Refprop 91 Install -

Installation Guide for REFPROP 91

Overview REFPROP (Reference Fluid Thermodynamic and Transport Properties) is an industry-standard software developed by the National Institute of Standards and Technology (NIST). Version 9.1 is a legacy release that provides accurate thermophysical property data for a wide range of fluids and mixtures. Because Version 9.1 is older than the current Windows operating systems, the installation process requires specific attention to file directories and administrative privileges to function correctly.

System Requirements and Prerequisites Before beginning the installation, ensure your system meets the basic requirements for this legacy software:

Operating System: Windows 7, 8, 10, or 11 (may require compatibility settings on newer OS).
Disk Space: Approximately 150 MB of free space.
Privileges: You must be logged in as an Administrator to install the software.

Step-by-Step Installation Procedure

Locate the Installer: Navigate to the directory containing your REFPROP 91 installation files. This is typically provided as a downloadable executable (e.g., REFPROP91.exe) or an ISO file. If you have an ISO, mount it to a virtual drive to access the setup file.
Run as Administrator: Right-click the setup executable and select "Run as administrator." This is crucial; failing to do so may result in the software being unable to write necessary files to the system directories.
User Account Control (UAC): If prompted by Windows User Account Control, click "Yes" to allow the program to make changes to your device.
Installation Directory: The installer will prompt you to choose a destination folder.
- Default Path: By default, the installer often suggests C:\Program Files (x86)\REFPROP. This is the recommended location.
- Important Note for Legacy Users: If you are updating from a previous version (like 8.0), the path might default to C:\REFPROP. It is generally safer to install 9.1 in the Program Files directory to avoid file permission conflicts, though advanced users may prefer a root directory for easier access to fluid files.
Completing the Setup: Follow the remaining on-screen prompts to finalize the installation. Once complete, you may launch the program. On Windows 10 or 11, if the program fails to launch or crashes immediately, right-click the REFPROP shortcut, select Properties, navigate to the Compatibility tab, and check "Run this program in compatibility mode for Windows 7."

Licensing and Activation REFPROP is commercial software. Unlike modern versions that utilize an online license manager, REFPROP 91 typically relies on a physical hardware key (dongle) or a specific license file (often named license.key or similar) placed in the installation directory.

Ensure that if you use a dongle, it is plugged into a USB port before launching the application.
If using a file-based license, copy the license file provided by NIST or your distributor into the main REFPROP installation folder.

Integration with Other Software Many users utilize REFPROP as a backend for Excel or MATLAB.

Excel Add-in: To use REFPROP in Excel, you must load the Refprop.xla or Refprop.xlam add-in via the Excel Options menu. Note that you must point the Excel add-in to the specific Fluids and Mixtures directories within your REFPROP 91 installation folder.
MATLAB: You will need to add the REFPROP directory to the MATLAB path and ensure the active directory in MATLAB points to the REFPROP folder to allow the DLL calls to function correctly.

Troubleshooting Common Issues

"Unable to find fluid files": This error occurs when the software cannot locate the .fld files. Open REFPROP, go to Options > Preferences, and manually set the correct path for the Fluids and Mixtures directories.
License Error: If the software opens in demo mode or closes immediately, verify that your license file is valid for Version 9.1 and is not expired. Note that licenses for Version 10 do not automatically work for Version 9.1.

Disclaimer NIST no longer officially supports Version 9.1, as it has been superseded by Version 10 and Version 11 (REFPROP 2024). Users are encouraged to upgrade to the latest version to ensure compatibility with the newest fluid models and Windows security updates.

How to Install and Set Up NIST REFPROP 9.1 NIST REFPROP 9.1 is a specialized database for calculating the thermodynamic and transport properties of industrially important fluids and mixtures. Released by the National Institute of Standards and Technology (NIST), version 9.1 introduced key updates like 121 pure fluids and a 64-bit DLL (REFPRP64.dll) for improved integration with modern applications. 1. System Requirements

Before installation, ensure your PC meets these minimum specifications:

Operating System: Windows XP, 7, 8, 10, or 11 (32-bit or 64-bit). Storage: At least 10–20 MB of available hard disk space. 2. Standard Installation Steps

To install the full version of REFPROP 9.1 on a Windows machine:

Run the Setup: Locate your installation file (typically named nist2391.exe for version 9.1) or insert the REFPROP CD-ROM.

