Design (i.e., determine the overall area and a suitable arrangement of shell and tube passes) for a tubular-feed water heater capable of heating 2,300 kg/h of water from 21 to 90°C. The following specification are given 

(a) Saturated steam at 920 kPa absolute pressure is condensing on the outer tube surface, 

(b) Heat transfer coefficient on steam side is 6800 W/(m² K), 

(c) Tubes are of copper, 2.5 cm, 2.3 cm ID, 24 m long, and 

(d) Water velocity is 0.8 m/s.

GIVEN

• A tubular-feed water heater, condensing saturated steam on outside
• Water flow rate (m_w) = 2300 kg/h = 0.639 kg/s
• Water temperatures
• T_w,in = 21°C
• T_w,out = 90°C
• Steam temperature = 920 kPa absolute
• Heat transfer coefficient on steam side (h_o) = 6800 W/(m² K)
• Tubes are copper
• D_i = 2.3 cm = 0.023 m
• D_o = 2.5 cm = 0.025 m
• Water velocity (V) = 0.8 m/s

Steam Tmout = 90C Tuch - 21C Water