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BUILDING LOADS DISCUSSION

This section presents an analysis of residential building loads under steady ambient conditions in order to provide further insight for the predicted results for the 2700 simulation runs.

Test Conditions

As mentioned earlier, TARP has the capability to determine heating and cooling requirements for a conditioned space for a single "design day." Two new environment input files were prepared for heating and cooling that specified fixed ambient temperatures of -1.1 °C (30 °F) and 26.7 °C (80 °F), respectively. A clear sky condition was selected and a geographic location 40 degrees latitude and 90 degrees longitude (near Springfield, Illinois) was selected arbitrarily. The annual ground temperature for this location was obtained from Kusuda (1981). The date for the analysis was chosen as 21 September to provide equal parts of daylight and night. A transient solar profile was provided by a built-in function of TARP and the proportion of solar beam and diffuse radiation was determined by a correlation function. Examples of the input files are presented in Appendix C.

Test Plan

The experimental plan was a full factorial design for the three factors shown in Table 12. The total number of runs is 12 (=2x3x2). The roof solar reflectance was varied at 3 levels from 0.1 to 0.8 and the ceiling R-value was varied at one of two values; either "none" (uninsulated attic) or R¬6.7 m2•K/W (R-38 ft2-°F•h/Btu). The attic ventilation rate and mass framing area were fixed at 0.5 air changes per hour and 38.7 m2 (417 ft2) (see Table 7). All other input factors - site and shading, interior thermostat settings, internal load, etc. - were the maintained at the same settings as the previous simulation runs (see Residential Models).

Reflective Roof NIST Report 1998 Factor and Levels for Constant Ambient Test Conditions

Effect of Roof Solar Reflectance on Building Loads

For each run, two response variables were determined: heating and cooling load. Figure 25 plots the predicted loads for both heating and cooling as a function of roof solar reflectance under constant ambient temperature conditions. The effect of ceiling R-value was treated parametrically and varied from "none" (i.e., uninsulated attic) to R-6.7 m2.K/W (R-38 ft2•°F-h/Btu). The trends in Figure 25 for heating and cooling are quite similar to those observed in Figures 13 through 18 for annual loads. In general, at higher values of roof solar reflectance, the heating load increased and, conversely, the cooling load decreased. Note that for cooling, the loads for the insulated (R-6.7 m2•K/W [R-38 ft2-°F-h/Btu)) attic and uninsulated case cross over at values of roof solar reflectances of p>0.7.  As mentioned earlier, this condition seems somewhat counter-intuitive and was investigated further.

For a roof solar reflectance of 0.8, the hourly profiles for the cooling load, attic air temperature, and outside heat flux for the south face of the roof are plotted in Figure 26 for the insulated and uninsulated cases. In Figure 26a, note that the hourly cooling load for the uninsulated case is greater than the insulated case only for the hours of 09:00 (9AM) to 19:00 (7PM), essentially the sunlit hours of the cycle. During the rest of the diurnal cycle (night hours), the cooling load for the uninsulated case is less than the insulated case. In fact, for the hours 03:00 (3AM) to 06:00 (6AM), the hourly cooling load for the uninsulated case is zero - no cooling required. The net difference between the curves represents the difference in cooling loads observed in Figure 25 at p = 0.8. Additional insight is provided by Figures 26b and 26c, which show that the ambient air temperature and heat flux of the outside south roof face are also greater for the uninsulated case for most of the diurnal cycle.

The results shown in Figure 26 are indicative of night-time radiative cooling of the structure. Essentially, the building's exterior surfaces "see" a clear-sky effective temperature of 13 °C (55 °F), as determined in the simulation by TARP. Heat conducted through the building envelope warms the exterior surfaces resulting in long-wave radiation exchange with the clear-sky. An increase in the temperature of the exterior surface increases the radiant heat exchange with the surroundings. This effect is illustrated in Figures 26b and 26c. Recall that the thermostat for the interior space is maintained at 25.6 °C (78 °F) under cooling conditions. At night, the heat loss through the ceiling warms the attic air. For the uninsulated case, the air temperature is approximately 1.5 °C (2.7 °F) greater than the insulated case during the night hours (Figure 26b). This elevated attic air temperature warms the roof and results in an increase in the outside heat flux of the roof (Figure 26c). The presence of the ceiling insulation reduces the effect of night-time radiative cooling.

Figure 26 shows two counter effects, radiative cooling of the roof during night hours and solar gain during sunlit hours. For the given inputs to the model it would seem, as evident above and in the previous plots (Figures 13 through 18), that radiative cooling is important for the simulations presented in this report, particularly at higher values of roof solar reflectance. This may not be the case, however, if the inputs to the model were changed or modified. For example, the thermostat control of most residential buildings, in practice is probably set lower than the prescribed value of 25.6 °C (78 °F) given in ASHRAE 90.2-1993 (ASHRAE 1993). As a check, the thermostat setting for cooling was reduced to 21.1 °C (70 °F) and the above runs repeated; all other conditions the same.

Reflective Roof NIST Report 1998 Predicted Loads Under Constant Ambient Conditions

Reflective Roof NIST Report 1998 Hourly Load Attic Temperature and Heat Flux Profile


The resulting predicted cooling loads for uninsulated and insulated cases did not intersect as noted above in Figure 25.

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ROOF TEMPERATURES

Additional computer simulations were conducted for each geographic location to provide predicted exterior temperatures of the roof surface at hourly intervals. Again, one year (8760 hours) of input WYEC weather data was utilized. However, in these runs, the TARP models were modified to provide hourly output of the exterior roof temperatures. Because of the large amount of output data, the test plan was limited to only 30 simulation runs. The predicted temperatures are presented graphically as described below.

