A thermoacoustic refrigerator was built to explore scaling to large heat flux. The refrigerator was constructed according to a modular design so that various stack, heat exchanger, and resonator sections are easily interchangeable. The resonator is driven by a commercial 10-in. woofer. Initial tests, using pure helium gas as the working fluid and steel honeycomb (0.8-mm cell) for the stack, pumped 60 W of heat against a 10 °C temperature gradient. Measurements of heat flux and efficiency will be reported as functions of stack structure (e.g., pore size and shape) and will be compared with theoretical predictions.