@article{29569,
  keywords = {Energy saving, Simulation, Modelica, Active beams, HVAC systems, Low-energy},
  author = {Alessandro Maccarini and Michael Wetter and Alireza Afshari and Goran Hultmark and Niels Bergsoe and Anders Vorre},
  title = {Energy saving potential of a two-pipe system for simultaneous heating and cooling of office buildings},
  abstract = {<p>This paper analyzes the performance of a novel two-pipe system that operates one water loop to simultaneously provide space heating and cooling with a water supply temperature of around 22 °C. To analyze the energy performance of the system, a simulation-based research was conducted. The two-pipe system was modelled using the equation-based Modelica modeling language in Dymola. A typical office building model was considered as the case study. Simulations were run for two construction sets of the building envelope and two conditions related to inter-zone air flows. To calculate energy savings, a conventional four-pipe system was modelled and used for comparison. The conventional system presented two separated water loops for heating and cooling with supply temperatures of 45 °C and 14 °C, respectively. Simulation results showed that the two-pipe system was able to use less energy than the four-pipe system thanks to three effects: useful heat transfer from warm to cold zones, higher free cooling potential and higher efficiency of the heat pump. In particular, the two-pipe system used approximately between 12% and 18% less total annual primary energy than the four-pipe system, depending on the simulation case considered.</p>},
  year = {2017},
  journal = {Energy and Buildings},
  volume = {134},
  pages = {234 - 247},
  month = {01/2017},
  issn = {03787788},
  doi = {10.1016/j.enbuild.2016.10.051},
}