Dr. Hanmin Cai

Email: hanmin.cai@empa.ch

Phone: +41 58 765 40 77

Affiliation: Empa - Urban Energy Systems Lab, 

Address: Überlandstrasse 129, 8600 Dübendorf, Switzerland

Group: www.empa.ch/web/energy-hub/

Lab: www.empa.ch/web/s313

Links: Linkedin | Google Scholar | ORCID 


About me

I have been working as a postdoctoral researcher with the Urban Energy System Lab at Empa since January 2020. Prior to joining Empa, I worked as a Ph.D. student with the Center for Electric Power and Energy (CEE) at the Technical University of Denmark (DTU). I was mainly involved in developing and demonstrating future energy solutions within the EnergyLab Nordhavn project, using a full-scale smart city energy lab in Copenhagen.

My focus area is the intersection of multiple fields, including building energy flexibility, multi-energy system operation, and machine learning. I am interested in both theoretical research and experimental implementation/validation. Check out our state-of-the-art NEST building. 

Ongoing research projects

K3 - Handwerkcity

The overall objective of this project is to show a system-related contribution of the Swiss gas industry to the implementation of the Swiss Energy Strategy 2050. Empa will provide a quantification of energetic flexibilities and free capacities. Additionally, we are conducting an optimization for future adaptions of operation. We evaluate the system stability based on measurement data, and we will evaluate economical factors related to electrical self-sufficiency in the K3 building complex.

K3, a commercially used building complex, will serve as a validation area. Its energy system consists of roof and façade PV systems, air-to-water heat pumps, water-to-water heat pumps, a CHP unit, and several hot- and cold-water storage units.

Funding body: FOGA
Partners: Die Werke Wallisellen, SVGW


CAPITAL - Carbon footprint optimization of electricity in smart buildings

Will be updated soon.



Will be updated soon.

Funding body: Swiss Federal Office of Energy SFOE


Past research project(s)


Existing infrastructure in buildings, such as heat pumps or domestic hot water heaters is usually operated to purely satisfy the thermal needs of residents. However, thanks to thermal storage capacities available in buildings' thermal mass or water tanks, there exists energy flexibility in when to charge these storages. These flexibilities can be coordinated to satisfy other interests, e.g. from other players in the electric or thermal distribution grid. In a joint project with the aliunid AG, controllers that optimally utilize these flexibilities are developed and implemented in the NEST demonstrator.

Funding body: Swiss Federal Office of Energy SFOE
Partners: aliunid AG, HSG, BFH


EnergyLab Nordhavn


From 2015 until 2019 the project EnergyLab Nordhavn – New Urban Energy Infrastructures has developed and demonstrated future energy solutions. The project has utilized and consolidated Copenhagen’s Nordhavn as a full-scale smart city energy lab and demonstrated how electricity and heating, energy-efficient buildings and electric transport can be integrated into an intelligent, flexible, and optimized energy system.

Funding body: EUDP (Energy Technology Development and Demonstration Programme) Denmark

Selected journal publications

  • Hekmat N., Cai, H., Zufferey, T., Hug, G., and Heer, Philipp. (2021). Data-Driven Demand-Side Flexibility Quantification: Prediction and Approximation of Flexibility Envelopes. arXiv preprinthttps://arxiv.org/abs/2110.12796

  • Cai, H., and Heer, P. (2021). Experimental implementation of an emission-aware prosumer with online flexibility quantification and provision. arXiv preprinthttps://arxiv.org/abs/2110.12831

  • Gasser, J., Cai, H., Karagiannopoulos, S., Heer, P., and Hug, G. (2021). Predictive energy management of residential buildings while self-reporting flexibility envelope. Applied Energy, 288, 116653.

  • Cai, H., Thingvad, A., You, S. and Marinelli, M., 2020. Experimental evaluation of an integrated demand response program using electric heat boosters to provide multi-system services. Energy, 193, p.116729. 

  • Cai, H., You, S. and Wu, J., 2020. Agent-based distributed demand response in district heating systems. Applied Energy, 262, p.114403. 

  • Wang, J., You, S., Zong, Y., Cai, H., Træholt, C. and Dong, Z.Y., 2019. Investigation of real-time flexibility of combined heat and power plants in district heating applications. Applied Energy, 237, pp.196-209.

  • Klyapovskiy, S., You, S., Cai, H. and Bindner, H.W., 2019. Incorporate flexibility in distribution grid planning through a framework solution. International Journal of Electrical Power & Energy Systems, 111, pp.66-78. 

  • Klyapovskiy, S., You, S., Cai, H. and Bindner, H.W., 2018. Integrated planning of a large-scale heat pump in view of heat and power networks. IEEE Transactions on Industry Applications, 55(1), pp.5-15.

  • Cai, H., Ziras, C., You, S., Li, R., Honoré, K. and Bindner, H.W., 2018. Demand side management in urban district heating networks. Applied energy, 230, pp.506-518.

  • Cai, H., You, S., Wang, J., Bindner, H.W. and Klyapovskiy, S., 2018. Technical assessment of electric heat boosters in low-temperature district heating based on combined heat and power analysis. Energy, 150, pp.938-949.


Student supervision

  • PhD student, Varsha Behrunani, Msc ETH, project title: Decentralized control of multi-energy systems. Co-supervision with Prof. John Lygeros (IfA ETH Zurich), Dr. Kristina Orehounig and Philipp Heer.

2021, Spring semester

  • Master thesis student, Nami Hekmat, Msc ETH Zurich, project title:Data-Driven Demand-Side Flexibility Quantification. Co-supervision with Thierry Zufferey and Prof. Gabriela Hug (PSL ETH Zurich)

2020, Autumn semester

  • Semester project student, Timmy Frischknecht, Msc ETH Zurich, project title: Coordinate flexible buildings to support distribution system operation. Co-supervision with Thierry Zufferey and Prof. Gabriella Hug (PSL ETH Zurich)
  • Master thesis student, Muriel Beaud, Msc ETH Zurich, project title: Evaluating the impact of dispatch strategy on different energy system configuration. Co-supervision with Dr. Dasun Perera and Prof. Roy Smith (IfA ETH Zurich)