Design standards for residential N-ZEBs in mild Mediterranean climate

In this paper the authors intend to investigate into the possibility of obtaining the Net Zero Energy Building (N- ZEB) standard for a residential building type widespread in Mediterranean climate. To this aim, the study considers a terraced-house apartment building with an external envelope made of clay blocks and concrete structure, which is a very common solution in Italy. At first, the building is thought to be designed according to the current national regulations concerning the insulation level of the envelope; for such configuration, the current energy needs for heating, air-conditioning, lighting and hot water production are calculated through dynamic simulations tools. Then, the study discusses the interventions, both on the envelope and on the energy systems, needed to transform this conventional building into an N-ZEB, avoiding excessive modifications to its design. Due to the diffusion of this typology, the case considered in the paper is very representative, and the conclusions might be extended to a significant portion of the building real estate. The final aim is to define a construction standard that might become a reference for the design of future residential N-ZEBs in Mediterranean countries.