The concept of smart grids being developed involves interdependence between the electrical, thermal and material flows. Control strategies are required for the optimal operation of these modern grids. This paper studies the optimal design of multi-node microgrids integrating heat pumps and cogeneration units considering optimal predictive control strategies. A few case studies have been implemented to demonstrate the interest of the optimal design strategies at various levels of the modern grids: at local level, multiple building level and at the grid level. This has been further elaborated by studying the influence of electrical pricing and electrical grid constraints. (C) 2013 Elsevier Ltd. All rights reserved.