Comparison of Thermal Plants for the Energy Retrofit of a Building Block

The Directive EPBD recast in 2010 states that buildings in the public sector have to become nearly zero energy in the next years. To reach this task is important to reduce energy consumption in buildings working on envelope thermal performance and efficiency of thermal plants. Heat pumps are suggested by the Directive as means to produce thermal energy whenever it is economically advantageous. Hence, it is fundamental understand when is convenient to use this kind of systems comparing energy performance and economical feasibility, taking into account the cost of energy produced. Geothermal heat pumps (GHP), using ground as thermal source in summer and winter period, can produce huge amount of energy and economical advantages for heating and cooling of commercial and residential buildings compared with conventional systems. It must be underlined that the higher investment cost of GSHP systems leads to a relevant energy saving in short term and economical reduction of management costs in long term period. The case study presented in this work is a building block in Milan, Italy, where an important renovation took place and GSHP and EGS were analyzed as the heating and cooling alternative to standard technological solutions. In this study different plants are compared and the economical feasibility and profitability is quantified. Moreover, advanced heat pumps can obtain a zero impact on term of CO2 emissions. The objective of this study is to show the cost-effectiveness of different systems to provide energy to a building block of about 60.000 m³.