Absorption Capacity of Ammonia into Ionic Liquids for Absorption Refrigeration Applications

Abstract

Abstract. In this paper ionic liquids are proposed as a novel absorbent for absorption refrigeration application with ammonia as refrigerant. The main objective of this work is to develop a measurement setup to study the absorption capacity of the ammonia vapour in ionic liquids in a pool type absorber. This investigation is essential in order to identify the most suitable ionic liquid as an absorbent for ammonia refrigerant. . The absorption processes are observed within 20 minutes in each experiment at different temperatures and pressures. The detail of the methodology and experimental setup are explained in this paper and measurement results of absorption capacity of ammonia into ionic liquid are discussed. Among all ionic liquids studied in this paper [EtOHmim] + based ionic liquids shows higher absorption capacity than [emim] + based ionic liquids, which means that the OH structure in the cation may improve the absorption capacity of ammonia. IntroductionAbsorption refrigeration system is a good known technology. The absorption systems, which can utilize renewable energy such as solar and geothermal energy or waste heat sources such as exhausts of diesel engines and industrial plants to produce cold, carries a primary energy saving, and thus emission reduction. In addition, the absorption systems contain non-HFC and thus, environmentally friendly and becomes a competitive alternative to the conventional vapour compression refrigeration systems. Similar to the compression cycle, absorption cycle is based on the cooling and heating process associated with phase changes of evaporation and condensation of refrigerant fluid at different temperatures and pressures. The working fluid consists of refrigerant and absorbent, so that the boiling temperature can be modified by changing the pressure or composition of the mixture.One of the most common working fluid pair in absorption refrigeration systems is ammonia/water. In this working pair, ammonia works as refrigerant and water as absorbent. The ammonia/water absorption cycle is used mainly for refrigeration purpose, since it can produce cold below 0°C. Being natural fluids, both are emission free and ozone friendly resulting with zero global warming potential (GWP) and ozone depletion potential (ODP). However, the characteristic of water is volatile, thus it is necessary to add an additional component, namely rectifier, to minimize the amount of water entering to the condenser.

Performance Evaluation of R1224yd as Alternative to R123 and R245fa for Vapor Compression Heat Pump System

“…The energy and exergy analysis are conducted based on thermodynamic analysis and mass balance equations which are listed in Eqs. (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”

“…Recently, one of the hot topics in High Ventilating Air Conditioning and Refrigeration (HVACR) system are the search for alternative working fluid and refrigerant [1]- [9]. Chloro Fluoro Carbons (CFCs) as the first refrigerant for HVAC system banned in 1987 in Montreal Protocol and are being replaced by Hydro Fluoro Carbon (HFC) and Hhdro Chloro Fluoro Carbon (HCFC).…”

Diffusivities in Binary Mixtures of Ammonia Dissolved in n-Hexane, 1-Hexanol, or Cyclohexane Determined by Dynamic Light Scattering and Molecular Dynamics Simulations

“…So far, some experimental − and theoretical − studies are available for self-diffusion coefficients, also referred to as intradiffusion coefficients in the literature, of pure NH 3 or corresponding mixtures. Until now, however, only limited data are available for D 11 in gaseous mixtures with NH 3 or mixtures consisting of a liquid and dissolved NH 3 . − …”

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“…A prediction by CEMAC [14] suggests a 4.5-times increase in air conditioning demand for non-Organization of Economic Coordination and Development (OECD) countries and a 1.3-times increase for OECD countries. Considering the need to reduce greenhouse gas emissions while maintaining performance, selecting the refrigerant for heat pump applications is an essential stage in the design process [15][16][17]. For example, a R32 refrigerant in a Heat Pump Water Heater offers advantages such as low Global Warming Potential (GWP) and near-zero ozone depletion potential.…”