cZ3C

Public Workshop

on

Residential Furnace and Boiler Venting

May 8, 2002

The following slides provide back-up material in preparation to the venting workshop.

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EE-RM/STD-01-350 COMMENT 23C
Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides

List of Topics

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EE-RM/STD-01-350 COMMENT 23C
Furnaces/Boilers Rulemaking Workshop - NFGC Analysis - NFGC Background

Venting Research Sources

Several sources have been reviewed.

ANSI ANSI Standard Gas-fired Central Furnaces ANSI Z21.47-2001 ANSI Standard 2001

NFPA & ANSI National Fuel Gas Code ANSI Z21.47-2001 NFPA & ANSI 1999

NFPA 54-1999 Standard

Indiana Community Codes for Venting Combustion Appliances Andrews, T. Affordable Comfort 1999

Action Association Conference

GRI Assessment of Technology for Improving the Efficiency of Jakob, F.E., GRI-94/0175 1994

Residential Gas Furnaces and Boilers J.J.. Crisafulli, et al.

GRI Venting Gas Appliances into Exterior Masonry Chimneys Phillips, D. B., GRI-94/0193 1994

A. L. Rutz, et al.

GRI Corrosion Test Method for Gas Furnaces and Vents Talbert, S. G. and GRI-94/0050 1993

B. Hindin

GRI Presentation of the Vent-II Solution Methodology Rutz, A. L., GRI-92/0149 1992

R. D. Fischer, et al.

GRI Analysis of the Effects of Dilution Air and Appliance Efficiency Rutz, A. L., GRI-92/0357 1992

on Venting Cat I Appliances G. R. Whiacre, et al.

GRI A Reappraisal of Categorization Criteria for Venting Gas Borgeson, R. A. GRI-90/0150 1990

Appliances

GRI User's Manual for Vent-II (Version 4.1) Rutz, A. L., et at. GRI-90-0178 1990

GRI Venting Guidelines for Category 1 Gas Appliances w/ Fan- D. D. Paul, GRI-89/0016 1989

Assisted Comb Systems G.L.Whitacre, et al.

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EE-RM/STD-01-350 COMMENT 23C
Pubiic Workshop on Residential Furnace an ! Suiier Venting issues - Support Slides

List of Topics

3

EE-RM/STD-01-350 COMMENT 23C
Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides

Difference Between SSE and AFUE

ADL-commissioned ITS test results (teardown units).

Modulating Jacket

Loss SSE-AFUE

Input

Capacity

(Btu/hr)

Unit 1 Y 0.22% 0.7% 75,000

Unit 2 Y 0.44% 1.4% 66,000

Unit 3 Y 0.17% N/A 75,000

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EE-RM/STD-01-350 COMMENT 23C
Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides

Difference Between SSE and AFUE

Results of tests from the ADL database.

Modulating SSE-AFUE

Input

Capacity

(Btu/hr)

Unit I N 1.2% 75,000

Unit 2 N -0.1% 100,000

Unit 3 N 0.1% 75,000

Unit 4 N 2.4% 46,000

Unit 5 N 1.5% 45,000

Unit 6 N 1.8% 50,000

Unit 7 N 0.5% 75,000

Unit 8 N 2% 50,000

Unit 9 N 1.9% 40,000

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EE-RM/STD-01-350 COMMENT 23C
Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides

Difference Between SSE and AFUE

_V^1%ZIM;'Nat AM

GAMA s ubmitted test results.

Jacket Loss Input Capacity (Btu/hr)

Unit 1 0.75% 40,000

Unit 2 0.40% 40,000

Unit 3 0.39% 50,000

Unit 4 0.48% 60,000

Unit 5 0.52% 60,000

Unit 6 0.42% 75,000

Unit 7 0.23% 80,000

Unit 8 0.23% 80,000

Unit 9 0.11% 100,000

Unit 10 0.33% 100,000

Unit 11 0.50% 100,000

Unit 12 0.57% 100,000

Unit 13 0.41% 100,000

Unit 14 0.33% 115,000

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EE-RM/STD-01-350 COMMENT 23C
Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides

Difference Between SSE and AFUE

Test data gathered through ASHRAE SPC 103.

