Description

Absorption refrigeration (ABR) processes are affected in real operating environments by exogenous disturbances (e.g., ambient conditions) and by switching between different operating conditions (e.g., partial cooling load operation). The ABR operational performance is highly dependent on the selection of the working fluid with current selection approaches considering only steady-state ABR behavior. Working fluids that exhibit good steady-state performance, may be highly sensitive to disturbances and fluctuating operating conditions. In such a case, the implemented control system would require intense utilization of resources and possibly fail to reach the satisfaction of the desired load specifications. In this respect, it is imperative to evaluate ABR performance with different working fluids under variability in addition to their steady-state performance. In this work, the dynamic performance of a model-predictive controller (MPC) implemented on a single effect ABR utilizing different organic working fluids is investigated aiming at the selection of the most suitable working fluid. The dynamic performance of the closed-loop system is then evaluated in terms of resource utilization, speed of response and deviation from the desired setpoints under a specific disturbance scenario that involves load demand changes. Two comprehensive indices are utilized to evaluate and select the optimal working fluid; one describing the setpoint tracking ability and another describing the resource utilization. It is observed that Acetaldehyde/DMF (dimethylformamide) exhibits the best performance in terms of setpoint tracking resource utilization under variability, followed by NH3/H2O. The latter further ranks second in terms of COP under steady-state operation. This indicates that dynamic performance is equally important to steady-state operation as a criterion for working fluid selection.

Citation: 2021 Virtual Conference Papers

Product Details

Published:

2021

Number of Pages:

9

Units of Measure:

Dual

File Size:

1 file , 890 KB

Product Code(s):

D-VC-21-C038