Capillary assisted vaporization of water for thermal heat pumps

Contact

Seiler, Jan

Name

Jan Seiler

Group Leader Sorption Systems Engineering

Phone

work
+49 241 80 98177

Email

E-Mail
  Image with coated and uncoated plain and finned tubes Copyright: LTT

Adsorption heat pumps often employ the natural refrigerant water, since water combines a high enthalpy of vaporization with benign environmental properties. However, at typical working conditions of adsorption heat pumps, water has a very low saturation pressure, which hinders the evaporation process. Better evaporation of the refrigerant can be obtained by higher wall superheats in the evaporator but at the cost of efficiency losses in the heat transfer process. Therefore, the development of evaporators with high overall heat transfer coefficients is crucial for efficient evaporation of water at low pressures.
To enhance heat transfer, macroscopic structures such as micro-fins as well as microscopic structures such as (porous) coatings have been proposed. These structured surfaces enable capillary action to wet the heat exchanger surface with a thin liquid film, which improves the heat transfer into the refrigerant.

 
 

Sponsor

Logo of the Federal Ministry for Economic Affairs and Energy Copyright: BMWi

Supported by Federal Ministry for Economic Affairs and Energy on the basis of a decision by the German Bundestag

 

Project Details

Project Duration

2,5 Years

Project Partner

Pallas GmbH & Co. KG