This is the spectral analysis of the refrigerator in my allergist’s office that stores the allergen doses, as measured with my Smartphone. Spectral peaks occur at 60, 129, 133.5, 267, 401 & 641 Hz.
The 133.5 Hz peak has integer harmonics at 267 & 401 Hz. These peaks could represent tube internal acoustical frequencies.
Further explanation of the peaks is pending.
Excerpt from Specifaction
Factory engineered, self-contained, capillary tube system using environmentally friendly R290 hydro carbon refrigerant that has zero (0) ozone depletion potential (ODP), & three (3) global warming potential (GWP).
High capacity, factory balanced refrigeration system that maintains cabinet temperatures of 33°F to 38°F (.5°C to 3.3°C) for the best in food preservation.
State of the art, electronically commutated evaporator and condenser fan motors. ECM motors operate at higher peak efficiencies and move a more consistent volume of air which produces less heat, reduces energy consumption and provides greater motor reliability.