Heat transfer and thermal characteristics analysis of direct air-cooled combined heat and power plants under off-design conditions

2018 ◽  
Vol 129 ◽  
pp. 260-268 ◽  
Author(s):  
Ningling Wang ◽  
Yumeng Zhang ◽  
Peng Fu ◽  
Pengpai Feng ◽  
Yongping Yang
Keyword(s):  
Heat Transfer ◽  
Power Plants ◽  
Thermal Characteristics ◽  
Combined Heat And Power ◽  
Characteristics Analysis

Methods to Reduce Hot Return Condensate Temperature Without Compromising Plant Efficiency for Combined Heat and Power Plants

2017 ◽  
Author(s):  
Anil Kumar Addanky
Keyword(s):  
Heat Transfer ◽  
Water Quality ◽  
Power Plant ◽  
Power Plants ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Combined Heat And Power ◽  
Higher Plant ◽  
Improve Water Quality ◽  
Plant Efficiency

This paper describes five methods to achieve effective heat transfer and higher plant efficiency when condensate return temperature is high and treatment is needed to improve water quality in the water treatment plant before sending it to the deaerator for a combined heat and power plant.

scholarly journals Heat Transfer Enhancement in Condensers in Steam Turbine Based Combined Heat and Power Plants

2015 ◽  
Vol 12 (Special-Edn2) ◽  
pp. 617-623
Author(s):  
Alexander Valentinovich Kurshakov ◽  
Artem Vyacheslavovich Ryzhenkov ◽  
Valerij Dmitrievich Burov ◽  
Oleg Vyacheslavovich Ryzhenkov ◽  
Marat Ravilevich Dasaev
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Steam Turbine ◽  
Power Plants ◽  
Combined Heat And Power ◽  
Transfer Enhancement

scholarly journals KARAKTERISTIK PERPINDAHAN PANAS KONVEKSI ALAMIAH ALIRAN NANOFLUIDA AL2O3-AIR DI DALAM PIPA ANULUS VERTIKAL

2016 ◽  
Vol 18 (1) ◽  
pp. 21
Author(s):  
Reinaldy Nazar
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Power Plants ◽  
Convection Heat Transfer ◽  
Thermal Characteristics ◽  
Heat Transfer Fluid ◽  
Empirical Correlations ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Vertical Annulus

ABSTRAK KARAKTERISTIK PERPINDAHAN PANAS KONVEKSI ALAMIAH ALIRAN NANOFLUIDA AL2O3-AIR DI DALAM PIPA ANULUS VERTIKAL. Hasil beberapa penelitian menunjukan bahwa nanofluida memiliki karakteristik termal yang lebih baik dibandingkan dengan fluida konvensional (air). Berkaitan dengan hal tersebut, saat ini sedang berkembang pemikiran untuk menggunakan nanofluida sebagai fluida perpindahan panas alternatif pada sistem pedingin reaktor. Sementara itu, konveksi alamiah di dalam pipa anulus vertikal merupakan salah satu mekanisme perpindahan panas yang penting dan banyak ditemukan pada reaktor riset TRIGA, reaktor daya generasi baru dan alat konversi energi lainnya. Namun disisi lain karakteristik perpindahan panas nanofluida di dalam pipa anulus vertikal belum banyak diketahui. Oleh karena itu penting dilakukan secara berkesinambungan penelitian-penelitian untuk menganalisis perpindahan panas nanofluida di dalam pipa anulus vertikal. Pada penelitian telah dilakukan analisis numerik menggunakan program computer CFD (computational of fluids dynamic) terhadap karakteristik perpindahan panas konveksi alamiah aliran nanofluida Al2O3-air konsentrasi 2% volume di dalam pipa anulus vertikal. Hasil kajian ini menunjukkan terjadi peningkatan kinerja perpindahan panas (bilangan Nuselt- NU) sebesar 20,5% - 35%. Pada moda konveksi alamiah dengan bilangan 2,4708e+09 £ Ra £ 1,9554e+13 diperoleh korelasi empirik untuk air adalah dan korelasi empirik untuk nanofluida Al2O3-air adalah   Kata kunci: Nanofluida Al2O3-air, konveksi alamiah, pipa anulus vertikal     ABSTRACT THE CHARACTERISTICS OF NATURAL CONVECTIVE HEAT TRANSFER OF AL2O3–WATER NANOFLUIDS FLOW IN A VERTICAL ANNULUS PIPE. Results of several research have shown that nanofluids have better thermal characteristics compared to conventional fluid (water). In this regard, currently developing ideas for using nanofluids as an alternative heat transfer fluid in the reactor coolant system. Meanwhile the natural convection in a vertical annulus pipe is one of the important mechanisms of heat transfer and is found at the TRIGA research reactor, the new generation nuclear power plants and other energy conversion devices. On the other hand the heat transfer characteristics of nanofluids in a vertical annulus pipe has not been known. Therefore, it is important to do research continuously to analyze the heat transfer nanofluids in a vertical annulus pipe. In the research has been carried out numerical analysis by using computer code of CFD (computational of fluids dynamic) on natural convection heat transfer characteristics of nanofluids flow of Al2O3-water 2% volume in the vertical annulus pipe. The results showed an increase in heat transfer performance (Nusselt numbers - NU) by 20.5% - 35%. In natural convection mode with Rayleigh numbers 2.4708e+09 £ Ra £ 1.9554e+13 obtained empirical correlations for water is and empirical correlations for Al2O3-water nanofluids is .   Keywords: Al2O3-water nanofluids, the natural convection, the vertical annulus pipe

