ANALYSIS OF THERMAL CALCULATION OF THE HEATING DEVICES BASED HEAT TRANSFER COEFFICIENT AND THE HEAT BALANCE EQUATION

2016 ◽  
Vol 1 (11) ◽  
pp. 108-113
Author(s):  
Artem- Seminenko- ◽  
Yuliya- Elistratova-
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Balance Equation ◽  
Heat Balance ◽  
Heat Balance Equation ◽  
Thermal Calculation ◽  
The Heat Balance

Calculation of Hourly Output of a Solar Still

1993 ◽  
Vol 115 (4) ◽  
pp. 231-236 ◽  
Author(s):  
V. B. Sharma ◽  
S. C. Mullick
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Balance ◽  
Solar Still ◽  
Balance Equations ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Hourly Output ◽  
The Heat Balance

An approximate method for calculation of the hourly output of a solar still over a 24-hour cycle has been studied. The hourly performance of a solar still is predicted given the values of the insolation, ambient temperature, wind heat-transfer coefficient, water depth, and the heat-transfer coefficient through base and sides. The proposed method does not require graphical constructions and does not assume constant heat-transfer coefficients as in the previous methods. The possibility of using the values of the heat-transfer coefficients for the preceding time interval in the heat balance equations is examined. In fact, two variants of the basic method of calculation are examined. The hourly rate of evaporation is obtained. The results are compared to those obtained by numerical solution of the complete set of heat balance equations. The errors from the approximate method in prediction of the 24-hour output are within ±1.5 percent of the values from the numerical solution using the heat balance equations. The range of variables covered is 5 to 15 cms in water depth, 0 to 3 W/m2K in a heat-transfer coefficient through base and sides, and 5 to 40 W/m2K in a wind heat-transfer coefficient.

Reducing the Risk of Fire Fighting in Harsh Climatic Conditions

2021 ◽  
pp. 69-74
Author(s):  
T.A. Kulagina ◽  
◽  
T.A. Yenutina ◽  
V.I. Tereshkov ◽  
◽  
...  
Keyword(s):  
Heat Transfer ◽  
Balance Equation ◽  
Heat Balance ◽  
Climatic Conditions ◽  
Maximum Length ◽  
Heat Balance Equation ◽  
Ambient Temperatures ◽  
First Law Of Thermodynamics ◽  
Flow And Heat Transfer ◽  
The Heat Balance

The sustainability of the development of the northern territories of Russia from the Urals to the Pacific Ocean, where the bulk of the country natural resources is concentrated in the twenty-first century, is determined by the integrated approach to planning and managing the risks of using machines, structures and equipment, critical and hazardous industrial facilities and technological support and support at the stages of their operation. Climatic factors have a noticeable effect on increasing the risks of abnormal situations occurrence in emergency situations, for example, on the efficiency of fire departments activity in the winter period of the year and at extinguishing fires in harsh climatic conditions, when water may freeze inside the hoses and in the working chamber of the feed pump. Due to a malfunction in the fire equipment, the scale of the territory covered by the flames can significantly increase, and the extinguishing process will become more complicated. Operability of the hose lines in low temperature conditions is calculated using Methodological Recommendations for ensuring the operability of pump and hose systems of fire trucks when extinguishing fires in the conditions of extremely low temperatures, determining the maximum length of the hose line before icing begins. It is shown in the paper that the maximum length of the hose line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer. At the same time, it is required to combine thermal and hydraulic calculations. The methods are presented in the article for predicting the operability of pumps and hose lines in the conditions of extremely low ambient temperatures, used in fire truck systems for extinguishing fires, including at the energy facilities. It is shown that there are errors and shortcomings in the Methodological Recommendations for ensuring the operability of pump and hose systems of the fire trucks when extinguishing fires in the conditions of extremely low ambient temperatures, including at the energy facilities. It is also shown that the maximum length of the hole line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer.

