dECOnhealth – Demand-controlled ventilation in hospitals

We investigate the energy savings potential of hospital buildings

Project duration

1.4.2018. – 31.3.2022

Source of funding

Business Finland

Total funding

309000 €

The building sector consumes a notable amount of energy worldwide. Healthcare facilities typically have high specific energy demand due to their high IAQ standards and 24 hours per day functions. One potential mechanism to reduce hospital energy consumption is demand-controlled ventilation, which is generally considered as one of the main methods in reducing building energy consumption.

The objective of the project was to investigate the energy savings potential of hospital buildings and develop feasible demand-controlled ventilation methods and control strategies. Energy savings potential was assessed with measurements and building simulations of two case-study hospital buildings: HUS Triangle Hospital in Helsinki and Uniklinikum in Aachen. Different control strategies were studied, and the performance of these strategies related to indoor air quality and thermal comfort was tested in laboratory experiments.

The project showed that there is a notable potential for energy savings in hospital buildings with demand-controlled ventilation. Airflow reduction potential was assessed in field experiments based on occupancy estimates with room CO2 measurements. The measured occupancy rates were around 80 % for the patient and isolation rooms and 30 % for the reception, treatment, and office rooms. The reduction potential of ventilation airflow rates with demand-controlled ventilation was estimated to be 10 – 60 % depending on the space type and control strategy.

Building simulations gave higher reduction potential as they also included thermal demands. In addition, the airflow rates with demand-controlled ventilation were based on recommendation in standards and guidelines whereas the measurement-based estimate used existing airflow rates in the building. The savings potential was estimated to be 60 – 90 % of the HVAC energy demand by the simulations.

The project was funded by Business Finland and the participating companies. It was carried out in international cooperation between Turku University of Applied Sciences and RWTH Aachen University.

Publications

Hagström K, Grönvall I, Kalliomäki P, Maula H, Sivula A, Comfort evaluation of a dynamic protective airflow system using human test subjects, Proceedings of Clima 2022, REHVA 14th HVAC World Congress, 22nd -25th May, Rotterdam, The Netherlands 

Heinonen Henri 2021, Ilmanvaihdon energiatehokkuus sairaaloissa – case: yliopistollinen sairaala, opinnäytetyö YAMK, Turun ammattikorkeakoulu 2021, 61 p.

Kalliomäki, Petri; Rätz, Martin; Mathis, Paul; Müller, Dirk; Koskela, Hannu, Potential of Demand-controlled Ventilation in Different Space Types in a University Hospital Building: A Case Study, Proceedings of 15th Roomvent Virtual Conference – Energy Efficient Ventilation for Healthy Future Buildings, Roomvent 2020, 15.-18.2.2021, Turin, Italy, Pages 242-245

Kalliomäki P, Koskela H, Room air distribution strategies in hospital isolation rooms, RenhetsTeknik 2:2021, pages 21-25.

Kalliomäki P, Maula H, Koskela H, Tilojen käyttöaste ja tarpeenmukaisen ilmanvaihdon säästöpotentiaali sairaalatiloissa, Sisäilmastoseminaari 2021, Sisäilmastoyhdistys raportti 39, 2021, p 101-106.

Maula H, Kalliomäki P, Koskela H, Thermal comfort in a hospital isolation room – A laboratory study, Healthy Buildings 2021–Europe. Proceedings of the 17th International Healthy Buildings Conference 21–23 June 2021, SINTEF Academic Press 2021.

Maula H, Kalliomäki P, Koskela H, Lämpöviihtyvyys sairaalan eristystilassa, Sisäilmastoseminaari 2021, Sisäilmastoyhdistys raportti 39, 2021, p 207-212.

Rätz, Martin; Kalliomäki, Petri; Mathis, Paul; Koskela, Hannu; Müller, Dirk, Analyzing the Energy-Saving Potential of Demand-Controlled Ventilation in Hospitals via Dynamic Building Simulations, Proceedings of 16th Conference of the International Society of Indoor Air Quality & Climate, Indoor Air 2020, 2.-4.11.2020, Seoul, South Korea, Pages: 1026-1031

Rätz, Martin; Kalliomäki, Petri; Kremer, Martin; Koskela, Hannu; Müller, Dirk, Real-Time Occupancy Detection in Hospital Patient Rooms Using Sensor Fusion Proceedings of 13th International Industrial Ventilation Conference for Contaminant Control, ASHRAE Ventilation 2022, June 22-24, 2022 Toronto, Canada