19. Energy

Many products require a variety of forms of energy for purposes ranging from electronic control to motive power. The need to obtain energy can be a limiting factor on the application of the product. On the other hand the ability to supply and store energy within a product can allow it to achieve its purposes in ways that enhance its application.

The energy requirements of a product have a variety of effects that need to be limited to retain product usability. In this sense, the requirements for energy can run counter to the efficiency of the application of the product.

Replenishment

There are generally two methods of energy replenishment employed, periodic or continuous.

Periodic

Periodic replenishment strategies mean that the product must have means of energy storage and means of transforming the energy from its stored form into a usable form. This has a major impact on the functionality and cost of a product. To define a product properly the duration and periodicity of the replenishment activity needs to be defined. In addition, it should be made clear what the sources of energy replenishment are. It must be ensured that they are appropriate to the product's application and usage.

Continuous

Continuous replenishment is most often a major limitation on the application of a product. It means the product has to be permanently in contact with its source of energy supply at all times that it is in use. Therefore, access to the source of energy supply is a key factor in determining the marketability of these types of products. A product that requires continuous supplies of energy is a liability once the source of supply is cut. Consideration of the risks to the product's reputation within its applications environment need to be made to limit the effect if supply is a sensitive issue. The need for continuous replenishment may limit the mobility of the product.

Consumption

Energy storage systems tend to be somewhat inefficient. Hence there is a need within the product definition to identify the performance requirements in terms of periods of continuous operation at maximum energy consumption levels as well as at economy energy consumption levels. Consideration should be given to energy consumption in storage or quiescent states as well as in normal operating modes.