Test Plan

The experimental plan was a full-factorial design for the two factors shown in Table 7. The full factorial design consisted of all possible combinations of levels of the two factors, so the total number of runs is 30 (=6x5). For each geographic location, the primary factor, roof solar reflectance, was varied at 5 levels from 0.1 to 0.8. The ceiling insulation levels were set to their respective "base case" values of R-5.3 m'IC/W (R-30 h-ft2-°F/Btu) for Miami and R-6.7 m2K/W (R-30 Irfe.°F/Btu) for all other locations. The attic ventilation rate was fixed at a low constant rate of 0.5 air changes per hour for all simulation runs.

Reflective Roof NIST Report 1998 Factor and Levels for Exterior Roof Temperature Analysis

 
Effect of Solar Reflectance on Roof Temperature

The effect of solar reflectance on the exterior roof temperatures was investigated using graphical analysis commonly known as a box plot. Figure 27 shows a series of box plots for each city. Each box plot represents a statistical summary by percentile of 8760 hours of temperature data for one simulation run. In other words, the temperature data has been mapped to a percentile basis from 0 to 100 (minimum predicted temperature to maximum) and plotted on that basis. For each city, the exterior temperature of the roof is plotted on the y-axis and the five levels of solar reflectance, on the x-axis. The box plot for each simulation of 8760 hours is constructed as follows: the bottom tic is the minimum temperature (of the simulation); the lower solid circle is the estimated 5 % point; the bottom of the box is the estimated 25 % point; the x is the median (50 %); the top of the box is the estimated 75 % point; the upper solid circle is the estimated the 95 % point; and, the upper tic is the maximum temperature. So, for example, the 95 % point means that approximately 95 % of the 8760

eflective Roof NIST Report 1998 Box Plot Roof Temperatures by City


roof temperatures are below that data point and 5 % are above. The upper tic mark represents the peak roof temperatures. As noted in Figure 27, only the roof temperatures above the median decreased as the solar reflectance increased from 0.1 to 0.8 (Figure 27). The implication is that the higher temperatures occurred during sunlight hours and, parenthetically, the low temperatures were during night and unaffected by changes in roof solar reflectance. At the estimated 95 % point and above, the decrease was substantial. For example, at Miami, the estimated 95 % point decreased from approximately 64 °C at p = 0.1 to 37 °C at p = 0.8 for a decrease of 27 K (49 °F). The estimated 95 % point temperatures for other locations are summarized in Table 14.

Reflective Roof NIST Report 1998 Predicted Exterior Roof Temperatures


Examination of the exterior temperature profiles provides further insight to the effect of the roof solar reflectance. Figure 28 illustrates the effect of solar reflectance on the daily temperature profile for a typical summer day (18 July) for each city. In each case, the temperature of the roof decreased substantially during sunlit hours as the solar reflectance increased. For Phoenix, the peak roof temperature (at hour 12) decreased about 40 K (72 °F) when p was increased from 0.1 to 0.8. (Note that the jagged changes in the profiles for Birmingham and Bismarck were due to the presence of cloud cover.) Figure 29 illustrates the seasonal effect of solar reflectance on the monthly average roof temperatures for the one-year simulation of weather data. In general, the exterior roof temperatures increased during spring and summer, and decreased during the autumn and winter. The effect of the solar reflectance was generally greater in summer months, as would be expected.

Reflective Roof NIST Report 1998 Daily Roof Temperature Profile for 18 July

 

Reflective Roof NIST Report 1998 Average Monthly Roof Temperatures

 ECONOMIC DISCUSSION
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 Reflective roofs can provide a number of benefits. For utility companies, buildings with reflective roofs can help reduce the annual and peak cooling loads that the utilities must provide. For manufacturers of roofing materials, reflective roofs can reduce peak roof temperatures and thereby perhaps increase the service life of their product. For a homeowner, reflective roofs may in fact reduce the annual cost of cooling but may also increase the annual cost of heating. While a complete analysis of the advantages and disadvantages of solar reflective roofs is outside the scope of this report, a comparison of the annual energy costs can provide information about the conditions under which reflective roofs are cost effective to homeowners.

This section provides a simple comparative analysis of the annual energy costs for the ranch-style house with different levels of roof solar reflectance and ceiling insulation. The costs are computed for six different U.S. climates, using local residential utility rates and the TARP annual heating and cooling loads. Local residential utility rates for the summer of 1994 and winter 1994-1995 were obtained from the 17th nationwide survey of residential utility bills conducted by the National Association of Regulatory Utility Commissioners (NARUC 1995, 1996). Table 15 summarizes the average electric and gas rates for the six cities of interest for the summer of 1994 and winter 1994¬1995


Reflective Roof NIST Report 1998 Average Local Utility Rates


Recall that only annual (sensible) cooling loads for Miami, Phoenix, Birmingham, Washington, D.C., Portland ME, and Bismarck have been presented previously. In order to determine the total (sensible and latent) cooling load for each location, latent cooling loads for Miami, Phoenix, Birmingham, Washington, D.C., Portland ME, and Bismarck were determined by running additional TARP computer simulations. For these simulations, the relative humidities in the residences were limited to 60 % RH (ASHRAE Standard 90.2-1993). Because the latent load was essentially independent of the previously investigated parameters, only one run was conducted for each location. The solar reflectance of the roof, the attic ventilation, and attic mass framing area were fixed at 0.45 (mid¬level), 0.5111 (lowest level), and 38.7 m2 (mid-level), respectively. The residential building models utilized insulation levels set to their respective "base case" (Table 3). For these conditions, the annual latent cooling load for Miami, Phoenix, Birmingham, Washington, D.C., Portland ME, and Bismarck were determined to be approximately 11,700 MJ, 560 MJ, 4,400 MJ, 3,100 MJ, 970 MJ, and 160 MJ, respectively. The total (sensible and latent) annual cooling loads were determined by combining the annual sensible cooling loads (see Figures 13 to 18) and annual latent cooling loads for each location.

