Column: Diversification of heat-pump-related technologies

Heat pumping technologies are not only useful for temperature control. They can also be used for control and regulation of indoors humidity. This creates a hybrid system with humidity control and air conditioning, which potentially has a very high performance.


A challenge when it comes to humidity control is the desiccant. These substances either absorb humidity from the air, or release it into the air, depending on the present need. Previously, liquid lithium chloride was a common desiccant. Not so anymore, as the substance is highly corrosive. Our research group has focused on liquid desiccants in air conditioning systems and has developed an ionic fluid desiccant which is non-corrosive.

The research group has also developed a hybrid system where this non-corrosive desiccant is combined with a chiller where water is used as refrigerant. It is used for metro stations with high humidity. Results from a specifically designed simulator for energy system analysis show positive results: annual CO2 emissions are reduced with over 40% when this system is used.

These developments are in line with Japan’s commitment to become carbon-neutral by 2050. The commitment is backed up with an intention to support technological initiatives and innovations for this to become true.

Kiyoshi Saito
Professor, School of fundamental science and engineering department of applied mechanics & aerospace engineering,
Waseda University, Japan

The text has been shortened by the HPC team

Read the full HPT Magazine no 1/2021 >