### 7

- B

- i A P PENDIX 7

- B

. DETERMINATION OF BOI LER ENERGY USE IN TH E L IFE

C YCLE C OST ANALYSIS

TABLE OF CO NTENTS

7

- B.1 INTRODUCTION

................................ ................................ ................................ . 7

- B

- 1

7

- B.2 DETERMINATION OF SPA CE HEATING ANNUAL FU EL ENERGY

CONSUMPTION

................................ ................................ ................................ ... 7

- B

- 1

7

- B.2.1 Thermal Efficiency Adjustments

................................ ................................ ........... 7

- B

- 2

7

- B.2.1.1 Conversion Between Combustion Efficiency and Thermal Efficiency

................................ ................................ ............................. 7

- B

- 2

7

- B.2.1.2 Adjustment to Rated Thermal Efficiency Based on Return Water Temperature Application, Part Load, and Cycling

.............................. 7

- B

- 3

7

- B.2.1.3 Adjustment to Rated Thermal Efficiency Based on Part Load and Cycling

................................ ................................ ................................ . 7

- B

- 7

7

- B.2.2 Assigning Boiler Equipment Characteristics to Sampled Buildings

..................... 7

- B

- 9

7

- B.2.2.1 Input Capacity of Existing and New Equipment

............................... 7

- B

- 13

7

- B.2.3 Derivation of Existing Efficiencies

................................ ................................ ...... 7

- B

- 13

7

- B.3 DETERMINATION OF ANN UAL ELECTRICAL ENERG Y

CONSUMPTION

................................ ................................ ................................ . 7

- B

- 16

7

- B.3.1 Boiler Electrical Components

................................ ................................ .............. 7

- B

- 16

7

- B.3.2 Standby Energy

................................ ................................ ................................ .... 7

- B

- 17

LIST OF TABLES

Table 7

- B.2.1 Linear Fit Parameters for Converting Combustion Efficiency to Thermal Efficiency

................................ ................................ .............. 7

- B

- 3

Table 7

- B.2.2 Return Water Temperatures at Each Outsid e Air Temperature Bin

.... 7

- B

- 4

Table 7

- B.2.3 Adjustment to Thermal Efficiency Based on RWT Application and Part Load or Cycling Opera tion for Commercial Packaged Boilers

.... 7

- B

- 7

Table 7

- B.2.4 Part Load and Cycling at Each Outside Air Temperature Bin

............. 7

- B

- 8

Table 7

- B.2.5 Adjustment to Thermal Efficiency Based on Part

- Load and Cycling Operation

................................ ................................ ................ 7

- B

- 9

Table 7

- B.2.6 Range of Existing Heating Energy Use Based on CBECS 2003 and RECS 2009 Data for Each Boiler Equipment Class, MMBtu/year

... 7

- B

- 10

Table 7

- B.2.7 Range of Adjusted Heating Load for Each Boiler Equipment Class, MMBtu/year

................................ ................................ ....................... 7

- B

- 11

Table 7

- B.2.8 Range of Baseline Boiler Heating Annual Operating Hours for Each Boiler Equipment Class, hours

................................ ................. 7

- B

- 12

Table 7

- B.2.9 Historical Efficiencies by Equipment Class, Natural Draft Boilers

.. 7

- B

- 14

Table 7

- B.2.10 Historical Efficiencies by Equipment Class, Mechanical Draft

Boilers

................................ ................................ ................................ 7

- B

- 14

Table 7

- B.3.1 Electrical Component Power

................................ ............................. 7

- B

- 17

### 7

- B

- ii LIST OF FIGURES

Figure 7

- B.2.1 Efficiency vs. Return Water Temperature, Condensing Boilers

.......... 7

- B

- 5 Figure 7

- B.2.2 Average Curve for Condensing Boil ers

................................ ............... 7

- B

- 5 Figure 7

- B.2.3 Efficiency vs. Return Water Temperature, Non

- Condensing

Boilers

................................ ................................ ................................ .. 7

- B

- 6 Figure 7

- B.2.4 Fulton Caliber Condensing Boiler Relationship between Burner Input and Thermal Efficiency

