Modular Simulation of Absorption Systems User's Guide (Windows Version 5.0) [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2000.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Additional Creators:
- Oak Ridge National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- ABSIM (an acronym for ABsorption SIMulation) is a user-oriented computer code designed for the simulation of absorption systems at steady state, in both flexible and modular form. ABSIM makes it possible to investigate various cycle configurations with different working fluids, to calculate their operating parameters, to predict their performance and to compare them with each other on a uniform basis. A graphical user interface enables the user to draw the cycle diagram on the computer screen, enter data interactively, run the program and view the results either in the form of a table or superimposed on the cycle diagram. Special utilities enable the user to plot the results and produce a pressure-temperature-concentration (P-T-X) diagram of the cycle. Most absorption systems consist of a number of standard components or units (e.g., absorber, condenser) that may be combined in different forms to produce various cycles. Recognizing this, ABSIM has been structured around unit subroutines, each of which contains the governing equations for the particular unit. These subroutines are activated by a main program that interprets the input for the cycle, calls the units, and links them to each other in an order corresponding to the user's specification to form the complete system. Each unit subroutine, when activated, addresses a property database for the thermodynamic properties of the working fluids. The equations generated by the code are listed and solved simultaneously by a mathematical solver routine. The code requires relatively simple inputs, consisting of the minimum information needed to define an absorption system properly. After drawing the cycle in terms of the units recognizable by the code and showing their interconnections, the user must specify the size of each exchange unit in terms of its heat and mass transfer characteristics, the working fluid(s) at each state point; and the given operating conditions, such as temperatures, flowrates, and the like, fixed at specific state points. Based on this information, the program calculates the temperature, flowrate, concentration, pressure, and the vapor fraction at each state point in the system and the heat duty at each unit, from which the coefficient of performance may be determined. ABSIM has been used successfully to simulate a variety of single-, double- and triple-stage absorption chillers, heat pumps and heat transformers using the working fluids LiBr-H₂O, H₂ONH₃, LiBr/H₂O-NH₃, LiBr/ZnBr₂-CH₃OH and more. Some of these results will be described briefly in Sect. 8. Eleven absorption fluids are presently available in the code's property database, and 12 units are available to compose practically every absorption cycle of interest. The code in its present form may be used not only to evaluate new cycles and working fluids, but also to investigate a system's behavior in off-design conditions, to analyze experimental data, and to perform preliminary design optimization. This user manual is organized into eight sections and two appendices. The remainder of this section describes the background for the ABSIM code and presents its special features in comparison with other simulation codes. Section 2 contains information on installation of the code and on basic operations for the first-time user. Section 3 describes the structure of the code, including the input, the output, and the main program. Section 4 describes the unit subroutines containing the governing equations for the 12 unit modules of the code. Section 5 reviews the property database that contains the thermodynamic properties of the working fluids. Section 6 describes the solver package and the method of solution for the equations generated by the code. Section 7 instructs the user on how to use the graphical interface. Some results of the simulation are described in Sect. 8. Appendix A is an input manual describing in detail each item in the input, its significance, and its format. Appendix B contains cycle ...
- Report Numbers:
- E 1.99:ornl/sub/86-xsy123v
- Published through SciTech Connect.
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