REFPROP 9.1 is a reliable workhorse, but it is aging. If you encounter persistent issues, consider:
With careful attention to compatibility mode and environment variables, REFPROP 9.1 will continue to serve as an accurate and indispensable tool for thermodynamic calculations for years to come.
This guide applies to REFPROP Version 9.1 (circa 2013). For the latest updates, please visit the official NIST REFPROP website.
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:
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
How to Install REFPROP 9.1: A Complete Step-by-Step Guide REFPROP (Reference Fluid Thermodynamic and Transport Properties), developed by NIST, is the gold standard for scientists and engineers needing accurate properties of industrially important fluids and mixtures. While newer versions exist, REFPROP 9.1 remains widely used in legacy academic environments and specific industrial workflows.
If you need to get REFPROP 9.1 up and running on your machine, follow this comprehensive installation and setup guide. 1. System Requirements & Prerequisites Before beginning, ensure your system meets the following:
OS: Windows XP through Windows 11 (REFPROP is natively a Windows application).
Permissions: Administrative privileges are required to write to the C:\Program Files (x86) directory.
Media: You must have the original installation files (usually an .exe installer or a folder containing SETUP.EXE). 2. Step-by-Step Installation Process Step 1: Run the Installer
Locate your REFPROP 9.1 installation file (often named REFPROP91.EXE or found within a disk image). Right-click the installer and select Run as Administrator. The InstallShield Wizard will launch. Click Next. Step 2: License Agreement and User Info
Read and accept the NIST license agreement. Enter your User Name and Organization when prompted. Step 3: Choose Destination Location
By default, the software installs to:C:\Program Files (x86)\REFPROP
Pro Tip: If you plan on using REFPROP frequently with Python, MATLAB, or Excel, some users prefer installing it to a shorter path like C:\REFPROP to avoid issues with spaces in file paths during API calls. Step 4: Complete the Installation
Follow the remaining prompts and click Install. Once finished, click Finish. You should now see a REFPROP icon on your desktop. 3. Post-Installation Configuration refprop 91 install
Installing the software is only the first half. To make it useful, you usually need to link it to other tools. Adding REFPROP to System Environment Variables
To call REFPROP from any command line or external program, add it to your System Path:
Search for "Edit the system environment variables" in your Windows Start menu. Click Environment Variables.
Under "System variables," find Path, select it, and click Edit.
Click New and paste your installation path (e.g., C:\Program Files (x86)\REFPROP). Click OK on all windows. 4. Integrating with Third-Party Software Excel Integration Open Excel and go to File > Options > Add-ins. At the bottom, select Excel Add-ins and click Go. Click Browse and navigate to your REFPROP folder. Select REFPROP.xla (for older Excel) or REFPROP.xlam.
Ensure "Refprop" is checked in the list. You can now use functions like =PropSI(...). MATLAB Integration
Copy the refpropm.m file from the scripts folder in your REFPROP directory to your MATLAB work folder. You will also need to ensure the REFPROP.DLL is accessible in the system path. Python (CoolProp Wrapper)
Most Python users utilize the wrapper provided by CoolProp to access REFPROP 9.1: pip install CoreProp Use code with caution.
In your script, you will point the wrapper to your C:\Program Files (x86)\REFPROP directory to load the high-accuracy NIST fluid files. 5. Troubleshooting Common Issues
"DLL Not Found" Error: This usually means the system cannot find REFPROP.DLL. Ensure the installation folder is correctly added to your Windows System Path (see Section 3).
Fluid File Errors: If you get an error saying a fluid file (like NITROGEN.FLD) is missing, ensure you are running the application from the directory where the /fluids/ folder is located.
Excel Macros Blocked: If the Excel functions don't work, go to Trust Center > Trust Center Settings > Macro Settings and ensure "Enable all macros" (or "Disable with notification") is selected.
Installing REFPROP 9.1 is a straightforward process, but its utility depends on correct pathing and integration with your calculation tools. By following the steps above, you’ll have a robust thermodynamic engine ready for complex fluid analysis.
While Version 10 is the current standard, REFPROP 9.1 remains in use for legacy compatibility and specific research workflows. The following comprehensive guide details the installation, system configuration, and common troubleshooting steps for setting up REFPROP 9.1. 1. Core Installation and System Requirements
REFPROP 9.1 is designed for Windows environments (XP through Windows 10) and requires approximately 10 MB of hard disk space.
Standard Setup: Run the installer executable (typically from a CD-ROM or digital download from NIST).
Default Path: The program usually installs to C:\Program Files (x86)\REFPROP.
Mini-REFPROP: For educational or student use, a free "Mini" version is available that follows a similar installation wizard process. 2. Linking with Microsoft Excel
Integrating REFPROP 9.1 with Excel is one of its most common use cases, allowing for thermodynamic calculations directly within spreadsheets. Enabling the Add-in: Open Excel and navigate to the Developer tab. Select Excel Add-ins and click Browse.
