Acoustic refrigerator

The sound waves produced by the speakers cause pressure variations in the tube. In low-pressure areas the gas cools in high-pressure areas the gas becomes hot. The hot areas are cooled by a heat exchanger and over time the gas in the tube becomes very cold. Garrett s acoustic refrigerator uses 205 watts of power to cool its main compartment to 4°C and the freezing compartment to -22°C. 

Acoustic refrigeration units have some real advantages they have no moving parts (except the speaker drivers) and they are environmentally safe. Presently the sound-fridge is neither as cheap nor as efficient as conventional cooling devices, but Garrett believes that the unit can be made competitive within several years. ... 

Scientists have created an acoustic refrigerator, which uses a standing sound wave in a resonator to provide the motive power for operation. Oscillating gas particles increase the local temperature, causing heat to be transferred to the container walls, where it is expelled to the environment, cooling the interior. 

Moderate (attenuation and limitation of effects) Use vacuum to reduce boiling point Reduce process temperatures and pressures Refrigerate storage vessels Dissolve hazardous material in safe solvent Operate at conditions where reactor runaway is not possible Place control rooms away from operations Separate pump rooms from other rooms Acoustically insulate noisy lines and equipment Barricade control rooms and tanks... 

Fig. 3.2. Scanning system for cryogenic acoustic microscopy in a dilution refrigerator (Rugar et al. 1982 Foster and Rugar 1985).

The purpose of the regenerator is to transmit oscillating PV power, or acoustic power, from ambient temperature to some lower temperature with a minimum of losses. Just as with the recuperative heat exchangers discussed in section 5, the losses are those due to imperfect heat transfer, pressure drop AP, and conduction The gross refrigeration power available at the cold... 

Swfit, G.W., 2002, Thermoacoustics A unifying Perspective for Some Engines and Refrigerators, Acoustical Society of America (ASA) Publications, NY... 

Flenpol . [Flexible Prods.] Rigid or flexible polyurethane systems for decorative molding, flotation, furniture, walk-in refrigeration, water heater, acoustic, pkg toys, seats and cushioning, integral skin applies. 

Acoustic Noise No louder than conventional domestic refrigerator. Less than 50 dBA sound level measured 1.5 m from the unit. 

Polyurethane foams cellular plastics basically of three types flexible urethane foams used for upholstery, matresses, textile linings, acoustic insulation, etc rigid urethane foams used for heat insulation (eg refrigeration), cold stores, building-panel cores, etc and semi-flexible foams used for arm rests, packaging, etc. 

The Vuilleumier refrigeration cycle has frequently been described as a Stirling cycle with a thermal compressor instead of a mechanical compressor. Recently, it has generated much interest in the area of spacecraft applications where the advantages of long-lifetime operation, low acoustical noise, and minimal wear of moving parts have been extensively examined. 

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