................................ .............................. 7

- B

- 8

### 7

- B

- 1 APPENDIX 7

- B. DETERMINATION OF BOI LER ENERGY USE IN TH E L IFE

C YCLE C OST ANALYSIS

7

- B.1 INTRODUCTION

For calculating the energy consumed by commercial packaged boilers, the U.S. Department of Energy ( DOE ) consider s the energy use associated with providing space heating and domestic water heating. DOE develop s a methodology for estimating the space heating and water heating energy use provided by boilers. The calculation to determine the total energy use per unit is as follows:

EEEEEE UU TTTTT 

### = FF F SS 

### + FF F W 

### + E EE E TTTTT 

### Eq. 7

- B

. 1

Where:

FF F SS 

### = fuel used for space heating,

FF F W 

### = fuel used for water heating, and

E EE E TTTTT 

### = electrical energy use

Refer to Chapter 7 for the space heating and water heating energy use calcul ation methodology. This appendix provides details on some of the inputs used in the calculations.

7

- B.2 DETERMINATION OF S PACE H EATING ANNUAL FUEL E NERGY

CONSUMPTION

DOE calculate s the annual fuel consumption ( FuelUse ) for each boiler using the following formula :

FF F SS 

### = BBB SS 

### × Q ii 

### Eq. 7

- B

. 2

Where:

BOH SH 

### = space heating burner full

- load operating hours (hr/yr), and
Q in 

### = input capacity of existing boiler (kBtu/hr).

DOE derive s space heating burner operating hours ( BOH ) from the building heating load served by a single boiler. Building heating load i s determined from annual fuel consumption for heating reported in the U.S. Energy Information Administration (EIA) Commercial Buildings

### 7

- B

- 2 En ergy Consumption Survey (CBECS) and Residential Energy Consumption Survey (RECS)

, and is based on the efficiency of the existing boiler. a



### 7

- B.2.1 Thermal Efficiency Adjustments

In the determination of the annual fuel energy consumption, DOE adjusts the rated

the rmal efficiency (TE) to account for the conversion between combustion efficiency and thermal efficiency when applicable, part

- load operation (in the case of multi

- stage equipment) and cycling losses (for single

- stage equipment), as well as return water tem peratur e (RWT)

.

7

- B.2.1.1 Conversion B etween C ombustion E fficiency and T hermal E fficiency

DOE uses t he Air

- Conditioning, Heating, and Refrigeration Institute ( AHRI ) database to determine the relationship between combustion efficiency and thermal efficiency for the four
equipment classes with combustion efficiency as the efficiency metric

. 1



### , DOE develops a linear relationship between the two efficiency metrics f rom boiler models where both combustion efficiency and therm al efficiency are listed . The parameters are determined separately for gas

fired and oil

- fired boilers. The following formula illustrates the relationship between the two efficiency metrics:

T = a × C + b
Eq. 7

- B

. 3

The linear fit parameters are in Table 7

- B.2.1 :

a CBECS is a national sample survey that collects information on the stock of U.S. commercial buildings, including
their energy

- related building characteristics and energy usage data (consumption and expenditures). See http://www.eia.gov/consumption/commer cial/about.cfm

. RECS is a nationally representati ve data sample of

information about the energy characteristics o f housing unit s
, including usage patterns, and household
demographics. This information is combined with data from energy suppliers to the homes to estimate energy costs
and usage for heating, cooling, appliances and other end uses . See http://www.eia.gov/consumption/residential/index.cfm

### 7

- B

- 3 Table 7

- B.2.1 Linear F it P arameters for Converting Combustion Efficiency to Thermal Efficiency

Oi l Gas

a 0.9804 1.0867

b 0.4721

- 8.0927

7

- B.2.1.2 Adjustment to R a ted T hermal E fficiency B ased on R eturn W ater

T emperature Application, Part Load , and Cycling

Rated thermal efficiency and combustion efficiency for commercial packaged boilers are determined during laboratory testing under subpart E of Title 10 of the Code of Federal Regulations, Part 431 (10 CFR Part 431), sect ion 431.86. b 

