced floor temperatures and real temperature due to changes in thermal performance arising from reinforced insulation and air tightness. In this study, the indoor thermal environment was analyzed against the apartment unit household in the type of individual heating, central heating, and District Heating methods in order to determine the operational status of indoor thermal environments and heating system by Heating supply systems. The temperature of hot water supplied at the time the indoor loads occurs to the maximum by Heating supply systems was found to rise in order to individual heating (70℃) , central heating(47℃) and District Heating (41℃). The hot water supply frequency showed variable changes in the range of 3 to 6 times per day in cases of individual heating while periodical changes was ranging from 3 or 4 times a day in the case of central heating and district heating. The width of variation of floor surface temperatures depending on the temperature of the supply water was found to be in order of Individual Heating, District Heating, and Central Heating. The average floor surface temperature appeared similar to the hot water supply temperature pattern in the order of 26.4 to 30.2℃ for Individual Heating, 28.2 to 28.6℃ for Central Heating, and 24.8 to 29.4℃for District Heating. In the case of non-heating where heating is not implemented, the temperature of the floor surface was 22.8℃ to 26.0℃ showing the same temperature as the indoor temperature. Heating supply appeared to be maintained in a stable manner overall in a sporadic manner ranging from 3 to 6 times a day, which was maintained in a stable manner on the whole regardless of the heating method.

난방용 온수분배기의 성능 평가 방법

권우철(Woo Chul Kwon),윤준용(Joon-yong Yoon),이병휘(Byeong-Huee Lee) 한국유체기계학회 2006 유체기계 연구개발 발표회 논문집 Vol.- No.-

Distribution manifolds for room heating systems are used to optimally distribute the heating fluid in ondol(Korean underfloor heating system) circuits for each room heating separately in a house whose heating systems are district , central or individual heating systems. Recently, the energy saving is one of hot issues in industrial and engineering fields, so distribution manifolds for room heating systems are developed to improve the heating efficiency and save heating cost. In this study, Items and methods of distribution manifolds for performance evaluation of room heating systems are researched. For performance evaluations, flow rate distribution accuracy test, hydraulic characteristics per flow rate control valve’s indicat or and noise tests are researched.

중앙난방방식을 지역난방과 소형열병합난방 방식으로 전환 시 경제성 비교 분석

김규생(Kyu Saeng Kim) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.10

This study was conducted to determine the LCC of apartment complexes with district heating and a cogeneration system. For the purpose of analyzing LCC according to the size of the apartment complex, 500, 1,500, and 4,000-unit model apartments were selected. Analysis was performed on the design of the heating system and the life cycle cost including total construction cost, maintenance and operation cost for the duration of the project period (15 years). According to the calculated results, 1) The initial cost of the cogeneration system for 500, 1,500, and 4,000-unit apartments is higher than that of the district heating system by 20%, 13%, and 12%, respectively. 2) In the case of the cogeneration system, the payback period by electric generation was found to be 5.21, 4.92 and 4.47 years, and saving cost was calculated to be 29 billion won, 94 billion won and 262 billion won after the payback period for 500, 1,500, and 4,000-unit apartments, respectively. 3) The LCC values of the cogeneration system were 1.12, 1.07 and 1.06 times larger than those of the district system according to the size of the apartment complex. In this study, the district heating system was found to be more efficient than the cogeneration system in terms of LCC reduction. 4) District heating is affected by fuel bills, so energy efficiency should be improved through recovering waste heat (incineration heat, etc.). Also, district cooling should be provided according to heat use to keep the temperature high in winter and low in summer.

노후된 아파트단지 리모델링시 경제성분석에 의한 난방방식 비교 검토

임용훈(Yong Hoon Im),박화춘(Hwa-Choon Park) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.11

Development of PCS to utilize differential pressure energy in district heating systems with reduced DC-link voltage variation

Bak, Yeongsu,Lee, Kyo-Beum The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4

This paper proposes a power conversion system (PCS) to utilize the differential pressure (DP) energy in district heating systems with reduced DC-link voltage variation. A differential pressure control valve (DPCV) is usually used to regulate pressure for heat transmission to remote areas in district heating systems. However, there is a high probability of malfunctions and failures of the DPCV, due to cavitation, since high-pressure fluids are used in district heating systems. Therefore, a PCS for utilizing DP energy in the district heating system replacing the DPCV is proposed in this paper. In addition, the DC-link voltage of the PCS greatly fluctuates when a sudden change occurs in a hydraulic turbine. It is effectively relieved by using the feed-forward control method. The effectiveness of the PCS for utilizing the DP energy in district heating systems with reduced DC-link voltage variation is verified by simulation and experimental results.

Waste heat recovery and its integration with district heating systems: Case study for ceramic industry

Habin Cho,윤세광,Jae Ha Lee,Haejin Cho,Jin-Kuk Kim,Sung Chul Yi 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.1

Industrial waste heat available from ceramic plants is investigated to understand economic benefits gained from the heatintegration of waste heat with the district heating systems. One of the scenarios for the case study is to consider the combineduse of waste heat for generating electricity via the ORC (Organic Rankine Cycle), as well as for supplying heat as a heatingsource to the district heating systems, while the other is to maximize the utilization of waste heat as heating only. A processsimulation framework using AspenHYSYS® is built to estimate the amount of waste heat available from the kiln exhaust gas. The integration of ORC and district heating systems is also modeled by an established framework. Two profiles forcharacterizing changes in heating demand are considered on a daily basis and annual basis, while three levels of insulationefficiency for the heat storage facility are considered. Case study clearly illustrates that heat recovery with only using districtheating systems can provide more benefits than using ORC about 64~86% of cost savings. Technical issues related to overthe-fence heat recovery in practice are discussed.

