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Aircraft electrical power consumption has dramatically increased in recent years. Technological advancements have led to the replacement of traditional hydraulic and pneumatic systems with electrically powered devices. In addition, new functions such as deicing and entertainment systems have been added, which further increases the demand for electrical power. As power needs increase, voltage or current, or both, must be increased. Increased current can be the least desirable result as it leads to larger and heavier wires. To mitigate the issue of wire weight and distribution losses, the latest “More Electric Aircraft” have adopted 230 V ac as the main power bus voltage. However, this presents a problem as a significant amount of existing electrical aircraft equipment (actuators, pumps, etc.) have been designed to use 270 V dc power, which is obtained by a direct rectification of 115 V ac power. Two hundred seventy volts dc cannot be as simply produced from a 230 V ac bus.

Radiative heat transfer calculation is not regarded as an important power supply design issue and often ignored for the reasons that 1) Radiative heat transfer is insignificant compared with convection and conduction; 2) to use radiation portion of the heat transfer as safety factor in thermal design; 3) building a radiation model is time consuming. Although these excuses are true in some cases, they are wrong in many others. The answer depends on the material and the local thermal conditions. This paper studies the radiation phenomena in airborne electronic packaging; identifies dominating factors; presents engineering guidelines of when, where and why the radiative heat transfer can be ignored and how to use simplified radiative heat transfer method to save time and budget in certain circumstances.