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Air conditioning based on thermal solar energy- development of a low temperature absorption chiller for larger scale solar cooling in the building sector (large scale solar cooling)


Objectives and Problems to be solved:
In recent years large scale solar thermal energy utilization has seen considerable development in terms of the number and size of applications. Further potential and quite promising applications of thermal solar energy use include building air conditioning. Systems using solar thermal energy for building air conditioning are referred to as Solar Cooling Systems. A strong argument for the use of solar cooling systems is that the highest cooling demand occurs at the time of the highest solar energy availability. Despite the large potential demand for solar cooling systems in the building sector, their application has been limited to a small number of pilot and demonstration projects. The main reason for this is the current level of technical and economic development. General problems for solar cooling systems encompass the heat temperature required for efficient operation of the absorption chiller, and the stability of operation of the absorption chiller subject to variation of input temperature. The objective of this project is to overcome current problems of solar cooling systems in terms of the technical/economic feasibility and competitiveness, in particular for large scale applications.
Description of the work:
A wide range of research projects has been conducted in recent years focusing particularly on the technical improvement of chillers. One of these research projects was conducted in Austria between 1996 and 1999 by the Solar frost research company. The project focused on the development of a low temperature absorption chiller for use in small-scale applications (< 400 W cooling capacity), employing ammonia (NH3) as the coolant. This new development is known as Advanced Ammonia Absorption Cooling, subsequently referred to as AAAC. The specific targets include the upscale of the AAAC technology for large-scale applications, the improvement of the technical and economic performance of LSSC systems and the development of a LSSC simulation tool. To overcome the expected problems in terms of technical and economic feasibility and performance will require Research & Development action.
Seven Work Packages (WP) are envisaged.
These are
WP 1: Development and application of a simulation software to support AAAC based Solar Cooling System design and performance evaluation,
WP 2: Planning and detail design of a AAAC based Solar Cooling System,
WP 3: Construction and installation of the absorption chiller,
WP 4: Performance evaluation of the absorption chiller,
WP 5: Analysis of the technical and economic feasibility of LSSC systems,
WP 6: Dissemination of Project Results and
WP 7: Project Management. Expected results and Exploitation Plan.
The Research and Development activities shall result in:
- an upscale of the cooling capacity to a minimum level typically required for air conditioning in buildings (the targeted refrigeration capacity should be a minimum of 30 kW, but may reach 50 kW or above),
- the improvement of the technical / economic competitiveness of Large Scale Solar Cooling systems - a wide spread application on an European basis. The project results and their dissemination provides for the basis to exploit the market potential beyond the project period. A Technology Implementation Plan (TIP) shall indicate all potential foreground rights and intentions for use and the dissemination of results.
A 500 Watt test machine. As the bubble pump did not generate a constant mass flow it had to be replaced by a gear pump. Unknown comportment of the layering behaviour of NH3 and H2 gas requires deeper investigations in the function of the thermodynamic cycle and the layering comportment. The key question in the cycle is the design of the condenser and evaporator zone in order to maintain a stable cooling capacity.

Funding Scheme

CSC - Cost-sharing contracts


Kaiserstrasse 45
1070 Wien

Participants (3)

Vasa Hus 8
Faradaygasse 3, Obj. 230
1030 Wien
Herrgottwiesgasse 188
8010 Graz