7

- i C HAPTER 7. ENERGY USE ANALYSIS

TABLE OF CONTENTS

7.1 INTRODUCTION

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

- 1

7.2 BUILDING SAMPLE

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

- 2

7.3 COMMERCIAL PACKAGED BOILER ENERGY CONSUM PTION

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

- 7

7.3.2 Space

- Heating Fuel Consumption

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

- 8

7.3.2.2 Determina tion of Space

- Heating Burner Operating Hours (BOH SH )

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

- 9

7.3.2.3 Determination of Equipment Sizing

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

- 11

7.3.3 Water

- Heating Energy Consumption

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

- 12

7.3.4 Electricity Consumption

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

- 13

7.4 SUMMARY OF ENERGY U SE RESULTS

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

- 13

LIST OF TABLES

Table 7.1.1 Commercial Packaged Boiler Equipment Classes Analyzed

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

- 1

Table 7.2.1 Selection of CBECS 2003 Records for Commercial Packaged Boilers

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

- 5

Table 7.2.2 Selection of RECS 2009 Records for Commercial Packaged Boil ers

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

- 6

Table 7.2.3 Fractions of Commercial Boilers in New Construction Buildings based on the Shipment Model Developed in the NIA (Commercial Sample)

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

- 7

Table 7.4.1 Average Annual Energy Consumption and Savings for Commercial Packaged Boilers

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

- 14

LIST OF FIGURES

Figure 7.3.1 Space

- Heating Energy Use M ethodology

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

- 87

- 1 CHAPTER 7. ENERGY USE ANALYSIS

7.1 I NTRODUCTION

The purpose of the energy use analysis is to determine the annual energy consumption of commercial packaged boilers in use in the United S tates and to assess the energy savings potential of increase s in efficienc y ( t hermal e fficiency ( TE ) or c ombustion e fficiency ( CE ) )

. In

contrast to the commercial packaged boiler test procedure under Title 10 of the Code of Federal Regulations, Part 431, which use s fixed operating conditions in a laboratory setting, the energy use analysis for commercial packaged boiler s seeks to estimate the range of energy consumption

of the equipment in the field. The U.S. Department of Energy ( DOE ) estimate s the annual energy consumption of such boiler s at specified energy efficiency levels across a range of climate zones

, building c haracteristics , and space and water heating applications

.

For the calculation of the energy consumed by commercial packaged boilers, DOE

consider s the energy use associated with providing space heating and water heating in either

commercial or residential buildings

. Space heating applications for commercial packaged boilers

include forced air using fan coils or central air handlers and radiant heating ( i n

- floor, radiant panels, radiators, baseboard). W ater heating applications for commercial packaged boilers include indirect water heating, combination equipment, and tankless coil

- type

. The energy use analysis provides estimates of the distribution of annual energy consumption for boiler s at each efficiency standard level considered.

DOE devel op s energy consumption estimates for the key equipment classes listed in

Table 7.1.1

. The boilers analyzed utilize gas or oil fuel for heating water or steam and the associated electric energy to power a water pump, a draft inducer, an ignit e r, and other auxiliary equipment.

