• Title/Summary/Keyword: solar cooling and hot water system

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Analysis of Thermal Performance in Roof Evaporative Cooling System (지붕 증발냉각시스템의 열성능 해석)

  • Shin, U.C.
    • Journal of the Korean Solar Energy Society
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    • v.21 no.3
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    • pp.9-18
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    • 2001
  • This paper reports on an theoretical study of heat transfer from evaporative cooling system by the flow of recirculated water over the roof. In this system tile water is distributed at the top of the pitched roof, collected at the bottom by a gutter and recirculated by a pump. To analysis the system, the energy balance equations are developed and solved using a finite difference method. The calculation results show a good agreement with the measured ones obtained from our experiment. Based on the results, it was seen that the roof-evaporative cooling system reduced the heat flux significantly compared with the conventional roof structure even in the hot-humid summer climate of Korea.

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The Energy Performance Analysis of Large Scale Store Using Dynamic Thermal Analysis Simulation Program (동적열해석프로그램을 이용한 대형할인매장의 에너지 소비 특성 분석)

  • Kim, Byoung-Soo;Hong, Won-Pyo
    • Journal of the Korean Solar Energy Society
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    • v.30 no.6
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    • pp.44-49
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    • 2010
  • The purpose of this study is to analyze the situation of energy consumption and its characteristics in large scale store. The related survey is carried out in large scale store to investigate the energy consumption and energy use trend of heating, cooling, hot water, lighting, ventilation, equipments and others. The area of large scale discount store is about $65000m^2$, located in Daejeon. For Annual Energy Analysis of building, We surveyed used energy for 1 year and simulated using a building energy simulation(TRNSYS 16). The results of this study are as follows. 1)The amount of annual total energy consumption are 18615.244MWh/yr(286.4KWh/$m^2yr$), The rate of heating, cooling and base energy(for hot water, lighting, ventilation, equipments, cooking and others) is 3054MWh/yr(47kWh/$m^2yr$), 5660.09MWh/yr(87.08kWh/$m^2yr$), 9900.47MWh/yr(152.31KWh/$m^2yr$) respectively. The total used energy is higher than others building in Korea. Especially, The energy consumption of large scale store is very depends on operating period and pattern such as space temperature, occupancy, lighting system, equipments operating schedule and etc.

Experimental Study for Estimation of Air Heating Performance and Improvement of Thermal Performance of Hybrid Solar Air-water Heater (태양열 공기-물 가열기의 공기 가열 성능 평가 및 열적 성능 개선을 위한 실험적 연구)

  • Choi, Hwi-Ung;Kim, Young-Bok;Yoon, Jung-In;Son, Chang-Hyo;Choi, Kwang-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.37 no.1
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    • pp.47-57
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    • 2017
  • Solar energy is one of the important renewable energy resources. It can be used for air heating, hot water supply, heat source of desiccant cooling system and so on. And many researches for enhancing efficiency have been conducted because of these various uses of solar thermal energy. This study was performed to investigate the air heating performance of hybrid solar air-water heater that can heat air and liquid respectively or simultaneously and finding method for improving thermal performance of this collector. This collector has both liquid pipe and air channel different with the traditional solar water and air heater. Fins were installed in the air channel for enhancing the air heating performance of collector. Also air inlet & outlet temperature, ambient temperature and solar collector's inner part temperature were confirmed with different air velocity on similar solar irradiance. As a result, temperature of heated air was shown about $43^{\circ}C$ to $60^{\circ}C$ on the $30^{\circ}C$ of ambient temperature and thermal efficiency of solar collector was shown 28% to 73% with respect to air velocity. Also, possibility of improvement of thermal performance of this collector could be ascertained from the heat transfer coefficient calculated from this experiment. Thus, it is considered that the research for finding optimal structure of hybrid solar air-water heater for enhancing thermal performance might be needed to conduct as further study based on the method for improving air heating performance confirmed in this study.