Study on the Flashover Criteria for Compartmental Fires

1997 ◽  
Vol 15 (2) ◽  
pp. 95-107 ◽  
Author(s):  
W.K. Chow
Keyword(s):  
Balance Equation ◽  
Heat Balance ◽  
Lower Layer ◽  
Heat Balance Equation ◽  
Zone Model ◽  
Heat Temperature ◽  
Fire Environment ◽  
Smoke Layer ◽  
Mass Flow Rates ◽  
The Heat Balance

Criteria on the possibility of having flashover in a compartment fire were reviewed. The heat balance equation in the compartment was studied. The zone model CFAST 2.0 was applied to study the fire environment in a small compartment with a door of different area. Important parameters including the average upper and lower layer temperature, the smoke layer interface height, and the mass flow rates for intake air and outgoing smoke were calculated. Those pre dicted results were substituted back to the heat balance equation for determining the possibility of having flashover. The analysis shows that it is possible to deter mine the likelihood for flashover by using a well-validated zone model. From the heat-temperature curves derived, effect of the sprinkler can also be studied.

scholarly journals ANALISIS KINERJA CONDENSER SHELL AND TUBE UNIT 2 DI PT. PLN (PERSERO) SEKTOR ASAM-ASAM KALIMANTAN SELATAN

JTAM ROTARY ◽  
2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Hairudin Hairudin ◽  
Aqli Mursadin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Balance ◽  
Balance Sheet ◽  
Average Heat ◽  
Shell And Tube ◽  
Fouling Factor ◽  
The Heat Transfer Coefficient

Theecondenser is a type of heat exchanger that functions to condense fluid. On steam powermsystems. Thevmain function ofmthe condenser is to convert steam into liquid. The purpose of this study is to determine the value and influence of heat balance, heat transfer coefficient, pressure drop and condenser efficiency.Thewresults offthissstudy indicate that in 2018 thee average heat balance (Q) was obtained at 356,017,533.46 Kj / hour while in 2019 the results of the average heat balance (Q) were 640,293,647,066 Kj / hour, fouling factor was not affect the balance sheet. The average gross heat transfer coefficient (UD) in 2018 amounted to 204,274.25 Kj / hour.m2. C and the average net heat transfer coefficient (UC) was 206,378 Kj / hr.m2. ° C whereas in 2019 the average heat transfer coefficient is obtained by the average gross heat transfer coefficient (UD) of 366,544.07 Kj / jam.m2. ° C and the Clean heat transfer coefficient (UC) is 448,554 Kj / h.m2. ° C.Fouling factor is very influential onnthe heatwtransfer coefficient because the greater the fouling in the tube will result in the inhibition of theeheat transfer rate in the tube, so that the heat transfer coefficient decreases. The pressure drop in 2018 is still within the permissible limits, with an average of 504.28 bars and 2019 of 513.03 bars. The effectiveness of the condenser in 2018 is an average of 23.330 after maintenance has been obtained, the average effectiveness of the condenser in 2019 is 40.743

scholarly journals The heat loss calculating methods of external walls in the buildings reconstruction

2018 ◽  
Vol 230 ◽  
pp. 02038 ◽  
Author(s):  
Varvara Vinnichenko ◽  
Azat Gabitov ◽  
Aleksandr Salov ◽  
Askar Gaisin ◽  
Dmitriy Kuznetsov
Keyword(s):  
Finite Element ◽  
Heat Conduction ◽  
Heat Loss ◽  
Balance Equation ◽  
Heat Balance ◽  
Operating Experience ◽  
Energy Performance ◽  
Heat Balance Equation ◽  
The Heat Balance ◽  
Window Frames

Heat loss analysis in cladding of brick buildings under reconstruction is presented. Thermograms obtained under thermovision inspection and window systems operating experience in conditions of the Republic of Bashkortostan are thoroughly studied. Live issue of increasing buildings energy performance in public utilities sector may largely be solved by replacement of existing window units made of wood to new PVC profile windows equipped with multi-glazed glass units both in brick and frame-panel old buildings. Significant heat loss occurs in junctions between the window frames and the wall in jamb areas. Therefore for the heat conduction matrix for the finite element is used the heat balance equation. Use of the software application to choose certain measures to eliminate the thermal bridges enables to get the thermotechnical calculations in the junction between the window and the exterior wall in the form of temperature fields. Practical recommendations for arrangement of heat insulation in junctions between the window frames and the wall to eliminate actual defects and for normal room conditions are made under examinations. To get the heat conduction matrix for the finite element we will use the heat balance equation.