Table 7.1.1 Commercial Packaged Boiler Equipment Classes Analyzed

Heating

Medium Subcategory Size category (input) Draft Type Abbreviation

Hot Water Gas

- fired ≥300,000 Btu/hr and ≤2,500,000 Btu/hr Natural Draft SGNDHW

Hot Water Gas

- fired >2,500,000 Btu/hr Natural Draft LGNDHW

Hot Water Oil

- fired ≥300,000 Btu/hr and ≤2,500,000 Btu/hr Natural Draft SONDHW

Hot Water Oil

- fired >2,500,000 Btu/hr Natural Draft LONDHW

Steam Gas

- fired ≥300,000 Btu/hr and ≤2,500,000 Btu/hr Natural Draft SGNDST

Steam Gas

- fired >2,500,000 Btu/hr Natural Draft LGNDST

Steam Oil

- fired ≥300,000 Btu/hr and ≤2,500,000 Btu/hr Natural Draft SONDST

Steam Oil

- fired >2,500,000 Btu/hr Natural Draft LONDST

Hot Water Gas

- fired ≥300,000 Btu/hr and ≤2,500,000 Btu/hr Mechanical Draft SGMDHW

Hot Water Gas

- fired >2,500,000 Btu/hr Mechanical Draft LGMDHW

Hot Water Oil

- fired ≥300,000 Btu/hr and ≤2,500,000 Btu/hr Mechanical Draft SOMDHW

Hot Water Oil

- fired >2,500,000 Btu/hr Mechanical Draft LOMDHW

Steam Gas

- fired ≥300,000 Btu/ hr and ≤2,500,000 Btu/hr Mechanical Draft SGMDST

Steam Gas

- fired >2,500,000 Btu/hr Mechanical Draft LGMDST

Steam Oil

- fired ≥300,000 Btu/hr and ≤2,500,000 Btu/hr Mechanical Draft SOMDST

Steam Oil

- fired >2,500,000 Btu/hr Mechanical Draft LOMDST7

- 2 DOE estimate s the energy consumption of commercial packaged boilers in commercial buildings and housing units by developing a building sample for each of the 16 equipment

classes based on the Energy Information Administration’s (EIA) 2003 Commercial Building Energy Consumption Survey (CBECS 2003) and EIA’s 2009 Residential Energy Consumption Survey (RECS 2009 )

. 1

, 2 These are the latest available surveys for commercial and residential

buil dings. a This sample is further described in section 7.2

.

DOE used CBECS 2003

- or RECS 2009

- reported heating energy consumption (based on the existing heating system) to calculate the space

- heating load of each building . The heating load represents the amount of heating required to keep a building comfortable throughout an

average year. In buildi ngs where DOE finds that the boiler also serves hot water heating needs,

DOE use s the CBECS 2003

- or REC S 2009

- reported water

- heating energy (based on the existing water heating system) to calculate the water heating load of each building

.

DOE assign s t he energy efficiency of existing systems based on a historical distribution of energy efficiency for boiler s by equipment class . In addition, DOE ma kes adjustments based on historical weather data, average estimated return water temperature, projections of shell efficiency and building square footage, and for buildings that had secondary heating equipment that used the same fuel as the boiler. To complete the analysis, DOE calculate s the energy consumption of alternative (more energy

- efficient) equipment if they replaced existing systems

in each commercial building or housing unit

.

7.2 BUILDING SAMPLE

DOE’s determination of the annual energy use of commercial packaged boilers relie s on
data from CBECS 2003 and RECS 2009

. 1

, 2 CBECS 2003 include s energy

- related data from 5,215 buildings representing 4.9 million buildings. RECS 2009 include s energy

- related data from 12,083 housing units that represent almost 113.6 million households.

The subset CBECS 2003 or RECS 2009 records used in the analysis me e t all the following criteria:

• use a boiler as the main or secondary source of heat;

• use a heating fuel that is natural gas (not including liquid petroleum gas (LPG)) or fuel oil; and

• ha ve a heating energy consumption greater than zero

.

DOE disaggregate s EIA’s CBECS 2003

- and RECS 2009

- derived commercial packaged

boiler subset into further subsets based on the boiler fuel, size, heating medium ( steam or hot

water )

, and draft type (natural or mechanical draft). These subsets are designed to isolate the buildings that are equipped with each of the different equipment classes ( Table 7.2.1 for

a EIA is currently working on the 2013 version of RECS, which is not expected to be available until 2015. Additionally, EIA determined that the 2007 Commercial Buildings Energy Consumption Survey did not yield valid statistical estimates of building counts, energy characteristics, consumption and expenditures and therefore did not release the majority of the data tables and public use files.7

- 3 commercial applications and Table 7.2.2 for residential applications ). To sample between the commercial and residential samples, DOE use s the square foot age weighted fractions of each equipment class sample. The new construction sample is based on the same selection algorithms as the replacement sample but only includes buildings built after 1990, which DOE believes would have more similar building charact eristics to the new construction buildings in 2019 ( e.g. building insulation, regional dis tribution of the buildings, and so forth

. ).

