scholarly journals Heat transfer computational methods which can also be applied to geothermal field of study for energy saving and environmental benefits

2012 ◽  
Author(s):  
Ζωή Σαγιά
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
Computational Methods ◽  
Geothermal Field ◽  
Environmental Benefits ◽  
Field Of Study

Η παρούσα εργασία επικεντρώνεται στα συστήματα αβαθούς γεωθερμίας που έχουν κατακόρυφο κλειστό κύκλωμα γεωεναλλακτών. Πολλοί παράγοντες που επηρεάζουν την απόδοση του συστήματος εξετάζονται. Δύο διαφορετικές προσεγγίσεις αναπτύσσονται. Με την πρώτη, η απόδοση του συστήματος εξετάζεται συνολικά χρησιμοποιώντας τα λογισμικά GLD 2009, GLHEPRO 4.0a και TRNSYS 17. Το σύστημα εξετάζεται ως ένα σύνολο από αναπόσπαστα συνδεδεμένα τμήματα. Μια παραμετρική ανάλυση εκτελείται για να μελετηθεί η επίδραση της αδιατάρακτης θερμοκρασίας του εδάφους, του μήκους του γεωεναλλάκτη και της απόστασης των γεωτρήσεων στα λειτουργικά χαρακτηριστικά του συστήματος έτσι ώστε να καλυφθούν τα δεδομένα φορτία του κτηρίου. Με τη δεύτερη, η λειτουργία των τμημάτων του συστήματος εξετάζεται ανεξάρτητα. Η θερμική αντίσταση της γεώτρησης μελετάται με διαφορετικά είδη ανάλυσης όπως με αναλυτικές σχέσεις, με το εμπορικό λογισμικό GLD 2009 και με μια δισδιάστατη ανάλυση πεπερασμένων στοιχείων μέσω του COMSOL 4.0a. Παρά τα διαφορετικά είδη ανάλυσης, οι αποκλίσεις είναι μικρές και γι’ αυτό τα αποτελέσματα της θερμικής αντίστασης της γεώτρησης θεωρούνται ικανοποιητικά. Επιπλέον, αναπτύσσονται κώδικες ΜΑΤLAB οι οποίοι προσομοιώνουν τη λειτουργία της αντλίας θερμότητας και του ψυκτικού πύργου ο οποίος μπορεί να συμπεριλαμβάνεται σε ένα υβριδικό σύστημα αβαθούς γεωθερμίας. Μελετώντας τον ψυκτικό κύκλο της αντλίας θερμότητας, προτείνονται εναλλακτικά ψυκτικά μέσα για το R-410A. Επίσης, η απόδοση του ψυκτικού πύργου εκτιμάται με το λόγο της πτώσης πίεσης προς το ύψος του πληρωτικού υλικού για τέσσερα εξεταζόμενα πληρωτικά υλικά. Τα αποτελέσματα είναι γενικά εφαρμόσιμα στην εκτίμηση της απόδοσης αυτών των συσκευών και δεν περιορίζονται μόνο στις γεωθερμικές εφαρμογές. Ακόμα, μελετάται ένα υβριδικό γεωθερμικό σύστημα με ψυκτικό πύργο κλειστού κυκλώματος. Μια νέα στρατηγική αναπτύσσεται για να ελεγχθεί η λειτουργία του συστήματος ώστε να ελαχιστοποιηθεί η κατανάλωση της ηλεκτρικής του ενέργειας. Παρά το γεγονός ότι σχεδιάζεται μόνο για την περίοδο αποκλειστικής ψύξης, είναι μια πολλά υποσχόμενη στρατηγική διότι βασίζεται στη συνεχή παρακολούθηση του συστήματος την προηγούμενη ώρα έτσι ώστε να προσαρμόσει τη λειτουργία του την αμέσως επόμενη (ανάδραση).