The annual energy costs for heating and cooling were computed by assuming performance efficiencies for electric and gas equipment. The annual heating load was considered to be entirely satisfied by either electric resistance HVAC equipment or a gas furnace. The (local) performance efficiency of the electric equipment was assumed to be unity (1.0). The minimum requirement for the "annual fuel utilization efficiency" (AFUE) of the gas furnace was taken as 78 %, based on specifications in ASHRAE Standard 90.2-1993. For the cooling equipment, a "seasonal energy efficiency ratio" SEER of 10 was assumed (ASHRAE Standard 90.2-1993). The author acknowledges that the COP, varies with location (due to outdoor temperature) and application, but for simplicity only a single value was used for the economic analysis. Recall, also that the air distribution system was assumed to be located within the conditioned space and, therefore, any thermal losses were neglected. The annual energy costs for heating and cooling for Miami, Phoenix, Birmingham, Washington, D.C., Portland ME, and Bismarck are illustrated graphically in Figures 30 to 35, respectively. Each figure plots annual energy cost in U.S. (1994-1995) Dollars ($) on the y-axis and solar reflectance of the roof on the x-axis for different levels of ceiling thermal resistance. These figures provide a relatively quick assessment whether the reflective roof can reduce annual energy costs for a given location. In general, if the slopes of the curves are negative (i.e., slope down with increasing solar reflectance), then a reflective roof reduces costs. Indeed, the greater the slope, the higher the potential savings. If the slopes of the lines are either horizontal (zero slope) or positive, then the effect is either inconsequential or detrimental (i.e., heating penalty results in higher cost), respectively.

As noted in Figures 30 and 31 for Miami and Phoenix, respectively, increasing the solar reflectance of the roof reduced the annual heating and cooling costs regardless of energy source and, in particular, for the case when the attic is uninsulated (i.e., "none"). In fact, for the uninsulated case, the annual heating and cooling savings for Miami and Phoenix were substantial, on the order of $100, or more by increasing the solar reflectance from 0.1 to 0.8. For the other locations, the reduction in annual energy costs depended on the cost of heating energy, particularly for the heating dominated climates of Portland ME and Bismarck. For Portland ME and Bismarck, the effect was mostly inconsequential (i.e., very small effect) regardless of type of heating. In intermediate cooling climates such as Birmingham or Washington D.C., however, the effect depended on the type of heating. For gas heating, increasing the solar reflectance of the roof for an uninsulated attic reduced the annual heating

Reflective Roof NIST Report 1998 Miami Florida Annual Heating and Cooling Costs

Reflective Roof NIST Report 1998 Phoenix Arizona Annual Heating and Cooling Costs

 

Reflective Roof NIST Report 1998 Birmingham Alabama Annual Heating and Cooling Costs


Reflective Roof NIST Report 1998 Washington DC Annual Heating and Cooling Costs


Reflective Roof NIST Report 1998 Portland Maine Annual Heating and Cooling Costs


Reflective Roof NIST Report 1998 Bismarck North Dakota Annual Heating and Cooling Costs

and cooling costs for Birmingham and, to a lesser extent, for Washington D.C. It is important to note, however, that for the well-insulated residences (i.e., base case ceiling levels of thermal insulation), the annual energy savings were less.

At least three important factors qualify the analysis. First, Figures 30 through 35 do not include the initial costs of a reflective roof; these costs may vary significantly. A more complete analysis which includes initial costs is necessary to determine whether reflective roofs are indeed life-cycle cost effective to homeowners. Second, it is yet to be determined whether reflective roofs can, in practice, sustain the higher levels of solar reflectance (p z 0.7) shown in the figures. Roofs with this level of reflectivity may be cost effective but additional factors may have to be considered such as periodic cleaning, re-coating, etc. Finally, the analysis is valid only for the models examined. The results may not apply to other building geometries or geographical locations outside the conditions shown in Figure 1 or 2.

SUMMARY AND CONCLUSIONS
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Annual heating (cooling) loads, peak heating (cooling) loads, and exterior roof temperatures have been computed for a small one-story "ranch style" house using the Thermal Analysis Research Program (TARP). Thermal performance requirements for the house were based, in part, on the prescriptive criteria established in ASHRAE Standard 90.2-1993 (ASHRAE 1993). The model, with minor modifications in the thermal envelope for different geographic locations, was subjected to hourly weather data compiled in the Weather Year for Energy Calculations (Crow 1981) for locations: Birmingham, Alabama; Bismarck, North Dakota; Miami, Florida; Phoenix, Arizona; Portland, Maine; and, Washington D.C. These geographic locations were specifically selected to examine the extreme and mid-climatic conditions in the contiguous United States.

Building Loads

The results of the building load analysis can be summarized as follows.

• Geographic Location: Of the five factors studied - roof solar reflectance, geographic location, ceiling thermal resistance, attic ventilation, and attic mass framing area - geographic location had the greatest global effect on annual heating (cooling) and peak heating. Increasing the ceiling thermal resistance from none to R-8.6 m2•K/W (R-49 h-ft2•°FBtu) had the greatest global effect on peak cooling.

• Ceiling Thermal Resistance: In almost all geographic locations, the effect of increasing the ceiling thermal resistance was beneficial. That is, for higher levels of thermal insulation, both the annual and peak heating (cooling) loads were reduced, although, in general, the effects diminished as the levels of ceiling thermal resistance increased.

• Roof Solar Reflectance: In all geographic locations, the effect of increasing the roof solar reflectance 1) reduced annual and peak cooling loads, 2) was insignificant for peak heating loads, and 3) detrimental (meaning increased requirements) for annual heating loads. Further, the lowest annual cooling load was obtained at the highest level of roof solar reflectance. An analysis of the subset of the annual and peak heating (cooling) data for each geographic location indicated the following:

     *  The effect of increasing the roof solar reflectance appeared to result in a linear decrease in cooling load requirements.