Experimental Study on Thermal Characteristics of Finned Coil LHSU Using Paraffin as Phase Change Material

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Guansheng Chen ◽  
Nanshuo Li ◽  
Huanhuan Xiang ◽  
Fan Li
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Phase Change ◽  
Phase Change Material ◽  
Water Flow ◽  
Water Flow Rate ◽  
Thermal Characteristics ◽  
Heat Transfer Fluid ◽  
Latent Heat Storage ◽  
Change Material

It is well known that attaching fins on the tubes surfaces can enhance the heat transfer into and out from the phase change materials (PCMs). This paper presents the results of an experimental study on the thermal characteristics of finned coil latent heat storage unit (LHSU) using paraffin as the phase change material (PCM). The paraffin LHSU is a rectangular cube consists of continuous horizontal multibended tubes attached vertical fins at the pitches of 2.5, 5.0, and 7.5 mm that creates the heat transfer surface. The shell side along with the space around the tubes and fins is filled with the material RT54 allocated to store energy of water, which flows inside the tubes as heat transfer fluid (HTF). The measurement is carried out under four different water flow rates: 1.01, 1.30, 1.50, and 1.70 L/min in the charging and discharging process, respectively. The temperature of paraffin and water, charging and discharging wattage, and heat transfer coefficient are plotted in relation to the working time and water flow rate.

scholarly journals The use of a solution of the inverse heat conduction problem to monitor thermal stresses

2019 ◽  
Vol 108 ◽  
pp. 01003
Author(s):  
Jan Taler ◽  
Piotr Dzierwa ◽  
Magdalena Jaremkiewicz ◽  
Dawid Taler ◽  
Karol Kaczmarski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Power Plants ◽  
Thermal Stresses ◽  
Thermal Power ◽  
Temperature Fields ◽  
Thick Wall ◽  
Fluid Temperature ◽  
Unsteady Temperature

Thick-wall components of the thermal power unit limit maximum heating and cooling rates during start-up or shut-down of the unit. A method of monitoring the thermal stresses in thick-walled components of thermal power plants is presented. The time variations of the local heat transfer coefficient on the inner surface of the pressure component are determined based on the measurement of the wall temperature at one or six points respectively for one- and three-dimensional unsteady temperature fields in the component. The temperature sensors are located close to the internal surface of the component. A technique for measuring the fastchanging fluid temperature was developed. Thermal stresses in pressure components with complicated shapes can be computed using FEM (Finite Element Method) based on experimentally estimated fluid temperature and heat transfer coefficient

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