A shell and tube heat exchanger has steam condensation at 100°C on the shell side with a projectile pass. Two tube passes are used with air on the tubes entering at 10°C. The total surface of the exchanger is 30 m2 and the global heat transfer coefficient can be taken as 150 W/m2 · ◦C. If the exchanger is 85 percent effective, what is the total rate of heat transfer?