AHRI Standard 1330 Discussion

Scope

Definitions

Influencing Factors

What A Higher Radiant Efficiency Means

Increased Comfort

Fuel & Electrical Savings

Optimum Building Performance

INTRODUCTION

INFRARED FACTOR (IF):

The rating of units based on the radiant coefficient, or the percentage of radiant output listed as Infrared Factor (IF) from 7 to 15.

CAN/ANSI/AHRI Standard 1330-2015 Performance rating standard for radiant output of gas-fired infrared heaters

PURPOSE: The purpose of this standard is to establish for infrared heaters:

definitions; test requirements; rating requirements; nomenclature;

minimum data requirements for published ratings

SCOPE: This standard applies to infrared heaters that are gas-fired

high-intensity infrared heaters and gas-fired low-intensity

infrared heaters with inputs up to and including 400,000 BTU/h

per burner intended for installation in and heating of indoor or

outdoor spaces.

COMBUSTION EFFICIENCYIMPORTANT DEFINTIONS

Radiant Efficiency: A colloquial term that is used to describe the radiant performance of an appliance. This term is created by considering the Gross Radiant Coefficient as a percentage

INFRARED FACTOR (IF): A published rating based upon Gross Radiant Coefficient. The Infrared Factor, or “IF”, categorizes radiant coefficient into increments of 0.05 in a range of IF-7 through IF-15. A ratio of 0.35 and below corresponds to the minimum rating, an IF-7. Any coefficient breaching 0.7 is recognized as an IF-15. This factor allows for a quick comparison of multiple appliances and provides a neutral footing for all gas-fired radiant units.

Gross Radiant Coefficient: Heat emitted by the infrared appliance through the appliance’s radiation plane divided by the gross heat input of the test gas. This can be interpreted as the useable heat radiated by the system divided by the input to determine a ratio

CAN: The Standards Council of Canada

AHRI: The Air-Conditioning, Heating and Refrigeration Institute

Radiant Efficiency Infrared Factor (IF)

≤ 35% 7

> 35% ≤ 40% 8

> 40% ≤ 45% 9

> 45% ≤ 50% 10

> 50% ≤ 55% 11

> 55% ≤ 60% 12

> 60% ≤ 65% 13

> 65% ≤ 70% 14

> 70% 15

Infrared FACTOR

Determining the INFRARED FACTOR

(RADIANT EFFICIENCY)

REQUIRED EQUIPMENT – Measuring Radiant Efficiency

Radiometer

Gas meter

Data Acquisition

Controller (DAQ) /

Computer with

specialized software

Thermometer /

Barometer

Measuring Grid

Radiation Reference Plane

INFLUENCING FACTORS

Radiant Efficiency

Heat Exchanger Material

Reflector Material

Reflector Design

Convective Losses

Orientation

Thermal Efficiency

Combustion Efficiency

Does NOT explain how well energy

turns into comfort heating

COMBUSTION EfficiencyConvert fuel to ENERGY

THERMAL EfficiencyEnergy NOT LOST to exhaust

Does NOT explain how well energy

turns into radiant heat

CONVECTIVE LOSSESEnergy LOST to exhaust or poor appliance design

Plays a significant role in determining radiant

efficiency

EMISSIVITY

MATERIAL EMISSIVITYAluminized Steel (Heat Treated) 0.79Hot Rolled Steel 0.80Porcelainized Steel 0.92 to 0.96Cast Iron 0.35 to .70Stainless Steel (Type 304) 0.36 to 0.73Schedule 40 Black Steel Pipe 0.95

REFLECTIVITY

MATERIAL REFLECTIVITYAluminum (Mill Finish) 0.91Aluminum (Polished) 0.91Stainless Steel (Type 304) 0.27 to 0.64

OVERALL DESIGNCombining high quality materials and innovation

ROBERTS GORDON® considered all factors to

increase radiant output

• Converting energy input into useable radiant heat

• AHRI 1330 measurement methodology

ROBERTS GORDON® Infrared Heaters

deliver more radiant heat to the floor than

any other infrared heater in the industry

BENEFITS OF A

HIGHER RADIANT EFFICIENCY

“Recognizing the reduced fuel requirement for these applications, …. it is desirable for manufacturers of radiant heaters to recommend installation of equipment with a rated output that is 80 to 85% of the heat loss calculated by methods described in Chapters 17 and 18 of the 2013 ASHRAE Handbook – Fundamentals.”