Hybrid Photovoltaic/Thermal Solar System with Pulsating Heat Pipe Type Absorber (진동형 히트파이프 흡열판이 결합된 하이브리드 태양광/열 시스템)

  • Kim, Chang-Hee;Jeon, Dong-Hwan;Kong, San-Gun;Kim, Jong-Su
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2148-2153
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    • 2007
  • The electricity conversion-efficiency of solar cell for commercial application is about 6-15%. More than 85% of the incoming solar energy is either reflected or absorbed as heat energy. Consequently, the working temperature of the photovoltaic cells increases considerably after prolonged operations and the cell's efficiency drops significantly. PV/T refers to the integration of a PV module and a solar thermal collector in a single piece of equipment. By cooling the PV module with a fluid steam like air or water, the electricity yield can be improved. At the same time, the heat pick-up by the fluid can be to support space heating or service hot-water systems. In this study, a pulsating heat pipe solar heat collector was combined with single-crystal silicon photovoltaic cell in hybrid energy-generating unit that simultaneously produced low temperature heat and heat and electricity. This experiment was investigating thermal and electrical efficiency for evaluation of a PV/T system.

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Heating and Cooling Performance Analysis of Ground Source Heat Pump System in Low Energy House (저에너지주택의 지열히트펌프시스템 냉·난방 성능분석)

  • Baek, Namchoon;Kim, Sungbum;Shin, Ucheul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.10
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    • pp.387-393
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    • 2016
  • A ground source heat pump system maintains a constant efficiency due to its stable heat source and radiant heat temperature which provide a more effective thermal performance than that of the air source heat pump system. As an eco-friendly renewable energy source, it can reduce electric power and carbon dioxide. In this study, we analyzed one year of data from a web based remote monitoring system to estimate the thermal performance of GSHP with the capacity of 3RT, which is installed in a low energy house located in Daejeon, Korea. This GSHP system is a hybrid system connected to a solar hot water system. Cold and hot water stored in a buffer tank is supplied to six ceiling cassette type fan coil units and a floor panel heating system installed in each room. The results are as follows. First, the GSHP system was operated for ten minutes intermittently in summer in order to decrease the heat load caused by super-insulation. Second, the energy consumption in winter where the system was operated throughout the entire day was 7.5 times higher than that in summer. Moreover, the annual COP of the heating and cooling system was 4.1 in summer and 4.2 in winter, showing little difference. Third, the outlet temperature of the ground heat exchanger in winter decreased from $13^{\circ}C$ in November to $9^{\circ}C$ in February, while that in summer increased from $14^{\circ}C$ to $17^{\circ}C$ showing that the temperature change in winter is greater than that in summer.

The feasibility study for the building integrated geothermal system using the horizontal heat exchanger (수평형 지중열교환기를 이용한 건물일체형 지열시스템의 도입타당성 분석)

  • Chae, Ho-Byung;Nam, Yujin;Yoon, Sung-Hoon
    • Journal of the Korean Solar Energy Society
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    • v.35 no.1
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    • pp.81-87
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    • 2015
  • Recently, in order to prevent increasing energy usages in the international community, many countries have attempted to develop the innovative renewable energy systems. Among the renewable energy systems, Ground source heat pump(GSHP) system which supply the heating, cooling and hot water in the building has been attracted by its stability of heat production and high efficiency. However, the initial drilling costs become very expensive and the construction period takes longer the other systems, because GSHP system needs more than 100 m depth drilling. In this study, in order to reduce initial costs of the GSHP, the building integrated geothermal system using the horizontal heat exchanger was developed. The heating and cooling load in the standard housing model was calculated by a simulation and the system design capacity in the high-rise apartment was decided by the total load. Based on the system design capacity, the high-rise apartments were applied to a BIGS and vertical GSHP system and there are analyzed about initial costs. In the result, the initial cost of BIGS could reduce 24% of the initial cost of the vertical GSHP system.

The Energy Performance & Economy Efficiency Evaluation of Micro Gas Turbine Installed in Hospital (대형병원 건물에 마이크로 가스터빈 적용을 위한 에너지성능 및 경제성 평가)

  • Kim, Byoung-Soo;Hong, Won-Pyo
    • Journal of the Korean Solar Energy Society
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    • v.29 no.5
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    • pp.8-13
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    • 2009
  • Feasibilities of the application of a micro gas turbine cogeneration system to a large size hospital building are studied by estimating energy demands and supplies. The energy demand for electricity is estimated by surveying and sorting the consumption records for various equipment and devices. The cooling heating, and hot water demands are further refined with TRNSYS and ESP-r to generate load profiles for the subsequent operation simulations. The operation of the suggested cogeneration system in conjunction with the load data is simulated for a time span of a year to predict energy consumption and gain profile. The simulation revealed that the thermal efficiency of the gas turbine is about 30% and it supplies 60% of the electricity required by the building. The recovered heat can meet 56% of total heating load and 67% of cooling, and the combined efficiency reaches up to 70%.

