A Heat-Balance Study on Sørbreen, Jan Mayen

Abstract The techniques and results of a heat-balance programme on Sørbreen, Jan Mayen, are presented and discussed. Estimates of 24 hr. heat-transfer totals under frontal and non-frontal weather conditions are then made. Transfer is found to be higher during frontal conditions, due to an increase in latent and to a lesser extent sensible heat transfer. Consideration of upper air temperatures and humidities suggests this higher transfer is experienced by the glacier as a whole. It is then proposed that summer rainfall totals will provide an index of frontal activity which may be used to indicate relative ablation from one summer to another. A statistical comparison of ablation measured on the glacier and rainfall recorded at the Jan Mayen meteorological station supports this suggestion.

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Ablation and Heat Balance of the Yukikabe Snow Patch in the Daisetsu Mountains, Hokkaido, Japan

Annals of Glaciology ◽

10.3189/1984aog5-1-122-126 ◽

1984 ◽

Vol 5 ◽

pp. 122-126 ◽

Cited By ~ 1

Author(s):

A. Sato ◽

S. Takahashi ◽

R. Naruse ◽

G. Wakahama

Keyword(s):

Latent Heat ◽

Air Temperature ◽

Heat Balance ◽

Meteorological Parameters ◽

Heat Sources ◽

Sensible Heat ◽

Net Radiation ◽

Ice Caps ◽

Air Temperatures ◽

The Heat Balance

A good correlation was found between the ablation of snow and degree day index (cumulative values of positive daily mean air temperature) during the summer of 1978 on the Yukikabe snow patch in the Daisetsu mountains, central Hokkaido. The volume change of the snow patch in the ablation season of any year can hence be estimated from air temperature using this relationship. Each of the heat-balance terms controlling the ablation is evaluated separately by using empirical equations and assumed values for meteorological parameters at the snow patch. Triangular diagrams are constructed in order to illustrate the relative contributions of sensible heat, latent heat, and net radiation, the main three heat sources. A higher contribution from sensible and latent heat is found for the snow patches of Japan than for many glaciers and ice caps elsewhere. This may be due to higher mid-summer air temperatures than in other glaciated parts of the world.

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Thermal Performance of Heat Exchanger Using Zeolite/vapour Adsorption

MATEC Web of Conferences ◽

10.1051/matecconf/202133303006 ◽

2021 ◽

Vol 333 ◽

pp. 03006

Author(s):

Soichiro Ohno ◽

Shuji Hironaka ◽

Jun Fukai

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Balance ◽

Flow Direction ◽

Packed Bed ◽

Maximum Temperature ◽

Sensible Heat ◽

Humid Air ◽

Adsorption Heat Pump ◽

The Heat Balance

About 60% of the energy input in the chemical industry is discarded from the plant. Energy saving can be achieved in the entire plant by recovering these waste heats and reusing them as power and heat sources in the power plant. An adsorption heat pump has been developed for the purpose of regeneration of such unused energy. In this study, saturated humid air was supplied to a device packed with 13X zeolite particles of 4 mm in diameter. The time variation of temperature in the apparatus was measured experimentally. Then, the maximum temperature was estimated from the relationship between heat balance and adsorption equilibrium. The trend of the maximum temperature calculated from the heat balance is consistent with experiment. Further, it was found from the result of the heat balance equation that the sensible heat of the humid air supplied and the heat of adsorption of the zeolite are mainly distributed to the sensible heat of the zeolite. In the future, it is important to make effective use of the sensible heat of this zeolite. In order to extract more thermal energy from the device, it is necessary to improve the heat transfer between the packed bed and medium. A double pipe heat exchanger having a zeolite packed bed on the annular side was proposed as an apparatus. Flow direction of the humid air supplied to device was changed in two different ways. The one of them is supplying humid air radial flowly to the device and another is supplying the air in parallel flow. The influence of flow direction on heat transfer between packed bed and medium is studied with numerical simulation.

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Ablation and Heat Balance of the Yukikabe Snow Patch in the Daisetsu Mountains, Hokkaido, Japan

Annals of Glaciology ◽

10.1017/s026030550000361x ◽

1984 ◽

Vol 5 ◽

pp. 122-126 ◽

Cited By ~ 2

Author(s):

A. Sato ◽

S. Takahashi ◽

R. Naruse ◽

G. Wakahama

Keyword(s):

Latent Heat ◽

Air Temperature ◽

Heat Balance ◽

Meteorological Parameters ◽

Heat Sources ◽

Sensible Heat ◽

Net Radiation ◽

Ice Caps ◽

Air Temperatures ◽

The Heat Balance

A good correlation was found between the ablation of snow and degree day index (cumulative values of positive daily mean air temperature) during the summer of 1978 on the Yukikabe snow patch in the Daisetsu mountains, central Hokkaido. The volume change of the snow patch in the ablation season of any year can hence be estimated from air temperature using this relationship. Each of the heat-balance terms controlling the ablation is evaluated separately by using empirical equations and assumed values for meteorological parameters at the snow patch. Triangular diagrams are constructed in order to illustrate the relative contributions of sensible heat, latent heat, and net radiation, the main three heat sources. A higher contribution from sensible and latent heat is found for the snow patches of Japan than for many glaciers and ice caps elsewhere. This may be due to higher mid-summer air temperatures than in other glaciated parts of the world.

