• Title/Summary/Keyword: Amount of Heat

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Effects of Gas Injection on the Heating Performance of a Two-Stage Heat Pump Using a Twin Rotary Compressor with Refrigerant Charge Amount

  • Heo, Jae-Hyeok;Jeong, Min-Woo;Jeon, Jong-Ug;Kim, Yong-Chan
    • International Journal of Air-Conditioning and Refrigeration
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    • v.16 no.3
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    • pp.77-82
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    • 2008
  • For heat pumps used in a cold region, it is very important to obtain appropriate heating capacity. Several studies using a variable speed compressor and an additional heater have been performed to enhance heating capacity at low ambient temperatures. However, for outdoor temperature conditions below $-15^{\circ}C$, it is still difficult to obtain enough heating capacity above the rated value. In recent studies, the application of gas injection technique into a two-stage heat pump yielded noticeable heating performance improvement at low temperature conditions. In this study, the heating performance of a two-stage gas injection heat pump with a rated capacity of 3.5 kW was measured and analyzed by varying refrigerant charge amount and EEV opening at the standard heating condition. The heating performance of the two-stage gas injection heat pump was compared with that of a two-stage non-injection heat pump. The heating capacity and COP of the two-stage gas injection heat pump were improved by 2-10% at the optimal charging condition over those of the two-stage non-injection heat pump.

Experiment Results of 30,000 CMH class Heat Exchangers for Wasted Heat Recovery in Winter (30,000CMH급 폐열회수열교환기 겨울철 성능실험 결과)

  • Ha, Byeong-Yong;Im, Hong-Seok;Kim, Dong-Gyu;Kum, Jong-Soo;Jeong, Seok-Kwon;Chung, Yong-Hyun;Kim, Geun-Oh;Myeong, Jin-Pil
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.83-86
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    • 2009
  • The field of the large volume heat exchanger for wasted heat recovery ventilation system is being expanded enormously seeing as the fact that the quantity of reducing energies are huge due to the large volume heat exchanger for wasted heat recovery system at large buildings and factories, which consume large amount of energies while it has been arising huge amount of losses in Korea because of the lack of technology.

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Effect of the Amount of Retained Austenite on the Mechanical Properities of Austempered Ductile Iron (오스템퍼드 구상흑연주철품의 기계적 성질에 미치는 잔류오스테나이트량의 영향)

  • Choi, J.O.;Lee, S.H.;Park, S.T.;Choi, C.O.
    • Journal of the Korean Society for Heat Treatment
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    • v.15 no.4
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    • pp.178-187
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    • 2002
  • Austempered Ductile Iron (ADI) castings having various chemical composition and heat treatment conditions were investigated. Especially, this study was investigated the influence of various parameters on austempering temperature and alloying elements. The addition of Mo, Cu, and Ni individually or combined in these alloys also investigated. The alloying elements influence the austempering reaction, the microstructures, mechanical properties and amount of retained austenite. In this study, the mechanical properties (ultimate tensile strength(UTS), hardness, elongation) are analysed to show the relationship between alloying elements, austempering temperatures and amount of retained austenite. The amount of retained austenite was the range of 15 - 40%. In case of the alloy to witch Mo, Cu, and Ni was added, the amount of retained austenite was the largest at a constant austempering temperature.

A Study on the Potential Energy Reserve Amount of Domestic River Water as Unutilized Energy Resource (국내 하천수 미활용에너지 부존량에 관한 조사연구)

  • Park Il-Hwan;Yoon Hyung-Kee;Park Jun-Taek;Chang Ki-Chang;Lee Young-Soo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.6
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    • pp.521-528
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    • 2005
  • This study has been conducted to investigate the potential energy reserve amount of river water as energy resource with useful temperature difference. Since the river water temperature is one of the primary parameters deciding the potential amount of river water energy reserve amount, the climate change effects on it are critically important. In this study, the heat exchange processes and the inter-relationship between the air temperature and river water temperature have been theoretically analyzed. Based on the present study, the potential energy reserve of river water is calculated to amount to 192,000 Tcal/year. Among this, it is estimated that approximately 2,000 Tcal/year can be directly utilized for heat pump energy sources.

Estimation of Heat Losses From the Receivers for Solar Energy Collecting System of Korea Institute of Energy Research

  • Ryu, Siyoul;Seo, Taebeom
    • Journal of Mechanical Science and Technology
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    • v.14 no.12
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    • pp.1403-1411
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    • 2000
  • Heat losses from the receivers for a dish-type solar energy collecting system constructed at Korea Institute of Energy Research are analyzed. The Stine and McDonald's model is used to estimate the convection loss. The Net Radiation method and the Monte-Carlo method are used to calculate the radiation heat transfer rate from the inside surface of the receiver to the surroundings. Two different receivers are suggested here and the performances of the receivers are estimated and compared with each other based on the prediction of the amount of heat losses from the receivers. The effects of the receiver shape and the radiation properties of the surface on the thermal performance are investigated. The performance of Receiver I is better than that of Receiver II, and the amount of solar irradiation that is not captured by the captured by the receiver after being reflected by the concentrator becomes significant if the temperature of the working fluid is low.