Reduced LS-SVM을 이용한 지역난방 동절기 공동주택 난방부하의 모델링

박영칠(Young Chil Park) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.6

A model of apartment heating load in a district heating system could be useful in the management and utilization of energy resources, since it could predict energy usage and so could assist in the efficient use of energy resources. The heating load in a district heating system varies in a highly nonlinear manner and is subject to many different factors, such as heating area, number of people living in that complex, and ambient temperature. Thus there are few published papers with accurate models of heating load, especially in domestic literature. This work is concerned with the modeling of apartment heating load in a district heating system in winter, using the reduced least square support vector machine (LS-SVM), and with the purpose of using the model to predict heating energy usage in domestic city area. We collected 23,856 pieces of data on heating energy usage over a 12-week period in winter, from 12 heat exchangers in five apartments. Half of the collected data were used to construct the heating load model, and the other half were used to test the model’s accuracy. The model was able to predict the heating energy usage pattern rather accurately. It could also estimate the usage of heating energy within of mean absolute percentage error. This implies that the model prediction accuracy needs to be improved further, but it still could be considered as an acceptable model if we consider the nonlinearity and uncertainty of apartment heating energy usage in a district heating system.

지역난방 이용 공동주택 통합배관시스템의 효용성 검증

오규성(Gyu Sung Oh),김영일(Young Il Kim),김선혜(Sean Hay Kim) 대한설비공학회 2018 설비공학 논문집 Vol.30 No.10

This study validates effectiveness of a combined piping system for an apartment using district heating. The existing district heating system is composed of four pipes (four-pipe system), but the suggested combined piping system is composed only of two pipes (two-pipe system). Thanks to this simplification, the two-pipe system will reduce heat loss of supplied heating energy. Performance of the four-pipe system and the two-pipe system were analyzed using TRNSYS 17 in the aspect that 1) If it can provide sufficient heating energy for space heating and hot water simultaneously, and 2) How much of the heat loss of the hot water supply pipe may be reduced. Measured energy consumption were compared with simulation results, that revealed good agreement. This study also proposes an optimal operation strategy of the hot water set temperature for the two-pipe system. It is confirmed that the two-pipe system can provide sufficient heating energy and uses less energy compared to the four-pipe system.

지역난방 공동주택에서 외기온도가 난방부하 패턴에 미치는 영향에 관한 연구

정광섭(Chung Kwang-Seop),김성민(Kim Sung-Min) 대한건축학회 2009 대한건축학회논문집 Vol.25 No.2

During the last decade, an increasing interest in district heating system has emerged. In this paper, the physical measurements and data monitoring by internet were carried out with regard to heating energy consumption at the three apartment housings with district heating system in Ilsan district, Korea. Measurements were made of the thermal factors such as the pressure of heating pipe, flow rates, hot water temperature and etc. The purpose of this paper is to evaluate comprehensively the effect of variable outdoor temperature upon the heating load pattern in apartment housings with district heating system in order to develope the design criteria of this system and to understand the heating energy consumption pattern of user. Furthermore, the paper sets up the database of heating energy consumption in order to forecast the heating energy demand of apartment housings. As the result of the study, it can be seen that average heating load per unit area decrease to the rate of 7.1% according to the rise of 1℃ of the average outdoor temperature. Thus, it suggests the basic data for assessing the design criteria of heating energy consumption based on the field measurements and survey in district heating system.

설비공학회 분야의 최근 연구 동향

이대영(Dae-Young Lee),김현정(Hyun-Jung Kim),김동선(Dong-Seon Kim),박준석(Jun-Seok Park),임병찬(Pyeong Chan Ihm) 대한설비공학회 2018 설비공학 논문집 Vol.30 No.6

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2017. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) In building mechanical system research fields, twenty studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (2) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to the ventilated cavity of curtain-wall system for enhancing insulation and preventing condensation, the improvement plans of condensation defect examples in apartment building and the calculation method for the transmitted solar irradiance using the total horizontal irradiance. The subjects of building energy are worked on the energy consumption characteristics in office buildings, energy performance analysis for energy saving potentials in a hospital building, outdoor air cooling system operated with load prediction, building energy efficiency rating changes by enhanced building envelope standards, energy saving effect for the external insulation construction, energy reduction of a heating network through the application of an absorption heat pump, analysis of thermal load profile according to the window retrofit in an old school building, calculating regional balance point temperature for heating degree-days in korea, short-term load prediction using artificial neural network models, the simple window model applied to EnergyPlus, possibility of building energy saving through the building data, optimal cooling operation of a single family house model equipped with renewable energy facility by linear programming. The remained studies are related to the comparison between korea and china evacuation laws in office building, the effect of cold air stimulation during the driver’s drowsiness, the calculation of the attachedpiping-material rate for the building mechanical-service system in office buildings, the development of a modularlightweight steel ceiling system and the evaluation of local loss coefficients for different waveguide-below-cutoff (wbc) arrays of electromagnetic pulse. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, research subjects include the improvement of Type II and double-effect absorption heat pumps, the seasonal performance of compression heat pumps, a vertical receiver in a compression heat pump, the performance of a domestic built-in ice maker and the performance characteristics of a surface water heat pump system. In the alternative refrigeration/energy system category, subjects include a membrane dehumidification system, a CO₂-hydrate circulation system, a Zeolite 13x chemical thermal energy storage system and the performance criteria for heat pumps as a renewable energy device. In the system control category, subjects include a defrosting control system using photoelectric sensors and the control method for an organic thermal storage-chiller system. (4) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for prediction of stratification model for diffusers in underfloor air distribution system using