Technical notes of interest to Marine Engineers

Sizing a radiators

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Data required for sizing of industrial radiators for diesel engines

Proper sizing of an engine radiator must take into account engine data as well as installation characteristics. The following data is typically required by a radiator manufacturer in order to size a product for a specific application.

Heat load rejected to coolant - expressed in "British thermal units per minute" or BTU/min. This data is found in the engine application data sheet and relates to the engine heat dissipated to the engine cooling fluid (coolant).

Fluid flow - expressed in "gallons per minute" or GPM. This data is also found in the engine application data sheet and relates to the flow rate of fluid through the engine's cooling circuit (sometimes referred to "jacket water circuit").

Fluid type - expressed as a percentage of water and another solution. Typically a mixture of 50% Ethylene Glycol (E.G.) and 50% water, but sometimes found in lower or higher ratios. This fluid type is determined by the specifying engineer.

Top tank temperature - expressed in degrees Fahrenheit or Celsius. This is the desired maximum coolant temperature exiting the engine (or entering the radiator). This temperature is specified by the engine manufacturer in the engine data sheets.

Air temperature at radiator core - expressed in degrees Fahrenheit or Celsius. This is the ambient air temperature as measured at the radiator core. This temperature will vary depending on location, surrounding equipment and existence of enclosures or ventilation restrictions.

Many applications requiring large radiators use a "remote" type radiator for ease of installation. These may be of vertical or horizontal configuration and are typically installed in roof tops or parking lots. Their cooling fan is typically electric driven and requires power connections. The advantages of a remote radiator versus a local, or engine mounted radiator should be reviewed for specific applications.