The Energy-Saving Optimization of the Organic Heat Transfer Material Heater

2012 ◽  
Vol 455-456 ◽  
pp. 284-288
Author(s):  
Wei Li Gu ◽  
Jian Xiang Liu
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
Flue Gas ◽  
Theoretical Basis ◽  
Operation Management ◽  
Exergy Loss ◽  
Irreversible Processes ◽  
Design Parameters ◽  
Gas Temperature

this paper studies the typical irreversible processes such as combustion and heat transfer with temperature difference based on the theory of thermodynamics, analyzes the influencing factors on exergy loss in irreversible processes, on the basis of this analysis, proposes the energy-saving optimization measures on design and operation management of the organic heat transfer material heater, and specially points out that in the design process, objective function can be constructed with the exergy loss as evaluation index to determine the outlet flue gas temperature of furnace and the flue gas temperature, and provides theoretical basis for the determination of design parameters.

Heat Transfer Analysis and Energy-Saving Methods of the Exterior Windows in the Northern Area

2014 ◽  
Vol 881-883 ◽  
pp. 1233-1236
Author(s):  
Zhong Hua Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Energy Saving ◽  
Outdoor Environment ◽  
Heat Transfer Analysis ◽  
Radiation Heat ◽  
Mathematical Formula ◽  
Factors Affecting ◽  
Northern Area ◽  
Indoor And Outdoor

In this paper, ways of heat transfer through windows and doors between the indoor and outdoor environment in the northern area are summarized. And every heat transfer way is described by mathematical formula. On this basis, methods to improve the energy saving performance of exterior windows are put forward according to factors affecting heat transfer through windows. The first method is increasing solar radiation heat, and then reducing heat loss by infiltration, and increasing the thermal resistance as much as possible. Ideal form of energy-saving window is proposed based on compared windows with different material and thermal resistance.

Membrane Evaporation for Energy Saving in CO2 Chemical Absorption Process Using a Polybenzimidazole Film: Mass and Heat Transfer

2017 ◽  
Vol 31 (10) ◽  
pp. 11091-11098 ◽  
Author(s):  
Qinhui Ma ◽  
Mengxiang Fang ◽  
Tao Wang ◽  
Hai Yu ◽  
Paul H. M. Feron
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
Absorption Process ◽  
Chemical Absorption ◽  
Mass And Heat Transfer

Comparative studies of energy saving polymers and fabrication of high performance transparent polymer by solvent bonding

2018 ◽  
Vol 39 (1) ◽  
pp. 68-75
Author(s):  
S.P. Aadhy ◽  
T. Hema Sinega ◽  
C. Karthikeyan ◽  
S. Akshay ◽  
Mohan Kumar Pitchan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
High Performance ◽  
Solvent Mixture ◽  
Heat Transfer Analysis ◽  
Compression Moulding ◽  
Lap Shear ◽  
Visible Wavelengths ◽  
Pass Through ◽  
Solvent Bonding

Abstract This work investigates the possibility of using polyetherimide (PEI) as an energy saving alternative to glass, polymethylmethacrylate (PMMA) and polycarbonate (PC) by carrying out heat transfer analysis and suggests vaporized solvent bonding as a viable bonding technique for the fabrication of PEI. By heat transfer analysis using building energy simulation, it is observed that less energy is expended for space-conditioning of a building with windows made of PEI when compared to glass, PMMA and PC. The compression moulding technique is used to mould PEI and fabrication is done using a solvent mixture of dimethyl sulfoxide and tetrahydrofuran in 1:1 ratio. The optical properties of the bonded specimen are studied using UV-visible spectrophotometry and it is found that PEI does not allow UV wavelength radiation to pass through while transmitting visible wavelengths. The mechanical strength of the bond is tested using lap shear tensile strength test and the type of failure is observed to be cohesive from the structure. This is indicative of the fact that using this particular solvent to bond PEI results in the maximum possible strength.

