Thermal Storage
ASHRAE Technical Committee 6.9

Scope of TC 6.9

TC 6.9 is concerned with the storage of thermal energy for use in heating and/or cooling and with charging or discharging this energy at a controllable rate. The TC collects and disseminates information on storage processes, materials, containers, components, systems and costs as well as on analytical methods for evaluating and predicting storage performance.


The ASHRAE Handbook is published in a series of four volumes, one of which is revised each year, ensuring that no volume is older than four years.

TC6.9 is responsible for the following handbook chapter:

Thermal storage systems remove heat from or add heat to a storage medium for use at another time. Thermal energy storage (TES) for HVAC applications can involve various temperatures associated with heating or cooling. High-temperature storage is typically associated with solar energy or high-temperature heating, and cool storage with air-conditioning, refrigeration, or cryogenic-temperature processes. Energy may be charged, stored, and discharged daily, weekly, annually, or in seasonal or rapid batch process cycles. Currently, most use of thermal storage is cool storage for comfort and process cooling applications as a way to reduce the total utility bill and/or size of cooling equipment, and much of the discussion in this chapter pertains specifically to cool storage.

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Technical committees develop and sponsor technical sessions at the winter and annual conferences. Information about their future technical program is discussed at each TC meeting and at the TC’s Program Subcommittee meeting

ASHRAE publishes papers and transactions from presentations at its conference events. In addition, ASHRAE records most of the seminar sessions from its conferences on DVD. These DVDs are ideal for use at chapter meetings, in university courses, or company lunch and learns. Products available from the most recent conference may be found here.


Technical Committees are responsible for identifying research topics, proposing research projects, selecting bidders, and monitoring research projects funded by ASHRAE. Information about their specific research program is discussed at each TC meeting and at the TC’s Research Subcommittee meeting.

TC 6.9 is responsible for the on-going research project:


The principal goals of the research are to: Identify the additional value propositions TES provides for buildings, campuses (or micro-grids), and power systems that have large penetrations of as-available renewable energy. Develop a methodology to evaluate those value propositions.


ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry. ASHRAE publishes the following three types of voluntary consensus standards: Method of Measurement or Test (MOT), Standard Design and Standard Practice. ASHRAE does not write rating standards unless a suitable rating standard will not otherwise be available. ASHRAE is accredited by the American National Standards Institute (ANSI) and follows ANSI's requirements for due process and standards development. Standards may be purchased at the ASHRAE Bookstore.

TC 6.9 is cognizant for the following standards:
Std.94.2:  Method of Testing Thermal Storage Devices with Electrical Input and Thermal Output Based on Thermal Performance
Std.150: Method of Testing the Performance of Cool Storage Systems

Other Activities

TIP: If MTG involvement add here otherwise leave blank.

TC 6.9 participates in these multidisciplinary task groups:

Avoided Sources of Energy Consumption Due to Waste Heat Recovery and Heat Pumping Technologies
MTG.ASEC will coordinate development of credible quantification methodologies of the avoided electric power generation and/or primary energy consumptions resulting from the application of heat pump and waste energy recovery technologies. 

Hot Climate Design Guide
MTG.HCDG will coordinate TC/TG/TRG technical Activities to help support the development of the technical basis and adoption of the Hot Climate Design Guide. Responsibilities include suggestions for Research, Development and Presentations and special publications detailing aspects of the Hot Climate Design Guide.


ASHRAE Technical FAQs are provided as a service to ASHRAE members, users of ASHRAE publications, and the general public. While every effort has been made to ensure their accuracy and reliability, they are advisory and provided for informational purposes only, and in many cases represent only one person’s view. They are not intended and should not be relied on as an official statement of ASHRAE. Technical questions not addressed may be submitted to the ASHRAE Technical Services department at