Future Comforts: Policy Studies Institute

Do you want to control the Temperature?

Max Fordham

• We can provide control of temperature

• People have preferences

• Control of temperature uses fossil fuel!

But...

People are adaptable

How much control do we need?

1 kW/m2 Short Wave Radiation from the Sun

RADIATION

RESPIRATION

EVAPORATION

35ºC

25ºC

CONVECTION

Wet Air

Dry Air

Heat Exchange of the Bodywith the Environment

• Bedford Air temperature & RadiationUK, Early 20th century

• Webb Equatorial Comfort Index: Wet bulb temperature= Enthalpy

• ASHRAE Air temperature, Humidity, Air speed.(Statistics), US, Mid 20th century

• Belding & Hatch All Parameters, Simple PhysicsUS, Mid 20th century

• Ole Fanger All ParametersISO 7730. Recent.

• Dusan Fiala Develop Fanger add involuntaryreactions. Recent.

• ASHRAE Consider Voluntary Reactions.

Comfort Research Summary

-6

-4

-2

0

2

4

6

8

15 20 25 30 35Temperature [°C]

Socks, shoes, briefs, long sleeved shirt, tie, lightsweater, vest, jacket, heavy trousersSocks, shoes, briefs, light long sleeved shirt, tie,jacket, light trousersSocks, shoes, briefs, light short sleeved shirt,light trousersFlip Flops, shorts, briefs, light short sleevedshirtNo clothes at all!

Comfort Conditions by Fanger

Cold comfort boundary

Hot comfort boundary

Singapore(28°C, 90% r.H.)

PsychrometricChart

Saudi Arabia(46°C, 20% r.H.)

Average UK Winter(10°C, 20% r.H.)

10

Room UK Winter(20°C, 10% r.H.)

Spe

cific

Ent

halp

y [k

J/kg

]

Dry Bulb Temperature [°C] 30 4020

1.5

10

13.5

21.5

51

61

83

129M

oistu

re Co

nten

t [g W

ater/kg A

ir]Air leaving Body(35°C, 100% r.H.)

14

Room Condition(25°C, 50% r.H.)

Con

vect

ion

Eva

pora

tion

• Otterbourne 30C not enough to open sash windows

• 43 Gloucester Crescent Is it really 30 C?

• Hong Kong Teaching 27C 56% RH radiant temp =air temp

Light clothes: no adjustment wanted 20 building professionals

Anecdotes

QED

References[1] Fordham S M. Building Physics - Reducing air conditoining

needs in extreme climates. CIBSE Conference 1978.

[2] Climate change and it’s impact. Meteorological Office, 1998.

[3] Health & Safety Executive. EH 40/97 Occupational Exposure Limits 1997, Table 2 Page 22. (ISBN 0-7176-1315-1).

[4] Total Carbon Cycle (tba).

[5] Nuclear Energy - the future climate. The Royal Society and The Royal Academy of Engineering, 1999 (ISBN 0-85403-5262).

[6] Fanger P O. Olf and decipol: New units for preceived air quality. Building Services Engineering Research & Technology, 1984.

[7] Fiala D. Dynamische Simulation des menschlichen Wärmehaushalts und der thermischen Behaglichkeit. De Montfort University, 1998.

[8] Field Studies of Thermal Comfort and Adaption. ASHRAE Technical Data Bulletin, Volume 14, Number 1. January 1998.