Flowfield and Heat Transfer Numerical Analysis of a Stator Vane Endwall With High Freestream Turbulence

2015 ◽  
Author(s):  
A. Andreini ◽  
C. Bianchini ◽  
E. Burberi ◽  
B. Facchini ◽  
R. Abram ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Computational Methods ◽  
Gas Flow ◽  
Three Dimensional ◽  
Computational Procedure ◽  
Industrial Applications ◽  
Turbulence Modelling ◽  
Large Set ◽  
Present Contribution ◽  
Stator Vane

Among the different parts subjected to hot gas flow, endwall heat transfer evaluation is particularly challenging because the flow is strongly affected by secondary effects. Large three-dimensional flow structures introduce remarkable spatial variation of heat transfer, both along streamwise and spanwise directions, making the use of simplified modelling approaches questionable in terms of reliability, and at the same time increasing the challenge for high fidelity computational methods. The aim of the present contribution is to describe the work done in the assessment of computational methods for the estimate of high pressure vane endwall heat transfer for industrial applications. Efforts were first devoted to the development and validation of an accurate computational procedure against a large set of aerodynamic and heat transfer data, available from literature, for both airfoil and endwall of a low-pressure linear cascade with low and high inlet turbulence levels. The analysis, focused on steady state computations, is principally devoted to the turbulence modelling assessment, including non-linear turbulence closure as well as transition modelling. Obtained results showed that the aerodynamics of both passage and endwall are well captured independently of the turbulence modelling while a large impact on both pattern and averaged value is verified for the heat transfer.

A Kind of Energy Saving Method Based on Improving Turbine Condenser Vacuum

2011 ◽  
Vol 347-353 ◽  
pp. 3116-3119
Author(s):  
Jing Hong Yao
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
Cooling Water ◽  
Economic Indicator ◽  
Heat Transfer Analysis ◽  
Vacuum System ◽  
Cooling Water Temperature ◽  
Heat Transfer Efficiency ◽  
Turbine Condenser ◽  
Production Practice

Vacuum is an important economic indicator of influencing turbine load and thermal efficiency. And heat transfer efficiency affects the level of vacuum directly. From the point of heat transfer analysis, combining with the production practice in a power plant, this paper proposes a method of improving heat transfer effectiveness and the condenser exchanging condition. Through the method of reducing the heat load of condenser, improving the tightness of the vacuum system, cleaning the heat surface and reducing the cooling water temperature, we improve the vacuum and reach the aim of energy saving.

Waste Heat Recovery and Utilization in Cotton Manufacturing Enterprise: Energy Saving and Emission Reduction Aspects of a Case Study

2011 ◽  
Vol 347-353 ◽  
pp. 1425-1430 ◽  
Author(s):  
Min Zhu ◽  
Fan Long Kong ◽  
Yue Li ◽  
Nan Wang ◽  
Min Xi ◽  
...  
Keyword(s):  
Energy Saving ◽  
Emission Reduction ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Environmental Benefits ◽  
Manufacturing Enterprise ◽  
Accurate Analysis ◽  
The Status ◽  
Original Production

In this paper, a detailed description of a project designed to recovery and utilize waste heat in a cotton manufacturing enterprise in Shandong, Jin Mao Textile Co., Ltd(China) is presented: both energy saving and emission reduction(ESER) aspects have been thoroughly considered. First of all, an accurate analysis of the status of the previous cotton mill for production process was developed, to identify possible improvement opportunities; then an energy saving reformation of waste heat recovery in cotton mill was proposed and designed. After that, by means of a comprehensive feasibility analysis, the ESER indices were calculated assuring good environmental benefits of the plant modification investment. The modifications to the system make it possible to achieve consistent annual savings of coal, electricity and waste heat, CO2, SO2 emissions through effective recovery and utilization of the waste heat that was discharged into the atmosphere in the original production. Implementation of the reformation system fulfilled the waste heat recovery and utilization. And also create good environmental benefits.

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