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    The SRCC is a non-profit,that provides authoritative performance ratings, certifications and standards for solar thermal products. Welcome to the SRCC, a non-profit organization whose primary purpose is to provide authoritative performance ratings, certifications and standards for solar thermal products, with the intention of protecting and providing guidance to consumers, incentive providers, government, and the industry. Our combined programs provide: Standardized comparisons of solar thermal products. One-time certification. National recognition. Product credibility.


    In November of 1980 SRCC established its certification and rating program for solar collectors. The program provides a means for evaluating the maintainability of solar collectors and a thermal performance rating characteristic of all-day energy output of a solar collector under prescribed rating conditions.

    The scope of the program includes swimming pool and recreational heating, space heating, cooling, and water heating. The program is administered according to SRCC Document OG-100, "Operating Guidelines for Certifying Solar Collectors," and its companion document, SRCC Standard 100, "Test Methods and Minimum Standards for Certifying Solar Collectors."

    Program participation is voluntary and all manufacturers of applicable products are eligible to participate in the SRCC solar collector certification program.

    Certification Requirements

    In order for a collector model to be certified and rated by SRCC, the collector must first pass a series of tests performed on a sample unit that has been randomly selected by SRCC from the manufacturer's production. The series of tests are conducted according to the methods specified in SRCC Standard 100 by an independent laboratoryapproved by SRCC.

    Testing is a combination of durability and performance with the test procedures for performance being specified by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE Standard 93, "Methods of Testing to Determine the Thermal Performance of Solar Collectors," and ASHRAE Standard 96, "Methods to Testing to Determine the Thermal Performance of Unglazed, Flat Plate, Liquid Solar Collectors.")


    SRCC calculates collector ratings according to SRCC Document RM-1, "Methodology for Determining the Thermal Performance Rating for Solar Collectors." This rating methodology utilizes the data from the ASHRAE test on the collector. The SRCC thermal performance rating is an analytically derived set of number representing the characteristic all-day energy output of the solar collector under prescribed rating conditions. It is valid only when either of the two ASHRAE standards sufficiently characterize the thermal performance of the collector panel. The SRCC rating numbers are valid only for the fluid and flow rate used to generate the test data. The ratings are only measures of performance under a specified set of conditions. Since the performance of a solar collector will vary from minute to minute, depending upon the amount of sunshine, the air temperature, the collector's tilt and orientation, etc., the purpose of the rating is to show a consumer how two or more collectors would perform under an assumed set of conditions.

    The SRCC collector performance ratings are, in some respects, analogous to energy efficiency ratings as applied to household appliances and mileage ratings as applied to automobiles. The numbers contained on the SRCC label say to the solar user that under standard conditions this collector will collect "x" number of Btus (British Thermal Units), which may or may not be as many as a competing model.



    In response to its industry participants, SRCC developed a solar water heating system rating and certification program, short-titled OG-300.

    The purpose of this solar water heating system certification and rating program is to improve performance and reliability of solar products.

    It integrates results of collector tests and system tests with evaluations against minimum standards of system durability, reliability, safety and operation; as well as factors affecting total system design, installation, maintenance and service.

    Giving suppliers the opportunity to submit their solar domestic hot water (SDHW) system designs to an open-ended review encourages them to produce the best products possible.


    Under the OG-300 system rating and certification program:

    • Systems must meet or exceed all criteria required to meet HUD Minimum Property Standards.
    • Rating includes a simple way for consumers to compare expected performance and energy savings.

    Unique features of this certification program include:

    • Evaluation of system design, safety, installation procedures, operation and maintenance manuals and system performance.
    • Rating label that is comparable to the Energy Guide Label required by the Federal Trade Commission for most gas and electric hot water heaters.

    Process for rating and certifying systems

    The process for rating and certifying solar water heating systems under the OG-300 protocol includes ten steps for each system. The process is described below and illustrated in Table 1.

    1. The "Supplier" of a solar water heating system is the entity responsible for the assembly and installation of the system. The first step in the certification process is for the Supplier to decide which components are to be included in the system. These components must be listed on an OG-300 application form.
    2. The solar collecting portion of the system must be tested. The testing to be done is determined by the system design:

    a. The collectors that are part of the system must be tested and rated under the OG-100 protocol.

    b. Passive systems in which the collector cannot be tested separately must be rated and certified under a system test protocol.

    3. A diagram must be prepared showing the relative location and interconnection of all system components.
    4. Manuals must be written to describe installation, operation, and maintenance of the system. The manuals must include a copy of the system diagram as well as all information required in section 6.6 of the OG-300 document.
    5. Labels must be prepared in accordance with OG-300. A summary of the required labels is attached to the application form.
    6. The application and all supporting documents are reviewed by SRCC staff and then forwarded to the SRCC Design Review Team for review and discussion. Major system components, the contents of the manual delivered with the system, and the suppliera™s instructions for system installation must be approved by SRCC.
    7. Data from the OG-100 collector test, the system test and review of design and installation guidelines are input to a computer program called TRNSYS to calculate the performance rating. 
    When all reviews have been completed, SRCC will notify the applicant of any outstanding items to be submitted.
    8. When the application is complete and all fees have been paid, SRCC will finalize the performance rating, prepare a new page for the directory, and mail the program agreement and/or license(s) to the Supplier for signature.
    9. Upon receipt of the signed document(s) SRCC will prepare a certification award and rating label artwork and will publish the directory pages.