- “Infrared Radiant Heating.” 2016 ASHRAE Handbook HVAC

Systems and Equipment. Atlanta, GA: ASHRAE,

2016. 16.1. Print.

ADJUSTMENT FACTOR FOR INFRARED EQUIPMENT SIZING

ADJUSTMENT FACTOR FOR AIR EQUIPMENT SIZING

ADJUSTMENT FACTOR FOR INFRARED EQUIPMENT SIZING

ADJUSTMENT FACTOR FOR INFRARED EQUIPMENT SIZING

ADJUSTMENT FACTOR FOR FUEL SAVINGS!

ADJUSTMENT FACTOR FOR EVEN MORE FUEL SAVINGS!

LOWER YOUR THERMOSTAT

AND ACHIEVE THE SAME

COMFORT LEVELS

Mean Radiant Temperature (MRT)“The net amount of Infrared Energy

available from surfaces to provide comfort”

OPERATIVE TEMPERATURE (To)

Calculations with STANDARD REFLECTOR

MRT + T To = AIR

2Formula:

Operative Temperature can be

defined as the average of the mean

radiant and ambient air temperature

Air Heating

MRT = 65°F TAIR = 75°F

=65 °F+ 75°F

= 70°F2

To =75 °F+ 65°F

= 70°F2

To

Infrared Heating

With Standard Reflectors

MRT = 75°F TAIR = 65°F

TURNING THE THERMOSTAT DOWN

For every degree that you lower the thermostat setting, you save approximately 3-4% in fuel usage

REMEMBER:

“Equivalent perceived comfort at lower air temperatures”

Infrared Heating

To =75°F + 65°F

= 70°F2

Calculations with STANDARD REFLECTOR

INCREASING THE MRT

WITH A HIGHER RADIANT EFFICIENCY

Floor Temperature – Standard Reflector

Ave temp 95.4Max temp 117.4

Floor Temperature – High Efficiency Reflector

Ave temp 99.7Max temp 122

End Wall Temperature – Standard Reflector

Ave temp 93.4Max temp 104.2

End Wall Temperature – High Efficiency Reflector

Ave temp 97.4Max temp 108.6

Side Wall Temperature – Standard Reflector

Ave temp 92Max temp 97

Side Wall Temperature – High Efficiency Reflector

Ave temp 95.9Max temp 100.8

MRT increase (Deg F)

Std High Eff

Floor 95.4 99.7 4.3

End Wall 93.4 97.4 4.0

Side Wall 92.0 95.9 3.9

Average MRT increase: 4.1 Deg F

MRT - is simply the weighted mean

temperature of all the objects

surrounding the body

MRT also has a strong influence on thermophysiological comfort indexes such

as predicted mean vote (PMV). (ASHRAE 55)

OPERATIVE TEMPERATURE (To)

Calculations with HIGH EFFICIENCY REFLECTOR

MRT + T To = AIR

2Formula:

Operative Temperature can be

defined as the average of the mean

radiant and ambient air temperature

Air Heating

MRT = 65°F TAIR = 75°F

=65 °F+ 75°F

= 70°F2

To =79 °F+ 61°F

= 70°F2

To

Infrared Heating

With High Efficiency

Reflectors

MRT = 79°F TAIR = 61°F

TURNING THE THERMOSTAT DOWN

For every degree that you lower the thermostat setting, you save approximately 3-4% in fuel usage

REMEMBER:

“Equivalent perceived comfort at lower air temperatures”

Infrared Heating

To =79°F + 61°F

= 70°F2

Calculations with HIGH EFFICIENCY REFLECTORS

Q & A