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Vulnerability of sweet cherry cultivars to continuous periods of spring frosts in Plovdiv, Bulgaria

Agricultural Science and Technology ◽

10.15547/ast.2020.04.055 ◽

2020 ◽

Vol 12 (4) ◽

pp. 348-352

Author(s):

S. Malchev ◽

S. Savchovska

Keyword(s):

Sweet Cherry ◽

Weather Conditions ◽

Frost Damage ◽

Cold Weather ◽

Bud Burst ◽

Intermediate Group ◽

Air Temperatures ◽

Wide Range ◽

Group Form ◽

Sweet Cherry Cultivars

Abstract. The periods with continuous freezing air temperatures reported during the spring of 2020 (13 incidents) affected a wide range of local and introduced sweet cherry cultivars in the region of Plovdiv. They vary from -0.6°C on March 02 to -4.9°C on March 16-17. The duration of influence of the lowest temperatures is 6 and 12 hours between March 16 and 17. The inspection of fruit buds and flowers was conducted twice (on March 26 and April 08) at different phenological stages after continuous waves of cold weather conditions alternated with high temperatures. During the phenological phase ‘bud burst’ (tight cluster or BBCH 55) some of the flowers in the buds did not develop further making the damage hardly detectable. The most damaged are hybrid El.28-21 (95.00%), ‘Van’ (91.89%) and ‘Bing’ (89.41%) and from the next group ‘Lapins’ (85.98%) and ‘Rosita’ (83.33%). A larger intermediate group form ‘Kossara’ (81.67%), ‘Rozalina’ (76.00%), ‘Sunburst’ (75.00%), ‘Bigarreau Burlat’ (69.11%) and ‘Kuklenska belitza’ (66.67%). Candidate-cultivar El.17-90 ‘Asparuh’ has the lowest frost damage values of 55.00% and El.17-37 ‘Tzvetina’ with damage of 50.60%.

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A heat balance integral approach for two-dimensional heat transfer in solids with ablation

10.2514/6.1984-394 ◽

1984 ◽

Author(s):

J. HSIAO ◽

B. CHUNG

Keyword(s):

Heat Transfer ◽

Heat Balance ◽

Integral Approach ◽

Two Dimensional

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Modeling of ethanol dehydration by diffusion distillation in consideration of the sensible heat transfer

Korean Journal of Chemical Engineering ◽

10.1007/bf02705950 ◽

1996 ◽

Vol 13 (3) ◽

pp. 275-281 ◽

Cited By ~ 5

Author(s):

Seong Cheol Kim ◽

Dong Woo Lee ◽

Won Hi Hong

Keyword(s):

Heat Transfer ◽

Sensible Heat ◽

Ethanol Dehydration

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Thermal Modeling of Unlooped and Looped Pulsating Heat Pipes

Journal of Heat Transfer ◽

10.1115/1.1409266 ◽

2001 ◽

Vol 123 (6) ◽

pp. 1159-1172 ◽

Cited By ~ 197

Author(s):

Mohammad B. Shafii ◽

Amir Faghri ◽

Yuwen Zhang

Keyword(s):

Heat Transfer ◽

Finite Difference ◽

Heat Pipes ◽

Analytical Models ◽

Charge Ratio ◽

Sensible Heat ◽

Governing Equations ◽

Heating Wall ◽

Heat Mode ◽

Explicit Finite Difference

Analytical models for both unlooped and looped Pulsating Heat Pipes (PHPs) with multiple liquid slugs and vapor plugs are presented in this study. The governing equations are solved using an explicit finite difference scheme to predict the behavior of vapor plugs and liquid slugs. The results show that the effect of gravity on the performance of top heat mode unlooped PHP is insignificant. The effects of diameter, charge ratio, and heating wall temperature on the performance of looped and unlooped PHPs are also investigated. The results also show that heat transfer in both looped and unlooped PHPs is due mainly to the exchange of sensible heat.

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Solid Media Thermal Storage Development and Analysis of Modular Storage Operation Concepts for Parabolic Trough Power Plants

Journal of Solar Energy Engineering ◽

10.1115/1.2804625 ◽

2007 ◽

Vol 130 (1) ◽

Cited By ~ 41

Author(s):

Doerte Laing ◽

Wolf-Dieter Steinmann ◽

Michael Fiß ◽

Rainer Tamme ◽

Thomas Brand ◽

...

Keyword(s):

Heat Transfer ◽

Power Plants ◽

Heat Storage ◽

Storage Systems ◽

Storage System ◽

Sensible Heat ◽

Economic Optimization ◽

Parabolic Trough ◽

Solid Media ◽

Exergetic Analysis

Cost-effective integrated storage systems are important components for the accelerated market penetration of solarthermal power plants. Besides extended utilization of the power block, the main benefits of storage systems are improved efficiency of components, and facilitated integration into the electrical grids. For parabolic trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option in terms of investment and maintenance costs. For commercial oil trough technology, a solid media sensible heat storage system was developed and tested. One focus of the project was the cost reduction of the heat exchanger; the second focus lies in the energetic and exergetic analysis of modular storage operation concepts, including a cost assessment of these concepts. The results show that technically there are various interesting ways to improve storage performance. However, these efforts do not improve the economical aspect. Therefore, the tube register with straight parallel tubes without additional structures to enhance heat transfer has been identified as the best option concerning manufacturing aspects and investment costs. The results of the energetic and exergetic analysis of modular storage integration and operation concepts show a significant potential for economic optimization. An increase of more than 100% in storage capacity or a reduction of more than a factor of 2 in storage size and therefore investment cost for the storage system was calculated. A complete economical analysis, including the additional costs for this concept on the solar field piping and control, still has to be performed.

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