The question may be elaborated for clarity.  Assuming that it is needed on the air side, the pressure drop can be estimated with relevant equations available in the literature. Based on whether it is a finned tube or water tube condenser the equation has to be selected.  Since the steam flows inside the tube, appropriate two phase pressure drop correlations for flow in a tube can to be used in the analysis.  Books such as Process Heat Transfer by Donald Q Kern, Heat Exchangers edited by Kakac, Aung, Viskanta and other books available may be referred. 

This information may be used for your research

Module #1

PROCESS DESIGN OF HEAT EXCHANGER: TYPES OF HEAT EXCHANGER,

PROCESS DESIGN OF SHELL AND TUBE HEAT EXCHANGER, CONDENSER AND REBOILERS

PROCESS DESIGN OF SHELL AND TUBE EXCHANGER FOR TWO

PHASE HEAT TRANSFER

2.1. Condenser

2.1.1. Types of condensers

2.1.2. Condenser design

2.1.2.1. Mean temperature difference

2.1.2.2. Calculation of heat transfer co-efficient during

condensation

2.1.2.3. Pressure drop calculation

2.1.3. De-superheating and sub-cooling

REF; NPTEL – Chemical Engineering – Chemical Engineering Design - II

nptel.ac.in/courses/103103027/pdf/mod1.pdf

Hi Sudhir,

Could you mail me with your problems details so i can able to give my opinion precisely.