### The DOE website for com mercial
packaged boilers provides additional information about the test procedure

. 2 

### The test procedure prescribes a supply water temperature of 180°F. The test procedure allows a range of boiler inlet water temperatures at which the boiler may be tested. DOE assume s that all boilers are rated at a

return water temperature of 80°F. The boiler return water temperature in typical installations varies by heating load and by heating application. DOE assume s that all boilers operate with supply water temperature reset. That is, at the peak heating load the supply water temperature is

at it s design temperature , or the highest temperature . At lower heating loads, the supply water temperature resets down to lower temperatures. In typical non

- condensing boiler installations the design supp ly water temperature is 180°F and can reset down to 155°F . In typ ical condensing

boiler installations the design supply water temperature is 160°F and can reset down to 104°F

. Some condensing boilers are installed in high temperature applications, in which the supply water temperatures are higher , with a design of 180°F and resetting down to 130°F

. DOE

assume s an average temperature drop between the supply water temperature and the return water temperature of 20°F. See Table 7

- B.2.2 for the assumed return water temperature as it varies with outside air temperature.

b See http://www.ecfr.gov/cgi

- bin/text

idx?type=simple;c=ecfr;cc=ecfr;sid=26fa9f9a78e320d5d603e37c3675a135;idno=10;region=DIV1;q1=431;rgn=div5
;view=text;node=10%3A3.0.1.4.19

### 7

- B

- 4 Table 7

- B.2.2 Return Water Temperatures at E ach Outside Air Temperature Bin

Temperature

Bin Condensing

Units

- Low

RWT ( °F ) Condensing

Units

– High RWT ( °F ) Non

Condensing

Units

– High RWT ( °F )

Over 68 °F

- - -
50

- 68 °F 84 110 135

41

- 50 °F 112 132 150

28

- 41 °F 116 136 155

14

- 28 °F 129 149 160

At or below

14 °F 140 160 160

T he relationship between RWT and efficiency for both condensing and non

- condensing commercial packaged boilers is described below.

Several manufacturers publish a relationship between boiler TE and RWT for certain

boiler series. 3

, 4

, 5

, 6

, 7 

### DOE uses t h e information to develop an average TE versus RWT relationship representative of boiler performance for a range of re turn water temperatures. The analysis assumes that the efficiencies scale according to the relationship reported for the TE

. Figure 7

- B.2.1 presents the information from these sources and the derived average efficiency

curve for condensing boilers

. c

c The average efficiency curve represents the mean efficiency at each ret urn water temperature reported in the

manufacturers’ information.

### 7

- B

- 5 Figure 7

- B.2.1 Efficiency vs. Return Water Temperature , Condensing Boilers

For condensing boilers, the analysis use s the average relationship shown in Figure 7

- B.2.2 to establish the magnitude of the efficiency adjustment required for the high and low

temperature condensing boiler applications. As shown in Figure 7

- B.2.2 , the relationship

ind icates an approximate reductio n of 8 percent thermal efficiency for an average return water
temperature of 14 0 ° F and approximate reduction of 4.5 percent thermal efficiency for an average
return water temperature of 115 ° F

.

Figure 7

- B.2.2 Average Curve for Condensing Boilers 80 85 90 95 100

60 80 100 120 140 160 180Thermal Efficiency (%)

Return Water Temperature 

## Boiler Efficiency vs Return Water Temperature
(Condensing)

Hydrotherm

Hydrotherm 2

Aerco

Burderus

ASHRAE

Deppman

Crest

Average Curve

### 7

- B

- 6 For non

- condensing boilers, the analysis use s the average efficiency/RWT relationship at

the 140

- 180 ° F temperature range to establish the efficiency adjustment required for the high
temperature applications. The data for temperatures between 140 ° F and 180 ° F i s used to

extrap olate the efficiency at 8 0 ° F using linear regression. As shown in Figure 7

- B.2.3

, the relationship resulted in an approximate reduction of 4.2 percent thermal effic iency for an average
return water temperature of 155 ° F

.

Figure 7

- B.2.3 Efficiency vs. Return Water Temperature, Non

- Condensing Boilers

As described above, DOE addresses three different water temperature scenarios: high

temperature non

- condensing (RWT 135 ° F to 160 ° F ), high temperature condensing (RWT 110 ° F

to 160 ° F ), and low temperature condensing (RWT 84 ° F to 140 ° F ). DOE analyze s each of these

three scenarios in each of the American Society of Heating, Refrigerating and Air Conditioning Engineers ( ASHRAE ) 16 climate zones. For each scenario, the annual average return water

temperature is determined in each climate zone . For each average return water temperature, a thermal efficiency adjustment i s determined per the figure s above. The thermal efficiency adjustments in the analysis are shown in Table 7

- B.2.3

.

