To make adsorption dehumidification run on heat supply temperatures as low as 50°C, and allow an effective use of solar thermal collectors, a new system concept is developed. The aim is to achieve a quasi-isothermal adsorption of water vapour in solid desiccant by carrying out the process in a finned-tube heat exchanger. Heat is removed or supplied by a water circuit. Air flows through a silica gel bed, packed between the fins. A key issue in this solution is to optimize the bed porosity, in order to minimize the pressure drop on the air side. The present experimental study adapts the Ergun equation to packed beds between two flat plates, where the ratio of wall distance to spheres diameter is within the scarcely investigated range of 1÷2. Packed bed porosity estimation is achieved by adapting transitional structure theory in thin layers of spheres to the present case, and extending it to multi-diameter spheres packing.

Fluid dynamics optimization of a novel isothermal adsorption dehumidification system for solar driven applications

PISTOCCHINI, LORENZO;GARONE, SILVIA;MOTTA, MARIO
2014-01-01

Abstract

To make adsorption dehumidification run on heat supply temperatures as low as 50°C, and allow an effective use of solar thermal collectors, a new system concept is developed. The aim is to achieve a quasi-isothermal adsorption of water vapour in solid desiccant by carrying out the process in a finned-tube heat exchanger. Heat is removed or supplied by a water circuit. Air flows through a silica gel bed, packed between the fins. A key issue in this solution is to optimize the bed porosity, in order to minimize the pressure drop on the air side. The present experimental study adapts the Ergun equation to packed beds between two flat plates, where the ratio of wall distance to spheres diameter is within the scarcely investigated range of 1÷2. Packed bed porosity estimation is achieved by adapting transitional structure theory in thin layers of spheres to the present case, and extending it to multi-diameter spheres packing.
Proceedings of the 2nd International Conference on Solar Heating and Cooling for Buildings and Industry (SHC 2013)
solar cooling; adsorption dehumidification; packed bed; porosity; pressure drop
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/762663
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