Follow the Wizard: Execute the installer and follow the on-screen prompts.

Default Directory: The software installs by default to C:\Program Files (x86)\REFPROP on 64-bit systems or C:\Program Files\REFPROP on 32-bit systems.

Registration: For specialized 64-bit COM object registration, you may need to run regsvr32.exe refpropco64.dll at a command prompt. 3. Setting Up the Excel Add-In

One of the most common ways to use REFPROP is within Microsoft Excel. To link version 9.1 to Excel: Linking REFPROP with Other Applications

How to Install REFPROP 9.1: A Complete Step-by-Step Guide NIST’s REFPROP (Reference Fluid Thermodynamic and Transport Properties) is the gold standard for researchers and engineers needing accurate thermophysical properties of fluids. While newer versions exist, REFPROP 9.1 remains widely used due to its stability and compatibility with legacy academic and industrial software.

If you are looking to get REFPROP 9.1 up and running on your system, this guide covers the installation process and how to link it with common platforms like Excel, MATLAB, and Python. 1. Prerequisites and System Requirements Before starting, ensure you have the following:

The Installer: REFPROP is a commercial product. You must have the REFPROP91.EXE setup file or the physical media purchased from NIST.

Administrative Rights: You will need permission to write to the C:\Program Files (x86) directory.

Operating System: Windows 7, 8, 10, or 11 (32-bit or 64-bit). 2. Running the Core Installation Launch the Setup: Double-click the REFPROP91.EXE file. License Agreement: Read and accept the NIST license terms.

Destination Folder: By default, the installer suggests C:\Program Files (x86)\REFPROP. refprop 91 install

Pro-tip: If you plan on using Python or MATLAB extensively, some users prefer installing to a simpler path like C:\REFPROP to avoid permission issues or "Space in filename" errors in code.

Select Components: Ensure that "Full Installation" is selected so that all fluid files (.fld) and mixture files (.mix) are included.

Finish: Click install. Once finished, you will see a "REFPROP" shortcut on your desktop. 3. Integrating REFPROP 9.1 with Microsoft Excel

Most users utilize REFPROP via the Excel Add-in. Here is how to enable it: Open Excel and go to File > Options > Add-ins.

At the bottom, select Excel Add-ins from the "Manage" dropdown and click Go.

Click Browse and navigate to your installation folder (usually C:\Program Files (x86)\REFPROP). Select REFPROP.xlam (for modern Excel) or REFPROP.xla.

Important: You must also copy the file REFPROP.DLL from the installation folder to your C:\Windows\SysWOW64 directory (for 64-bit Windows) or C:\Windows\System32 (for 32-bit Windows). This allows Excel to "see" the engine. 4. Connecting to MATLAB

To use REFPROP 9.1 in MATLAB, you need a wrapper file (often provided in the MATLAB subfolder of the installation). In MATLAB, use addpath('C:\Program Files (x86)\REFPROP'). Use the refpropm.m function to call properties.

Example: density = refpropm('D', 'T', 300, 'P', 101.325, 'water')

Ensure your MATLAB bit-version matches the DLL (use a 64-bit wrapper if using 64-bit MATLAB). 5. Connecting to Python

Python users typically use the ctypes based wrapper or the popular CoolProp interface to call REFPROP.

Via CoolProp: If you have CoolProp installed, you can call REFPROP fluids by setting the "Alternative Path."

Direct Call: You will need to point your script to refprop.dll. Ensure your Python environment is the same "bitness" (32-bit vs 64-bit) as the DLL you are calling. 6. Troubleshooting Common Errors

"File Not Found" for Fluids: This happens if the program doesn't know where the /fluids folder is. Go to the REFPROP GUI, select Options > Paths, and ensure the path points to your installation folder.

DLL Errors in Excel: If you see #NAME? in Excel, it usually means the REFPROP.xlam is active but it cannot find the REFPROP.dll in the Windows system folders.

Permission Denied: If you cannot save changes to fluid mixes, run the REFPROP GUI as an Administrator.