### 7

- B

- 7 Table 7

- B.2.3 Adjustment to Thermal Efficiency Based on RWT Application and Part Load or Cycling Operation for Commercial Packaged Boilers

ASHRAE

Climate ASHRAE

Climate Condensing Non

- Cond

Zone # Zone Code Low Temp High Temp High Temp Operation Operation Operation

1 1A

- 4.07

- 7.14

- 4.03

2 2A

- 4.60

- 7.55

- 4.12

3 2B

- 4.18

- 7.23

- 4.05

4 3A

- 5.11

- 7.89

- 4.16

5 3B

- CA

- 4.03

- 7.10

- 4.02

6 3B

- other

- 4.45

- 7.44

- 4.11

7 3C

- 4.14

- 7.19

- 4.04

8 4A

- 5.52

- 8.13

- 4.19

9 4B

- 5.03

- 7.84

- 4.16

10 4C

- 4.49

- 7.47

- 4.11

11 5A

- 6.07

- 8.38

- 4.22

12 5B

- 5.79

- 8.26

- 4.20

13 6A

- 6.35

- 8.48

- 4.23

14 6B

- 6.14

- 8.41

- 4.22

15 7

- 6.68

- 8.58

- 4.24

16 8

- 7.10

- 8.64

- 4.26



### 7

- B.2.1.3 Adjustment to R ated T hermal E fficiency B ased on Part Load and

Cycling

Typical non

- condensing boilers may be single stage or two

- stage, but do not often modulate beyond that. DOE assume s that all no n

- condensing boilers are single

- stage. In a single

stage boiler when the load is low, the boiler cycles on and off to meet the load. The cycling produces losses as heat is lost to the mechanical room when the boiler cycles off. In view of
information from consultants, DOE understands tha t t he cycling losses increase as the heating

load decreases. See Table 7

- B.2.4 for the assumed cycling losses at different outside air

temperatures

.

Condensing boilers on the other hand typically modulate to meet the heating load. That is, if the heating load is low, then the firing rate will reduce in order to meet the load. Thermal efficiency increases as the boiler firing rate decreases

. A typical relationship between burner input ratio and thermal efficiency is shown for one manufacturer in Figure 7

- B.2.4

. See Table 7

- B.2.4 for the fraction of boiler input capacity required at differe nt outside air temperatures.

### 7

- B

- 8 Figure 7

- B.2.4 Fulton Caliber Condensing Boiler Relationship b etween Burner Input and Thermal Efficiency d



### Table 7

- B.2.4 Part L oad and Cycling at E ach Outside Air Temperature Bin

Temperature

Bin Condensing

Fraction of

Boiler Capacity Non

Condensing Adjustment for Cycling

Over 68 °F

- -
50

- 68 °F 20%

- 10%

41

- 50 °F 40%

- 2%

28

- 41 °F 60%

- 1%

14

- 28 °F 80% 0%

At or below

14 °F 100% 0%

For each of the 16 ASHRAE Climate Zones, the average percentage that the boiler is loaded compared to its full capacity is calculated based on outside air temperature. In view of the

average load percentage, a cycling

- load adjustment and a part

- load adjustment can be calculated

for non

- condensing boi lers and condensing boilers, respectively . These adjustments are given in

Table 7

- B.2.5

.

d Fulton Caliber Condensing Boiler, http://www.fulton.com/product

- profile.php?ptc=hw&uid=40

### 7

- B

- 9 Table 7

- B.2.5 Adjustment to Thermal Efficiency Based on Part

- Load and Cycling Operation

ASHRAE

Climate ASHRAE

Climate Condensing

Part Load Non

- Cond Cycling

Zone # Zone Code Adj. Adj.

