Energy saving potential of a two-pipe system for simultaneous heating and cooling of office buildings

TitleEnergy saving potential of a two-pipe system for simultaneous heating and cooling of office buildings
Publication TypeJournal Article
Year of Publication2017
AuthorsMaccarini, A, Wetter, M, Afshari, A, Hultmark, G, Bergsoe, N, Vorre, A
JournalEnergy and Buildings
Volume134
Pagination234 - 247
Date Published01/2017
ISSN03787788
Keywordsactive beams, energy saving, HVAC systems, low-exergy, modelica, simulation
Abstract

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.

DOI10.1016/j.enbuild.2016.10.051
Short TitleEnergy and Buildings