Modulating Jacket Loss SSE-AFUE

Input

Capacity

(Btu/hr)

Unit I Y 0.75% .35% 60,000

Unit 2 Y 040% -0.02% 100,000

Unit 3 Y 0.39% 0.07% 80,000

Unit 4 Y 0.48% 0.65% 100,000

Unit 5 Y 0.52% 0.65% 80,264

Unit 6 Y 0.42% 0.48% 99,612

Unit 7 Y 0.23% 0.94% 125,250

Unit 8 Y 0.23% 0.84% 100,588

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EE-RM/STD-01-350 COMMENT 23C
60 1 600/16 Assume Jacket Loss = 0.5%

50 i

40 40% I

I

U I

30 C

L I L

U

C)

20 0200%

10

O 0%

The GAMA directory and the CEC directory show a similar distribution

of S - E values.

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Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides

Difference Between SSE and AFUE

0.5 1 1.5 2 2.5 3

SSE - AFUE (%)

0 0.5

Assume Jacket Loss = 0.5%

I

I

I

a

a

1 1.5 2

SSE-AFUE (°/d

CEC

2.5 3

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EE-RM/STD-01-350 COMMENT 23C
Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides

Tubular vs. Clam Shell Heat Exchanger

From a preliminary analysis of the GAMA directory , furnaces with clamshell heat exchangers appear to have lower SSE-AFUE values than

appliances with tubular heat exchangers.

80% j 80%

60%

20%

0%

<0.5

60%

0.6-1

I

1.1-1.5 1.6-2

SSE-AFUE (%)

I

2.1-2.5

Clam Shell

(average SSE-AFUE = 0.6%)

2.6-3

N

d

40%

U

O

20%

0%

<0.5 0.6-1 1.1-1.5 1.6-2

ScEE-AFUE (%)

0

2.1-2.5 2.6-3

Tubular

(average SSE-AFUE = 0.9%)

Non-condensing gas fired furnaces. Assume a 0 .4% jacket loss to calculate SSE.

We assigned one kind of heat exchanger for each brand.

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EE-RM/STD-01-350 COMMENT 23C
Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides

List of Topics

According to a GRI study*, tolerances need to be taken into account

when setting maximum SSE value.

83% Steady-State Efficiency Limit (NFGC)

-- - - - - - - - - - - - - - -

I,

Heat Content (0.3%)

Air Flow (0.3%)

Room Temperature (0.1 %)

Test Procedure Tolerance (0.25%)

SSE-AFUE

Variability among the same product line

* Assessment of Technology for Improving the Efficiency of Residential Gas Furnacef aria Boilers , 1994, page 4-10.

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EE-RM/STD-01-350 COMMENT 23C
Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides

List of Topics

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EE-RM/STD-01-350 COMMENT 23C
Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides

NFGC Tables at Higher SSE

The process of creating input temperature profile to be used in

conjunction with VENT-II to generate tables at higher steady-state

efficiency (SSE) consist of two tasks.

- Replicate the shape of the temperature profile, assuming different

peak temperatures depending on SSE.

- Validate the curves with experimental data.

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EE-RM/STD-01-350 COMMENT 23C
Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides

NFGC Tables at Higher SSE

Temperature profiles were created for steady state efficiencies greater

than 83%, based on the NFGC input profile.

300

100

280

260

240

160

140

120

0 2 4 6 8 10 12 14 16 18

Time (min)

Higher steady-state efficiencies correspond to lower peak temperatures (see next slide).

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EE-RM/STD-01-350 COMMENT 23C
Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides

NFGC Tables at Higher SSE

The peak temperature decreases at higher steady state efficiency.

We assumed:

- 65% excess air

- 60OF ambient (typical operating condition)

Steady State Efficiency (°I°) Flue Temperature (°F)

81 339

82 308

83 277

84 245

85 214

86 183

87 151

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EE-RM/STD-01-350 COMMENT 23C
Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides

NFGC Tables at Higher SSE

The practical necessity to use higher level of excess air when taking

the experimental data resulted in lower exhaust temperatures.

160

VENT II Input

/ 87% efficiency with

I 65% excess air

ea

U 100

90

80

70 !-

0

87ff ' th

Experimental Data

° e iciency wi

110% excess air

5 10 15 20

Time (mmn)

However, the slopes of the heat u p and cool down portions of the

curves are very similar.

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EE-RM/STD-01-350 COMMENT 23C
Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides

NFGC Tables at Higher SSE

By overlaying the two curves we noticed that the slope of the

experimental curve closely matches the VENT 11 profile and validates

the higher efficiency curves.

Time (min)

VENT 11 Input

87% efficiency with

65% excess air

Experimental Data

87% efficiency with

110% excess air

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EE-RM/STD-01-350 COMMENT 23C