     *  The greatest effect of increasing the roof solar reflectance was for the case of an uninsulated attic. For higher levels of ceiling thermal resistance, increasing the roof solar reflectance reduced the annual and peak cooling loads, but to a lesser extent.

• Attic Ventilation: In all geographic locations, the effect of increasing the attic ventilation provided beneficial results for annual and peak cooling loads and detrimental results (meaning increased requirements) for annual and peak heating loads. It is important to note, however, that other considerations such as moisture control should be considered in determining the proper ventilation rates for an attic.

• Attic Mass Framing Area: In all geographic locations, the effect of the attic mass framing area was inconsequential.

• Constant Ambient Conditions Analysis: An extended analysis of building loads was conducted using the building model at an arbitrary site subjected to a transient solar profile and steady ambient conditions of either -1.1 °C (30 °F) for heating or 26.7 °C (80 °F) for cooling.

     *  The behavior of the predicted heating and cooling loads under steady ambient conditions was similar to the annual loads computed for hourly weather data.
      *  Radiative cooling of the structure at night significantly affected the cooling load and was particularly noticeable at high values of roof solar reflectance. The presence of thermal insulation in the ceiling reduced the effect of night-time radiative cooling.

Exterior Roof Temperatures

The results of the exterior roof temperature analysis for one year of weather data are summarized as follows.

• Statistical Summary: The exterior surface roof temperatures above the median value decreased when the roof solar reflectance was increased. Surface temperatures at the 95 % level and above were reduced substantially.

• Daily and Average Monthly Profiles: These profiles verified that the peak exterior roof temperatures were reduced substantially by increasing the roof solar reflectance.

Economic Analysis

The results of the economic cost analysis are summarized as follows.

• Miami and Phoenix (Hot Climates): Substantial annual cost savings were realized for the case of an uninsulated attic for both gas or electric heating. For higher levels of ceiling thermal resistance, smaller annual cost savings were also evident.

• Birmingham and Washington D.C. (Intermediate Climates): Annual cost savings for Birmingham and, to a lesser extent Washington D.C., were realized for the case of an uninsulated attic and for gas heating.

• Portland ME and Bismarck (Cold Climates): Annual cost savings were generally small in all cases.
 

ACKNOWLEDGMENTS
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The author appreciates the many discussions with several individuals, including: Doug Burch and George Walton for modeling and execution of TARP; to Dale Bentz for development of the BASIC computer programs for pre- and post-processing of the TARP input and output files; to Dr. James Filliben for planning the experimental design and analyzing the resulting data; to Dr. Mark Ehlen and Brian Dougherty for assistance with the economic analysis; and, to Dr. Hunter Fanney for his review of the manuscript.
 
REFERENCES
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Akbari, H., Rosenfeld, A.H. and H. Taha. "Cool Construction Materials Offer Energy Savings and Help Reduce Smog," ASTM Standardization News, November 1995, pp. 32-37.

ASHRAE. "ASHRAE 90.2-1993, ASHRAE Standard: Energy-Efficient Design of New Low-Rise Residential Buildings," American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, Georgia 1993.

ASHRAE. 1993 Handbook of Fundamentals, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, Georgia, 1993.

Berhdahl, P. "Technical Issues for the Development of Cool Materials," Cool Building Materials Workshop, NIST, Gaithersburg, Maryland, February 1994.

Bretz S. And H. Akbari. "Field measurements of Solar Reflectance and Aging of White Roof Coatings," Cool Building Materials Workshop, NIST, Gaithersburg, Maryland, February 1994.

Burch D.M., Tsongas, G.A. and G.N. Walton. "Mathematical Analysis of Practices to Control Moisture in the Roof Cavities of Manufactured House," NISTIR 5880, National Institute of Standards and Technology, Gaithersburg, Maryland, August 1996.

Burch, D.M., Walton, G.N., Licitra B.A., and K. Cavanaugh. "Comparison of Measured and Predicted Sensible Heating and Cooling Loads for Six Test Buildings," NBSIR 86-3399, National Institute of Standards and Technology, Gaithersburg, Maryland, 1986.

Buchan, Lawton, Parent Ltd. "Survey of Moisture Levels In Attics," Canada Mortgage Corporation BLP File No. 2497, March 1991.

Carroll, J.A. "An `MRT Method' of Computing Radiant Energy Exchange in Rooms," Proceedings of the 2nd Systems Simulation and Economics Analysis Conference, 1980.

Crow, L.W. "Development of Hourly Data for Weather Year for Energy Calculations (WYEC)," ASHRAE Journal, 1981 October. Vol. 23, No. 10, pp. 37-41.

Department of Energy. "Insulation Fact Sheet," DOE/CE-0180, 1987.

Department of Energy. "Housing Characteristics 1990," DOE/ETA-0314(901, May 1992, p. 27.

Filliben, J.J. "Dataplot, Introduction and Overview," NBS Special Publication 667, National Institute of Standards and Technology, Gaithersburg, Maryland, June 1984.

Givoni, B. Man, Climate, and Architecture, Elsevier Publishing Company Limited, Amsterdam, 1969, p. 199.
 
Griggs, E.I. and G.E. Courville. "Changes in the Heating and Cooing Energy Use in Buildings Due to Lowering the Surface Solar Absorptance of Roofs," ORNL/TM-10339, Oak Ridge National Laboratory, Oak Ridge, Tennessee, February 1989.

Hastings, S.R. "Three Proposed Typical House Designs For Energy Conservation Research," NBSIR 77-1309, National Institute of Standards and Technology, Gaithersburg, Maryland, October 1977.

