NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefuleness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply iots endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Authors: William Marion and Stephen Wilcox Artists: Jon Leedholm and Dean Armstrong Cover photographs: Warren Gretz Editor: Mary Anne Dunlap ii For use by architects and engineers, the Solar Radiation The authors acknowledge Doug Balcomb and Ron Data Manual for Buildings provides solar resource in­ Judkofffrom NREL's Buildings and Energy Systems formation for common window orientations for the Division. Their efforts were instrumental in establishing United States and its territories. This information was the content of the data manual. The authors also ac­ modeled using solar radiation and meteorological data knowledge the contributions and reviews of Steve gathered from 1961 to 1990 and will permit quick evalu­ Ternoey (Lightforms); Richard Perez (State University ations of passive solar and daylighting features for of New York); and NREL staff members Scott Crowder, buildings. Gene Maxwell, Steve Slazak, and Tom Stoffel. This manual was produced by the National Renewable Energy Laboratory's (NREL's) Analytic Studies Division under the Resource Assessment Program, which is funded and monitored by the U.S. Department of Energy's Office of Solar Energy Conversion. Approved for the National Renewable Energy Laboratory Thomas D. Bath, Director Dave Renne, Manager Analytic Studies Division Resource Assessment Program iii Preface ........................................... " ..................... " ...... .iii Introduction .................................................................... 1 Technical Background ................................................... .2 Interpreting the Data Tables ............................................ 3 Station Description .................................................... 3 Solar Radiation .......................................................... 3 Solar Radiation Graph .............................................. .4 Climatic Conditions .................................................. .4 Illuminance ............................................................... .5 Electronic Data ...............................................................6 Data Tables .....................................................................7 Appendix - Methodology .......................................... .247 Calculating Incident Solar Radiation ................... .248 Calculating Transmitted Solar Radiation ............. .249 Calculating Incident Illuminance ......................... .250 Averaging Solar Radiation and Illuminance ......... .251 Estimating Solar Radiation and Illuminance Data Uncertainty ................................................... .251 Deriving Climatic Data ........................................ .253 References .............................................................. 254 Unit Conversion Factors ............................................ 255 iv Architects and engineers use solar resource information In addition to the solar radiation and illuminance data, to help design passive solar and day lighting features for this manual contains tables listing climatic conditions bUildings. Solar resource information includes data on such as average temperature, average daily minimum how much solar radiation and illuminance are available and maximum temperature, record minimum and maxi­ for different window orientations, and how they vary. mum temperature, average heating and cooling degree days, average humidity ratio, average wind speed, and This manual provides solar radiation and illuminance average clearness index. values for a horizontal window and four vertical win­ dows (facing north, east, south, and west) for 239 sta­ The solar radiation, illuminance, and climatic data are tions in the United States and its territories. The solar presented in tables. Data for each station are presented radiation values are monthly and yearly averages for the on a single page, and the pages are arranged alphabeti­ period of 1961-1990. Included are values showing the cally by the state or territory two-letter abbreviation. solar radiation incident on the window and the amount Within a state or territory, the pages are arranged alpha­ transmitted into the living space, with and without exterior betically by city or island. shading of the window. Illuminance values are presented for average diurnal profiles for 4 months of the year. Map showing the location of the 239 stations in the National Solar Radiation Data Base from which data were used to calculate values for this manual 1 The solar radiation and illuminance data in this manual Results of a comparison of the NSRDB with the were modeled using data from the National Solar SOLMET/ERSATZ data base provide the incentive to Radiation Data Base (NSRDB) Version 1.1, which was develop new solar radiation resource products, such as completed in March 1994 by the National Renewable this data manual. On an annual basis, 40% of the Energy Laboratory (NREL). The NSRDB contains NSRDB and SOLMET/ERSATZ station values are in hourly values of measured or modeled solar radiation disagreement for global horizontal radiation by more and meteorological data for 239 stations for the 30-year than 5%; some station values show disagreement of up period from 1961-1990. A complete description of the to 18% (Marion and Myers 1992). For direct beam radia­ NSRDB and how it was produced is presented in its tion, 60% of the NSRDB and SOLMET/ERSATZ station user's manual (NSRDB-Vol. 11992) and the final tech­ values are in disagreement by more than 5%; some sta­ nical report (NSRDB-Vol. 21995). The original version tions show disagreement of up to 33%. Disagreement of the NSRDB, Version 1.0, was completed in August between the two data bases is even greater when com­ 1992. Version 1.1 corrects two types of minor errors in pared on a monthly basis. Most of the disagreement is Version 1.0 that affected about 10% of the stations attributed to differences in the instruments' calibration (Rymes 1994). procedures and models. There are two types of stations in the NSRDB: primary This manual presents solar radiation and illuminance (denoted by asterisks in the station map) and secondary values to enable quick estimates of the incident solar (denoted by dots in the station map). Primary stations, of energy for common window orientations. The solar which there are 56, measured solar radiation for a part radiation and illuminance values were computed using (from 1 to 27 years) ofthe 30-year period. The remaining models and NSRDB hourly values of direct beam, global 183 stations, designated secondary stations, made no horizontal, and diffuse horizontal solar radiation, and solar radiation measurements. Their data are modeled dew point temperature. Climatic data were obtained solar radiation values derived from meteorological data from the NSRDB and from climatic data sets provided such as cloud cover. Both primary and secondary sta­ by the National Climatic Data Center, Asheville, North tions are National Weather Service stations that collected Carolina. The Appendix describes in more detail how meteorological data for the period 1961-1990. this manual was produced. Succeeding the older 1952-1975 SOLMET/ERSATZ References data base, the NSRDB accounts for any recent climate changes and provides more accurate values of solar radia­ Marion, W.; Myers, D. (1992). A Comparison of Data tion. The NSRDB data are more accurate for several from SOLMETIERSATZ and the National Solar reasons: Radiation Data Base. NRELlTP-463-5118, Golden, CO: National Renewable Energy Laboratory. • More measured data NSRDB- Vol. 1 (1992). User's Manual-National • Better model for estimating values (More than 90% Solar Radiation Data Base (1961-1990). Version 1.0. of the solar radiation data in both data bases are Golden, CO: National Renewable Energy Laboratory modeled.) and Asheville, NC: National Climatic Data Center. • Improved instrument calibration methods NSRDB-Vol. 2 (1995). Final Technical Report: National Solar Radiation Data Base (1961-1990). • Rigorous procedures for assessing quality of data. NRELlTP-463-5784, Golden, CO: National Renewable Energy Laboratory. Rymes, M. (1994). "Beyond the NSRDB Version 1.0." Proceedings of the 1994 Annual American Solar Energy Society Conference; June 25-30,1994, San Jose, CA. 2 For each of the 239 stations, a data page contains a The diffuse radiation data in the tables do not include the . description of the station location; presents average solar direct beam radiation component. Diffuse radiation is the radiation and illuminance values for a horizontal window sum of sky radiation and radiation reflected from the and vertical windows facing north, east, south, and west; ground in