heat exchanger design formula Sheet
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Formulas for heat exchanger design
![1 - For plane wall
UA=
ଵ
ோ௧
=
൬
2 - For a tubular pipe
ଵ
భ
భ
ା
ା
൰
ಲ
಼ಲ ಲ
UA= ܷ ܣ = ܷ ܣ =
ଵ
ோ௧
=
ቌ
భ
ା
ಲ
ଵ
ೝ
൬ బ ൰
ೝ
భ
ା
ቍ
మഏ಼
బ ಲబ
3 – For a unclean surface(Fouling /scaling)
∆ࢀ࢙
ࡽ
= ࡾ࢙ = ࢎ =
࢙
ࡾࢌ
ࡾ࢙ ୀࡿࢉࢇࢍ ࢘ࢋ࢙࢚ࢇࢉࢋ
∆ࢀ࢙ ୀࢀࢋ ࢍ࢘ࢇࢊࢋ࢚ ࢇࢉ࢙࢙࢘ ࢛ࢉࢋࢇ ࢙࢛࢘ࢌࢇࢉࢋ
4 – For a fouled surfaces
= ܜ܀
ܑ ۯ ܑܐ
۹ܑۯ
+
Q = hA [1 -
+ + ܟ܀
ܑ ܀
R ୵ = Wall resistance
ܐ ۯ
5 – Overall heat transfer (taking efficiency in account)
(1 - Ƞ )] ∆T
6 – Overall heat transfer coefficient
ܷ = ܗۯ
ାܗ ۯ
ܑ ۯȠ ܑܐ
ଵ
܀
܀ ۯ
ܟ ܀ା ܑ ܗା ܗା
ܑ ۯȠ
Ƞ
ܐ ۯ](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
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heat exchanger design formula Sheet
- 2. 1 - For plane wall UA= ଵ ோ௧ = ൬ 2 - For a tubular pipe ଵ భ భ ା ା ൰ ಲ ಼ಲ ಲ UA= ܷ ܣ = ܷ ܣ = ଵ ோ௧ = ቌ భ ା ಲ ଵ ೝ ൬ బ ൰ ೝ భ ା ቍ మഏ಼ బ ಲబ 3 – For a unclean surface(Fouling /scaling) ∆ࢀ࢙ ࡽ = ࡾ࢙ = ࢎ = ࢙ ࡾࢌ ࡾ࢙ ୀࡿࢉࢇࢍ ࢘ࢋ࢙࢚ࢇࢉࢋ ∆ࢀ࢙ ୀࢀࢋ ࢍ࢘ࢇࢊࢋ࢚ ࢇࢉ࢙࢙࢘ ࢛ࢉࢋࢇ ࢙࢛࢘ࢌࢇࢉࢋ 4 – For a fouled surfaces = ܜ܀ ܑ ۯ ܑܐ ۹ܑۯ + Q = hA [1 - + + ܟ܀ ܑ ܀ R ୵ = Wall resistance ܐ ۯ 5 – Overall heat transfer (taking efficiency in account) (1 - Ƞ )] ∆T 6 – Overall heat transfer coefficient ܷ = ܗۯ ାܗ ۯ ܑ ۯȠ ܑܐ ଵ ܀ ܀ ۯ ܟ ܀ା ܑ ܗା ܗା ܑ ۯȠ Ƞ ܐ ۯ
- 3. *a=m(table)
- 5. = In case of multipass arrangement Ft= Correction Factor
- 6. Temperature Effectiveness : Series Coupling over all counter flow ܶଵଶ ܶଵଵ ܶଶଶ A ܶଶଵ ܲଵ = ܼଵ = ்భమ ି ்భభ ்మమ ି ்భభ ܲଵ = ܶଵଷ B ଵ –ோభ భಲ ଵ –ோభ భಳ = ଵ – భಳ ்మమ ି ்భయ ்మభ ି ்భభ ்మయ ି ்భయ ்మమ ି ்భమ ܶଶଵ ܲଵ = ்మయ ି ்భమ ் ௗ ு = ܶଶଷ ்భయ ି ்భమ ் ௗ௩ௗ௨ ௨ௗ ଵ – భಲ ܶଵଵ = ்భమ ି ்భభ ்భయ ି ்భభ C ்భయ ି ்భభ ்మయ ି ்భభ = ்మమ ି ்మభ ்మయ ି ்మభ ܶଵଷ ܶଶଷ
- 7. ଵ – భ ଵ –ோభ భ = ଵ – భಲ ଵ –ோభ భಲ × ଵ – భಳ ଵ –ோభ భಳ = ்మయ ି ்భయ ்మభ ି ்భభ General formula for ܲଵ ܲଵ = For R=1 ∏ ( ଵିோభ భಲ )ି ∏ ( ଵିభಲ ) సభ సభ ∏ ( ଵିோభ భಲ ) ି ோభ ∏ ( ଵିభಲ ) సభ సభ Pଵ = ∑ ൭ ୀଵ ುభಲ ൫భషುభಲ ൯ ುభಲ ൨ ଵା∑ సభ ൫భషು భಲ ൯ ൱൩ Series Coupling overall parallel flow ܶଵଶ ܶଵଵ ܶଶଶ ܶଶଵ ܲଵ = ଵ ଵାோభ ܶଵଷ ܶଶଷ ܶଵଵ ܶଶଵ ሼ1 − ∏ ሾ1 − (1 + ܴ)ܲଵ ሿሽ ୀଵ NTU = ∑ ܷܰܶଵ ୀଵ
- 8. DOUBLE PIPE HEAT EXCHANGER Counter Flow ( Cold-Tube Side , Hot- Shell Side) (ଵି) = (ଵିோ) ∆ܶ = ଵ ே் = ் ି ்ೠ ்ೠ ି ் (் ି ் ) (ோିଵ) (ோିଵ) ݈݊ቀ1−ܲቁ ܴܲ ቀ భషು ቁ ುೃ NTܷ = ோ For n- pass heat exchangers 1- Cold fluid in parallel and hot fluid in series flow ߠ= భൗ భ ) భషುೃ) (( ೃ ( ିଵ) భ ൗ భ ൗ ቌଵିೃ ቍାೃ 2- Cold fluid in series and hot fluid in parallel flow ߠ= (ଵିோ)⁄ (ଵିோ)ቀ భ ቁ భషು భ ାோ൩
- 9. CHARTS