Kusuda T. "Heat Transfer Analysis of Underground Heat and Chilled-Water Distribution Systems," NBSIR 81-2378, National Institute of Standards and Technology, Gaithersburg, Maryland, November 1981.

NARUC. "Residential Electric Bills: Summer 1994," National Association of Regulatory Utility Commissioners, Washington D.C., June 2, 1995.

NARUC. "Residential Electric Bills: Winter 1994-95," National Association of Regulatory Utility Commissioners, Washington D.C., December 1, 1995.

NARUC. "Residential Gas Bills: Winter 1994-95," National Association of Regulatory Utility Commissioners, Washington D.C., January 18, 1996.

Parker, D.S., Cummings, J.B., Sherwin, J.R., Stedman, T.C. and J.E.R. McIlvaine. "Measured Residential Savings from Reflective Roof Coatings in Florida," ASHRAE Transactions, V. 100, Pt. 2, 1994.

Parker, D.S., Huang, Y.J., Konopacki, S.J., Gartland, L.M., Sherwin, J.R. and L.Gu. "Measured and Simulated Performance of Reflective Roofing Systems in Residential Buildings," ASHRAE Transactions, V. 104, Pt. 1, 1998.

Reagan, J.A. and D.M. Acklam. "Solar Reflectivity of Common Building Materials and Its Influence on the Roof Heat Gain of Typical Southwester USA Residences,"  Energy and Buildings, 1979, pp. 237-248.

Samuelson I. "Moisture Control in Crawl Spaces," ASHRAE Technical Data Bulletin, Vol. 10, No.3, January 1994, pp. 58-64.

Walton, G.N., "Thermal Analysis Research Program - Reference Manual," NBSIR 83-2655, National  Bureau of Standards, National Institute of Standards and Technology, Gaithersburg, Maryland, March 1983, Update 1985.

Walton, G.N. and K. Cavanaugh. "Validation Tests of the Thermal Analysis Research Program," NBSIR 85-3211, National Institute of Standards and Technology, Gaithersburg, Maryland, July 1985.
 
Yarbrough, D.W. "Solar Reflectance Measurements for Twenty Custom-Blended Radiation Control Coatings," Cool Building Materials Workshop, MST, Gaithersburg, Maryland, February 1994.
 

APPENDIX A
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 Environment input data prepared for Miami, Florida. Note, the dollar ($) symbol specifies a comment for TARP.

$ EF1 Environment Input File - use in conjunction with BD1
$ Project: Assessment of Reflective Roof Coatings
$ Location: Miami, Florida
$
$ Ground temperatures were taken from Appendix A, NBSIR 81-2378, "Heat
$ Transfer Analysis of Underground Heat and Chilled-Water Distribution
$ Systems". Geographic data was taken from the 1993 ASHRAE Fundamentals
$ Handbook, Chapter 24. Weather data were taken from ASRHRAE Weather
$ Year for Energy Calculations (WYEC). Site number identifies the weather
$ recording site.
$
RC(DEM/UIN=ENGLISH/UOUT=ENGLISH)
LOC(DESC='MIAMI, FLORIDAYLATD=25.8/LONG=80.3/TZ=5/ALT=7)
GRND(GRT=12*75.0)
WTAP(DESC=WYEC DATA FOR MIAMUTYPE=WYEC/SITE=12839)
$
 
APPENDIX B
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Building Description Input File prepared for Miami, Florida. Note, the dollar ($) symbol specifies a comment for TARP.

