Page 140 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

magnetocaloric materials, which are materials that heat up when in a magnetic field. A magnetic
refrigerator operates without a compressor and therefore does not need a refrigerant like Freon, which
vaporizes and condenses in the vapor-compression cycle. Is there a need for such a refrigerator?

What are the advantages of such a refrigerator? There are two obvious ones. One is that a refrigerant like
Freon is not needed. This may have spurred the initial research effort; however, the development of new
refrigerants with more favorable environmental properties may have diminished this advantage. The other
is the lack of a compressor, probably the most costly component of a vapor-compression refrigerator,
both in capital cost and in operating cost. There are energy costs associated with the magnetic
refrigerator, including a pump to circulate the cooling fluid and a motor to cycle the magnetocaloric
material into and out of the magnetic field. Therefore, the savings created by compressor removal may be
small. Based on these two factors, it is unclear whether there is a need for a magnetic refrigerator.

Example 4.4

With the advent of portable electric devices such as laptop computers, cellular phones, personal digital
assistants, MP3 players, and so on, the length of time they can run before recharging and/or replacement
of their power source is becoming an issue. Is there a product need here?

Anyone who has ever used a laptop computer where there is no source of power has probably, at one time
or another, been frustrated by a battery that has run out before the desired work was completed. However,
does this mean there is a need for a longer-lasting power source? Or will this be a high-end, niche
market? Consider the situations when one uses a laptop computer for long periods of time away from a
power source. One of the most common situations is on an airplane. However, newer aircraft now have
fitted power connections at every seat. Some older aircraft have already been retrofitted with such power
connections. As older aircraft are replaced or as they are modernized, will all aircraft used for longer
flights have power available? If so, this could diminish the need for a longer-lasting power source,

especially one that might require new technology and be costly.

4.3 Ideas

The generation of ideas is tantamount to brainstorming. Just as in brainstorming, when ideas are being
generated, there are no bad ideas. They will be screened in the next step, selection. Ideas can be sought
from a variety of sources, including, but not limited to, members of the product development team,
potential customers, and published literature. If there is a time for “pie in the sky,” it is at this step.

It is important to remember not to “get married” to an idea at this stage. The chances of the first idea
generated being the best one are slim or none. As many ideas as can be imagined should be generated
before moving on to the selection step.

Examples 4.5 through 4.7 illustrate generation of ideas.

Example 4.5