Refrigeration Technology

Development of a solar-powered chiller for air-conditioning and refrigeration purposes

The aim of the project by the technology transfer centre at Bremerhaven University is the development of a solar-powered chiller for air-conditioning and refrigeration purposes. The chiller's primary component is a two-phase/two-component jet pump operated using a mixture of ammonia and water. The intention is to combine the benefits of the adsorption and the compression principle.  

 

Summary

Air-conditioning for rooms and refrigeration of foodstuffs require cooling that can be achieved using a variety of power sources. Utilisation of solar power during the summer months offers a promising opportunity for saving larger quantities of fossil fuels.

The project's aim is to develop and test in experimental trials a solar-powered chiller for air conditioning and refrigeration. The chiller's primary component is a two-phase/two-component jet pump operated using a mixture of ammonia and water. As a natural refrigerant, ammonia presents an environmentally sound alternative to CFCs. Both the delivery and the suction flow in the developed plant can be two-phase. This allows, on the one hand, the benefits of the adsorption and the compression principle to be combined. On the other, this is intended to achieve a compact design. After completion of the thermodynamic and kinetic calculations, the operation of the two-phase/two-component jet pump was examined using a pilot plant with a refrigeration output of approx. 20 kW. In doing so, the cooling ratio (COP value) was recorded as the primary characteristic of the chiller's efficiency. The COP value is defined as the "cooling output" divided by the "input heating power".

Results:

  • It was found that pure ammonia is a better operating medium than the ammonia/water mixture. The experiments were therefore conducted using pure ammonia.
  • COP values in the range from 0.3 to 0.35 were achieved. This value is substantially higher than those of conventional steam-jet pump chillers (in the range of 0.1 to 0.15) and thus more efficient.
  • Good steam content lies in the range of approx. 0.7 to 0.75 volume share on the suction flow side.
  • The steam share on the delivery side has no significant effect on the plant's COP value until a moderate steam content is reached.

More Project Informations

Project number:  0329151L

Project period:  1998 - 2001

Project region:  Germany (Bremen)

Project contact:

Herr Prof. Mostofizadeh

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Source: German National Library of Science and Technology Hannover (TIB)