$ BD1
$ Building Description Input File - use in conjunction with EF1 $ Project: Assessment of Reflective Roof Coatings
$ Location: Miami, Florida
$ Data will be converted from English units input to Metric for the simulation and reports.
PROJECT[
RC(DEWUIN=ENGLISH/UOUT=METRIC/DESC=ASSESSMENT OF REFLECTIVE ROOF COATINGS') RPT(DAILY/WIDTH=80)
$ Heating and cooling day schedules are specified according to ASHRAE Standard 90.2.1993: 20°C (68°F) for
$ heating with night setback of 15.6°C (60°F); and 26°C (78°F) for cooling. Daily internal gains for occupancy,
$ lighting, and equipment were based on the profile provided in ASHRAE Standard 90.2-1993, Table 8-1.
$ Infiltration air day schedules were assumed constant. The building envelope above grade is wood-frame
$ construction with a crawl space foundation. Thermal transmission properties for materials are taken from
$ the 1993 ASHRAE Fundamentals Handbook. Solar absorptance for exterior surfaces is 0.5, per 90.2-1992,
$ except roof asphalt shingles. The solar absorptance (a=A) of the roof asphalt shingles varies from A=0.90
$ non-reflective, to A=0.80, reflective. Infrared emittance, e=0.9.
LIBRARY [
$ LIB(ALL) $ Remove comment for detailed library reports.
DS(NAME=H1/DESC='ZONE2 HEATING SETBK/T=6*60.0,17*68.0,1*60.0) DS(NAME=C1/DESC='ZONE2 COOLING TEMPSYT=24*78.0) DS(NAME=OC/DESC='ZONE2 OCCUPANCY'/FFC=0.5,4*0.45,0.55,3*0.8,2*0.95,8*0.8,
3*0.7,0.6,0.5)
DS(NAME=LT/DESC=20NE2 LIGHTINGTFC=5*0.05,0.1,0.25,0.5,0.4,0.2,6*0.0,0.3,
2*0.55,0.5,2*0.45,0.35,0.1)
DS(NAME=EQ/DESC='ZONE2 EQUIPMENT/FFC=0.19,0.17,3*0.16,2*0.17,0.33,0.35,
0.51,0.65,0.48,0.47,0.23,0.20,0.24,0.45,2*0.38,2*0.25,0.33,0.26,0.19) DS(NAME=IN/DESC='INFILTRATIONTFC=24*1.0)
WS(NAME=HEAT/DESC='HEATING'/ALL=H1)
WS(NAME=COOUDESC='COOLINGYALL=C1)
WS(NAME=OCCU/DESC='OCCUPANCYIALL=0C)
WS(NAME=LAMP/DESC='LIGHTING '/ALL=LT)
WS(NAME=EQPT/DESC='EQUIPMENT/ALL=EQ)
WS(NAME=INFUDESC=INFILTRATIONYALL=IN)
MATL(NAME=AOR/DESC='AIR SPACE RESISTANCE'/R=0.91/AIR)
MATL(NAME=ASP/DESC='ASPHALT ROOF SHINGLE/K=0.0236/D=70.0/CP=0.30/A=0.25/E=0.9) MATL(NAME=CRP/DESC='CARPET & PAD'/R=1.23)
MATL(NAME=CMU8/DESC.'8 CMU, OPEN CORE/K=0.654/D=136.0/CP=0.22/A=0.5/E=0.9) MATL(NAME=FLT/DESC='FELT BUILDING MEMBRANE'/R=0.06) MATL(NAME=FSH/DESC='FIBERBOARD SHEATHING'/K=0.0317/D=18.0/CP=0.31)
MATL(NAME=R19/DESC='FGL R19 INSULATIONIR=19.0) MATL(NAME=R30/DESC=TGL R30 INSULATION'/R=30.0) MATL(NAME=R38/DESC='FGL R38 INSULATION'/R=38.0) MATL(NAME=R49/DESC='FGL R49 INSULATION'/R=49.0) MATL(NAME=R11/DESC='FGL R11 WALL INSULATION'/R=11.0) MATL(NAME=R13/DESC='FGL R13 WALL INSULATION'/R=13.0) MATL(NAME=R15/DESC='FGL R15 WALL INSULATION'/R=15.0) MATL(NAME=GLS/DESC='GLAZING, SINGLE 1/8 PANE'/GLASS/R=0.28/SC=0.5) MATL(NAME=GLD/DESC='GLAZING, DOUBLE 1/8 PANE/GLASS/R=1.98/SC=0.7) MATL(NAME=GYP/DESC='GYPSUM WALLBOARINK=0.0925/D=50.0/CP=0.26) MATL(NAME=PLY/DESC='PLYWOOD FIR SHEATHING7K=0.0672/D=34.0/CP=0.29)
 MATL(NAME=XPS/DESC='POLYSTYRENE SHEATHING1K=0.0167/D=2.7/CP=0.29) MATL(NAME=WOD/DESC=SOFTWOOD FRAMINGYK=0.0667/D=38.0/CP=0.39) MATL(NAME=DRT/DESC='SOIL, TYPICALYK=0.8/D=120.0/CP=0.2/A=0.7) MATL(NAME=SND/DESC='STONE, LIME, SAND FILL/K=2.0/D=140.0/CP=0.2) MATL(NAME=WSD/DESC=WOOD SIDING, LAPPEDYK=0.0513/D=27.0/CP=0.28/A=0.5/E=0.9) MATL(NAME=DOR/DESC='WOOD DOOR, SOLID CORE/R=1.65/A=0.5/E=0.9) CONS(NAME=WALL1A/DESC='EXTERIOR FRAME WALL, CAVITY INSULATION'/
MATL=0.0417,WSD,0.0833,XPS,0.0,R15,0.0417,GYP/ORGH=6) CONS(NAME=WALL1B/DESC='EXTERIOR FRAME WALL, 2 by 4 STUD'/
MATL=0.0417,WSD,0.0833,XPS,0.292,WOD,0.0417,GYP/ORG H=6) CONS(NAME=WALL2/DESC='CRAWL SPACE WALL'/
MATL=0.6354,CMU8/ORGH=2)
CONS(NAME=WALL3A/DESC='ATTIC GABLE WALL, CAVITY/ MATL=0.0417,WSD,0.0417,FSH/ORGH=6)
CONS(NAME=WALL3B/DESC='ATT1C GABLE WALL, 2 by 4 STUD/ MATL=0.0417,WSD,0.0417,FSH,0.292,WOD/ORGH=6)
CONS(NAME=CEIL1A/DESC='ATTIC FLOOR ZONE1, CAVITY INSULATION/ MATL=0.0417,GYP,0.0,R38)
CONS(NAME=CEIL1B/DESC=ATTIC FLOOR ZONE1, 2 by 4 TRUSS JOIST/ MATL=0.0417,GYP,0.292,WOD)
CONS(NAME=CEIL2A/DESC=10EILING ZONE2, CAVITY INSULATION'/
MATL=0.0,R38,0.0417,GYP)
CONS(NAME=CEIL2B/DESC='CEILING ZONE2, 2 by 4 TRUSS JOIST/
MATL=0.292,WOD,0.0417,GYP)
CONS(NAME=ROOF1A/DESC='ASPHALT SHINGLE ROOF, CAVITY/ MATL=0.0208,ASP,O,FLT,0.0521,PLY/ORGH=3)
CONS(NAME=ROOF1B/DESC='ASPHALT SHINGLE ROOF, 2 by 4 RAFTER'/ MATL=0.0208,ASP,O,FLT,0.0521,PLY,0.292,WOD/ORGH=3)
CONS(NAME=FLOOR2A/DESC='FRAME FLOOR ZONE2, CAVITY INSULATION'/ MATL=0.0, R19,0.0521, PLY,O,CRP)
CONS(NAME=FLOOR2B/DESC='FRAME FLOOR ZONE2, 2 by 10 FLOOR JOIST/ MATL=0.792,WOD,0.0521,PLY,O,CRP)
CONS(NAME=FLOOR3A/DESC='FRAME FLOOR ZONE3, CAVITY INSULATION/ MATL=0,CRP,0.0521,PLY,0.0,R19)
CONS(NAME=FLOOR3B/DESC='FRAME FLOOR ZONE3, 2 by 10 FLOOR JOIST/ MATL=0,CRP,0.0521,PLY,0.792,WOD)
CONS(NAME=PART/DESC='PARTITION WALL/MATL=0.0417,GYP,0.0,AOR,0.0417,GYP) CONS(NAME=DOOR/DESC='SOLID WOOD DOORI/MATL=0.0,DOR)
CONS(NAME=TRUSS/DESC=ATTIC WOOD TRUSSYMATL=0.125,WOD/ORGH=4) CONS(NAME=CRSPFUDESC=1CRAWL SPACE FLOORMATL=1.0,DRT,0.333,SND) CONS(NAME=WINDOW/DESC=SINGLE PANE GLAZING'/MATL=0.0,GLS/ORGH=6)
