ATHENA
Système de production de froid à partir d’énergie thermique intégrant un éjecteur dans le cycle à absorption ammoniac-eau
In the face of constantly increasing global temperatures, the demand for cooling has surged worldwide. Mechanical compression air conditioners and chillers have met this demand, contributing to a significant increase in electricity consumption. The International Energy Agency (IEA) reported that around 20% of global building electricity use is attributed to air conditioners and fans, increasing greenhouse gas and CO2 emissions. An encouraging alternative is the adoption of absorption chillers, operating with abundant and sustainable heat sources, like solar radiation or industrial waste heat. The commonly used absorption couple ammonia/water (NH3/H2O) benefits from high-pressure and temperature operating conditions suitable for low temperature applications as the freezing point of NH3 is -77 °C.
Even though ammonia/water absorption chillers are well known in the literature, research is still needed to improve the system performance when the chillers are required to work in severe conditions, particularly in hot climates (> 40 °C). In such conditions, the main factor limiting the performance is the absorption capacity, which significantly drops when the ambient temperature is too high for absorption of the ammonia vapour into the solution at a relatively low pressure. To push this limit and broaden the machine working ranges, the ATHENA project aims at developing an innovative chiller by upgrading the ammonia/water absorption cycle with integration of an ejector. To boost the performance, the integrated ejector uses a part of the high-pressure refrigerant vapour from the generator to drive and compress the low-pressure refrigerant vapour from the evaporator. The outlet vapour comes to the absorber at an intermediate pressure, which enables higher absorption capacity compared to the classical cycle without the ejector.
At the end of the project, we target validation at TRL4 with development of a prototype for cold production at 5-10 kWth scale. To achieve this objective, the project proposes to conduct research on different aspects:
- Development of a novel ejector working with ammonia-water vapour to improve the performance of the baseline absorption chiller
- Development of an innovative absorption prototype with thermodynamic analysis to
- investigate the impacts of the ejector on the design, the performance and operation of the chiller
- Mapping of the potential applications and techno-economic analysis of the chiller integrated in a district heating or an industrial heating network.
Le consortium
Institut National des Sciences Appliquées de Lyon, Université de Lorraine, Université Savoie Mont Blanc
Coordination
