How efficient are thermoacoustic refrigerators?
There are two classes of thermoacoustic machines, distinguished by the pore size of the porous element in the machine that stores and releases thermal energy during an acoustic period. When this element is loosely packed compared to a acoustic thermal boundary layer (called a “thermal penetration depth”) it is called a “stack” and the machine works best if the acoustic phasing between pressure and volume velocity is nearly 90ยบ (mostly standing wave phasing). If the pore size of the thermal energy storage element is small compared to a thermal penetration depth, then the element is called a “regenerator” and the machine works best if the acoustic wave phasing is predominantly in phase, like a traveling wave. The latter class of machine is sometimes referred to as an acoustic-Stirling machine. The efficiency of stack-based thermoacoustic refrigerators is 20-30% lower than their vapor compression counterparts. Part of that lower efficiency is due to the intrinsic irreversibility of the th
Related Questions
- When thermoacoustic refrigerators and air conditioners become commercially available, will they cost more than their conventional vapor compression equivalents?
- How large/heavy are thermoacoustic refrigerators compared to their vapor compression counterparts?
- How soon will we be able to purchase commercial thermoacoustic refrigerators and air conditioners?
