Refprop 91 Install !full! May 2026

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

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 refprop 91 install

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. How to Install REFPROP 9

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.

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 Ensure EES points to the correct REFPROP version

Post-Installation Verification

You have completed the refprop 91 install – but does it work? Run these checks:

EES (Engineering Equation Solver)

EES has a built-in REFPROP call. After installation, simply write:

rho = Density(Water, T=300, P=101.3)

Ensure EES points to the correct REFPROP version via Options > REFPROP Path.

Key Feature for Installing REFPROP 9.1:

"Seamless integration with Excel via the REFPROP Add-In"

In REFPROP 9.1, one of the most useful installation features is the automatic Excel Add-In setup. After a successful installation, the installer places REFPROP.xla (or .xlam) in the installation folder and can register it with Excel. This allows you to:

• Call REFPROP fluid properties directly from Excel cells using functions like =REFPROP("water","T","P",300,101.325,"H")
• Avoid manual file path configuration if you select the "Register REFPROP with Excel" option during install
• Use the Add-In without needing to locate DLL files manually

Step 1: Run the Installer (with Compatibility)

1. Locate setup.exe on your installation CD or downloaded folder.
2. Critical: Do not double-click it normally. Instead, right-click setup.exe and select Properties.
3. Navigate to the Compatibility tab.
4. Check “Run this program in compatibility mode for:” and select Windows 7 or Windows XP (Service Pack 3).
5. Check “Run this program as an administrator”.
6. Click Apply, then OK.
7. Double-click setup.exe to begin.

Step 3: Apply the License File

After the file copy completes, the installer will prompt: “Please locate your REFPROP.LIC file.”

1. Click Browse.
2. Navigate to the location of your license file (CD root or download folder).
3. Select REFPROP.LIC and click Open.
4. If successful, you will see a confirmation: “License installed successfully.”

Troubleshooting: If the installer fails to recognize the license, manually copy REFPROP.LIC into the installation folder (C:\Program Files (x86)\REFPROP) after installation.

2. Locate Your License and Installer

Unlike freeware, REFPROP requires a paid license. For version 9.1, you need:

• The original installation media (CD-ROM or downloaded .exe).
• A valid license file (often named license.txt or refprop.lic).
• Alternatively, a serial number provided upon purchase.

Important note for 2025: NIST no longer sells new licenses for version 9.1. You can only install it if you purchased it before the version was superseded. If you lack a legitimate installer and license, consider purchasing the current version from NIST or using the free NIST REFPROP web API.

Pre-Installation Checklist

A successful REFPROP 9.1 install begins long before you double-click the setup file. Follow this checklist to avoid frustration.

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."