Finding new solutions for energy recovery in buildings is crucial to diminish the energy consumption. Some proposals may unveil innovative products to solve this challenge. However, reinventing and reformulating the configuration of available solutions might be another way to find an inventive answer to the energetic problem. The main aim of this article is to check if several cores connected in a cascade layout and installed in two different rooms can provide a better performance making use of energy from exhaust air. This study was inspired by the rete mirabile of tuna. This strategy proposed by nature has been translated into building services. Thanks to this reinterpretation, a new configuration of heat recovery ventilators (HRVs) has been simulated with CFD software. The results obtained show that up to 44.5% of energy could be saved with the new configuration making it a promising solution and a foreseeable application for energy recovery in buildings. (C) 2016 Elsevier B.V. All rights reserved.