7-B-i

APPENDIX 7-B. INTERNAL LOADS SCHEDULES AND PART-LOAD 

PERFORMANCE CURVES 

TABLE OF CONTENTS

LIST OF TABLES

Table 7B.1. Occupancy, Lighting and Plug Loads Schedules........................................7-B-1

Table 7B.2. CAC and CHP Performance Curves Used in Small Office Modeling........7-B-2
7-B-1

APPENDIX 7-B. INTERNAL LOADS SCHEDULES AND PART-LOAD PERFORMANCE CURVES

Table 7-B.1. Occupancy, Lighting and Plug Loads Schedules

Schedule Day of 

Week

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Lighting

(1.0 W/sf)

Weekday 0.18 0.18 0.18 0.18 0.18 0.23 0.23 0.42 0.90 0.90 0.90 0.90 0.80 0.90 0.90 0.90 0.90 0.61 0.42 0.42 0.32 0.32 0.23 0.18

Sat 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18

Sun, Hol, 

Other

0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18

Plug 

Equipment

(0.63 

W/sf)

Weekday 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.50 1.00 1.00 1.00 1.00 0.94 1.00 1.00 1.00 1.00 0.50 0.20 0.20 0.20 0.20 0.20 0.20

Sat 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20

Sun, Hol, 

Other

0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20

Occupancy Weekday 0.00 0.00 0.00 0.00 0.00 0.00 0.11 0.21 1.00 1.00 1.00 1.00 0.53 1.00 1.00 1.00 1.00 0.32 0.11 0.11 0.11 0.11 0.05 0.00

Sat 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Sun, Hol, 

Other

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Heating 

Setpoint

Weekday 60.0 60.0 60.0 60.0 60.0 60.0 65.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 60.0 60.0 60.0 60.0 60.0

Sat 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0

Sun, Hol, 

Other

60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0

Cooling 

Setpoint

Weekday, 85.0 85.0 85.0 85.0 85.0 85.0 80.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 75.0 85.0 85.0 85.0 85.0 85.0

Sat 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0

Sun, Hol, 

Other

85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0 85.0

Fan 

Operation 

and 

Ventilation

Weekday, 0.0 0.0 0.0 0.0 0.0 0.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.0 0.0 0.0 0.0 0.0

Sat 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Sun, Hol, 

Other

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Infiltration Weekday, 1.00 1.00 1.00 1.00 1.00 1.00 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 1.00 1.00 1.00 1.00 1.00

Sat, 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

Sun, Hol, 

Other

1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

Hot Water Weekday, 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.27 0.55 0.64 0.64 0.82 1.00 0.91 0.55 0.55 0.73 0.37 0.37 0.18 0.27 0.09 0.00 0.00

Sat, 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Sun, Hol, 

Other

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
7-B-2

Table 7-B.2. CAC and CHP Performance Curves Used in Small Office Modeling

Type Performance Curve

Equation Curve Coefficients

a b c d e f

CAC Total Cooling Capacity Function of Temperature Curve

e EDB f WB EDB

COOL CAP FT a b WB c WB d EDB

+ × + × ×

− − = + × + × + ×

2

2

1.248093 -0.034629 0.0015801 0.00322596 -0.00008841 -0.00025978

Total Cooling Capacity Function of Flow Fraction Curve 

2 COOL −CAP − FF = a + b× FF + c× FF

0.7662 0.24227 -0.008473 NA NA NA

Energy Input Ratio Function of Temperature Curve

d EDB e EDB f WB EDB

COOL EIR FT a b WB c WB

+ × + × + × ×

− − = + × + ×

2

2

0.436666 0.046707 -0.0013704 -0.014704 0.0007657 -0.0003674

Energy Input Ratio Function of Flow Fraction Curve 

2 COOL − EIR − FF = a + b× FF + c× FF

1.5578 -0.7241 0.16628 NA NA NA

Cooling Part Load Fraction Correlation Curve

2 COOL − EIR − PLR = a + b× PLR + c× PLR

0.81 0.19 0.0 NA NA NA

PTHP Heating Capacity Function of Temperature Curve

2 HEAT −CAP − FT = a + b× DB + c× DB

0.824161 0.02277 0.0000103 NA NA NA

Heating Capacity Function of Flow Fraction Curve

2 HEAT −CAP − FF = a + b× DB + c× DB

1.5578 -0.7241 0.16628 NA NA NA

Heating Energy Input Ratio Function of Temperature Curve

2 3 HEAT − EIR − FT = a + b× DB + c× DB + c× DB

1.14084 -0.0244301 0.0013092 -0.000057 NA NA

Heating Energy Input Ratio Function of Flow Fraction Curve

2 HEAT − EIR − FF = a + b× FF + c× FF

1.5578 -0.7241 0.16628 NA NA NA

Heating Part Load Fraction Correlation Curve

2 HEAT − EIR − FPLR = a + b× PLR + c× PLR

0.771 0.229 0.0 NA NA NA
7-B-3

Where:

COOL − CAP − FT = Total Cooling Capacity Function of Temperature,

COOL −CAP − FF = Total Cooling Capacity Function of Flow Fraction Curve,

COOL − EIR − FT = Energy Input Ratio Function of Temperature,

COOL − EIR − FF = Energy Input Ratio Function of Flow Fraction,

COOL − EIR − FPLR = Total Cooling Part Load Fraction Correlation Curve Name,

HEAT − CAP − FT = Heating Capacity Function of Temperature Curve Name,

HEAT −CAP − FF = Heating Capacity Function of Flow Fraction Curve Name,

HEAT − EIR − FT = Heating Energy Input Ratio Function of Temperature Curve Name,

HEAT − EIR − FF = Heating Energy Input Ratio Function of Flow Fraction Curve 

Name,

HEAT − EIR − FPLR = Heating Part Load Fraction Correlation Curve Name,

WB = entering coil wet-bulb temperature (° F),

DB = outside dry-bulb temperature (° F),

EDB = entering coil dry-bulb temperature (° F), and

PLR = Part Load Ratio (cooling load/steady-state capacity).

Normalized performance curves for the CAC and CHP condensing units were developed 

based on manufacturers catalog data for York CZB model (CZB036) for cooling performance 

and York YZB (YZB036) equipment for heating performance.1,2 Equations are in formats 

accepted for use in the EnergyPlus simulation tool input files (*. idf) files for each simulation 

run. Part load fraction correlation curves were based on commercial performance data used in the 

DOE Benchmark model for cooling part-load performance degradation. Nomenclature used for 

left hand side of each performance curve equation based on DOE2.1E descriptors for these 

parameters and is not normally found in the EnergyPlus documentation. 

 

1. York performance data for CAC. York CZB (13 SEER) Tech Guide 561909-YTG-A0410.pdf. Available at www.yorkupg.com/PDFFiles/561909-YTG-A-0410.pdf. (Last 

accessed July 2010.)

2. York performance data for CHP. YZB (13 SEER) Tech Guide 561921-YTG-A-0410.pdf.

Available at www.yorkupg.com/PDFFiles/561921-YTG-A-0410.pdf (Last accessed July 

2010.)