1 1A 2.15

- 0.10

2 2A 1.65

- 0.07

3 2B 2.03

- 0.08

4 3A 1.41

- 0.06

5 3B

- CA 2.20

- 0.10

6 3B

- other 1.73

- 0.06

7 3C 2.07

- 0.09

8 4A 1.10

- 0.05

9 4B 1.41

- 0.05

10 4C 1.70

- 0.06

11 5A 0.80

- 0.04

12 5B 0.95

- 0.04

13 6A 0.66

- 0.04

14 6B 0.76

- 0.04

15 7 0.51

- 0.04

16 8 0.33

- 0.04



### 7

- B.2.2 Assigning Boiler Equipment Characteristics to Sampled Buildings

To estimate the heating load of each sample building , DOE represent s the existing boiler by assigning an input capacity and efficiencies to the boiler in the CBECS and RECS sample building units.

Table 7

- B.2.6 shows the original CBECS 2003 and RECS 2009 heating energy use.

### 7

- B

- 10 Table 7

- B.2.6 Range of Existing Heating Energy Use Based on CBECS 2003 and RECS

2009 Data for Each Boiler Equipment Class, MMBtu/year

Equip ment Class Min Max Average Percentiles

5% 25% 50% 75% 95%

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 0.0 17132.1 996.9 78.7 343.8 727.1 1202.3 2647.4

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000

Btu/hr 0.0 39381.5 4016.3 172.4 1360.0 2881.9 5300.9 11697.8

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 0.1 4641.0 773.9 6.6 62.4 601.6 1223.3 2163.9

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 24518.8 2863.6 16.9 443.8 2482.4 5122.5 7469.6

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 3.5 17132.1 901.1 80.0 343.8 746.0 1194.1 2096.6

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 39381.5 4451.2 331.4 1729.6 3669.5 5811.4 12349.3

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 6.1 4641.0 1086.6 116.0 598.3 950.3 1404.4 2238.3

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 13464.8 3598.2 37.0 761.4 4419.5 5227.4 8182.9

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 0.0 17132.1 1022.1 78.7 350.6 740.5 1319.0 3017.6

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000

Btu/hr 0.0 39381.5 3691.7 16.1 1137.1 2437.7 4928.4 10304.5

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 0.1 4641.0 855.9 44.6 259.6 639.7 1265.4 2238.3

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000

Btu/hr 0.0 24518.8 2732.5 16.9 432.5 1802.8 5122.5 7144.8

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 3.5 17132.1 910.7 80.0 341.4 740.5 1194.1 2096.6

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000

Btu/hr 0.0 39381.5 4358.7 294.1 1729.6 3657.8 5507.4 12098.5

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 6.1 4641.0 1067.8 116.0 580.1 938.3 1404.4 2235.9

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 13464.8 3600.2 37.0 761.4 4419.5 5227.4 8182.9



### Table 7

- B.2.7 shows the results for the range in adjusted heating load among sample buildings and households

.

### 7

- B

- 11 Table 7

- B.2.7 Range of Adjusted Heating Load for Each Boiler Equipment Class, MMBtu/year

Equipment Class Min Max Average Percentiles

5% 25% 50% 75% 95%

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 0.0 10507.2 587.7 45.9 208.3 430.7 708.5 1575.0

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000

Btu/hr 0.0 22755.8 2400.7 106.8 808.6 1709.2 3161.1 6790.7

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 0.1 2832.7 460.7 4.0 37.0 363.1 719.1 1307.8

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 15125.7 1697.5 10.3 270.0 1487.4 3010.0 4189.1

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 2.3 10084.6 508.7 44.3 203.9 413.3 668.9 1198.6

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 22089.4 2522.5 184.1 975.3 2099.5 3260.4 6899.3

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 3.7 2785.6 635.1 69.4 346.9 575.5 810.5 1332.4

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 7915.3 2093.4 22.1 451.9 2522.4 3022.4 4725.0

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 0.0 11502.6 662.4 50.3 228.7 477.7 850.1 1924.6

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000

Btu/hr 0.0 23818.0 2273.4 10.1 689.9 1517.8 2991.1 6281.9

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 0.1 2915.1 523.7 27.3 160.7 419.7 779.4 1388.0

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000

Btu/hr 0.0 15544.2 1661.2 10.6 272.0 1118.4 3052.4 4253.5

Mechanical Draft Gas

- Fired Steam

Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 2.4 10301.3 526.5 45.3 189.3 424.2 684.2 1224.8

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000

Btu/hr 0.0 22427.7 2510.3 166.2 975.6 2119.6 3224.7 6860.2

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 3.7 2806.6 629.4 70.0 341.5 553.2 811.7 1335.7

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 7895.2 2090.0 22.1 450.7 2516.3 3014.7 4712.6

### 7

- B

- 12 Table 7

- B.2.8 shows the results for the baseline heating boiler operating hours among sample buildings and households

.

