Building-integrated greenhouses raise energy co-benefits through active ventilation systems

Joan Muñoz-Liesa*, Mohammad Royapoor, Eva Cuerva, Santiago Gassó-Domingo, Xavier Gabarrell, Alejandro Josa

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review


Buildings and greenhouses consume vast amounts of energy and natural resources for heating and ventilation. It is still unclear how the synergetic effect of combining greenhouses and buildings' forced waste airflows could improve both systems' energy efficiency. This study quantified the energy recovery potential of exchanging airflows in a rooftop greenhouse (iRTG) integrated with an office building HVAC system in a Mediterranean climate. Using monitored and calibrated energy model data, the results showed that the iRTG can act as a solar collector and as a sink for a building's low-grade waste heat. The magnitude of harvested thermal energy that could be recirculated into the building by the integrated HVAC system was 205.2 kWh/m2y−1 and was limited by greenhouse low transmissivity (54%). The magnitude of building exhaust air was 198 kWh/m2y−1 at temperatures sufficient to heat and cool the iRTG. Compared to a passive ventilated configuration, the integration of active ventilation strategies doubled the energy benefits. Building ventilation requirements directly determined building and greenhouse waste flows and energy benefits, which increased by 63.1% when air changes per hour moved from 1.59 to 3.16. Overall, this demonstrates that greenhouse and building functionalities could be coupled to contribute to urban circularity and sustainability.

Original languageEnglish
Article number108585
Number of pages12
JournalBuilding and Environment
Publication statusPublished - 15 Jan 2022


  • Circular economy
  • Energy efficiency
  • HVAC systems
  • Industrial ecology
  • Rooftop greenhouses
  • Urban agriculture


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