Locate REFPRP91.XLA in your installation directory (or your user's library for Mac). Ensure the "Refprp91" box is checked in the Add-ins menu. Trust Center Configuration:
To prevent Excel from blocking the DLL, you must add the REFPROP folder as a Trusted Location via File > Options > Trust Center > Trust Center Settings.
Code Access: You can view or modify the underlying wrapper code by opening the Visual Basic editor and double-clicking Refprop91Code under the REFPROP/Modules project box. 3. Advanced Integration (Fortran & Python)
Fortran: Users can compile the 27 source files into a single project or create a .lib file for easier linking in Windows environments. Recommended compilers include Intel Fortran or gfortran.
Python Wrapper: Install the official wrapper using pip install ctREFPROP.
Environment Variable: The RPPREFIX variable should point to your installation folder so Python can locate the necessary .DLL and fluid files. 4. Troubleshooting and Version Conflicts
Installing multiple versions of REFPROP can lead to "DLL Hell," where the system calls the wrong version of the calculation engine. Answers to Frequently Asked Questions - NIST Pages REFPROP 9
Installing NIST REFPROP 9.1 typically involves the base software installation on Windows followed by linking the Dynamic Link Library (DLL) to applications like Excel, MATLAB, or Python. 1. Core Software Installation (Windows) REFPROP 9.1 is a licensed software provided by NIST. Run the Installer
: Use the executable provided with your purchase (often via CD-ROM or digital download). Default Directory : By default, it installs to C:\Program Files (x86)\REFPROP
. It is highly recommended to keep this path, as many third-party wrappers look for it there by default. Verification : After installation, open the REFPROP.EXE
(Graphical User Interface) to ensure the fluid files and mixture models load correctly. National Institute of Standards and Technology (.gov) 2. Linking to Microsoft Excel
The most common use case for version 9.1 is within Excel via the Locate the Add-in REFPROP.XLS in your installation folder. Save a copy as REFPROP.XLA REFPROP.XLAM to your local "Add-ins" folder. Set Trusted Locations Open Excel and go to File > Options > Trust Center > Trust Center Settings Trusted Locations and add the folder C:\Program Files (x86)\REFPROP Activate the Add-in File > Options > Add-Ins In the "Manage" dropdown at the bottom, select Excel Add-ins (or browse to find the file if it's not listed). Fixing DLL Links : If functions return errors, press to open the Visual Basic Editor. Check if the path to REFPROP.DLL in the module matches your actual installation path. National Institute of Standards and Technology (.gov) 3. Installation on macOS
Because REFPROP is a Windows-based Fortran program, macOS users must use a wrapper. Directory Setup : Create a folder named /Users/$USER/Library/Group Containers/UBF8T346G9.Office/ Copy Files : Copy your folders (must be capitalized) and the librefprop.dylib file into this new folder. Excel Setup REFPRP91.XLA
file specifically designed for Mac, which can be found in the NIST REFPROP-wrappers GitHub 4. Troubleshooting Common Issues Missing Fluids : Ensure the subdirectories are present in the main REFPROP folder. Path Environment Variable : If calling REFPROP from Python or MATLAB, adding C:\Program Files (x86)\REFPROP to your Windows System Environment Variables (Path) often resolves "DLL not found" errors. 32-bit vs 64-bit
: Ensure your Excel version (32 or 64-bit) matches the DLL version you are calling. REFPROP 9.1 typically provides both REFPROP.DLL (32-bit) and REFPRP64.DLL CoolProp can't load REFPROP v10 mixtures on Debian 9 #1829
To install NIST REFPROP 9.1 (Reference Fluid Thermodynamic and Transport Properties Database), follow the step-by-step procedures outlined below.
REFPROP is a widely used program developed by the National Institute of Standards and Technology (NIST) to calculate the thermophysical properties of pure fluids and mixtures. 🛠️ Step-by-Step Installation Guide Step 1: Obtain the Software
Purchase or download the installer through the official NIST Standard Reference Data Program. Ensure you have your specific license key ready.
Download the executable installation file (usually named REFPROP91.EXE or similar). Step 2: Run the Installer Locate the downloaded installation file on your computer. Right-click the file and select Run as administrator.
Follow the on-screen prompts provided by the installation wizard. Step 3: Choose the Installation Directory Select your preferred destination folder when prompted.
The default path is usually C:\Program Files (x86)\REFPROP or C:\REFPROP. Note this exact file path for future API linking. Step 4: Finalize the Setup Click Finish to complete the software installation.
Restart your computer if the installer prompts you to do so. 💻 Linking REFPROP to Other Software
Once installed, you can link the REFPROP database to external applications like MATLAB, Excel, or Python: Microsoft Excel Linking Open Microsoft Excel on your computer.
Go to Options, click Add-Ins, and select Go... at the bottom.
