  We propose a refrigeration scheme in a mesoscopic superconductor-quantum dot
hybrid device. The setup can significantly cool down a normal metal coupled to
the device by applying a bias voltage across the system. We demonstrate that
the cooling power can be as large as 0.05$\Delta_0^2/h$ where $\Delta_0$ is the
absolute value of superconducting order parameter. In contrast to previous
proposals, our device operates without any magnetic elements such as
ferromagnetic reservoirs or Zeeman splittings. The refrigeration scheme works
over a broad parameter range and can be optimized by tuning system parameters
such as level position and bias voltage. Our theory self-consistently
determines the temperature drop of the normal reservoir in the nonlinear
transport regime including electron-electron interactions at the mean field
level. Finally, we evaluate the refrigeration performance and find efficiencies
as large as half of the Carnot bound for realistic values of the coupling
strength.
