# 5-thermal.pdf - Energy Storage Thermal Energy Storage Anis...

• 36

This preview shows page 1 - 7 out of 36 pages.

Energy Storage Thermal Energy Storage Anis Allagui University of Sharjah Sustainable and Renewable Energy Engineering [email protected] Last Updated: April 12, 2017

Subscribe to view the full document.

Introduction Modes of Heat Transfer Thermal Energy Storage Technologies of TES Outline 1 Introduction 2 Modes of Heat Transfer 3 Thermal Energy Storage Definition Fundamentals of TES Efficiency 4 Technologies of TES Anis Allagui Energy Storage | Thermal Energy Storage 2/36
Introduction Modes of Heat Transfer Thermal Energy Storage Technologies of TES General Aspects of Heat Transfer Thermal processes involve the transfer of heat from one point to another: heating and cooling of gases, liquids, and solids, evaporation of water, and removal of heat liberated by chemical reaction Driving force is the temperature difference between the location where heat is taken and where heat originates ( temperature gradient ) Anis Allagui Energy Storage | Thermal Energy Storage 3/36

Subscribe to view the full document.

Introduction Modes of Heat Transfer Thermal Energy Storage Technologies of TES Conduction, Convection & Radiation I Heat Conduction: Fourier’s law of heat conduction, Q = - kA T , for rate of heat flow through a homogeneous solid object. Heat Convection: heat transfer mode within a fluid by mixing * one portion of the fluid with another; forced vs. natural (free, buoyancy forces) convection. heat transfer from solid to fluid: conduction/convection (flow , convection , conduction ; Bi = hL / k s ; Nu = hL / k l ) Q = hA ( T s - T f ) h : convection coefficient convection heat transfer within a fluid that is transferred is the sensible or internal thermal heat of the fluid convection heat transfer with phase change liquid–vapor is called latent heat. Anis Allagui Energy Storage | Thermal Energy Storage 4/36
Introduction Modes of Heat Transfer Thermal Energy Storage Technologies of TES Conduction, Convection & Radiation II L T A T B T s 1 T s 2 D B D A Figure 2.1: A wall subject to convection heat transfer on both sides; fluid A and fluid B Newton’s law of cooling: q = h A ( T A - T s 1 ) (1) q = h B ( T s 2 - T B ) (2) Heat transfer in thin films is by con- duction only: q = k A Δ A ( T A - T s 1 ) (3) q = k B Δ B ( T s 2 - T B ) (4) h A = k A / Δ A and h B = k B / Δ B Anis Allagui Energy Storage | Thermal Energy Storage 5/36

Subscribe to view the full document.

Introduction Modes of Heat Transfer Thermal Energy Storage Technologies of TES Conduction, Convection & Radiation III Heat transfer in the wall is: q = k L ( T s 1 - T s 2 ) If steady-state heat transfer: q = h A ( T A - T s 1 ) = h B ( T s 2 - T B ) = k L ( T s 1 - T s 2 ) (5) which yields to: q = T A - T B 1 / h A + L / k + 1 / h B (6) The term 1 1 / h A + L / k + 1 / h B is the overall heat transfer coefficient including different heat transfer coefficients. Anis Allagui Energy Storage | Thermal Energy Storage 6/36
Introduction Modes of Heat Transfer Thermal Energy Storage Technologies of TES Conduction, Convection & Radiation IV Heat Radiation: object emits radiant energy in all directions if T > 0 . If there is a receiver ( solid to solid ), a part may be: absorbed ( α ), transmitted ( τ ), reflected ( ρ ). By definition we have α + τ + ρ = 1 .
You've reached the end of this preview.
• Spring '12
• rauf

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern