Impact of Temperature on Occupants: Theory vs. Reality OPFMA 2004 Annual Conference November 17, 2004 E E S ENERGY & ENVIRONMENTAL SOLUTIONS, INC. 2004

Impact of Temperature on Occupants:Impact of Temperature on Occupants:

Theory vs. RealityTheory vs. Reality

OPFMA 2004 Annual Conference OPFMA 2004 Annual Conference

November 17, 2004November 17, 2004

EES ENERGY & ENVIRONMENTAL SOLUTIONS, INC. 2004©

Thanks & IntroductionsThanks & Introductions

Stephen Petty, P.E., C.I.H.

Energy & Environmental Solutions, Inc. President

Joseph A. Ventresca

Energy Coordinator, City of Columbus

Hi, my name is…


Objective(s)Objective(s)

ASHRAE 55 – ImpactsASHRAE 55 – Impacts Effects of Register Temp.Effects of Register Temp.

On Human ComfortOn Human Comfort Real World Thermal Comfort Real World Thermal Comfort

Experiences.Experiences.

What is This All About ...


ASHRAE 55 – 2004/1995/1992/1981ASHRAE 55 – 2004/1995/1992/1981


ASHRAE 55 OverviewASHRAE 55 Overview


Basis:Basis: Defines indoor human thermal comfort Defines indoor human thermal comfort

conditions for any building types.conditions for any building types. Based on majority conditions – 80% overall Based on majority conditions – 80% overall

acceptability (80% satisfied; 20% dissatisfied).acceptability (80% satisfied; 20% dissatisfied). Based only on thermal (temperature) so:Based only on thermal (temperature) so:

No lower limit set since no lower limit relates to No lower limit set since no lower limit relates to thermal comfort.thermal comfort.

Nevertheless, upper limit(s) provided since non-Nevertheless, upper limit(s) provided since non-thermal factors affect comfort.thermal factors affect comfort.

ASHRAE 55 – Changes in Upper ASHRAE 55 – Changes in Upper Humidity Limits With TimeHumidity Limits With Time


DateDate ValueValue BasisBasis19811981 Humidity Ratio: 0.012Humidity Ratio: 0.012 IAQ ConsiderationsIAQ Considerations

19921992 Summer: 60% R.H.Summer: 60% R.H. Relative Humidity Relative Humidity Winter: 60% R.H.Winter: 60% R.H. (Environmental Basis)(Environmental Basis)

1995a1995a Summer: 68F w.b. Summer: 68F w.b. Wet-Bulb TemperatureWet-Bulb TemperatureWinter: 64F w.b.Winter: 64F w.b. (Thermal Not Environ. (Thermal Not Environ.

Basis)Basis)

20042004 Humidity Ratio: 0.012Humidity Ratio: 0.012 Back to 1981; systems Back to 1981; systems designed to control designed to control humidity. D.P. 62.2 Fhumidity. D.P. 62.2 F(R.H. of 76% at 70F and(R.H. of 76% at 70F and R.H. of 54.6% at 80F).R.H. of 54.6% at 80F).

ASHRAE 55 – Humidity PlotsASHRAE 55 – Humidity Plots


2004 Edition2004 Edition

1995a Edition1995a Edition

ASHRAE 55 – Other Comfort ASHRAE 55 – Other Comfort Conditions (Floor Temp./Temp Conditions (Floor Temp./Temp

Variations – 15 minute Intervals)Variations – 15 minute Intervals)


Floor Temp: Floor Temp: Basis: 10% Dissatisfied – 66.2F to 84.2F Basis: 10% Dissatisfied – 66.2F to 84.2F wearing normal indoor Shoes; doesn’t apply to people wearing normal indoor Shoes; doesn’t apply to people who are barefoot or sitting on the floor.who are barefoot or sitting on the floor.

15 Minute Interval Temperature 15 Minute Interval Temperature Variation: 2.0F.Variation: 2.0F.

ASHRAE 55 – Other Comfort ASHRAE 55 – Other Comfort Conditions (Indoor vs. Outdoor T)Conditions (Indoor vs. Outdoor T)


ASHRAE 55 – Other Comfort ASHRAE 55 – Other Comfort Conditions (Radiant Temps.)Conditions (Radiant Temps.)


ASHRAE 55 – Other Comfort ASHRAE 55 – Other Comfort Conditions (Air Speed)Conditions (Air Speed)


Delivered Air At RegisterDelivered Air At Register

Real World ExampleReal World Example


Delivered Air At RegisterDelivered Air At Register


For the Same Load, How Does For the Same Load, How Does Different Delivered Air Temperatures Different Delivered Air Temperatures

Impact Comfort?Impact Comfort?

Consider the Following SituationConsider the Following Situation


Home Load: 66,500 BTUH (e.g., 80,000 Home Load: 66,500 BTUH (e.g., 80,000 BTUH furnace at 82% efficiency)BTUH furnace at 82% efficiency)

Return Air Temperature: 65FReturn Air Temperature: 65F Relative Humidity: 50%Relative Humidity: 50% Delivered Air Temperature: 70F to 120FDelivered Air Temperature: 70F to 120F

What is the Volumetric Flow Rate and What is the Volumetric Flow Rate and Velocity vs. Supply Temperature?Velocity vs. Supply Temperature?

Volumetric Air Flow Rate vs Supply Temperature

0

2,000

4,000

6,000

8,000

10,000

12,000

70 80 90 100 110 120 130

Supply Air Temp. (F)

Air

Flo

w R

ate

(C

FM

)


Ts V

70 11,729

75 5,925

80 3,991

85 3,024

90 2,445

95 2,059

100 1,783

105 1,577

110 1,417

115 1,290

120 1,186

125 1,087

130 1,003

ObservationsObservations


For the same heat load to the home, the For the same heat load to the home, the amount of air required changes from 2,445 amount of air required changes from 2,445 CFM at 90F supply air to 1,186 CFM at CFM at 90F supply air to 1,186 CFM at 120F supply air (drop of 51%)120F supply air (drop of 51%)

What happens to air velocity at the register?What happens to air velocity at the register?

Consider the Following SituationConsider the Following Situation


Home contains 15 registers.Home contains 15 registers. Each register is 4” x 12” in size.Each register is 4” x 12” in size. Each register has 75% effectively open Each register has 75% effectively open

area.area.

What is the Velocity vs. Supply Temperature?What is the Velocity vs. Supply Temperature?


Register Velocity vs Supply Temperature

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

70 80 90 100 110 120 130


Re

gis

ter

Vel

oc

ity

(F

PM

)

Ts v

70 3,128

75 1,580

80 1,064

85 806

90 652

95 549

100 476

105 421

110 378

115 344

120 316

125 290

130 268

ObservationsObservations


For the same heat load to the home, the amount of For the same heat load to the home, the amount of register air velocity changes from 652 CFM at register air velocity changes from 652 CFM at 90F supply air temperature to 316 CFM at 120F 90F supply air temperature to 316 CFM at 120F supply air temperature. supply air temperature.

Compare with real world delivered air temperatures.Compare with real world delivered air temperatures.


Register Velocity vs Supply Temperature

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

70 80 90 100 110 120 130


Re

gis

ter

Vel

oc

ity

(F

PM

)

Typical Typical For For HeatHeat

PumpPump

TypicalTypicalFor For

WarmWarmAir Air

FurnaceFurnace

BodyBodyTemp.Temp.

ImplicationsImplications


Lower temp. air supply systems like heat pumps supply Lower temp. air supply systems like heat pumps supply air at temperatures less than body temperature – feels air at temperatures less than body temperature – feels cold.cold.

Lower temp. air supply systems like heat pumps must Lower temp. air supply systems like heat pumps must deliver more air (i.e., higher velocity air to provide the deliver more air (i.e., higher velocity air to provide the same amount of heat).same amount of heat).

Higher temp. air supply systems like warm air furnaces Higher temp. air supply systems like warm air furnaces supply air at temperatures above the body temperature supply air at temperatures above the body temperature and at lower velocities.and at lower velocities.

New higher efficiency equipment (both gas and electric) New higher efficiency equipment (both gas and electric) will supply air at lower temperatures and higher will supply air at lower temperatures and higher velocities – velocities –

Implies that efficiency does not correlate with comfort!Implies that efficiency does not correlate with comfort!

THANK YOUTHANK YOU

ANY QUESTIONS?ANY QUESTIONS?


Thank YouThank You

EES

Stephen E. Petty, P.E., C.I.H.Stephen E. Petty, P.E., C.I.H.

84 N. High Street, Suite 2B84 N. High Street, Suite 2BDublin, OH 43017Dublin, OH 43017

Phone: (614) 798-4123Phone: (614) 798-4123Fax: (614) 798-4118Fax: (614) 798-4118

www.eesinc.ccwww.eesinc.cc


Documents

Impact of Temperature on Occupants: Theory vs. Reality OPFMA 2004 Annual Conference November 17, 2004 E E S ENERGY & ENVIRONMENTAL SOLUTIONS, INC. 2004