Study on the Regenerating Performance of Liquid Desiccant in the Cooling/Dehumidification System able to use a Solar Water Heater in Summer(On the Analysis of Source Effect by the Design of Experiments) (여름철 냉방/제습시스템 중 태양열 온수기를 적용할 수 있는 액체흡수제의 재생성능에 관한 연구(실험계획법에 의한 요인효과 분석에 관하여))

  • Choi, K.H.;Kim, B.C.;Kim, B.J.
    • Journal of the Korean Solar Energy Society
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    • v.22 no.1
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    • pp.1-8
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    • 2002
  • With the possibility of hot water being able to be used as a heating source in a liquid desiccant system, an experimental apparatus for regeneration of the liquid desiccant was set up and series of experiments were conducted in a climate-controlled chamber. This study was performed to ascertain the influences of experimental factors on regenerating performance and to suggest the optimal combination of factors affecting regeneration rate. Furthermore. in order to figure out the contribution ratio of the factors on regenerating performance, a multi-way factorial design among the design of experiments was adopted. According to experimental results, the most influential factor on regenerating performance was temperature of the liquid desiccant and its contribution ratio was about 79.4%. In addition. the optimal operating combination was as follows; $60^{\circ}C$ of solution temperature, $14\ell$/min of solution flow rate, and 190m3/h of air volume.

Energy Performance Evaluation of Low Energy Houses using Metering Data (실측데이터를 이용한 저에너지주택의 에너지성능평가)

  • Baek, Namchoon;Kim, Sungbum;Oh, Byungchil;Yoon, Jongho;Shin, Ucheul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.369-374
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    • 2015
  • This study analyzed analyzes the energy performance of six houses in Daejeon completed which were built in 2011. Observed The observed houses, which were all designed and constructed inof the same size and structure, are were highly insulated with triple Low-E coating windows; the insulation level of the walls is was $0.13W/m^2K$ and that of the roof is was $0.10W/m^2K$. As electric houses, all of the energy supplied to the houses, including for cooking, is was supplied by electricity. A and 3~4 kWp of photovoltaic system and a 3~5 kW of ground source heat pump (GSHP) were installed in each house tofor providing provide space heating/and cooling and hot water are installed. We constructed a Web-based remote monitoring system in order to understand energy consumption and the dynamic behavior of the energy system. T, and the results of our metering data analysis of 2013 are as follows. First, the annual residential energy consumption is was 4,400 kWh (${\sigma}=1,209$) and GSHP energy consumption is was 5,182 kWh (${\sigma}=1,164$). Second, residential energy consumption ranked highest in average energy usage, with at 45% of the total, followed by heating with at 30%, hot water supply with at 17% and cooling with at 6%. Third, the average energy independence rate is was 51.8%, the GFA (Gross gross floor area) criteria average energy consumption unit is was $48.7kWh/m^2yr$ (${\sigma}=10.1$), and the net energy consumption unit (except the energy yield of the PV systems) is was $24.7kWh/m^2yr$ (${\sigma}=8.8$).

The Performance Test and the Feasibility Study for a Dual-Source Heat Pump System Using the Air and Ground Heat Source (공기 및 지열 이용 Dual-Source 히트펌프 시스템의 성능실험 및 경제성 분석)

  • Nam, Yujin;Chae, Ho-Byung
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.5
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    • pp.212-217
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    • 2014
  • Recently, the use of renewable energy has been increased due to growing concern on the energy-saving at buildings and the reduction of $CO_2$ emission. In the field of architecture, to reduce the energy consumption of heating, cooling and hot water supply, heat pump systems with renewable energy has been developed and used in various applications. However, there have been many of researches on the large-scale commercial heat pump systems, but the research and the field application of a compact heat pump system is rare. Therefore, in order to develop the compact heat pump for the small-scale residential building, this study conducted the performance test and feasibility study for a hybrid heat pump using the heat source of air, solar and ground. In the results of experiments through a trial product, the average COP of cooling mode with ground heat source was 4.75, and it of heating mode was 4.03. Furthermore, the average COP of cooling mode with air heat source was 2.60, and it of heating mode was 2.92. Finally, payback period of the system was calculated as 9.2 years.