Heat transfer review What is required to size a heat exchanger Compact heat transfer solutions

2. Agenda • Heat transfer review • What is required to size a heat exchanger • Compact heat transfer solutions • Plate Heat Exchanger • Spiral Heat Exchanger • Welded Plate Heat Exchangers • Specialty Plate Heat Exchangers • Installation Photos • Design of Heat Exchanger Solutions • Order Flow Process

3. Heat TransferBasics

4. Three ways to transfer heat Reflected • Radiation • Electromagnetic waves • When it reaches a body it has 3 options: Absorbed Transmitted • Conduction • Molecular or atomic vibrations • No material transport • Convection • Energy is transferred by the motion and intermixing of small mass elements • Natural convection caused by density difference • Forced convection is man-made (ex., pump)

5. Flow Principles • Laminar • Conduction: low heat transfer rate • Turbulent • Convection: high heat transfer rate • Film layer at the wall - Conduction- Low heat transfer

6. Data needed to design a heat exchanger • Flows and temperatures for both sides • Fluid properties including: density, specific heat, thermal conductivity, and viscosity for at least two points. • For condensers and evaporators data such as a condensing curve, boiling point elevation, and/or other parameters may be required. • Process conditions and limitations such as system pressure, potential for fouling or plugging, pressure drop limitations etc. • The supplier may be able to use their experience to assist in determining proper values from above.

8. Heat Transfer Q = m Cp (T - T ) • Where Q = heat transferred (Kbtu/hr) m = mass flow rate (hot fluid) (lb/hr) C = specific heat (hot fluid) (Btu/lb,F) T = hot fluid entering temperature (F) T = hot fluid leaving temperature (F) HI HO p HI HO

9. T HI T CO T HO T CI Thermodynamics at work!! Q = m Cp (T - T ) = m Cp (T - T ) HI HO CO CI Temperature Length of Channel

10. Heat Transfer Q = U A (LMTD) • Where Q = heat transferred U = overall heat transfer coefficient A = heat transfer surface area LMTD = log mean temperature difference

11. T HI T CO T HO T CI (T -T ) - (T - T ) CO HO CI HI LMTD = (T -T ) CO HI ln (T -T ) HO CI Log Mean Temperature Difference Temperature Length of Channel

12. Therefore m C (T - T ) U (LMTD) A = HO HI P Determining Heat Transfer Area Q = mCp(T – T ) = U A (LMTD) HI HO Determining Proper “U” value is the key!!

13. Tube Plate Spiral Items That Effect “U” value and Fouling Tendency • Channel Geometry (turbulence) • Fluid velocity and wall shear • Fluid Properties (particularly viscosity) • *Viscosity also has a major impact on the pressure drop that will be seen in the heat exchanger

14. Heat Flow Hot Fluid Fouling Layers Cold Fluid Metal Temperature Temperature Temperature Wall Film Boundary Layers 1 U 1 h t k 1 h = + + + Rf Q = U A (LMTD) and

15. Heat Transfer Basics – Three Wise Men h Nusselt Number Prandtl Number Reynolds Number

16. T HI T HO T CI Cocurrent Flow Lower LMTD and no temperature cross means less efficiency Temperature T CO Length of Channel