# cZ3C



# Public Workshop on 

# Residential Furnace and Boiler Venting

M a

# y 8, 2002

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


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### Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

## List of Topics

1

### 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. 2

### Pubiic Workshop on Residential Furnace an ! Suiier Venting 

### issues
- Support Slides 

## List of Topics

3

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

## Difference Between SSE and AFUE ADL- co mm issioned 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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### Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

## Difference Between SSE and AFUE Results of tests fro m 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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### Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

## Difference Between SSE and AFUE
_V^1%ZIM;'Nat AM 

# GAMA s ubm itted 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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### Public workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

## Difference Between SSE and AFUE Test data g athered 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

760 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% 

## Th e GAMA directory and the CEC directory show a similar distribution of S - E values.

0 

### 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% III 

## aa

1 1.5 2 SSE-AFUE (°/d 

# CEC 2.5 3

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### Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

## Tubular vs. Clam Shell Heat Exchanger Fro m a p reliminary analysis of the GAMA directory , furnaces with clamshell he at exchangers appear to have lower SSE-AFUE values than ap p lian c es 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. 9

### Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

# List of Topics A ccordi ng to a G RI study*, tolerances need to be taken into account when settin g 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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### Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

## List of Topics

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

## NFGC Tables at Higher SSE The pro cess of creating input temperature profile to be used in conjun ction with VENT-II to generate tables at higher steady-state efficie n cy ( SSE) consist of two tasks. - Replicate the shape of the temperature profile , assuming different pe ak temperatures depending on SSE.

- Validate the curves with experimental data.

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

## NFGC Tables at Higher SSE Temperature p rofiles were created for steady state efficiencies greater th an 83 % , ba s e d 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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### Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

## NFGC Tables at Higher SSE Th e peak temperature decreases at higher steady state efficiency. We assu med: 

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

## NFGC Tables at Higher SSE Th e p ractical n ecessity 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 I 65% excess a r

ea U 100 90 80 70 !- 0 87ff ' th Experimental Data

i ° e iciency w 110% excess air

5 10 15 20

Time (mmn) 

## H owever, the slopes of the heat u p and cool down portions of the c urv es a re ve ry similar.

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### Public Workshop on Residential Furnace and Boiler Venting Issues - Support Slides 

## NFGC Tables at Higher SSE By overlayin g the two curves we noticed that the slope of the experi mental curve closely matches the VENT 11 profile and validates the hi gh er 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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