How do I choose a shell and tube heat exchanger? Choosing a heat exchanger involves considering factors like fluid properties, flow rates, temperature ranges, pressure drops, space limitations, maintenance requirements, and cost.How do you calculate shell and tube heat exchanger capacity? The heat exchanger capacity is usually calculated based on the heat transfer rate (Q) using the formula: Capacity = Q / ΔT, where ΔT is the temperature difference between the hot and cold fluids.Shell & Tube Heat Exchanger Calculator Hot Fluid Temperature (☌): Cold Fluid Temperature (☌): Heat Transfer Coefficient (W/m²☌): Heat Transfer Area (m²): Calculate Heat Transfer Rate