ENERGETIC ANALYSIS OF AN ABSORPTION CHILLER USING NH3/LiNO3 AS AN ALTERNATIVE WORKING FLUID

Abstract

This paper presents a thermodynamic model developed for a prototype absorption chiller using NH 3 / LiNO 3 with 10 kW of nominal capacity. The study was undertaken using thermodynamic modeling based on the mass and energy balance, takes the overall heat transfer coefficients into consideration and uses the characteristic equation method. First, the results obtained from the thermodynamic modeling developed were compared with those obtained from the characteristic equations of thermal power activation and the cooling capacity. These showed good agreement with the experimental data, there being maximum relative errors of around 5% for most of the operational conditions of the system. Secondly, a parametric analysis was made by altering the variables, such as temperature, mass flow rate, and configuring the heat dissipation that influences the overall performance of the prototype chiller.

Absorption Refrigeration Systems Based on Ammonia as Refrigerant Using Different Absorbents: Review and Applications

“…The use of mixtures based on ammonia/absorbents in absorption refrigeration processes has been studied, analyzed, and implemented by several authors over the years. Theoretical and experimental studies were carried out to analyze the performance of absorption refrigeration systems, using NH 3 /H 2 O [57][58][59][60] or NH 3 /LiNO 3 [61,62] or any other absorbent with NH 3 [63][64][65][66]. These techniques were investigated on prototypes or experimental apparatus and by applying the first and second Laws of Thermodynamic, as shown in Figure 3.…”

“…An essential aspect in the dimensioning and manufacturing of the NH 3 /LiNO 3 working fluids for absorption refrigeration systems is the no need for rectification components and with the possibility of using solar energy as the exclusive activation source as shown [19,20,121,125]. Many factors have been considered in the selection and use of these chemical components in the working fluids, as well as the use of compact heat exchangers that use loads of relatively small mixtures, leading to the construction of smaller absorption chillers [26,27,62,126], but with capacities similar to the commercial ones [127,128].…”

“…In this context, the use of plate exchangers as a basic component in heat and mass transfer was highlighted, where a flat plate heat exchanger [126,129] was studied to reduce the cost and size of the absorption chiller. In these studies it was noticed that even with the use of the alternative NH 3 /LiNO 3 mixture [20,40,121,125,130] and improvements in the overall performance of the absorption chiller [62,81], compared to ARS that use NH 3 /H 2 O [10,11,59,106], the problem of the viscosity of the mixture still represented an energy limitation, as established in the literature [95,125,130,131]. This led to the addition of water in the LiNO 3 absorber as a way to minimize these limitations.…”