Table 7

- B.2.8 Range of Baseline Boiler Heating Annual Operating Hours for Each

Boiler Equipment Class, hours

Equipment Class Min Max Average Percentiles

5% 25% 50% 75% 95%

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 0.0 8760.0 1035.0 88.8 415.7 803.1 1329.9 2766.2

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 6956.7 757.0 42.5 271.6 607.1 978.9 2081.1

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 0.1 4688.1 936.2 4.3 87.1 864.0 1412.4 2272.3

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 3907.6 585.6 3.8 78.8 494.5 939.6 1494.3

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 6.3 8760.0 1000.0 100.4 490.8 885.7 1283.1 2375.7

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 7125.8 861.5 87.3 388.7 883.3 1110.5 1890.1

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 2.2 4666.9 1197.2 112.7 735.8 1280.5 1524.6 2119.1

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 3905.9 734.9 5.6 189.6 833.6 1099.5 1655.6

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 0.0 8760.0 1121.5 95.8 435.2 901.9 1446.9 2589.6

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 7281.4 714.4 4.1 267.6 595.8 963.7 1749.2

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr
and ≤2,500,000 Btu/hr 0.1 4830.2 1024.0 51.9 197.3 1024.0 1472.5 2298.1

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 4015.2 574.6 3.9 78.5 457.5 917.0 1448.2

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 6.3 8760.0 1003.7 98.4 485.1 875.7 1285.4 2364.8

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 7041.3 838.1 76.3 381.4 854.6 1089.6 1863.9

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and
≤2,500,000 Btu/hr 2.2 4703.5 1184.1 113.0 722.8 1288.4 1519.4 2081.4

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 0.0 3896.0 730.1 5.6 189.0 831.4 1096.7 1651.4

### 7

- B

- 13 7

- B.2.2.1 Input Capacity of Existing and New Equipment

The determination of the input capacity of the boiler accounts for the adjusted heat ing load of the building (adjusted with the considerations described above) , the efficiency of the existing boiler, and the oversize factor. The boiler input capacity is assumed to be the same for the existing boiler and the boiler being considered under the standard.

Q ii 

### = AAA A A AAA A

T

ee e e 

### × O OO F

Eq. 7.1

Where:

AdjustedHeatLoad = estimated building heat loss adjusted for building weather location (kBtu/h),

TE existing 

### = TE of the existing boiler for each equipment class, and,

OversizeFactor = 1. 1

, based on input from consultants on typical sizing practices.

DOE calculate s the adjusted heat ing load for each sample building based on the applicable building characteristics and outdoor conditions derived from the CBECS and RECS

data. DOE assumed a nominal heating load of 30 btu/h/sqft based o n industry standard

. 8 

### DOE determined the heated building area by multiplying the reported building area by the reported percentage of area heated. DOE then adjusted this load by the design outdoor air temperature of the climate region.

The derivation of the exis ting boiler efficiency is described in Section 7

- B.2.3

. The boiler input capacity is assumed to be the same for the existing boiler and the boiler being considered

under the standard.

7

- B.2.3 Derivation of Existing Efficiencies

As described in Chapter 7 , the efficienc y of existing equipment already installed is required to calculate the building heating load. DOE develop s the historical distributions of

efficiencies by equipment class for existing boilers based on the AHRI database from 2007 to

20 09

. DOE calculates the average efficiency of all boilers in each equipment class from the 2009

AHRI database t o determine the existing efficiency for the year 2009. This calc ulated average i s assumed to be the representative efficiency for that equipment class in 2009. The same process

was used to determine the existing efficiencies in 2007 and 2008. DOE assume s that in 2005 and

2006 the existing efficiencies were equal to tho se in 2007. From 1973 to 2004 DOE has assumed

that the existing efficiency reduced by 1 percent every 5 years. For all years prior to 1973 DOE

has assumed that the efficiency was equal to that in 1973. See the historical efficiencies by equipment class in Table 7

- B.2.15 and Table 7

- B.2.16

.

