• Title/Summary/Keyword: Hybrid Heat Pump

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A Study on Hybrid Heating System with Anti-Superheating Devices (과열방지장치가 설치된 복합열원 난방시스템에 관한 연구)

  • Park, Youn-Cheol;Ko, Gwang-Soo;Han, Yu-Ry
    • Journal of the Korean Solar Energy Society
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    • v.27 no.2
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    • pp.19-27
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    • 2007
  • The previous study was conducted to develop an air source multi heat pump system that could be operated with the solar collector and air source heat exchangers as heat source of the system. There is a winter-sowing problems in air source multi heat pump system when the outdoor temperature goes down under freezing point. The winter-sowing problem was solved by adapting R-22 refrigerant as working fluid in the previous study. However, when the system operated at high temperature, another problems are come out such as overheating of the solar collector outlet which lead to the superheat of the compressor inlet of the heat pump system. The condition could deteriorates a compressor in some case. In this study, we installed the anti-superheating devices on the previously developed system. As results of system performance test, COP of the system with anti-superheating technique is 2.4. It is a little improved COP compare to previous study's 2.23. In the results of multi heat source heating system, during operating solar collector, COP is relatively high between $200\;W/m^2$ and $400\;W/m^2$ solar intensity. It is recommended to extend the study on performance optimization with balancing the solar collect and capacity of compressor at higher solar irradiation conditions.

Optimization Study of the Compression/Absorption Hybrid Heat Pump Cycle (증기압축식/흡수식 하이브리드 히트펌프 사이클에 관한 최적화 연구)

  • 전관택;박춘건;정동수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.1
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    • pp.48-58
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    • 2001
  • For the past few decades the vapor compression cycle with a solution circuit (VCCSC) has been known to provide high efficiency and variable capacity. In this study performance of a VCCSC cycle is examined through computer simulation. In the simulation heat exchangers were modelled by specifying UA or effectiveness values while the compressor performance was specified by an isentropic efficiency. Aqua/ammonia solution was chosen as the working fluid which can be used in the high temperature range. The results show that there exists an optimum operation condition which is dependent upon the temperatures of the external heat transfer fluids(HTFs). Besides the HTF\`s temperature, the maximum system pressure and the size of the solution heat exchanger are shown to have an influence on the optimum operation condition. Finally, as compared to a simple vapor compression heat pump with HFC134a, the COP of the VCCSC is shown to be 2∼22% higher.

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Analytical Study on the Optimal Operating Control of A Hybrid Geothermal Plant (지열복합 열원가기 최적운전채어에 관한 해석적 연구)

  • Jeon, Jong-Ug;Park, Jong-Sam;Myung, Woo-Ho;Kim, Young-Ki;Kim, Yong-Chan
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.6 no.2
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    • pp.1-7
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    • 2010
  • The objective of this study is to find the optimal control algorithm of a hybrid Plant, which is combined by renewable energy plant of the GSHP(Geothermal Source Heat Pump) and the normal plant (Chiller, boiler). The work presented in this study was carried out in the EnergyPlus(Version 2.0). The EnergyPlus was modified in order to simulate the hybrid plant. The plant system was controlled by the load-range-based operation in which schemes select a user specified set of equipment for each user specified range of a particular simulation condition. In the use of the load-range-based operation, four kind of control cases were defined and simulated in order to obtain the optimal control algorithm of the hybrid plant. The result showed that the Case 2 was the optimal control algorithm which used the GSHP as a base operating plant and the normal plant as an assistant operating plant. Even though the normal plant was operated in full load and the renewable energy plant of the GSHP was operated in partial load, the annual energy consumption of the normal plant was larger than that of the GSHP plant.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. 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) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) 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 general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

The Study on the Energy self-sufficiency and Economic Analysis of KIER Zero Energy Solar House (제로에너지 솔라하우스(KIER ZeSH)의 에너지 자립도 및 경제성 분석)

  • Jeong, Seonyeong;Baek, Namchoon;Yoo, Changkyoon;Yoon, Eungsang;Yoon, Jongho
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.64.1-64.1
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    • 2010
  • In this study, the energy and economic analysis of KIER Zero Energy Solar House (KIER ZeSH) was carried out. KIER ZeSH was designed and constructed in the end of 2009 for the purpose of more than 70% energy self-sufficiency in total load as well as less than 20% of additional construction cost. The several building energy conservation technologies like as super insulation, high performance window, wast heat recovery system, etc and renewable energy system. The renewable heating and cooling system is a kind of solar thermal system combined with geo-source heat pump as a back-up device. The capacity of 3.15kW solar BIPV system was also installed on the roof. The measurement by monitering system of ZeSH was conducted for one year from November 2009 to October 2010. The energy self-sufficiency and economic analysis were conducted based on the this monitering result. As a result, the energy self sufficiency is about 83% which is higher than that of the target and the payback period is 11 years.

