PhD defence by Alessandro Maccarini

PhD defence by Alessandro Maccarini

Title: A two-pipe system for simultaneous heating and cooling of office buildings


21.06.2017 kl. 13.00 - 17.00



Simultaneous heating and cooling demand occurs quite frequently in office buildings. A four-pipe system is the traditional configuration to provide heating to one room and cooling to another room by operating two separate hydronic circuits.

This thesis presents the energy analysis of a novel two-pipe system able to handle heating and cooling demand simultaneously by operating only one hydronic circuit with water temperatures of about 22 °C all year round, no matter whether a single room needs heating or cooling. This configuration shows two main benefits. First, waste heat from warm rooms in a building can be transferred to cold rooms. Second, sustainable energy sources can be easily exploited.

To analyze the energy performance of the system, a simulation-based study was conducted. A detailed mathematical model of the system was developed with the programming language Modelica. Several simulation experiments were carried out under different conditions in terms of climate, occupancy, control strategy and building envelope.

Simulation results for a typical office building show that the novel two-pipe system is able to use less energy than a conventional four-pipe system thanks to three effects: useful heat transfer from warm to cold rooms, higher free cooling potential and higher efficiency of heat pumps. In particular, annual primary energy savings of approximately between 12-18% can be obtained.

About Alessandro

Alessandro started his PhD at the Danish Building Research Institute/Aalborg University in 2013. His research focuses on the design, modeling and simulation of innovative HVAC systems for office buildings. He is currently participating in two international projects: the IEA-EBC Annex 60 and IEA-ECES Annex 31. The IEA-EBC Annex 60 project aims to develop the new generation of computational tools for building and community energy systems based on the Modelica programming language. The IEA-ECES Annex 31 project addresses the integration, control and automation of energy storage with energy efficient buildings and districts. Alessandro holds a MSc in Aerospace Engineering from the University of Padova, Italy.

Attend the PhD defence

Alessandro Maccarini defends his PhD 21 June 2017 at Aalborg University Copenhagen, Room 2.3.044.

All interested are invited to attend the PhD defence. After wards, SBi will host the reception.


Statens Byggeforskningsinsitut (SBi)


Room 2.3.044, Aalborg University Copenhagen, A.C. Meyers Vænge 15, 2450 København SV

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