Random noise can generate a unidirectional heat current across asymmetric nano-objects in the absence (or against) a temperature gradient. We present a minimal model for a molecular-level stochastic heat pump that may operate arbitrarily close to the Carnot efficiency. The model consists a fluctuating molecular unit coupled to two solids characterized by distinct phonon spectral properties. Hea...

BACKGROUND Ground source heat pumps is a building energy conservation technique. The underground buried pipe heat exchanging system of a ground source heat pump (GSHP) is the basis for the normal operation of an entire heat pump system. METHODS Computational-fluid-dynamics (CFD) numerical simulation software, ANSYS-FLUENT17.0 have been performed the calculations under the working conditions o...

an irreversible stirling heat pump cycle using ferromagnetic materials as a cyclic working substance is established. the influences of finite-rate heat transfer, heat leak, regeneration time, regenerative lossand the internal irreversibility on the cyclic performance of magnetic heat pumps are taken into account. on the basis of the thermodynamic properties of ferromagnetic materials, the perfo...