COMBINATION ZPACEIWATE R HEATING APPLIANCES

George E. Kelly

Building Environme nt Div.

MIST

EE-DET-94-101 COMMENT 05 '':''"", ' 

COMBINATION .SPACEIWATER HEATING APPLIANCES 

George E. Kelly 

Building Environment Div. 

NIST 
PERFORMANCE TESTING OF COMBINATION SPACE I WATER HEATING

APPLIANCES

**

**

Current Industry Standard - ANSI/ASHRAE Standard 124-1991

Types of appliances covered by the Standard:

TYPE I - Primary function: space heating. Secondary function: water heating

Space heating boiler with tankless water heater (heating coil)

* Space heating boiler with indirect* heated hot water storage tank

TYPE II - Primary function : water heating. Secondary.function: space heating

* Water heater combined with air handling unit (AHU)

* Water heater combined with hydronic system (baseboard convector)

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PERFORMANCE TESTING OF COMBINATION SPACE I WATER HEATING 

APPLIANCES 

** Current Industry Standard - ANSIIASHRAE Standard 124-1991 

** Types of appliances covered by the Stand~rd: 

TYPE I - Primary function: space heating. Secondary function: water heating 

* Space heating boiler with tankless water heater (heating coif) }'. 

* Space heating boiler with indirect heated hot water storage tank 

TYPE 11- Primary function: water h~ating. Secondary.function: space heating 

* Water heater combined with air handling unit (AHU) 

* Water heater combined with hydronic system (baseboard convector) 
TYPE 1 • Boiler with Tankless Coil

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TYPE I • Boiler with Tankless Coil 
TYPE I - Boiler with Indirect Fired Storage Tank

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TYPE I • Boiler with 'Indirect Fired Storage Tank 
TYPE 11 -Water. Heater with Air Handling Unit

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TYPE II - Water. Heater with Air Handling· Unit 
TEST PROCEDURES SPECIFIED IN ANSI/A E 124-1991

Tests Required : Two separate. tests are specified in the Standard.

Test 1. Space heating test in accordance to ASHRAE Standard 103:

* Steady state test: Steady-state efficiency (Effss)

* Cool-down and heat-up test: Heating seasonal efficiency (Eff,,s)

Test 2. Water heating, test in accordance with DOE test procedure for TYPE

II, or similar test for TYPE I appliance specified in.AS RAE 124:

* 24-Hour simulated use test: Energy Factor (EF)

EE-DET-94-101 COMMENT 05

TEST PROCEDURES SPECIFIED IN ANSI/ASHRAE 124·1991 

Tests Required: Two separate tests are specified in the Standard. 

Test 1. Space heating test in accordance to ASHRAE Standard 103: 

* Steady state test: Steady-state efficiency (Eff ss) 

* Coot·down and heat-up test: Heating seasonal efficiency (EffHS) 

Test 2. Water heating'test in accordance with DOE test procedure for TYPE . . 

II, or similar test for TYPE I appliance specified in ASHRAE 124: 

. * 24-Hour simulated use test: Energy Factor (EF) 
ENERGY PERFORMANCE CALCULATIONS

Space heating season (space and water heating):

Space heating at heating seasonal efficiency (Eff 8). (With off-cycle loss)

Water heating at steady-state efficiency (Effss). (No standby loss)

* Nonheating season (Water heating ): By energy factor (EF). (Standby loss)

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ENERGY PERFORMANCE CALCULATIONS 

* Space heating season (space and water heating): 

Space heating at heating seasonal eficiency (EffHS). (With off-cycle loss) 

Water heating at steady-state efficiency (Effss). (No standby loss) 

*. Nonheating season (Water heating): By energy factor (EF). (Standby loss) 
PERFORMANCE RATINGS SPECIFIED IN ANS I S E 124-1991

Energy Performance Rating Parameters:

Combined Heating Season Efficiency - CEHs

Nonheating Season Efficiency - CENS

Combined Annual Efficiency CAE

Rating parameters are calculated by combining Effss, EffHS , and EF through

weighting factors based on the fractions of the space heating load and water

heating load to the total seasonal and total annual space-water heating loads

and the length of the nonheating season to the length of the heating season.

EE-DET-94-101 COMMENT 05

.' , PERFORMANCE RATINGS SPECIFIED IN ANSI/ASHRAE 124 .. 1991 

Energy Performance Rating Parameters: 

Combined Heating Season Efficiency - CEtiS 

Nonheating Season Efficiency - CENS 

Combined Annual Efficiency - CAE 

Rating parameters are calculated by combining Effss• EffHS' and EF through 

weighting factors based on the fractions of the space heating load and water 

heating load to the total seasonat and total annual space-water heating loads 

and the length of the nonheating season to "the length of the heating season. 
TESTING OF COMBINATION APPLIANCES AT NI ST

Comparison Tests:

NIST conducted separate space heating and water heating tests and

combined space and water heating cyclic tests. Results of combined cyclic

spacing and water heating tests were compared with the results obtained

using ANSI/ASHRAE 124.

TYPE I - Oil-fired boiler with 'tankless heater

Cyclic space heating: On 9.68 min . Off 33. 26 min.

Water heating : 18-hour standby, 6 hourly draw of 20 gal. each time

TYPE II - Gas-fired water heater with air handling unit (AHU)

Water heating: 6 hourly draw of 10 .7.gal. each time, 18-hour stanby

Cyclic space heating: At several typical ratios of on-time to total

on-off time,

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TESTING OF COMBINATION APPLIANCES AT NIST 

, 'Comparison Tests: 

NIST conducted separate space heating and water heating tests and 

combined space and water heating cyclic tests. Resufts of combined cyclic 

spacing and water heating tests were compared with the results obtained 

using ANSIIASHRAE 124. 