Installing REFPROP 9.1 is straightforward, but the real work lies in the path configurations for your specific external software. Always ensure your .dll files are in a location where your system's PATH environment variable can find them.

The installation of NIST REFPROP 9.1 is a straightforward process for the standalone application, though linking it with tools like Excel requires additional manual configuration. 1. System Requirements

Before beginning, ensure your system meets these basic needs:

Operating System: Windows 98, 2000, XP, Vista, 7, 8, or similar (both 32-bit and 64-bit are supported).

Disk Space: Approximately 10–20 MB of available hard disk space. 2. Core Installation Steps

The primary installation typically occurs from a CD-ROM or an executable installer file.

Launch Installer: If using a CD, insert it and run the setup file (e.g., D:\NIST2391.EXE). If you have a downloaded version, double-click the .exe file (often named nist2391.exe).

Follow the Wizard: The setup wizard will guide you through the license agreement and destination folder selection. The default installation path is usually C:\Program Files\REFPROP or C:\Program Files (x86)\REFPROP.

Verification: Once finished, you can launch the graphical user interface (GUI) to calculate thermodynamic properties and view tables or plots. 3. Linking with Excel (Windows)

To use REFPROP functions directly in Excel spreadsheets, follow these steps to set up the Add-In: Operating System: Windows 7, 8, 10, or 11

Prepare the Add-In: Locate REFPROP.xls in your installation folder and save it as an Excel Add-In (.xla or .xlam) in the same directory.

Add Trusted Location: In Excel, go to File > Options > Trust Center > Trust Center Settings > Trusted Locations. Click Add new location and browse to your REFPROP folder (e.g., C:\Program Files\REFPROP).

Enable the Add-In: Go to File > Options > Add-ins. In the Manage drop-down at the bottom, select Excel Add-ins and click Go. Click Browse, navigate to your installation folder, select the .xla or .xlam file, and ensure it is checked in the list. Configure Environment Variables (Optional but Recommended):

Create a new user environment variable named RPPrefix and set its value to your installation path (e.g., C:\Program Files\REFPROP).

Add your installation path to the existing Path variable to ensure Excel can always locate the required DLLs (REFPROP.DLL or REFPRP64.DLL). 4. Common Troubleshooting Answers to Frequently Asked Questions - NIST Pages

Guide to Installing NIST REFPROP 9.1 NIST REFPROP (Reference Fluid Thermodynamic and Transport Properties) version 9.1 is a widely used software for calculating the thermophysical properties of industrially important fluids and their mixtures. While it has been officially superseded by REFPROP Version 10

, many researchers and engineers continue to use version 9.1 for consistency with older projects. System Requirements

Before beginning the installation, ensure your system meets these basic requirements: Operating System

: Windows 98, 2000, XP, Vista, 7, 8, or similar (both 32-bit and 64-bit are supported). Disk Space : Approximately 10–20 MB of available hard disk space. Core Installation Procedure

The standard installation typically involves a setup executable provided by NIST. Run the Installer : Locate your installation file (often named nist2391.exe or found on a provided CD-ROM). Follow the Wizard

: Execute the file and follow the on-screen prompts. The default installation path is usually C:\Program Files\REFPROP

: It is recommended to keep this default path as many external wrappers (like Excel) look for this specific directory. Environment Variables (Optional but Recommended)

: To access REFPROP from other applications, you may need to set specific environment variables:

: Set this variable to point to your main installation directory (e.g., C:\Program Files\REFPROP

: Add the REFPROP directory to your system's "Path" variable to allow the system to locate the REFPROP.DLL Linking REFPROP 9.1 with Microsoft Excel

One of the most common ways to use REFPROP 9.1 is through its Excel Add-in. Locate Add-in Files REFPRP91.XLA REFPROP.xlam is in your main installation folder. Add Trusted Location In Excel, go to

File > Options > Trust Center > Trust Center Settings > Trusted Locations C:\Program Files\REFPROP as a trusted location to ensure macros can run. Activate the Add-in File > Options > Add-ins At the bottom, select Excel Add-ins from the "Manage" dropdown and click Browse to your REFPROP folder and select the Verify the Connection : Test a simple command in a cell, such as =Density("water","TP","SI",300,1) , to ensure properties are being pulled correctly. Troubleshooting Common Issues Answers to Frequently Asked Questions - NIST Pages