scholarly journals LONG-TERM FIELD MEASUREMENT ON HEAT TRANSFER COEFFICIENT AND HEAT BALANCE ON GRASSLAND SURFACE

2000 ◽  
Vol 6 (11) ◽  
pp. 155-159 ◽  
Author(s):  
Aya HAGISHIMA ◽  
Jun TANIMOTO ◽  
Tadahisa KATAYAMA ◽  
Takashi NISHIYAMA
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Balance ◽  
Field Measurement ◽  
Term Field

Towards Improved Reaction Runaway Assessment Methods I. Simple Calorimetric Method Of Evaluation Of Heat Transfer Coefficient And Reactor Thermal Mass

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Maria Papadaki ◽  
Hosadu Parameswara Nawada
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Balance ◽  
Reaction Calorimetry ◽  
Small Scale ◽  
Heat Of Reaction ◽  
Overall Heat Transfer Coefficient ◽  
Reaction Calorimeter ◽  
Method Of Evaluation

The use of reaction calorimetry in the chemical industry is constantly growing. Its use aims at the assessment and subsequent reductions of the risks arising from reaction thermal runaways in the event of cooling system malfunction or agitation failure and at optimum process design.A reaction calorimeter is a small-scale automated jacketed reactor equipped with a precise temperature controller, which is capable of heat balancing. The reactor contents may be heated or cooled by heat-transfer oil and they are continuously agitated. A powerful thermostatic bath allows rapid adjustment of jacket temperature to maintain the desired reactor temperature-profile. The reactor and jacket temperatures as well as a number of other quantities are continuously measured. A heat balance, based on a number of assumptions, is used for the evaluation of the heat of reaction and its global kinetics. The evaluation of the overall heat transfer coefficient and the accumulated heat are achieved by means of calibrations. Their measurement is, in the main, long. Also it is very often lacking sufficient accuracy.In the present approach, a simple method for the accurate evaluation of the overall heat transfer coefficient is presented. It is also shown how the analysis of the heat-balance equations in different stages can be used for the simultaneous evaluation of a number of quantities and constants of the reaction calorimeter using a single set of calibration experiments.

A Computer Model of Glaze Accretion on Wires

1996 ◽  
Vol 118 (2) ◽  
pp. 148-157 ◽  
Author(s):  
G. Draganoiu ◽  
L. Lamarche ◽  
P. McComber
Keyword(s):  
Computer Model ◽  
Balance Equation ◽  
Heat Balance ◽  
Control Volume ◽  
Water Flux ◽  
Heat Balance Equation ◽  
Ice Accretion ◽  
Surface Geometry ◽  
Related Field ◽  
The Heat Balance

The design of power transmission lines requires a knowledge of combined wind and ice loading and of the dynamic behavior of wires loaded with ice accretion. The calculation of the wind forces, in turn, imposes a need for a more detailed computer model for determining glaze accretion shape. For this purpose, a computer model of glaze accretion on wires, was developed. It is based on experimental results in the area of ice accretion on wires, as well as on results in the related field of the glaze ice accretion on airfoils. The model incorporates the time dependent on feedback between the growing accretion and the air stream, the variation of the heat transfer coefficient around the cylinder, and the surface runback of water. The main components of the model are the computation of the air flow field, the computation of the impingement water at the control volume level, the solving of the heat balance equation, and the computation of the accretion shape on the wire. The surface air velocity is obtained through the solution of the potential flow around the iced wire and wake, followed by the integration on the surface of the laminar boundary layer. The water flux is computed in each control Volume down to the separation point. The heat balance equation derived from the energy equation is solved to determine the freezing fraction and the resulting modified ice surface geometry.

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