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Plate-fin-heat-exchanger technology in absorption systems


High power absorption heat-pump (250 kW) of compact design have already been tested. One of the main feature of the design is the use of plate-fin heat exchangers which are economical and compact and allows more flexibility in the choice of heat source. This technology still requires further research on physical characteristics of components.

The overall objective is to make the system as compact as possible and to reduce the primary energy requirements in order to make them more cost-effective.

The project is subdivided into three subprojects, which are independent as regards their implementation:

Subproject 1 : Plate-Fin-Heat-Exchanger (RWTH-LTT)

The knowledge of the behaviour of two-phase flow inside
Plate-Fin-Heat-Exchangers is necessary to design a failing film absorber. The heat and mass transfer will be investigated taking into account the following aspects :

- formation of the falling film
- influence of interfacial tension
- surface of construction materials

Subproject 2 : Solution Pumps (Universität Essen)

Colibri and Rendamax have developed a new solution pump based on thermal propulsion. Aim of this subproject is to gather more information to be able to decide whether there is a future for this pumping principle or not. Main topics of this subproject are:

- Ratio of energy consumption /delivery volume
- Pump design

Subproject 3 : Heat Source Facilities (COLIBRI)

Objective of this subproject is to overcome design problems for the energy collector and the brine circuit if ambient air is used as heat source, so that heat pumps with Plate-Fin-Heat-Exchangers including the heat source facilities can be manufactured at the lowest possible costs, but will be working with a high primary energy utilization degree.

Trying to achieve this, a device which may be called a "Heating Tower" will be studied: The cold brine will be sprinkled over heat exchanging surfaces and direct heat exchange with the ambient air will take place. Topics are:
- selection of a suitable type of brine
- geometry of the heat transfer surface
- crossflow or countercurrent flow between air and brine
- energy consumption of the ventilator
- energy consumption of brine pump
- contribution of the brine
- heat tranfer data
- ice removal from the brine

Call for proposal

Data not available


Colibri BV

6460 BA Kerkrade

Participants (2)

Rheinisch-Westfälische Technische Hochschule Aachen (RWTH)
Schinkelstraße 8
52062 Aachen
Universitatsstrasse 15
45117 Essen