### 7

- B

- 14 Table 7

- B.2.9 Historical Efficiencies by Equipment Class, Natural Draft Boilers

SGNDHW LGNDHW SONDHW LONDHW SGNDST LGNDST SONDST LONDST

TE CE TE CE TE TE TE TE

1973 75 75 76 78 71 72 74 75

1974 75 75 76 78 71 72 74 75

1975 76 76 77 79 72 73 75 76

1976 76 76 77 79 72 73 75 76

1977 76 76 77 79 72 73 75 76

1978 76 76 77 79 72 73 75 76

1979 76 76 77 79 72 73 75 76

1980 77 77 78 80 73 74 76 77

1981 77 77 78 80 73 74 76 77

1982 77 77 78 80 73 74 76 77

1983 77 77 78 80 73 74 76 77

1984 77 77 78 80 73 74 76 77

1985 78 78 79 81 74 75 77 78

1986 78 78 79 81 74 75 77 78

1987 78 78 79 81 74 75 77 78

1988 78 78 79 81 74 75 77 78

1989 78 78 79 81 74 75 77 78

1990 79 79 80 82 75 76 78 79

1991 79 79 80 82 75 76 78 79

1992 79 79 80 82 75 76 78 79

1993 79 79 80 82 75 76 78 79

1994 79 79 80 82 75 76 78 79

1995 80 80 81 83 76 77 79 80

1996 80 80 81 83 76 77 79 80

1997 80 80 81 83 76 77 79 80

1998 80 80 81 83 76 77 79 80

1999 80 80 81 83 76 77 79 80

2000 81 81 82 84 77 78 80 81

2001 81 81 82 84 77 78 80 81

2002 81 81 82 84 77 78 80 81

2003 81 81 82 84 77 78 80 81

2004 81 81 82 84 77 78 80 81

2005 82 82 83 85 78 79 81 82

2006 82 82 83 85 78 79 81 82

2007 82 82 83 85 78 79 81 82

2008 82 82 83 85 78 79 81 82

2009 82 82 83 85 78 79 81 82



### Table 7

- B.2.10 Historical Efficiencies by Equipment Class, Mechanical Draft Boilers

### 7

- B

- 15 SGMDHW LGMDHW SOMDHW LOMDHW SGMDST LGMDST SOMDST LOMDST

TE CE TE CE TE TE TE TE

1973 78 77 76 78 73 73 75 75

1974 78 77 76 78 73 73 75 75

1975 79 78 77 79 74 74 76 76

1976 79 78 77 79 74 74 76 76

1977 79 78 77 79 74 74 76 76

1978 79 78 77 79 74 74 76 76

1979 79 78 77 79 74 74 76 76

1980 80 79 78 80 75 75 77 77

1981 80 79 78 80 75 75 77 77

1982 80 79 78 80 75 75 77 77

1983 80 79 78 80 75 75 77 77

1984 80 79 78 80 75 75 77 77

1985 81 80 79 81 76 76 78 78

1986 81 80 79 81 76 76 78 78

1987 81 80 79 81 76 76 78 78

1988 81 80 79 81 76 76 78 78

1989 81 80 79 81 76 76 78 78

1990 82 81 80 82 77 77 79 79

1991 82 81 80 82 77 77 79 79

1992 82 81 80 82 77 77 79 79

1993 82 81 80 82 77 77 79 79

1994 82 81 80 82 77 77 79 79

1995 83 82 81 83 78 78 80 80

1996 83 82 81 83 78 78 80 80

1997 83 82 81 83 78 78 80 80

1998 83 82 81 83 78 78 80 80

1999 83 82 81 83 78 78 80 80

2000 84 83 82 84 79 79 81 81

2001 84 83 82 84 79 79 81 81

2002 84 83 82 84 79 79 81 81

2003 84 83 82 84 79 79 81 81

2004 84 83 82 84 79 79 81 81

2005 85 84 83 85 80 80 82 82

2006 85 84 83 85 80 80 82 82

2007 85 84 83 85 80 80 82 82

2008 87 85 84 85 80 81 82 82

2009 87 85 84 86 80 81 82 82

### 7

- B

- 16 7

- B.3 DETERMINATION OF ANN UAL ELECTRICAL ENERG Y

CONSUMPTION

DOE calculate s the electricity consumption as:

