Thermodynamics Research Center

TRC supplies thermodynamic properties tables, thermophysical properties data, models, standards and research for industry, public health and safety, and the environment.

For over 60 years, TRC has produced a great number of the periodical compilations and electronic databases that have become source data for scientific research and industrial process design. Subject areas include thermophysical properties and transport properties of pure compounds, binary mixtures and chemical reactions, clathrate hydrates, and ionic liquids. The goals of TRC are to establish a comprehensive archive of experimental data of well-defined composition and be a comprehensive source of critically evaluated data.

Functions

Located in Boulder, CO, TRC Group performs several functions related to providing state-of-the-art thermodynamic data:

Critically Evaluated Data

An important and useful aspect of our work here at TRC, and of the Thermophysical Properties Division of NIST as a whole, is to provide critically evaluated data. Critical evaluation is a process of analyzing all available experimental data for a given property to arrive at recommended values together with estimates of uncertainty, providing a highly useful form of thermodynamic data for our customers. The analysis is based on intercomparisons, interpolation, extrapolation,and correlation of the original experimental data collected at TRC. Data are evaluated for thermodynamic consistency using fundamental thermodynamic principles, including consistency checks between data and correlations for related properties. While automated as much as possible, this process is overseen by experts with a great deal of experience in the field of thermodynamic data. Professional staff are responsible for the evaluation of each set of data that is committed to the archive.

For many years TRC published two series of periodicals containing evaluated data for pure compounds. These were recently superceded by a web version of the TRC Tables. This product is called Web Thermo Tables (WTT), and comes in both a Professional Edition and a Lite Edition. Both are available by subscription through the NIST Standard Reference Data program (SRD). WTT - Professional Edition represents a complete collection of critically evaluated thermodynamic property data primarily for pure organic compounds. As of June, 2010, WTT contains information on 7915 compounds. WTT - Lite Edition represents a collection of critically evaluated thermodynamic property data for 150 commonly-used (primarily organic) pure compounds.

A critical resource is our extensive in-house collection of published thermodynamic and thermophysical properties, the SOURCE data system. All of the data catalogued for critical evaluation by TRC are stored in this data system. An important aspect of TRC's mission is to continue to expand this collection to make it as complete a repository as possible for all published thermodynamic and thermophysical property data.

This comprehensive mission is the evolution of the role of TRC as a source of thermodynamic data. For information on TRC's history see:

ThermoML: XML-Based Standard for Data Storage and Exchange

Efficient and reliable data dissemination is also at the core of our work and is the driver for our development of ThermoML as a standard format for data storage and exchange. We are currently partnering with five major journals to encourage authors to submit their data for validation as part of the publication process. As part of this cooperation we have created automated tools as part of the software infrastructure supporting the ThermoML standard: Guided Data Capture GDC guides authors through the process of data submission, and ThermoML Opener allows direct viewing of the data and metadata contained in a ThermoML file. All data submitted to NIST TRC through participating journals are publically available through our ThermoML Archive.

ThermoML is a new standard for thermodynamic data communication that has been developed within IUPAC Project (2002-055-3-024): XML-based IUPAC Standard for Experimentally and Critically Evaluated Thermodynamic Property Data Storage and Capture. The namespace, ThermoML, has been reserved by IUPAC.

TDE: ThermoData Engine

NIST TRC created the ThermoData Engine (NIST TDE), the first software product implementing the concept of dynamic data evaluation. This concept was itself formulated at NIST TRC. TDE is available in two editions: Standard Reference Database 103a - ThermoDataEngine - Pure Compounds only, and Standard Reference Database 103b - ThermoDataEngine - Pure Compounds, Binary Mixtures, and Chemical Reactions. The ThermoData Engine software provides critically evaluated thermodynamic and transport property data on demand using an expert system to extract data from the TRC Source data archive.