  We explore the possibility of enhancing the performance of small thermal
machines by the presence of common noise sources. In particular, we study a
prototypical model for an autonomous quantum refrigerator comprised by three
qubits coupled to thermal reservoirs at different temperatures. Our results
show that engineering the coupling to the reservoirs to act as common
environments lead to relevant improvements in the performance. The enhancements
arrive to almost double the cooling power of the original fridge without
compromising its efficiency. The greater enhancements are obtained when the
refrigerator may benefit from the presence of a decoherence-free subspace. The
influence of coherent effects in the dissipation due to one- and two-spin
correlated processes is also examined by comparison with an equivalent
incoherent yet correlated model of dissipation.