E EE E = BBB SS 

### × AAA BB 

### × E EEE EEE + E EE W 

### × E EEE EEE

+ S × S

Eq. 7

- B

. 4

Where:

BOH SH 

### = as defined previously, Adj BO H 

### = adjustment factor that takes into account part

- load operation (for condensing units only),

ElecPower = power of multiple electrical components required during boiler operation, (k W ),

Elec BOH WH 

### = assumed to be 20 percent of BOH SH 

### adjusted for part

- load operation

, StdbyPower = total standby power of the equipment, and StdbyHrs = standby hours, takes into account wat er heating times in the summer

7

- B.3.1 Boiler Electrical Components

DOE assume s that all hot water boil er s ha ve a circulating water pump. DOE assume s that small boilers have the same size pump and , likewise, large boilers have the same size pump.

Table 7

- B.3.1 depicts the applicable input power in watts for the circulating water pump and the

draft inducer

.

### 7

- B

- 17 Table 7

- B.3.1 Electrical Component Power

W ater

P ump

E lectrical

Power (watts) Draft

Inducer

Electrical

Power (watts)

SGNDHW 250 0

LGNDHW 950 0

SONDHW 250 0

LONDHW 950 0

SGNDST 250 0

LGNDST 950 0

SONDST 250 0

LONDST 950 0

SGMDHW 250 250

LGMDHW 950 500

SOMDHW 250 250

LOMDHW 950 500

SGMDST 250 250

LGMDST 950 500

SOMDST 250 250

LOMDST 950 500

7

- B.3.2 Standby Energy

DOE assume s that mechanical draft boilers have a standby power of 10.5 watts , based on
the engineering analysis done for the Residential Boilers rulemaking

. 9 

### Also, DOE assume s that

natural draft boiler d oes not use any power while in standby mode

.

### 7

- B

- 18 REFERENCES

1. Air Conditioning Heating and Refrigeration Institute, Directory of Certified Product Performance for Commercial Boilers, 2014. (Last accessed 5/26/2014, 2014.)

< http://www.ahridirectory.org/ahridirectory/pages/home.aspx >

2. U.S. Dep artment of Energy

- Office of Energy Efficiency and Renewable Energy, Energy Efficiency Program for Certain Commercial and Industrial Equipment: Test Procedures and Efficiency Standards for Commercial Packaged Boilers, October 21, 2004. Washington, DC.

3. Lochinvar, Crest Condensing Boiler, 2013. Lochinvar. (Last accessed October 11, 2013.) < http://www.lochinvar.com/_linefiles/FBN

- 04.pdf >

4. Buderus, SB Series Commercial Condensing Boilers, 2 008. Bosch Thermotechnology Corp. (Last accessed October 11, 2013.)

< http://www.buderus.us/files/201001151453140.sb_series12

- 08V21.pdf >

5. HydroTherm, HydroTherm KN Series

, (Last accessed October 11, 2013.)

< http://mesteksa.com/fileuploads/Literature/Hydrotherm%20Boilers/KN%20Series %20B oiler/KN%20Series%20Catalog%20%28KNAP

- 3%291.pdf >

6. Hall, N., The Importance of Turndown Ratio in Condensing Boilers & Water Heaters,

2009. R.L. Deppmann Co. (Last accessed October 11, 2013.)

< http://www.deppmann.com/2009/10/19th/ >

7. Benchmark 2.0 Low NO

x 

### Boiler, 2013. AERCO. (Last accessed October 11, 2013.)

< http://www.aerco.com/Products/Bo ilers/Benchmark

- Boilers/Benchmark

- 2

- 0

- Low

- NOx

Boiler >

8. Jr., A. A. B., Part 7: Heating Load Rules of Thumb . In HVAC Equations, Data, and Rules of Thumb . 2000. McGraw

- Hill: San Francisco

9. U.S. Department of Energy

- Energy Efficiency & Renewable Energ y, Energy Conservation Program for Consumer Products: Technical Support Document: Energy Efficiency Standards for Consumer Products: Residential Boilers , 2014. Washington,

DC.