T o disaggregate between large and small equipment classes, DOE develop s a scheme to determine the size of the boiler installed in the building. For both the commercial and residential sample s , the sizing of the equipment installed in the building is determined from the heated square footage of the building and on a heating loa d per floor area of 30 Btu/h/sqf t, and is adjusted to account for an oversize factor of 1.1, the efficiency of the equipment (which is based on the construction year), and the outdoor design temperature corresponding to the weather location of the building

.

The number of boilers for both the commercial and residential sample s are determined using the total sizing of the equipment: 3

1) when the total sizing is larger than 7.11 b MMBtu/hr, the number of boilers is equal to the total sizing divided by 6.7 c MMBtu/hr, 2) when the total sizing is below 7.11 MM Btu/h but larger than 2.5 d MMBtu/h, the number of boilers is equal to the total sizing divided by 4.4 e MMBtu/hr, 3) when the total sizing is below 2.5 MMBtu/h, the number of boilers is equal to the total sizing divided by 1.1 f MMBtu/hr,

T he sample is disaggregated by boiler size based on the sizing of all equipment and on the number of boilers in each building

.

Both the replacement and the new construction sample are disaggregated by natural and

mechanical draft by applying fractions of natural and mechanical draft data based on model data

extracted from the Air

- Conditioning, Heating, and Refrigeration Institute ( AHRI ) Directory of

Certified Product Performance

. 3

Steam boilers are assumed to be installed in 14 percent of buildings built before 1970 and in 0 percent of buildings built after 1970

. 4

b 7.11 MMBtu/hr, is the 90th percentile of the input capacity of the large commercial packaged boilers (above 2.5 MMBtu/hr) derived from the CBECS

- 2003

- based commercial sample that was determined for this analysis (all fuels, heating mediums and draft types)

c 6.7 MMBtu/hr, is the 90th percentile of the input capacity of large commercial packaged boilers (above 2.5

M MBtu/hr) found in the AHRI directory (all fuels, heating mediums and draft types)

d 2.5 MMBtu/hr is the limit in terms of input capacity, above which a boiler is considered large

e 4.4 MMBtu/hr, is the average input capacity of large commercial packaged bo ilers (above 2.5 MMBtu/hr) found in the AHRI directory (all fuels, heating mediums and draft types)

f 1.1 MMBtu/hr, is the average input capacity of small commercial packaged boilers (below 2.5 MMBtu/hr) found in the AHRI directory (all fuels, heating medi ums and draft types)7

- 4 Commercial packaged boilers are considered in residential applications when the total heated square footage of the building (equal to the heated square footage of each unit multiplied by the number of units in the building), is larger than 10,000 square feet (usually multifamily building s).

The CBECS 2003 and R ECS 2009 weighting indicates how commonly each commercial building or household configuration occurs on the national level, in 2003 and 2009 , respectively.

DOE adjusted EIA’s weightings for CBECS 2003 and RECS 2009 buildings to ad just for buildings with multiple boilers. Appendix 7

- A presents the variables included and their definitions, as well as further information about the derivation of the building samples, the adjustments to the boiler weights, and sampling fractions for eac h of the four samples

commercial and residential, both disaggregated between ne w construction and replacement.7

- 5 Table 7.2.1 Selection of CBECS 2003 Records for Commercial Packaged Boilers

Equipment Class No. of

Records CBECS

2003 DOE 2019 Fraction

of New

Construction Number of Buildings Number of

Boilers

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 482 10847 15619 18%

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 480 318 548 24%

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 73 8993 11218 26%

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 142 5479 8922 16%

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 266 40890 55621 0%

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 225 3986 6181 0%

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/ hr and ≤2,500,000 Btu/hr 50 1795 2450 0%