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A method for Application of Hybrid Geothermal Cooling-Heating System in Multi Family Apartment (공동주택용 하이브리드 지열 냉난방 시스템의 적용추진 전략)

  • Park, Yong-Boo;Park, Jong-Bae;Kim, Gil-Tae
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.1447-1454
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    • 2009
  • Currently, geothermal heat pump systems are being installed in new official and commercial building, welfare facilities, and school but there are a few cases for the housing heat sink in Korea. The reason is that there are no progressive taxes for the household electrical use, no actual output for the application of geothermal technology, high initial investment. For the overall use in multi family apartment such as the Green Home etc, technology development and building of the relevant research team need to be done through preliminary study. Core subjects for overall use include cooling heating load estimation for the multi family apartment, economical efficiency of the geothermal cooling and heating system, design and construction technology of the geothermal cooling and heating system for the multi family apartment, commercialization plan, and state of the art analysis. Selection of the detailed subjects with respect to core subject, driving schedule and commercialization plan, driving system, presentation of the utilization plan.

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Analysis of Performance and Energy Saving of a SOFC-Based Hybrid Desiccant Cooling System (건물용 연료전지 기반 하이브리드 제습냉방시스템 성능 및 에너지 절감 분석)

  • IN, JUNGHYUN;LEE, YULHO;KANG, SANGGYU;PARK, SUNGJIN
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.2
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    • pp.136-146
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    • 2019
  • A solid oxide fuel cell (SOFC) based hybrid desiccant cooling system model is developed to study the effect of fuel utilization rate of the SOFC on the reduction of energy consumption and $CO_2$ emission. The SOFC-based hybrid desiccant cooling system consists of an SOFC system and a Hybrid desiccant cooling system (HDCS). The SOFC system includes a stack and balance of plant (BOP), and HDCS. The HDCS consists of desiccant rotor, indirect evaporative cooler, electric heat pump (EHP), and heat exchangers. In this study, using energy load data of a commercial office building and SOFC-based HDCS model, the amount of ton of oil equivalent (TOE) and ton of $CO_2$ ($tCO_2$) are calculated and compared with the TOE and $tCO_2$ generation of the EHP using grid electricity.

An Evaluation of the Solar Thermal Performance of the Solar/Geo Thermal Hybrid Hot Water System for a Detached House (단독주택용 태양열/지열 융복합시스템의 태양열 급탕성능 평가)

  • Baek, Namchoon;Han, Seunghyun;Lee, Wang Je;Shin, Ucheul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.11
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    • pp.581-586
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    • 2015
  • In this study, an analysis was performed on the performance of the solar water heating system with geo-thermal heat pump for a detached house. This system has a flat plate solar collector ($8\;m^2$) and a 3 RT heat pump. The heat pump acts as an auxiliary heater of the solar water heating system. These systems were installed at four individual houses with the same area of $100\;m^2$. The monitoring results for one year are as follows. (1) The average daily operating time of the solar system appeared to be 313 minutes in spring (intermediate season), and 135 minutes and 76 minutes in winter and summer respectively. The reason for the short operating time in summer is the high storage temperature due to low water heating load. The high storage temperature is caused by a decrease in collecting efficiency as well as by overheating. (2) The geothermal heat pump as an auxiliary heater mainly operates on days of poor insolation during the winter season. (3) Despite controlling for total house area, hot water consumption varies greatly according to the number of people in the family, hot water usage habits, etc. (4) The yearly solar fraction was 69.8 to 91.5 percent, which exceeds the maximum value of 80% as recommended by ASHRAE. So the solar collector area of $8\;m^2$ appeared to be somewhat greater for the house with an area of $100\;m^2$. (5) The observed annual efficiency of solar systems was relatively low at 13.5 to 23.6%, which was analyzed to be due to the decrease in thermal efficiency and the overheating caused by a high solar fraction.