The installation of NIST REFPROP 9.1 (Reference Fluid Thermodynamic and Transport Properties) is a critical step for engineers and researchers who need high-accuracy fluid data. While now superseded by Version 10, Version 9.1 remains a staple in many legacy academic and industrial environments. 1. System Requirements & Preparation

Before beginning, ensure your system meets the baseline requirements for this legacy version:

Operating System: Windows 98, 2000, XP, Vista, 7, 8, or 10 (both 32-bit and 64-bit are supported). Storage: At least 10.0 MB of available hard disk space.

Administrative Rights: You typically need administrator privileges to write to the C:\Program Files\REFPROP directory. 2. Core Installation Steps

The installation process usually follows a standard executable wizard:

Run the Installer: Execute the nist2391.exe (or similar) file provided by NIST.

Default Directory: The program usually installs to C:\Program Files (x86)\REFPROP or C:\Program Files\REFPROP. Crucial: Avoid moving the REFPROP.DLL file to Windows system folders (like System32); it must remain in the application folder with its associated .FLD and .HMX fluid data files.

Registration (Optional): If using the CAPE-OPEN interface or certain COM objects, you may need to manually register the DLL using regsvr32.exe refpropco.dll in a command prompt. 3. Integrating with Excel

One of the most common uses for REFPROP 9.1 is within Microsoft Excel. Proper setup prevents the common #NAME? error. Step-by-Step Installation Procedure

Trusted Locations: Go to File > Options > Trust Center > Trust Center Settings > Trusted Locations. Add your REFPROP folder (e.g., C:\Program Files\REFPROP) and check "Subfolders of this location are also trusted".

Adding the Add-In: In Excel, go to File > Options > Add-Ins. At the bottom, select "Excel Add-ins" from the Manage dropdown and click Go. Browse to your REFPROP folder and select REFPROP.xlam.

Verify Links: If functions don't work immediately, go to the Data tab, click Edit Links, and ensure the source for the REFPROP add-in points to your local installation folder rather than a temporary or user-specific directory. 4. Troubleshooting Common Issues Potential Solution OCX Errors (339)

Run-time errors like MSHFLXGD.OCX missing often mean a firewall or antivirus blocked the registration of UI components. Missing Fluid Files

If Excel can't find fluid data, copy the *.FLD and HMX.BNC files into a default directory like C:\REFPROP\FLUIDS. Conflicting DLLs

If you previously had Version 7 or 8, search your computer for old Refprop.dll files (especially in System32) and delete them to prevent version conflicts. 64-bit Compatibility

Version 9.1 was the first to automatically include REFPRP64.dll, which is necessary for 64-bit versions of Excel or MATLAB. 5. Moving Forward

Here’s a helpful feature for installing REFPROP 9.1 (assuming you meant version 9.1, since REFPROP 10.x is more common now — but if you meant NIST REFPROP 9.1, the following applies):

1. Overview

REFPROP (Reference Fluid Thermodynamic and Transport Properties) is the industry-standard software developed by the National Institute of Standards and Technology (NIST). Version 9.1 is a legacy iteration that remains widely used in industry for its stability and extensive database of pure fluids and mixtures. Unlike modern subscription models, 9.1 was typically distributed as a perpetual license, making the installation process distinct from newer versions.

Step 1: Launch the Installer

Locate the Setup.exe file. Right-click and select "Run as Administrator." If User Account Control (UAC) prompts you, click "Yes."

4. Critical Post-Installation Steps (Licensing)

This is the most common failure point for new users. REFPROP 9.1 installs in "Demo Mode" by default. In Demo Mode, the software functions but randomizes output values, rendering it useless for actual engineering work.

To activate the full version:

Locate your Site Key or License File. This is typically emailed to the purchaser from NIST or a distributor.
Navigate to the installation directory (e.g., C:\Program Files (x86)\REFPROP\).
Look for a batch file or executable usually named Register.exe or Author.exe.
Run this utility as Administrator.
Input the Site Key exactly as provided (case-sensitive).
You should receive a confirmation message stating the license is valid.