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 79 2292 3752 0%

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 482 130409 187777 18%

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 480 38217 65777 24%

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 73 20542 25625 26%

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 142 5479 8922 16%

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 266 7638 10390 0%

Mechanical Draft Gas

- Fired Steam Commercial Packaged

Boiler > 2,500,000 Btu/hr 225 5983 9278 0%

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 50 7738 10559 0%

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 79 2292 3752 0%7

- 6 Table 7.2.2 Selection of RECS 2009 Records for Commercial Packaged Boilers

Equipment Class No. of

Records RECS

200 9 DOE

2019 Fraction

of New

Construction Number

of Buildings Number

of

Boilers

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 125 2585 2963 7%

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 29 15 18 16%

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 69 4931 5743 8%

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 12 266 327 12%

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 79 3144 3548 0%

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 13 55 68 0%

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 57 431 500 0%

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 10 35 42 0%

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 125 31082 35621 7%

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 29 1764 2129 16%

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 69 11264 13119 8%

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 12 266 327 12%

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 79 587 663 0%

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 13 82 103 0%

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 57 1857 2155 0%

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr 10 35 42 0%

To sample between the new construction and replacement markets, DOE uses the

fractions derived in the National Impact Analysis (NIA) of commercial packaged boilers shipped

to new and replacement construction (see Table 7.2.3 ).7

- 7 Table 7.2.3 Fractions of Commercial Boilers in New Construction Buildings based on the Shipment Model Developed in the NIA (Commercial Sample)

Equipment Class New Construction

Fractions

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 12%

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 1%

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 10%

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 13%

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 50%

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 71%

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr 39%

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler >2,500,000 Btu/hr 24%

7.3 COMMERCIAL PACKAGED BOILER ENERGY CONSUM PTION

To c alculate the energy use of commercial packaged boilers in each equipment classes

, DOE determine s the energy consumption associate d with space heating, water heating and

electric ity use during periods of space and wat er heating. For the space

- heating energy consumption determination, DOE estimate s the input capacity and burner operati ng hours of the existing boiler using the building heating energy consumption and boiler characteristics . For the water heating energy consumption determination, DOE identifie s the building water heating energy consumption and the recovery efficienc y of the existing boiler. The electric ity consumption i s determined using the burner operating hours associated with space and water heating a nd individual electrical measurements of all electrical components. The sum of the space heating, water heating

, and electrical energy consumption represents the estimated annual energy use of a sampled boiler. Additional details used for determining the t otal energy use can be found in the following sections.

The calculation for the determination of the total energy use is as follows:7

- 8 E nnnnn UU ttttt = FF F SS + FF F W + E E ttttt Eq. 7.1

Where:

FF F SS = t otal fuel consumption as a result of space heating loads

, FF F W = t otal fuel consumption as a result of water heating loads , and

E E ttttt = e lectrical consumption of all electrical components

.

7.3.2 Space

- Heating Fuel C onsumption

The space

- heating energy use methodology is illustrated by Figure 7.3.1

.

Figure 7.3.1 Space

- Heating Energy Use Methodology

D OE calculated the annual space

- heating fuel consumption ( FuelUse SH ) for each boiler using the following formula :

FF F SS = BBB SS × Q ii Eq. 7.2

Where:

BOH S H = full

- load space

- heating burner operating hours (hr /yr ), and Q in = input capacity of existing boiler (kBtu/hr). Efficiency Existing + Secondary Equip. Adjustment

* CBECS or RECS Energy Use HDD Adjust. + Building Shell Adjust.

* *

* Existing Equipment Adjustment

** Heating Load Adjustm ent to 2019 Heating Load

CE to TE Adjust. when Applicable

+ Return Water Temp. Adjust. (cond. ≠ non

- cond.)

+ Part Load/Cycling Adjust. Proposed

Rated Efficiency

Input Capacity (based on sample)

New Energy Use Burner Operating Hours7

- 9 DOE derive s the BOH from the building

- heating load served by a single boiler. The

b uilding

- heating load i s determined from annual fuel consumption for heating reported in

CBECS and RECS based on the efficiency of the existing boiler.

