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User's Guide to
Reciprocating Compressor Performance Computer Program
By Joe Honeywell

 

Introduction

This document is intended to assist engineers in the use of the Reciprocating Compressor Performance computer program. This simple to use computer-based program utilizes the Microsoft’s Excel spread sheet program and contains embedded macros that quickly solve basic reciprocating compressor problems with a minimum of set-up time. This user’s Guide will explain the required input parameters, output parameters and the methods used to solve basic compressor sizing and performance problems. It will also describe the program limitations and error checking capabilities. Example problems are given in both USC and SI units and are intended to help users understand how the computer program can be used to find reciprocating compressor limitations and solutions to everyday engineering problems.

This computer program was prepared with two purposes in mind. The first was to help engineers who are new to the field of reciprocating compressors learn about basic performance fundamentals without having to solve problems using tedious and repetitive hand calculations. Nothing hinders the learning experience more than the time consuming need to write down equations, gather data and calculate a solution only to get the wrong answer because of a rudimentary arithmetic error. Even more frustrating is an incorrect answer may not be known until the procedure is checked or verified by others. The other purpose of this computer program is to assist engineers with simple sizing and control techniques that limit machine performance. It is especially well suited to those simple sizing and performance problems that need minimal input data or require repetitive calculations to solve.

While this computer program may not be capable of solving all reciprocating compressor performance problems, it can teach users to solve basic sizing, performance and operating tasks. It will give the user a sense of how more complex vendor programs handle more comprehensive problems and reports that describe a machine’s performance.

Program Description

Analysis of a reciprocating compressor’s performance is based on a variety of complex formulas and algorithms used by manufacturers to solve problems found in a wide variety of applications. For this reason their programs and performance reports can be difficult to understand and use. Many engineers and compressor operators who set out to learn the basics of reciprocating machines can gain the desired knowledge from a simplified program. Learning the basics of sizing, operating and compressor performance begins with a single-throw, double-acting machine. The effects of speed, rod loads, cylinder clearances and losses, unloaders, temperature rise and power consumption can be found from this configuration. More complex applications can be analyzed with a two-stage, two-throw, double-acting machine. It provides basic solutions to more advanced applications that deal with multiple cylinders, inter-stage cooling and pressure losses.

The Reciprocating Compressor Performance computer program is easy to use and provides quick solutions to basic sizing and performance problems. Users of Microsoft’s Excel program will find it easy to install. Those with a basic knowledge of thermodynamics and compressor terminology will quickly adapt to the input data requirements and find how easy it is to modify the machine’s components for alternate solutions. Users will also find the results easy to understand.

The computer program utilizes four Excel worksheets to display input parameters, output parameters, command buttons and warning messages. The four worksheets are; 1. Menu, 2. 1-Stage, 3. 2-Stage and 4. Gas-Prop which are described below. With little effort the users can adjust input parameters and determine a range of “off-design” operating conditions for a given compressor size. It is also possible to optimize the compressor’s size and analyze the effects of changing gas properties.

The Reciprocating Compressor Performance program has been prepared to help engineers learn about basic performance from the two most common arrangements of reciprocating compressors. Typically, this involves finding the basic size, performance characteristics and operating limitations. It is important to note that more complex topics such as gas reheat, valve losses, pin reversals and pulsations to name just a few, have not been included in the program. Their effects are dependent on a particular compressor manufacturer’s design and are therefore ignored. The interested reader can find more about these effects and other related topics by reviewing the referenced literature.

Menu Worksheet

The Menu worksheet lists notes that briefly describe the program’s features, limitations and formulas used to determine the performance results and the units of measure. See the attachments section for an illustration of the Menu worksheet.

Reciprocating Compressor Performance Worksheet - USC           Reciprocating Compressor Performance Worksheet - SI

The worksheet is also used to select the units of measure. The two options for units of measure are as follows:
          1. United States Customary (USC)           2. Systeme Internationale (SI).
The user can select the desired units by pressing one of the follow command buttons. It is recommended to select units of measure before proceeding with input of other parameters.
For example:

flow rate button flow rate button

The Menu worksheet will display either USC or SI as the selected units.

 

 

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