Even if the variation of Nusselt number with Reynolds number has been observed before, little to no studies are concerning nanofluids. The present numerical data in the laminar regime were also found to correlate well with the Brinkman number for the individual sets and much better globally, by combining all the data sets for nanofluids and water. Thus, this work proposes a new correlation between heat transfer rate and Brinkman number which is a nondimensional number of viscosity, flow velocity and temperature. The results showed a good empirical equation that Nul(Re-0.62 Pr-0.33) is dependent on a power law function to the Brinkman number in laminar flow regime. The proposed correlation can be applied both to water and nanofluid flow, with respect to the nanoparticle loading. It is expected that the equation suggested by this work can be useful to design heating/cooling devices. (C) 2016 Elsevier Ltd. All rights reserved.