7.3.2.2 Determination of Space

- Heating Burner Operating Hours (BOH SH )

DOE calculate s space

- heating burner operating hours at full

- load for a boiler as :

BBB SS = BBB b bb Q ii × T r

, a Eq. 7.3

Where:

TE rated, a dj = r ated t hermal efficiency proposed , adjusted to account for the conversion between

combustion efficiency and thermal eff iciency when applicable

, g part

- load operation ( for

multi

- stage equipment) or cycling losses (for single

- stage equipment)

, and return water
temperature h (see appendix 7

- B for more detail )

, Q in = as defined in Eq. 7.2

, and

BHL boiler = b uilding heating load served by a single boiler operating at full load (kBtu/ yr )

.

S ee appendix 7

- B for more details on the adjustments made to rated thermal efficiency

.

The annual building

- heating load ( BHL boiler ) is the total amount of heat output from the

boiler that the building needs during the heating season. i DOE determined BHL t otal for each sampled building or housing unit , based on the efficiency of the existing b oiler , using the following calculation:

BBB b bb = Q YY × T
e

, a Eq. 7.4

Where:

Q YR = annual fuel consumption for space heating based on CBECS 2003 or RECS 2009 (kBtu/yr),

TE ex,adj = thermal e fficiency of the existing boiler ( TE

ex ) adjusted for the same considerations as

in the case of TE rated, adj

.

Both CBECS 2003 and RECS 2009 and report space

- heating energy use ( Q YR ) for each of the sampled buildings. See appendix 7

- B for more details about the derivation of the BHL

.

g DOE determines a relationship between the combustion efficiency and thermal efficiency f or the four equipment

classes using combustion efficiency as the efficiency metric

. See appendix 7

- B for more details.

h Return water temperature represents the average annual return water temperature for the different space heating applications.

i BHL is the load served by a single boiler. DOE assume s that 50 percent of buildings are served by two boilers that share the load equally, while the rem aining 50 percent are served by one boiler.7

- 10 The efficienc y of the existing boiler ( TE

ex ) is determined by matching historical efficiency data to the distribution of boiler age for CBECS 2003 buildings or reported age of the

boiler in RECS 2009

. j The efficiency of the existing boiler i s adjusted to accou nt for differences in average return water temperature (RWT) and cycling losses

. Appendix 7

- B provides additional detail regarding the derivation of the adjustment values.

Appendix 7B section 7.2.1 provide s the adjustments to the efficiency of the existing

boiler based on return water temperature ( RWT ) application type s , cycling losses, and part

- load operation

. High RWT is applied to all non

- condensing boiler installations . For condensing boiler

instal lations

, l ow RWT is applied to all boilers in th e new construction market

, 25 percent of replacement boilers in buildings built after 1990

, and 5 percent of replacement boilers in buildings built before 1990

. DOE assume s that all other condensing boiler installations are h igh RWT applications. The efficiency adjustment for low and high RWT is dependent on climate.

DOE adjust s the efficiency of two

- stage and modulating condensing boiler s to account for increased efficiency at part

- load operation. In addition, for non

- condensing boilers, DOE

acc ount s for the decrease in efficiency due to cycling. See a ppendix 7

- B for the adjustment factors used for RWT, part

- load operation, and cycling by climate zone.

DOE adjust s the B HL to reflect the expectation that the buildings in 20 19 will have a

somewhat different B HL than the buildings in the CBECS 2003 and RECS 2009 building sample. The adjustment involves multiplying the calculated BHL for each CBECS 2003 or RECS 2009 buil ding by the building shell efficiency index from AEO 2014

. k This factor d iffers

for commercial and residential buildings as well as new construction and replaceme nt buildings.

The factor in the analysis for commercial buildings range s from 0. 75 to 0.98 for replacements (depending on building type) and from 0.8 4 to 1.00 for new construction , while for residential buildings , it range s from 0. 79 to 0.97 for replacements and from 0.9 1 to 1.03 for new

construction

. This means that buildings on average will have lower or slightly lower space heating load compared to commercial buildings in 2003 or residential buildings in 2009

.