Click Browse and navigate to your REFPROP installation directory. Select the file named REFBRO32.XLA or REFPROP.XLA. Check the box next to REFPROP and click OK to activate it. Python Integration Open your command prompt or terminal.
Install the ctREFPROP wrapper or use the CoolProp library wrapper.
Point your script directly to the C:\REFPROP directory to call the DLL files.
If you run into any permission errors or cannot find the required .dll files, ensure you are checking the root directory where you originally extracted the program. To help me tailor the next steps for you:
Are you installing REFPROP for standalone use or to link with other software (like Python, MATLAB, or Excel)? Which operating system are you currently using?
The installation of REFPROP 9.1 (Reference Fluid Properties) follows a specific process depending on whether you are using the standalone program or integrating it with Microsoft Excel. Core Installation Steps
To install the base version of REFPROP 9.1, you typically need the original installation media (CD-ROM) or a digital installer purchased from NIST.
Run the Installer: Execute the nist2391.exe or Setup.exe file from your installation source.
Default Directory: The program usually installs to C:\Program Files\REFPROP (or C:\Program Files (x86)\REFPROP on 64-bit systems). With careful attention to compatibility mode and environment
System Requirements: It is designed for Windows environments; older documentation suggests compatibility back to Windows 95/NT, but it remains functional on modern Windows 10/11 systems with proper user permissions. Linking to Microsoft Excel
Integrating REFPROP 9.1 with Excel is one of its most common uses, allowing you to use thermodynamic functions directly in spreadsheets. Trusted Locations:
Open Excel and go to File > Options > Trust Center > Trust Center Settings.
Under Trusted Locations, click Add new location and browse to your REFPROP folder (e.g., C:\Program Files\REFPROP). Add-in Setup: Go to File > Options > Add-ins.
At the bottom, select Excel Add-ins in the "Manage" box and click Go.
Click Browse and locate the REFPRP91.XLA file in your REFPROP folder. Ensure "Refprp91" is checked in the list. Special Cases: macOS and Version Conflicts
macOS Installation: Installing on Mac requires creating specific directory structures in the Group Containers folder for Office and manually copying fluids, mixtures, and the librefprop.dylib file.
Upgrading to Version 10: If you have REFPROP 10 installed, you can still use the 9.1 interface for backward compatibility. NIST provides a specific REFPRP91.XLA patch to help version 10 users run older spreadsheets without changing formula syntax.
Uninstallation Issues: If an installation fails, ensure you run the unins.exe utility in the REFPROP folder to clear registry entries before attempting a fresh install.
Are you planning to use REFPROP 9.1 primarily for Excel macros or as a standalone GUI for fluid property tables?
REFPROP | NIST - National Institute of Standards and Technology
Q: Can I install REFPROP 9.1 on Windows 11?
A: Possibly, but it is not officially supported. Users report success using Windows 10 compatibility mode (right-click installer > Properties > Compatibility > Run as Windows 10).
Q: I lost my license file. Can NIST reissue it for version 9.1?
A: Likely not. NIST strongly encourages upgrading. If you have proof of purchase, contact refprop@nist.gov – but be prepared for a “no.”
Q: Does REFPROP 9.1 include mixtures?
A: Yes, it supports binary and pseudo-binary mixtures. Use the “Mixture” menu in the GUI or the REFPROPm DLL.
Q: Why does the installer ask for a disk 2?
A: Some CD distributions of REFPROP 9.1 span two disks. Download the full ISO or copy both disk images to the same folder.
Q: Is there a silent install for enterprise deployment?
A: Not natively. You can use AutoIt scripts or response files if you extract the MSI using Universal Silent Switch Finder.
The installer offers two typical options:
Note: Even on 64-bit Windows, REFPROP 9.1 installs to the Program Files (x86) folder because it is a 32-bit application.
Cause: Permissions issue with Windows Registry.
Solution: Run the installer under the hidden Administrator account. Enable it via:
net user administrator /active:yes
Then log out and log in as Administrator to run the installer.
Click Install. The process typically takes 1-2 minutes. Once finished, uncheck "Launch REFPROP" and click Finish.
Cause: Path mismatch or missing fluid database files.
Solution: Reinstall using the Custom option and explicitly select every fluid group. Alternatively, set the environment variable REFPROP_FLUID_PATH to the folder containing .FLD files.
Introduction: The Gold Standard in Fluid Properties
For decades, the National Institute of Standards and Technology (NIST) has maintained REFPROP (short for REfrigerant PROPerties) as the definitive program for calculating thermodynamic and transport properties of fluids. Version 9.1, while not the absolute latest release, remains widely used due to its stability and compatibility with older simulation platforms like EES, MATLAB, and LabVIEW.
However, installing REFPROP 9.1 on modern Windows operating systems (Windows 10/11) is not always plug-and-play. Legacy installer issues, 32-bit vs. 64-bit conflicts, and licensing hurdles are common. This article provides a step-by-step guide to a successful installation.