21 April 2010

Three Distinctly Different Refrigeration Cycles

The cycle shown on top is the conventional refrigeration cycle used by household refrigerators and air conditioners. Such a cycle utilises the phase changes of a refrigerant such as "freon" to move heat from one volume to another.

The cycle just below the conventional refrigerant cycle, is an electromagnetic refrigerant cycle, which uses switched electromagnetic fields to chill a magnetocaloric material. The electrogmagnetic cycle is supposed to save at least 20% of the energy used in refrigeration, compared to the conventional cycle.

The cooling cycle shown below is based upon the compression and de-compression of a special solid material, a Nickel Manganese Indium, or Ni-Mn-In alloy developed by a team of Spanish researchers.
Until recently, the most promising materials for applications in this field were giant magnetocaloric materials, which change temperature under the influence of an external magnetic field. The authors of this new study show that application of a moderate hydrostatic pressure to a nickel-manganese-indium alloy (Ni-Mn-In) produces results comparable to those achieved with the most effective magnetocaloric materials.
According to Lluís Mañosa, a professor with the Department of Structure and Constituents of Matter at the UB and principal investigator of the study, "the aim of this field of research is to identify materials that are efficient, economic and environmentally respectful, and the advantages of the alloy used in this study is that all of the component materials meet these requirements."
In addition, Antoni Planes, a professor with the same UN department, explains that, "this type of material can produce much greater caloric effects with only slight variations in pressure, which makes it ideal for domestic refrigeration systems (refrigerators, air conditioning, etc.)." When these alloys are submitted to an external field, either magnetic or pressure, the material undergoes a solid-state phase transition, and Lluís Mañosa explains that, "this phase change generates a considerable latent heat exchange." _ScienceDaily

The "phase change principle" is analogous to that used for conventional refrigerants, but occurs in a solid state material, and is called a solid-state phase transition. According to the authors, the Ni-Mn-In alloy can undergo a solid-state phase transition in response to either pressure or a magnetic field.

This method of refrigeration could offer multiple advantages over conventional refrigeration and air conditioning:
  1. At 20 to 30% more efficient, it will save power costs.
  2. The "refrigerant" is not likely to leak or become contaminated or incorrectly mixed.
  3. There will be no danger to the ozone layer or of "global warming" from solid state refrigerants.
  4. Design, installation, and servicing of systems should be much simpler.
  5. The systems should last longer with fewer maintenance problems.
  6. Disposal of obsolete systems will be simpler and less costly.
We are still looking for the perfect form of cooling and refrigerating, but the new solid-state approaches appear to be in the right direction.


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Blogger kurt9 said...

This is the sort of innovation that private companies can do, but that governments are incapable of doing. Which is why advocating expanded government power to deal with any crisis, whatsoever, always results in a situation worse than the original crisis that "required" the increased government power to begin with.

Bureaucracy is incapable of innovation because of the group-think and politicking that goes on with it. Since all government is bureaucracy, government, by its nature, cannot solve any kind of problem.

Wednesday, 21 April, 2010  
Blogger Loren said...

There's a forth one I heard about a few years ago using sound. Someone's supposed to be using it for ice cream freezers or something.

Wednesday, 21 April, 2010  
Blogger Unknown said...

Loren's right. Acoustic refrigerators have been worked on for over 20 years that I know of.

Wednesday, 21 April, 2010  
Blogger gtg723y said...

Yes but is there an upgrade package one can buy to update an old refrigerator, or a new fridge working on the old technology. Technology changes so fast that I can’t afford to keep purchasing a brand new widget every time an improvement is made.

Friday, 23 April, 2010  
Blogger al fin said...

If you are good with tools, Lori, you could probably adapt a refrigerator -- a large insulated box -- from old refrigerant technology to newer solid state technology.

The sonic technology referred to in comments above dates back to 1777, but I still can't seem to find any models based on that technology in Sears!

The sonic cooling idea utilises a (heavily) modified Stirling engine concept.

The US EPA will feel bad if solid state refrigeration is adopted -- it will take away a big part of its oversight and revenue from fines.

Friday, 23 April, 2010  

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