Heat exchange device useful more particularly for heat exchanges between gases

1990 ◽  
Vol 10 (4) ◽  
pp. xv
Keyword(s):  
Heat Exchange ◽  
Heat Exchanges

A Single-Stage Ammonia/Water Absorption Cycle With Integrated Heat Exchange Components

1981 ◽  
Vol 103 (1) ◽  
pp. 42-46 ◽  
Author(s):  
A. M. Johnston ◽  
C. H. O’Sullivan
Keyword(s):  
Heat Exchange ◽  
Water Cycle ◽  
Single Stage ◽  
Steel Plates ◽  
Ammonia Water ◽  
Useful Heat ◽  
Heat Exchanges ◽  
Absorption Cycle ◽  
Counter Current ◽  
Rectification Process

Thermodynamic analysis of the single-stage ammonia/water cycle indicates the importance of close temperature approach in the counter-current heat exchanges of the cycle and of recovering useful heat from the vapor rectification process. A novel style of heat exchange equipment, constructed in a laboratory by photo-etching flow passages into stainless steel plates which are then diffusion-bonded together, is capable of both of these services. In air-conditioning applications, coefficients of performance of 0.75 to 0.85 (for sink temperatures of 50°C to 30°C) appear to be achievable.

scholarly journals Joint Fluctuation Theorems for Sequential Heat Exchange

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 763 ◽  
Author(s):  
Jader Santos ◽  
André Timpanaro ◽  
Gabriel Landi
Keyword(s):  
Heat Exchange ◽  
Joint Distribution ◽  
Bubble Chamber ◽  
Joint Probability ◽  
Fluctuation Theorem ◽  
Joint Probability Distribution ◽  
Fluctuation Theorems ◽  
Natural Tendency ◽  
Multiple Collisions ◽  
Heat Exchanges

We study the statistics of heat exchange of a quantum system that collides sequentially with an arbitrary number of ancillas. This can describe, for instance, an accelerated particle going through a bubble chamber. Unlike other approaches in the literature, our focus is on the joint probability distribution that heat Q 1 is exchanged with ancilla 1, heat Q 2 is exchanged with ancilla 2, and so on. This allows us to address questions concerning the correlations between the collisional events. For instance, if in a given realization a large amount of heat is exchanged with the first ancilla, then there is a natural tendency for the second exchange to be smaller. The joint distribution is found to satisfy a Fluctuation theorem of the Jarzynski–Wójcik type. Rather surprisingly, this fluctuation theorem links the statistics of multiple collisions with that of independent single collisions, even though the heat exchanges are statistically correlated.

scholarly journals Heat exchange processes and productivity of carbon environment transformations of the water-plasma energy stream

2019 ◽  
Vol 109 ◽  
pp. 00016
Author(s):  
Serhii Demchenko ◽  
Yevhen Pihida ◽  
Serhii Davydov
Keyword(s):  
Heat Exchange ◽  
Coal Particle ◽  
Raw Materials ◽  
Reaction Chamber ◽  
Gaseous State ◽  
Plasma Energy ◽  
Exchange Processes ◽  
Coal Particles ◽  
Conversion Time ◽  
Heat Exchanges

The analysis of the process of thermal transformations of carbon environment at high temperature (T = 2000 K) processing in a chamber of a plasma-jet reactor with the use of a water vaporizer as an oxidizer is done. The influence of heat exchange parameters on the heating of coal particles of different sizes is established. The method of mathematical modeling of the process of conversion of dispersed carbon raw materials in a stream of water plasma at a temperature in the reaction chamber Tg = 2000 - 5000 K was developed. The technique allows to determine the influence of thermal and kinetic parameters on the process of heat exchange between coal particle and a steam-plasma environment. A conversion time of a coal particle into a gaseous state is determined. It is the time that laid the foundation for calculating the main geometric and regime parameters of the reactor. The expediency of increasing the temperature of the gases in the reactor Tg = 3000 K is proved. This determines the minimum time for conversion of carbon under the combined influence of convective and radiation heat exchanges.

A graphic analysis of respiratory heat exchange

1987 ◽  
Vol 63 (4) ◽  
pp. 1374-1380 ◽  
Author(s):  
P. Varene ◽  
C. Kays
Keyword(s):  
Water Vapor ◽  
Heat Exchange ◽  
Relative Humidity ◽  
Partial Pressure ◽  
Animal Species ◽  
Exchange Process ◽  
Graphic Analysis ◽  
Heat Exchange Process ◽  
Heat Exchanges ◽  
Respiratory Heat Exchange

A new graphic representation of respiratory heat exchange is proposed using the concept of equivalent temperatures directly related to enthalpy values. On such a diagram it is possible to 1) compute the value of the heat exchange (delta H) knowing the inspired temperature (TI) and the partial pressure of water vapor (PIH2O) [or the relative humidity (rhI)] of inspired gas; 2) estimate the variation in delta H following a given variation in TI and PIH2O or, inversely, to choose the variation in TI and PIH2O necessary to obtain a given variation in delta H; 3) dissociate inspiratory and expiratory exchanges and to evaluate the efficiency of the respiratory heat exchange process in different environmental situations; and 4) easily compare the results of different studies published on respiratory heat exchanges in humans or other animal species.

Numerical simulation of the tree higro-thermal response in forest fire environment

2020 ◽  
pp. 57-65
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Xavier Viegas ◽  
...  
Keyword(s):  
Forest Fire ◽  
Numerical Study ◽  
Thermal Response ◽  
View Factor ◽  
Tree Model ◽  
Pine Tree ◽  
Surface Temperatures ◽  
Fire Environment ◽  
Fire Front ◽  
Heat Exchanges

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.

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