$ The house is divided into three zones. Zone 1 is a vented attic; Zone 2, a conditioned living space; $ and Zone 3, a vented crawl space. Report variables, when needed, are ambient air (averge) and building $ consumption values. Simulation parameters are as follows: 1) default values for convergence criteria for $ temperature (0.05K, 0.01°F), heating and cooling loads (0.01 W), minimum load, and maximum number of $ iterations; 2) simple air flow algorithm (Flow = 0, default); 3) shading from 'SHD' surfaces only;
$ 4) heat balance method computed at the beginning of each time step; 5) detailed MRT network algorithm; $ and, 6) detailed algorithms for exterior and interior surface coefficients.
BUILDING [
SIM(ZON=ZONE1,ZONE2,ZONE3/SYS=LOADS/
CNVG=0.09,0.01,0.34,6/SLDS=0/HTB=0/RIM=2JHO=2/H1=2)
$ ZONE1 - attic. The volume of the attic is calculated on a net basis by subtracting the truss volume (22
$ members). Infiltration rates are taken from, "Survey of Moisture Levels In Attics" by Buchan, Lawton, &
$ Parent, Ltd and ranged from 0.5 to 10 air changes per hour. The surface mass is based on 22 trusses.
$ Framing percentages for 600 mm (24") O.C. trusses are 7 percent (93 percent cavity). Gable wall framing
$ percentages are 15 percent (85 percent cavity). The framing in the gable walls is handled as a
$ subsurface. Parallel paths for heat flow are assumed for the frame construction. The ceiling is defined
 $ as an interzonal partition.
$
ZONE[
GEOM(NAME=ZONE1NOL=4088.38)
INF(WS=INFUCAP=31.5/C=1.0/T=0.0N=0.0)
MASS(CONS=TRUSS/AREA=417.08)
SR F(EX/OP/BS/CONS=ROOF1A/AZM=0.0/TILT=22.620/SIZE=39.06,16.611) SRF(EX/OP/BS/CONS=ROOF1B/AZIA=0.0/TILT=22.620/SIZE=2.94,16.611) SRF(EX/OP/BS/CONS=ROOF1A/AZM=180.0/TILT=22.620/SIZE=39.06,16.611) SR F(EX/OP/BS/CONS=ROOF1B/AZM=180.0/TI LT=22.620/SIZE=2.94,16.611) SRF(I N/OP/BS/CONS=CEI L1A/AZM=180.0/TILT=180.0/SIZE=39.06,28.0/ZONE=ZON E2)
SR F(I N/OP/BS/CONS=C El L1B/AZM=180.0/TILT=180.0/SIZE=2.94,28.0/ZON E=ZONE2) SRF(EX/OP/BS/CONS=CEIL1A/AZM=180.0/TILT=180.0/SIZE=39.06,2.667) SR F(EX/OP/BS/CONS=CEIL1B/AZM=180.0/TI LT=180.0/SIZE=2.94,2.667) SRF(EX/OP/BS/CONS=WALL3A/AZM=90.0/TILT=90.0NRTS=30.667,0.0,15.333,6.389)
SR F(EX/OP/SS/CONS=WALL3B/SIZE=9.0,1.6327/OR G=10.8333,0.0,0.0) SRF(EX/OP/BS/CONS=WALL3A/AZM=270.0/TILT=90.0NRTS=30.667,0.0,15.333,6.389) SRF(EX/OP/SS/CONS=WALL3B/SIZE=9.0,1.6327/ORG=10.8333,0.0,0.0)
$ ZONE2 - conditioned space. The volume of the living space is calculated on a gross basis. No adjustments are
$ made for the volume of the interior furnishings or partitions. Two adults inhabit the house (all times).
$ Lighting is incadescent, 600 W. Major equipment totals 820 W (2.8 kBtuh), all electric. The infiltration
$ rate is 0.5 ACH (ASHRAE 90.2-1993). Mass is estimated from area of internal partition walls. Framing
$ percentages for 400 mm (16") O.C. studs are 25 percent (75 percent cavity); for 400 mm (16") O.C. floor
$ joists, 10 percent (90 percent cavity). Parallel paths for heat flow are computed for frame construction.
$ The ceiling and floor are defined as an interzonal partition. The roof overhangs the front (South) and rear
$ (North) elevations by 400 mm (16 in.). Window area combined on front and rear (includes glass door)
$ elevations. Windows and door are setback 25 mm (1 in.) in the wall.
ZONE[
GEOM(NAME=ZONE2NOL=9408.0)
PEO(WS=OCCU/CAP=2.0)
LIT(WS=LAMP/CAP=2.0/RAD=0.8NIS=0.1/REP=0.1)
EQP(WS=EQPT/CAP=2.8/EL)
INF(WS=INFUCAP=78.4/C=1.0/T=0.0N=0.0)
MASS(CONS=PART/AREA=880)
SRF(IN/OP/BS/CONS=CEIL2A/AZM=180.0/TILT=0.0/SIZE=39.06,28.0/ZONE=ZONE1) SRF(IN/OP/BS/CONS=CEIL2B/AZM=180.0/TILT=0.0/SIZE=2.94,28.0/ZONE=ZONE1)
SR F(EX/OP/BS/CONS=WALL1A/AZM=0.0/TI LT=90.0/SIZE=42.0,8.0) SHD(OHNG/SIZE=42.0,1.333/ORG=0.0,8.0,0.0)
SRF(EX/TR/SS/CONS=WINDOW/SIZE=11.0,5.0/ORG=2.0,2.0,0.0/RVL=0.0833,0.0,0.0,0.0)
SR F(EX/OP/SS/CONS=DOOR/SIZE=3.0,6.667/ORG=15.0,0.0,0.0/RVL=0.0833,0.0,0.0,0.0)
SR F(EX/OP/SS/CONS=WALL1B/SIZE=8.156,8.0/ORG=33.844,0.0,0.0) SRF(EX/OP/BS/CONS=WALL1A/AZM=90.0/TILT=90.0/SIZE=23.8,8.0) SR F(EX/OP/BS/CONS=WALL1B/A2M=90.0/TILT=90.0/SIZE=4.2,8.0) SR F(EX/OP/BS/CONS=WALL1A/AZM=180.0/TILT=90.0/SIZE=42.0,8.0) SHD(OHNG/SIZE=42.0,1.333/ORG=0.0,8.0,0.0) SRF(EX/TR/SS/CONS=WINDOW/SIZE=6.0,6.667/ORG=2.0,0.0,0.0/RVL=0.0833,0.0,0.0,0.) SRF(EX/TR/SS/CONS=WINDOW/SIZE=8.0,4.0/0FIG=10.0,3.0,0.0/RVL=0.0833,0.0,0.0,0.0) SRF(EX/OP/BS/CONS=WALL1B/SIZE=8.25,8.0/ORG=33.75,0.0,0.0) SRF(EX/OP/BS/CONS=WALL1A/AZM=270.0/TILT=90.0/SIZE=21.0,8.0) SR F(EX/OP/BS/CONS=WALL1B/AZM=270.0/TI LT=90.0/SIZE=7.0,8.0) SRF(IN/OP/BS/CONS=FLOOR2A/AZM=180.0/TILT=180.0/SIZE=37.8,28.0/ZONE=ZONE3) SRF(IN/OP/BS/CONS=FLOOR2B/AZM=180.0/TI LT=180.0/SIZE=4.2,28.0/ZONE=ZONE3)
$ ZONE3 - vented crawl space, 2 ft height. ACH = 1, based on paper by Samuelson, 1994.
ZONE[
GEOM(NAME=ZONE3NOL=2352.0)
INF(WS=INFUCAP=39.2/C=1.0/T=0.0N=0.0)
 SRF(IN/OP/BS/CONS=FLOOR3A/AZM=180.0/TILT=0.0/SIZE=37.8,28.0/ZONE=ZONE2) SRF(IN/OP/BS/CONS=FLOOR3B/AZM=180.0fT1 LT=0.0/SIZE=4.2,28.0/ZONE=ZONE2) SRF(EX/OP/BS/CONS=WALL2/AZM=0.0/TILT=90.0/SIZE=42.0,2.0) SRF(EX/OP/BS/CONS=WALL2/AZM=90.0/TILT=90.0/SIZE=28.0,2.0) SR F(EX/OP/BS/CONS=WALL2/AZM=180.0/TILT=90.0/SIZE=42.0,2.0) SRF(EX/OP/BS/CONS=WALL2/AZM=270.0/TILT=90.0/SIZE=28.0,2.0) SR F(EX/OP/BS/CONS=CRSPFUAZM=180.0/TILT=180.0/SIZE=42.0,28.0)
]
$
SYSTEM [
SYS(NAME=LOADS)
UNC(ZONE=ZONE1)
DES(ZONE=ZONE2/HTVVS=HEAT/CLWS=COOL)
UNC(ZONE=ZONE3)
]
 