*Note: Some versions used a specific REFPROP.key file that simply needed to be pasted into the installation folder. Overwriting the placeholder key with your purchased key

To install NIST REFPROP version 9.1, follow these standard procedures as outlined in the official NIST REFPROP 9.1 User's Guide Installation Steps System Requirements

: Ensure your PC runs a compatible Windows version (98, 2000, XP, Vista, 7, 8, or later). The program requires approximately of hard disk space. Run the Installer Place the REFPROP CD-ROM in your drive. , and type D:\NIST2391 with your specific CD drive letter). Follow the on-screen prompts to complete the setup. Default Directory : By default, the software installs to C:\Program Files\REFPROP

. You can change this during setup, but do not manually rename any internal files or subdirectories after installation. Linking with Other Applications Excel Add-in : To use REFPROP in Excel, navigate to File > Options > Add-ins for Excel Add-ins, then C:\Program Files\REFPROP folder to select REFPROP.xlam Environment Variables

: For some applications (like MATLAB), you may need to set a system environment variable named with the value of your installation path (e.g., C:\Program Files\REFPROP 64-bit Compatibility : Version 9.1 and higher includes REFPRP64.dll , which is necessary for 64-bit applications like the REFPROP CAPE-OPEN Manager Common Troubleshooting Conflicting Versions

: If you have issues upgrading to a newer version (like REFPROP 10), NIST recommends completely uninstalling version 9.1, deleting the installation folder, and clearing out any hidden files in your AppData\Local\VirtualStore directory. Missing Installer

: If you no longer have your original 9.1 installer and need to reinstall, you can contact NIST support at ian.bell@nist.gov for assistance. National Institute of Standards and Technology (.gov) Are you planning to use REFPROP with a specific application like Excel, MATLAB, or Python? Answers to Frequently Asked Questions - NIST Pages

Integrating REFPROP 9.1 (Reference Fluid Thermodynamic and Transport Properties) is a straightforward process, but it requires precise file placement to ensure it communicates correctly with external software like Excel, MATLAB, or Python. 1. Initial Extraction and Setup

The installation typically begins with the executable provided by NIST. Run the installer to unpack the high-accuracy property models and the graphical user interface. By default, the program installs to C:\Program Files (x86)\REFPROP

If you plan on using REFPROP with third-party wrappers (like Python’s

), many users prefer installing it to a simpler path without spaces, such as C:\REFPROP , to avoid path-string errors in code. 2. Linking the DLL The core of REFPROP is the REFPROP.DLL file. For the software to be "visible" to your system: System Environment Variables: Add the REFPROP installation folder to your Windows

. This allows other programs to call the DLL without you having to copy the file into every project folder. 32-bit vs. 64-bit:

Ensure you are using the version of the DLL that matches your calling application. REFPROP 9.1 includes both; the 64-bit version is often named REFPRP64.DLL 3. Integration with Excel To use REFPROP functions directly in spreadsheets: Open Excel and go to Options > Add-ins Excel Add-ins Browse to your REFPROP directory and select REFPROP.xlam Refprop.xla for older versions). Once enabled, you can use formulas like =Theoretical("T","Density", "SI", "Water") directly in cells. 4. Verification After installation, always run the standalone REFPROP GUI

first. If you can calculate a simple saturation table for a common fluid like Nitrogen, the underlying fluid files (.FLD) and mixture files (.MIX) are correctly placed. Are you planning to use REFPROP primarily through the Excel Add-in or via a programming language like

Integrating REFPROP 9.1 with Other Software

The true power of REFPROP 9.1 lies in its use as a calculation engine for other programs. The installer automatically places the necessary files here:

For MATLAB: The files refpropm.mexw32 and REFPROPn.m are found in the installation folder. Copy these to your MATLAB working directory. Use help refpropm in MATLAB for syntax.
For Excel: The installer adds a REFPROP Add-In. In Excel, go to File > Options > Add-ins > Manage: Excel Add-ins > Go. Check REFPROP Add-In. Use =REFPROP("water","T","P",300,101.325,"D") in a cell.
For EES (Engineering Equation Solver): Ensure REFPROP.DLL is in the same folder as EES.exe or in your system path.