DOE also adjust s the BHL TOTAL calculated using heating degree days reported in CBECS

2003 and RECS 2009 for each building, National Oceanic and Atmospheric Administration (NOAA) data by region to reflect historical average climate conditions

. 7 The adjustment factor s are calculated using the following equation :

j CBECS 2003 does not report the age of the equipment, so DOE created a uniform distribution to estimate the age of the equipment.

k The building shell efficiency index sets the heating load value at 1.00 for an average commercial building in 2003 and an average residential building (by type) in 2009 in each census division. The current analysis is b ased on information from the National Energy Modeling System (NEMS) simulation performed for EIA’s Annual Energy Outlook ( AEO 2013 5 for commercial buildings and AEO 2014 6 for residential buildings )

. _ENREF_4 See appendix 7

- B for m ore details.7

- 11 AA j

f f a a ccccccc = HH 10 y r aa HH b Eq. 7.5

Where:

HDD bldg = HDD in 2003 or 200 9 for commercial or residential buildings (respectively), for the specific region where the building is located, and

HDD 10 _yr_avg = 10

- year average HD D (200 4

– 20 1 3 ) based on NOAA data for the specific region

where the building is located. l

The adjustment factors for commercial buildings range from 0.9 4 to 0.97 ( i.e. , 200 3 was in general colder than the 10

- year average)

, while the residential sample factors range from 0.94

to 1.05

.

DOE understands that some of the sampled buildings use multiple heating appliances with the same fuel as the boiler(s)

, such as a central furnace, wall furnace, room heater, stove, or fireplace

. Therefore

, DOE adjust s the calculated BHL when necessary to reflect the use of secondary heating equipment using the same fuel as the boiler(s) . The adjustment factors are calculated using reported survey information from both CBECS 2003 and RECS 2009 regarding the fraction of heating that is met by different heating equipment

. Se e appendix 7

- B for more

details.

7.3.2.3 Determination of Equipment Sizing

To support the calculation of space

- heating energy use, DOE establish e s a methodology for deriving the boiler input capacities of each of the sampled buildings. The determination of the

i nput 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 th e boiler being

considered under the standard.

Q ii = AA A A AA AAA

T
e e × O OO

Eq. 7.6

Where:

AdjustedHeatL oad = estimated building heat loss adjust ed for building weather locat ion (kBtu/ h ) (see appendix 7

- B)

, TE existing = TE of the existing boiler for each product class (see appen dix 7

- B) , and,

OversizeFactor = 1. 1

, based on input from consultants on typical sizing practices

.

l The last 10

- year average is used to normalize the HDD values, which is similar to what is done in AEO 2014

.7

- 12 DOE calculate s the adjusted heat ing load for each sample building or housing unit based on the applicable building characteristics and outdoor conditions derived from the CBECS and

RECS data.

DOE develop s a methodology to derive the total heat loss of the building ( i.e

. , adjusted

heat ing load). Appendix 7

- B presents the variables used as well as further information about the building characteristics and heat ing load values used for the sizing of boiler equipment.

7.3.3 Water

- Heating Energy Consumption

Commercial packaged b oilers are often used to provide hot water in addition to space heating. The most common means of doing so are through an indirect water heater, tankless coil, or as an integrated part of the boiler.

CBECS 2003 and RECS 2009 do not provide information about when a commercial packaged boiler is use d to provide hot water. Whe re CBECS or RECS report that the buildings

use d the same fuel for both space and water heating , DOE assume s that 50 percent of the

installations also use boilers for water heating

.

To calculate t he water

- heating energy use, DOE calculate s the boiler fuel use for water heating based on the following equation:

FF F W = W

T

− AA j F W Eq. 7.7

Where:

WHL = water heating energy use based on CBECS 2003 or RECS 2009

, TE = TE of the selected efficiency level, and Adj_Factor WH = adjustment factor to take into account the difference between TE and recovery efficiency for w ater heating , which is assumed to be 4.5 percent TE for non

- condensing units

and 2

. 25 percent TE for conden sing units

. A h eat lo ss of 0. 5 kBtu /h was considered for

indirect water heaters.