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Effect of Heat Treatment Temperature on Amount of Stress-Induced ${\varepsilon}$ Martensite in an Fe-Mn Baesd Alloy (Fe-Mn계 합금에서 응력유기 ${\varepsilon}$ 마르텐사이트의 양에 미치는 열처리 온도의 영향)

  • Jee, K.K.;Han, J.H.;Jang, W.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.17 no.6
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    • pp.342-345
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    • 2004
  • In this work, a new method of measuring volume fraction of deformation-induced ${\varepsilon}$ martensite is proposed using endothermic heat on reverse transformation. As grain size increases, the amount of ${\varepsilon}$ martensite forming on cooling increases. However, with a decrease in grain size, more ${\varepsilon}$ is induced by deformation, improving shape memory effect.

A Heat Transfer Analysis of a Thermally Asymmetric Triangular Fin; Based on Fin Tip Effect (열적 비대칭 삼각 핀의 열전달 해석; 핀 끝 효과에 기준)

  • Kang, Hyung-Suk
    • Journal of Industrial Technology
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    • v.22 no.B
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    • pp.21-26
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    • 2002
  • The non-dimensional heat loss from a thermally asymmetric triangular fin is investigated as a function of a ratio of upper and lower surface Biot numbers (Bi2/Bi1), the non-dimensional fin length and tip surface Biot number using the two-dimensional separation of variables method. The effect of fin tip surface Biot number on the variation of the non-dimensional temperature along the sloped upper and lower surfaces for the thermally asymmetric condition is presented. The relationship between the non-dimensional fin length and the fin tip surface Biot number for equal amount of heat loss is also discussed as well as the relationship between upper surface Biot number and tip surface Biot number for equal amount of heat loss.

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The Energy Consumption Characteristics of Building Accordance with Air-Conditioning and Heating System (건축물 냉.난방 시스템에 따른 에너지 소비 특성 -서울 소재 A 대학교 건축물을 중심으로-)

  • Park, Kang-Hyun;Cha, Jung-Hoon;Kim, Su-Min
    • 한국태양에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.333-337
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    • 2011
  • Central control air-conditioning systems are being replaced with individually controlled air-conditioning system in the university. The amount of growth of electricity consumption is due to the increasing demand of electric heat pump. In winter and summer, the energy consumption showed a tendency to increase. On the other hand, showed less energy in spring and autumn. Increase the amount of electricity than the degree of decline in gas consumption was higher. Can be considered as transitional phenomena. Because electric heat pump, gas driven heat pump and the absorption chiller-heater are used at the same time in some of the buildings.

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A Study on The Trend of Occurrence and The Use Possibility of Mass Burning of Solid Waste in Seoul (서울시 쓰레기의 배출추세와 쓰레기 소각열의 이용에 관한 연구)

  • Kim, Shin-Do
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.15 no.1
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    • pp.97-104
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    • 1986
  • This is to supply the basic data for saving energy and the appropriate way of waste disposal. The amount of waste disposed and its heat after burning is guessed to get conclusions. 1. The amount of disposable waste in 1990 in Seoul area is expected to be 2.2kg per man/day, coal ashes (YONTAN) 0.7kg, non-coal ashes 1.5kg. 2. The amount of waste combustible and heat after burning will be increased, and it is useful when the waste has Less than $70\%$ of water. 3. The method to collect waste should be specially organized, because most of the waste collected In Korea Is wet. 4. As the heat emitted from mass burning is $4\times10^{12}kcal/y$ in 1985, it is considered to be in senses of energy saving and the rationnal way of waste disposal. 5. Special concern is needed because the environment contaminated will be polluted in result of burning.

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Analysis of the $CO_2$ emission amount and characteristics of combined heat and power plants in industrial complex by using the fuel analysis method (연료분석 방법을 적용한 산업단지 열병합발전소 이산화탄소 배출량 및 배출특성분석)

  • Kang, Seok-Hun;Chung, Dae-Hun
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1243-1248
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    • 2008
  • $CO_2$ emission amount and characteristics of combined heat and power (CHP) plant in industrial complex of Korea is evaluated by using the fuel analysis method. Fuel analysis methods of several foreign countries and developed one which is developed considering the operation characteristics of the surveyed CHP plants are used. The operation data is surveyed for all of the CHP plants in industrial complex and is composed of fuel consumption amount, generation, sale and efficiency of heat and electricity, condensed steam enthalpy, and etc of the each CHP.

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