TYPE I - Oil-fired boiler with tankless heater 

Cyclic space heating: On 9.68 min. Off 33.26 min. 

, Water heating: 18-hour standby, 6 hourly draw of 20 gal each time 

TYPE tl .. Gas-fired water heater with air handling unit (AHU) 

Water heating: 6 hourly draw of 10.7,gal. each time, 18-hour stanby 

Cyclic space heating: At several typical ratios of on-time to total 

on-off time . 
COMPARISON OF RESULT - COMBINED HEATING SEASON EFFICIENCY

COMBINED CYCLIC SPACE I WATER HEATING TESTS

versus

ASHRAE 124 CALCULATION PROCEDURE

TYPE Primary Secondary Heating Season Efficienc y - %

Function Function Combined Test 124 Calculation

----------------- --------- ---------- --------------------------------- _..----- _----- ----------

I Space Htg. Water Htg. 79.4 79. 2

11 Water Htg. Space Htg. 77.1 76.8

Individual performance test results used in ASHRAE 124 calculation:

TYPE I: Effss = 83.3% EffHS = 78.8% EF = 0.455 CAE = 76.0%

TYPE 11: EffSS = 81.4% Eff, s = 76.0% EF = 0.542 CAE = 73.8%

EE-DET-94-101 COMMENT 05

COMPARISON OF RESULT - COMBINED HEATING SEASON EFFICIENCY 

COMBINED CYCLIC -SPACE I WATER HEATING TESTS 

versus 

ASHRAE 124 CALCULATION PROCEDURE 

TYPE- . Primary 

Function 

Secondary Heating Season Efficiency ... 0/0 

Function Combined Test 124 Calculation 

-~-----~--~--~-~-~-------~~----------~-----------~----------------------------------~-------

II 

Space Htg. Water Htg. 

Water Htg. Space Htg. 

79.4 

77.1 

79.2 

76.8 

Individual performance test results used in ASHRAE 124 calculation: 

TYPE I: Effss = 83.3% 

TYPE -II: Effss = 81.4% 

EffHS = 78.8% 

EffHS = 76.0% 

EF = 0.455 

EF = 0.542 

CAE = 76.0% 

CAE = 73.8% 
TESTING OF COMBINATION APPLIANCES AT NIST AND ETL

Family Series Performance Tests - TYPE I Appliances:

Conducted tests as specified in ANSI/ASHRAE 124 to evaluate the

performance of a family series of TYPE I combination appliance.

TYPE I - Gas-fired boilers with identical external water storage tank

TYPE I - Oil-fired boilers with same size tankless heater (tested at ETL)

Separate tests of:

Space heating: Steady state, cool-down, heat-up tests per ASHRAE 103

Water heating: 6 hourly draw of 10.7 gal. each time, 18 hours standby

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TESTING OF COMBINATION APPLIANCES AT NIST AND ETl 

Family- Series Performance Tests .. TYPE I Appliances: 

* 

* 

Conducted tests as specified in ANSUASHRAE 124 to evaluate the 

performance of a family series of TYPE I combination appliance. 

TYPE I .. Gas-fired boilers with identical external water storage tank 

TYPE I - Oil-fired boners with same size tankless heater (tested at ElL) 

Separate tests of: 

Space heating: Steady state, cool-down, heat-up tests per ASHRAE 103 

Water heating: 6 hourly draw of 10.7 gal. each time, 18 hours standby 
TEST RESULTS - PERFORMANCE OF FAMILY SERIES OF APPLIANCES

1. Gas-fired boilers with identical external hot water storage tank:

Boiler Input: 75000, 112500 , 150000 Btu/h (22, 33, 44 kW)

Storage Tank Capacity: 40 Gallons

Oil-fired boilers with same size tankless coil (tested at ETL):

Boiler Input: 107400, 1414001. 179600 Btu/h

Test Results of Effss, EffHS(AFUE), EF, and CAE (by ASHRAE 124) shown on

graphs

4. Results indicated that linear interpolation of the rating parameters

within a family series of combination appliances is possi ble to reduce

the test burden on manufacturers.

EE-DET-94-101 COMMENT 05

TEST RESULTS • PERFORMANCE OF FAMILY SERIES OF APPLIANCES 

1. Gas ... fired boilers with identical external hot water storage tank: 

Boiler Input: 75000, 112500, 150000 Btuth (22, 33, 44 kW) 

Storage Tank Capacity: 40 Gallons 

2. Oil-fired boilers with same size tankless coil (tested at ETL): 

. Boiler Input: 107400, 141400,. 179600 Btuth 

3. Test Results of Effss, EffHS(AFUE), EF, and CAE (by ASH RAE 124) shown on 

graphs 

4. Results indicated that linear interpolation of the rating parameters 

within a family series of combination appliances is possible to reduce 

the test burden on manufacturers. 
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RAIEO INPUT - MW

bogy factor , steady - state efficiency , heating seasonal efficiency

and combined annual efficiency (CAE).aa a function of rated Input of a

family sorter of boilers with identical storage tank

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Type S Comb.App.--Boiler w/Tankless Coil

EF,CAE .EFFss & AFUE vs 001 - OIL BOILER

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50 70 90 110 130 150 170 190

(Thousonds)

RATED INPUT - 8TU/H

13 EF + CAE 0 EFFss A AFUE

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EF,CAE.Ef·Fss It ArUE vs OIN - OIL BOilER 

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RATED INPUT - 8TU/M 

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