Final Report Summary - NARILAR (New Working Fluids based on Natural Refrigerants and<br/>Ionic Liquids for Absorption Refrigeration)
The technology of absorption heat pumps and refrigeration systems has received growing attention in the past years from air-conditioning, refrigeration and heat pumps applications especially in connection with energy efficiency. The development of thermal cooling technologies and others sustainable energy technologies is promoted by the EU Research Policy. The properties of the working fluids are key factors in the performance of the absorption chillers. Conventional working fluids have technical limitations related with corrosion problems, crystallization, etc that have prevented a significant presence of absorption in the air conditioning and refrigeration market.
Ionic liquids (IL) or low temperature molten salts are considered today to constitute the class of liquids with the highest potential to revolutionize the chemical industry, as they constitute innovative fluids for chemical processing which are generally non-flammable and non-volatile at ambient conditions, and, thus, perceived as “green” solvents.
As a new type of fluids with a great solvent character and other interesting properties such as a good thermal stability and very low vapour pressure, Ionic Liquids can be excellent candidates as absorbents for absorption systems. In fact, the present state of art permits to “tailor” an ionic liquid with required characteristic for a given duty, by choosing the cation and the anion from thousands of possibilities. As a drawback, the IL are moderately to highly viscous, especially at low temperature, restricting the flow of the absorbent in the machine. This problem can be overcome by a careful choice of the IL or by the addition of a molecular solvent that can reduce dramatically the viscosity. As a consequence an adequate design of a mixture IL + molecular solvent can lead to more efficient cycles.
The NARILAR project aims to develop novel and more efficient working pairs for absorption refrigeration and heat pump systems using natural refrigerants (water, ammonia or carbon dioxide) and an absorbent based in a mixture of Ionic Liquid + molecular solvent.
The project implementation activities that will be carried out involve several steps, from selection of adequate systems, by a careful screening of existing data and foreseen measurable thermophysical properties, experimental measurement of thermodynamic and transport properties, development of prediction/estimation methods to avoid excess experimental commitment, heat transfer studies, thermodynamic cycle simulation and analysis and optimization of the working fluids.
The expected impact of NARILAR project is the development of new working fluids for absorption heat pumps and refrigeration systems, using mixtures of natural refrigerant and ionic liquid as absorbent. Thus, the goal is to obtain a working pair with the next characteristics:
- More environmentally friendly: the refrigerant is a natural compound (water, ammonia, CO2 and others). Besides, ionic liquids are considered as green solvents.
- More effective working fluids: the non-volatility of the ionic liquids promotes the separation between the refrigerant and the absorbent.
Ionic liquids (IL) or low temperature molten salts are considered today to constitute the class of liquids with the highest potential to revolutionize the chemical industry, as they constitute innovative fluids for chemical processing which are generally non-flammable and non-volatile at ambient conditions, and, thus, perceived as “green” solvents.
As a new type of fluids with a great solvent character and other interesting properties such as a good thermal stability and very low vapour pressure, Ionic Liquids can be excellent candidates as absorbents for absorption systems. In fact, the present state of art permits to “tailor” an ionic liquid with required characteristic for a given duty, by choosing the cation and the anion from thousands of possibilities. As a drawback, the IL are moderately to highly viscous, especially at low temperature, restricting the flow of the absorbent in the machine. This problem can be overcome by a careful choice of the IL or by the addition of a molecular solvent that can reduce dramatically the viscosity. As a consequence an adequate design of a mixture IL + molecular solvent can lead to more efficient cycles.
The NARILAR project aims to develop novel and more efficient working pairs for absorption refrigeration and heat pump systems using natural refrigerants (water, ammonia or carbon dioxide) and an absorbent based in a mixture of Ionic Liquid + molecular solvent.
The project implementation activities that will be carried out involve several steps, from selection of adequate systems, by a careful screening of existing data and foreseen measurable thermophysical properties, experimental measurement of thermodynamic and transport properties, development of prediction/estimation methods to avoid excess experimental commitment, heat transfer studies, thermodynamic cycle simulation and analysis and optimization of the working fluids.
The expected impact of NARILAR project is the development of new working fluids for absorption heat pumps and refrigeration systems, using mixtures of natural refrigerant and ionic liquid as absorbent. Thus, the goal is to obtain a working pair with the next characteristics:
- More environmentally friendly: the refrigerant is a natural compound (water, ammonia, CO2 and others). Besides, ionic liquids are considered as green solvents.
- More effective working fluids: the non-volatility of the ionic liquids promotes the separation between the refrigerant and the absorbent.