Urban Heat Island Effect on the Energy Consumption of Institutional Buildings in Rome

The urban heat island (UHI) effect is constantly increasing the energy consumption
of buildings, especially in summer periods. The energy gap between the estimated energy
performance - often simulated without considering UHI - and the real operational consumption
is especially relevant for institutional buildings, where the cooling needs are in general higher
than in other kind of buildings, due to more internal gains (people, appliances) and different
architectural design (more transparent façades and light walls). This paper presents a calculation
of the energy penalty due to UHI in two institutional buildings in Rome. Urban Weather
Generator (UWG) is used to generate a modified weather file, taking into account the UHI
phenomenon. Then, two building performance simulations are done for each case: the first
simulation uses a standard weather file and the second uses the modified one. Results shows how
is it necessary to re-develop mitigation strategies and a new energy retrofit approach, in order to
include urbanization ad UHI effect, especially in this kind of buildings, characterized by very
poor conditions of comfort during summer, taking into account users and occupant-driven
demand.