APPENDIX C
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Environment input data prepared for "design day" heating and cooling, arbitrary location. Note, the dollar ($) symbol specifies a comment for TARP.

$ EFDH1 Environment Input File - use in conjunction with BDD1 $ Project: Assessment of Reflective Roof Coatings
$ Location: Time Zone Meridian in U.S. (Springfield, IL)
$ Ground temperatures were taken from Appendix A, NBSIR 81-2378, "Heat $ Transfer Analysis of Underground Heat and Chilled-Water Distribution $ Systems".
$ 1-Day design data - HEATING.
RC(DEM/U IN=ENGLISH/UOUT=ENGLISH)
LOC(DESC=TIME ZONE MERIDIAN LONG 90, LAT 40'/LATD=40/LONG=90/T2=6/ALT=587) GRND(GRT=12*52.0)
DAY(DESC='24 TEMPERATURES7DATE=21SEPT/CLR=1/CLD=24*0/TA=24*30)
$ EFDC1 Environment Input File - use in conjunction with BDD1 $ Project: Assessment of Reflective Roof Coatings
$ Location: Time Zone Meridian in U.S. (Springfield, IL)
$ Ground temperatures were taken from Appendix A, NBSIR 81-2378, "Heat $ Transfer Analysis of Underground Heat and Chilled-Water Distribution $ Systems".
$ 1-Day design data - COOLING.
RC(DEM/UIN=ENGLISH/UOUT=ENGLISH)
LOC(DESC=TIME ZONE MERIDIAN LONG 90, LAT 407LATD=40/LONG=90/TZ=6/ALT=587) GRND(GRT=12*52.0)
DAY(DESC='24 TEMPERATURESI/DATE=21SEPT/CLR=1/CLD=24*0/TA=24*80)
 
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