The performance of the adsobent material used in water adsorption/desorption is crucial for their good perfomance. At Empa novel monolithic carbon adsorbents with very interesting properties have been developed.

The end energy consumption for heating applications accounts for around 50% of the total energy consumption in Switzerland. At present, high-grade chemical energy in the form of oil and gas is used to cover at least two-thirds of the low-grade heat demand, which results in unfavorable CO2 emissions. There is therefore a need to minimize the utilization of these fuels and, wherever possible, substitute them with readily available waste heat or renewable energy. A key component required for the effective utilization of thermal energy for low-grade heating and cooling applications is a thermally driven heat pump. Typical materials used for thermally driven heat pumps are zeolites, silica gels and activated carbons. The state of the art of carbon sorbents cannot be considered as wholly satisfactory because of their hydrophobicity. However the machineable, monolithic carbons, with tailorable hierarchical porosities, developed in our group show interesting sorption behavior for a range of heating pump applications, such as data center cooling, and are superior in terms of thermal conductivity and show very good performance in laboratory scale temperature swing measurements.

In addition to materials development work is also being done within the group to improve the understanding and prediction of the performance of a specific adsorbent within a heat pump under given cycle temperature boundary conditions determined by the application. This is the main task of the group within HyCool a European Horizon2020 project funded by the European Union.

Publications:

[1]       L. Huber, P. Ruch, R. Hauert, G. Saucke, S.K. Matam, B. Michel, et al., Monolithic nitrogen-doped carbon as a water sorbent for high-performance adsorption cooling, RSC Adv. 6 (2016) 25267–25278. https://doi.org/10.1039/C6RA00548A

[2]       L. Huber, P. Ruch, R. Hauert, K. Matam, G. Saucke, S. Yoon, et al., Water sorption behavior of physically and chemically activated monolithic nitrogen doped carbon for adsorption cooling, RSC Adv. 6 (2016) 80729–80738. https://doi.org/10.1039/C6RA18660B

[3]       S.E. Muehlemann, L. Huber, S. Zhao, S.K. Matam, M.M. Koebel, Facile synthesis of resorcinol-melamine-formaldehyde based carbon xerogel, Mater. Today Proc. 5 (2018) 13776–13784. https://doi.org/10.1016/j.matpr.2018.02.018