The objective of this paper is to discuss the various sources of uncertainty inherent in the estimation of actual measured energy savings from baseline regression models, and to present pertinent statistical concepts and formulae to determine this uncertainty. Regression models of energy use in commercial buildings are not of the “standard” type addressed in textbooks because of the changepoint behavior of the models and the effect of patterned and non-constant variance residuals (largely as a result of changes in operating modes of the building and the HVAC system). This paper also addresses such issues as how model prediction is impacted by both improper model residuals and models identified from data periods which do not encompass the entire range of variation of both climatic conditions and the different building operating modes.

1.
ANSI/ASME PTC 19.1, 1990, “Measurement Uncertainty: Instruments and Apparatus,” ANSI/ASME Standard PTC 19.1-1985, American Society of Mechanical Engineers, New York, NY.
2.
Beale
E.
,
1960
, “
Confidence Regions in Non-Linear Estimation
,”
J. R. Stat. Assoc.
,
B-22
, pp.
1
88
.
3.
Beck, J. V., and Arnold, K. J., 1977, Parameter Estimation in Engineering and Science, John Wiley and Sons, New York.
4.
Claridge, D., Haberl, J., Turner, W., O’Neal, D., Heffington, W. M., Tombari, C., and Jaeger, S., 1991, “Improving Energy Conservation Retrofits with Measured Savings,” ASHRAE Journal, October.
5.
Coleman, H. W., and Steele, W. G., 1989, Experimentation and Uncertainty Analysis for Engineers, John Wiley and Sons, New York.
6.
Dhar, A., Reddy, T. A., and Claridge, D. E., 1998, ASME JSEE Special Issue.
7.
Draper, N., and Smith, H., 1981, Applied Regression Analysis, 2nd Edition, John Wiley & Sons, New York.
8.
Goldberg, M., 1982, “A Geometric Approach to Nondifferentiable Regression Models as Related to Methods for Assesing Residential Energy Conservation,” Ph.D. Thesis, Department of Statistics, Princeton University, Princeton, NJ.
9.
Hinkley
D. V.
,
1969
, “
Inferences about the Intersection on Two-Phase Regression
,”
Biometrica
, Vol.
56
, pp.
495
504
.
10.
Katipamula
S.
, and
Claridge
D. E.
,
1993
, “
Use of Simplified Systems Model to Measure Retrofit Energy Savings
,”
ASME JOURNAL OF SOLAR ENERGY ENGINEERING
, Vol.
115
, pp.
57
68
, May.
11.
Katipamula, S., Reddy, T. A., and Claridge, D. E., 1994, “Development and Application of Regression Models to Predict Cooling Energy Consumption in Large Commercial Buildings,” ASME/JSME/JSES International Solar Energy Conference Proceedings, p. 307, San Francisco, March.
12.
Katipamula, S., Reddy, T. A., and Claridge, D. E., 1995. “Bias in Predicting Annual Energy Use in Commercial Buildings with Regression Models Developed from Short Data Sets,” Proceedings of the ASME International Solar Energy Conference, pp. 99–110, San Francisco, April.
13.
Katipamula, S., Reddy, T. A., and Claridge, D. E., 1998, ASME JSEE, Special Issue.
14.
Kissock, J. K., Reddy, T. A., Fletcher, D., and Claridge, D. E., 1993, “The Effect of Short Data Periods on the Annual Prediction Accuracy of Temperature-Dependent Regression Models of Commercial Building Energy Use,” Proceedings of the ASME International Solar Energy Conference, pp. 455–463, Washington D.C., April.
15.
Kissock, J. K., 1993, “A Methodology To Measure Retrofit Energy Savings In Commercial Buildings,” Ph.D. dissertation, Mechanical Engineering Department, Texas A&M University, December.
16.
Kissock, J. K., Reddy, T. A., and Claridge, D. E., 1998, ASME JSEE, Special Issue.
17.
Kline
S.
, and
McClintock
F. A.
,
1953
, “
Describing Uncertainties in Single-Sample Experiments
,”
Mech. Eng.
,
75
, pp.
2
8
.
18.
Liu, M., and Claridge, D. E., 1998, ASME JSEE, Special Issue.
19.
Montgomery, D. C., 1991, Design and Analysis of Experiments, 3rd Ed., John Wiley and Sons, New York.
20.
Pindyck, R. S., and Rubenfeld, D. L., 1981, Economic Models and Economic Forecasts, 2nd Edition, McGraw-Hill, New York.
21.
Reddy, T. A., Kissock, J. K., and Claridge, D. E., 1992, “Uncertainty Analysis in Estimating Building Energy Retrofit Savings in the LoanSTAR Program,” Proceedings of the ACEEE 1992 Summer Study on Energy Efficiency in Buildings, Vol. 3, pp. 225–238, American Council for an Energy Efficient Economy, Pacific Grove, CA, Aug.–Sept.
22.
Reddy
T. A.
,
Katipamula
S.
,
Kissock
J. K.
, and
Claridge
D. E.
,
1995
, “
The Functional Basis of Steady-State Thermal Energy Use in Air-Side HVAC Equipment
,”
ASME JOURNAL OF SOLAR ENERGY ENGINEERING
, Vol.
117
, pp.
31
39
, February.
23.
Reddy, T. A., Saman, N. F., Claridge, D. E., Haberl, J. S., Turner, W. D., and Chalifoux, A., 1997, “Baselining Methodology for Facility-Level Monthly Energy Use-Part 1: Theoretical Aspects,” ASHRAE BN-97-16-4, Boston, MA technical paper.
24.
Reddy, T. A., and Claridge, D. E., 1998, “Uncertainty of Measured Energy Savings from Statistical Baseline Models,” submitted to HVAC&R Journal.
25.
Ruch, D. K., Kissock, J. K., and Reddy, T. A., 1993, “Model Identification and Prediction Uncertainty of Linear Building Energy Use Models with Autocorrelated Residuals,” Solar Engineering 1993, Proceedings of the ASME International Solar Energy Conference, pp. 465–473, Washington D.C., April; accepted by ASME JSEE.
26.
Ruch
D. K.
, and
Claridge
D. E.
,
1993
, “
A Development and Comparison of NAC Estimates for Linear and Change-Point Energy Models for Commercial Buildings
,”
Energy and Buildings
, Vol.
20
, pp.
87
95
.
27.
Theil, H., 1971, Principles of Econometrics, John Wiley, New York.
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