Theoretical analysis on the performance of branched GAX chiller cycle

Abstract EN

In this study, a branched GAX absorption cycle operating with NH3-H2O pair has been investigated to assess its performance under steady state conditions.

The cycle modeling is implemented using Engineering Equation Solver (EES) software.

Analysis includes equations of mass, species and energy conservation.

The analysis is used to simulate a GAX absorption chiller utilization for air conditioning applications with a nominal capacity of 95 TR.

This chiller uses solar collectors as heat source.

The operating parameters are selected at different values of the heat source temperature (140 - 185°C), condenser exit temperature (30 to 48°C), evaporator exit temperature (2 to 11°C) ; split ratio (0 to 0.18); the difference in ammonia concentration(0.25-036), mass flow rate in solution pump mr=1 kg/s; heat exchanger effectiveness   0.8.

The results showed that the average COP is sensitive to operating conditions where the average COP and cooling capacity of the branched GAX absorption chiller increase with increasing generator and evaporator temperature whereas they decrease with increasing condenser temperature.

Simulation results also show that the split ratio and ammonia concentration difference have a significant impact on the performance of absorption chiller.