DOE use s the following equation to calculate the water heating load (WHL):

W = Q YY

, × ( T
e − AA j F W )
Eq. 7.8

Where:

Q YR,HW = annual fuel consumption for w ater heating based on CBECS 2003 or RECS 2009 (kBtu/yr),

TE

ex = TE of the existing boiler (see appendix 7

- B ), and Adj_Factor WH = as defined previously.7

- 13 7.3.4 Electricity Consumption

DOE calculate s boiler electricity consumption for the circulating pump

, the draft inducer (in the case of mechanical draft equipment) , and the ignit e r. The circulating pump move s water through the building whenever the boiler burner is on (adjusted for delay times between burner

and pump operation). If the boiler provides wate r heating , the circulating pump also operates in the cooling season (summer) when the re is a call for water heating . In the case of modulating condensing boilers, to accommodate for lower firing rates, the inducer provide s lower

combustion airflow to regul ate the excess air in the combustion process

.

DOE also t akes into account the electricity consumption of auxiliary equipment such as condensate pumps, which are sometimes installed with higher efficiency equipment. If a building require s a condensate pump, DOE assume s that consume s 60 watts and operate s at the same time

as the burner. Details of how DOE determine s whether a building required a condensate pump can be found in appendix 8

- D

.

DOE calculate s the electricity consumption as: m

E E ttttt = BBB SS × AA BB × E EE E + E E W × E EE E

+ S S × S S Eq. 7.3

. 1

Where:

BOH S H = as defined in Eq. 7.2

, 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

, ( kW ),

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 = s tandby hours, tak ing into account periods of water heating in the summer

Further details for calculating electricity consumption appear in appendix 7

- B

.

7.4 SUMMARY OF E NERGY U SE R ESULTS

This section presents the average annual energy use and the average energy savings for each considered energy efficiency level compared to the baseline energy eff iciency for each commercial packaged boiler equipment class. The results reflect energy use in both the

commercial and residential samples. The LCC and PBP analys e s use the results calculated for each sample building. Negative results indicate that energy use increases.

m For two

- stage and modulating equipment

, this formula includes parameters for the operation at full, modulating,

and reduced load. S ee appendix 7

- B.7

- 14 Table 7.4.1 Average Annual Energy Consumption and Savings for Commercial Packaged Boilers

EL Design Option Annual Fuel Use Annual Electricity Consumption of Auxiliary Components

Total Savings Total Savings
MMBtu/yr MMBtu/yr kWh/yr kWh/yr

Natural Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000

Btu/hr

0 80% TE

- Baseline 830.1

- 341.5

- 1 81% TE 819.7 10.4 337.3 4.2

2 82% TE 809.5 20.6 333.2 8.4

3 85% TE

- Max Tech 780.5 49.6 321.4 20.2

Natural Draft Gas

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

0 82% CE

- Baseline 3825.8

- 885.7

- 1 83% CE 3771.8 54.0 873.3 12.4

2 84% CE

- Max Tech 3719.4 106.4 861.3 24.4

Natural Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/ hr and ≤2,500,000

Btu/hr

0 82% TE

- Baseline 597.9

- 309.0

- 1 83% TE 590.3 7.6 305.0 3.9

2 85% TE 575.7 22.2 297.5 11.5

3 87% TE

- Max Tech 561.8 36.1 290.3 18.7

Natural Draft Oil

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

0 84% CE

- Baseline 2298.1

- 685.1

- 1 85% CE 2269.7 28.4 676.7 8.4

2 86% CE

- Max Tech 2241.9 56.1 668.5 16.7

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr

0 77% TE

- Baseline 747.6

- 330.0

- 1 79% TE 727.8 19.8 321.3 8.7

2 80% TE

- Max Tech 718.3 29.3 317.1 12.9

Natural Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr

0 77% TE

- Baseline 4051.9

- 1007.9

- 1 79% TE 3942.5 109.4 981.0 27.0

2 80% TE 3890.0 161.8 968.0 39.9

3 81% TE

- Max Tech 3838.9 213.0 955.4 52.5

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000 Btu/hr

0 81% TE

- Baseline 838.9

- 395.1

- 1 82% TE 828.1 10.8 390.0 5.1

2 83% TE

- Max Tech 817.6 21.3 385.1 10.0

Natural Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr

0 81% TE

- Baseline 2924.2

- 859.9

- 1 82% TE 2886.5 37.8 848.8 11.1

2 83% TE 2849.7 74.5 838.0 21.8

3 85% TE

- Max Tech 2778.8 145.4 817.3 42.6

Mechanical Draft Gas

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000

Btu/hr

0 80% TE

- Baseline 938.8

- 746.2

- 1 83% TE 903.7 35.1 720.3 25.9

2 85% TE 881.8 57.0 704.1 42.17

- 15 3 87% TE 860.9 77.9 688.7 57.5

4 92% TE 824.5 114.3 990.3

- 244.1

5 95% TE 797.5 141.3 959.7

- 213.5

6 98% TE

- Max Tech 772.2 166.5 931.1

- 184.9

Mechanical Draft Gas

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

0 82% CE

- Baseline 3698.9

- 1305.8

- 1 84% CE 3595.9 103.0 1271.1 34.7

2 86% CE 3498.5 200.4 1238.3 67.5

3 94% CE 3182.0 517.0 1662.0

- 356.2

4 97% CE

- Max Tech 3068.6 630.3 1604.7

- 298.9

Mechanical Draft Oil

- Fired Hot Water Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000

Btu/hr

0 82% TE

- Baseline 680.2

- 685.7

- 1 83% TE 671.6 8.6 677.6 8.1

2 84% TE 663.1 17.1 669.7 16.0

3 87% TE 639.1 41.1 647.1 38.6

4 98% TE

- Max Tech 573.8 106.4 857.8

- 172.1

Mechanical Draft Oil

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

0 84% CE

- Baseline 2240.9

- 1059.9

- 1 86% CE 2186.1 54.7 1035.2 24.7

2 88% CE 2134.0 106.8 1011.7 48.2

3 97% CE

- Max Tech 1976.1 264.7 1342.4

- 282.5

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000

Btu/hr

0 79% TE

- Baseline 752.4

- 672.7

- 1 80% TE 742.7 9.7 664.6 8.1

2 81% TE 733.3 19.1 656.7 16.0

3 83% TE

- Max Tech 715.2 37.3 641.5 31.2

Mechanical Draft Gas

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr

0 79% TE

- Baseline 3925.3

- 1524.2

- 1 80% TE 3873.0 52.3 1504.7 19.5

2 83% TE

- Max Tech 3724.3 201.0 1449.1 75.1

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler ≥300,000 Btu/hr and ≤2,500,000

Btu/hr

0 81% TE

- Baseline 830.1

- 785.7

- 1 83% TE 809.0 21.1 766.9 18.8

2 84% TE 798.9 31.2 757.9 27.8

3 86% TE

- Max Tech 779.3 50.8 740.4 45.2

Mechanical Draft Oil

- Fired Steam Commercial Packaged Boiler >2,500,000 Btu/hr

0 81% TE

- Baseline 2925.6

- 1334.2

- 1 83% TE 2851.0 74.6 1301.5 32.7

2 86% TE

- Max Tech 2746.0 179.6 1255.5 78.87

- 16 REFERENCES

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< http://www.eia.gov/consumption/residential/data/2009/ >

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< http://www.eia.gov/consumption/commercial/data/2003/index.cfm?view=microdata >

3. 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 >

4. Air Conditioning Heating and Refrigeration Institute, Directory of Certified Pro duct Performance for Residential Boilers, 2013.

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

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- Energy Information Administration, Annual Energy Outlook 2013 with Projections to 2040 , 2013. Washington, DC.

< http://www.eia.gov/forecasts/aeo/ >

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- Energy Information Administration, Annual Energy Outlook 2014 with Proj ections to 2040 , 2014. Washington, DC.

< http://www.eia.gov/forecasts/aeo/ >

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