Thermal Comfort Monitoring and Measurement - MORE ...

Thermal Comfort Monitoring and Measurement

2 th Module

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INNOVATION UNDER GRANT AGREEMENT NO 633477.nTHE INFORMATION IN THIS PUBLICATION DOES NOT NECESSARILY REPRESENT THE VIEW OF

THE EUROPEAN COMMISSION.

© MORE-CONNECT

Manuela Almeida | Luis Bragança

Sandra Silva | Ricardo Mateus | Ricardo Barbosa

University of Minho

Portugal

Module overview

1. Thermal Comfort Fundamentals

2. Measurements and Models

3. Building regulations

4. Impact of renovation solutions

Prehistoric pile house**

Caves*

Source: *Wikipedia, **UNESCO, ***Wikipedia, ****Wikipedia

No matter how long ago, no matter how long after now, no

matter where, people create shelters so as to:

1. be protected by natural phenomena and

2. feel good = feel comfortable

Modern house***

Means may change, efficiency too, but end always remains

the same.

The international modular

space station****

1.Thermal Comfort Fundamentals

Introduction

And feeling good includes:

• Not too hot

• Not too cold

• Not too dry

• Not too humid


Or as per EN ISO 7730:2005/par. 7 definition on thermal comfort:

Thermal comfort is that condition of mind which expresses satisfaction with the thermal environment

A subjective parameter. An objective parameter

(thermodynamics)

Introduction

Thermal ComfortSubjective

parameters

Objective

parameters

Stable over timeline

Applicable to

shelters

Change over timeline

Technical

MeansKnowledge

Today:

1. More people use shelters around the world

2. More architects and engineers familiarize with

thermal comfort context.

3. Scale economies gradually makes technology

available to greater population proportion.

More and more people live in a thermally comfortable

environment

Technical

Means


Introduction

• And as per EN ISO 7730:2005/par. 7:

Due to individual differences, it is impossible to specify a thermal environment that satisfy everybody. There

will always be a percentage dissatisfied occupants. But it is possible to specify environments predicted to be

acceptable by a certain percentage of the occupants.

Thus, thermal comfort context is about more

i.e. making more people feel thermally comfortable


Introduction

Comfort

• Is it about thermodynamics?

• How thermal comfort correlates to

human activity?

• How our body respond?

• What are the very factors affecting

thermal comfort?


Introduction

Thermodynamics

• Thermodynamics is a branch of physics concerned with heat and temperature and their relation to energy

and work.

• It defines macroscopic variables, such as internal energy, entropy, and pressure, that partly describe a body of

matter or radiation.

• It states that the behavior of those variables is subject to general constraints, that are common to all

materials, not the peculiar properties of particular materials.

• These general constraints are expressed in the four laws of thermodynamics.

Source: Wikipedia


Thermal balance

Thermodynamic laws apply:

Food energy = Heat + Work + Energy stored (fat)

Radiation

Convection

Conduction

Environment


What is heat?

• Heat is energy in transfer other than as work or by transfer of matter.

• When there is a suitable physical pathway, heat flows from a hotter body to a colder one.

• Heat refers to a process of transfer, not to a property of a system.

Source: Wikipedia


How is heat transferred?

Source: Wikimedia, By Kmecfiunit (Own work)


Radiation

Convection

Conduction

Environment

Sensible Heat Loss


Evaporative heat loss

Convection

Environment


• M = W+(R+C+K)+E+S

• M = metabolic rate

• W = external work

• R = radiant heat exchange

• C = convective heat exchange

• K = conductive heat exchange

• E = evaporative heat transfer

• S = Energy storage


What is temperature?

• Temperature is a comparative objective measure of hot and cold.

• Thus, temperature scales is a comparative measurement from a conventional defined point.

Celsius scale:

Measure of comparison = Ice formation conventionally set at 0 ºC

Kelvin scale:

Measure of comparison = Absolute zero, i.e. molecules not moving

Absolute zero = 0 ºK = -273,15 ºC


So…

• Thermal comfort is about applying thermodynamics to the medium that surrounds humans, i.e. air.

• But what is air just a gas?

Source: Wikipedia, "Cloud forest mount kinabalu"

Source: Wikipedia, "Antarctic Air Visits Paranal" by ESO/G. Brammer

Acknowledgement: F. Kerber (ESO)


Air composition

+

Source: Wikipedia, "Atmosphere gas proportions" by Mysid

Water vapour


Psychrometrics

Psychrometrics or psychrometry or hygrometry are terms used to describe the field of engineering concerned with

the determination of physical and thermodynamic properties of gas-vapor mixtures. The term derives from the

Greek psychron (ψυχρόν) meaning "cold“ and metron (μέτρον) meaning "means of measurement"

Source: Wikipedia


Basic terms of psychrometry

• Humidity is the amount of water vapor in the air.

• Relative humidity or RH (φ) is the ratio of the partial pressure of water vapor to the equilibrium vapor pressure

of water at the same temperature.

• Absolute humidity is the mass of water vapor per unit volume of air containing the water vapor.

• Dry-bulb temperature (DBT) is the temperature of air measured by a thermometer freely exposed to the air but

shielded from radiation and moisture.

• Wet-bulb temperature is the temperature a parcel of air would have if it were cooled to saturation (100%

relative humidity) by the evaporation of water into it.

• Dew point or saturation temperature is the temperature at which the water vapor in a sample of air at

constant barometric pressure condenses into liquid water at the same rate at which it evaporates.


Basic terms of psychrometry

• Sensible heat is the heat that changes the temperature of a substance when added to or abstracted from it.

• Latent heat is the heat that does not affect the temperature but changes the state of substance when added to

or abstracted from it.

• Enthalpy (h) is the combination energy which represents the sum of internal and flow energy in a steady flow

process. It is determined from an arbitrary datum point for the air mixture and is expressed as kJ per kg of dry

air.


Psychrometric chart

Dry Bulb Temperature

Specific

hum

idity

Relative

humidity lines


Psychrometric chart Flip


Psychometric chart


Specific

hum

idity

Humidification

Dehumidification

Cooling Heating


Mixing

𝑚3,𝑊3, ℎ3

𝑚1

𝑚2=𝑊3 −𝑊2

𝑊1 −𝑊3=ℎ3 − ℎ2ℎ1 − ℎ3

1

3

2

W1

W3

W2

t2 t3 t1

h2

h3

h1


Sensible heating


Specific

hum

idity

Specific humidity stays

put, but relative

humidity changes

Power needed 𝑄 = 𝑚 ∗ Δh

Air becomes warmer.


Sensible cooling


Specific

hum

idity

Specific humidity stays

put, but relative

humidity changes


Air becomes cooler.

t>dp


Cooling and Dehumidification


Specific

hum

idity

Specific humidity

changes.


Air becomes cooler.

t≤dp


Sources of heat inside buildings

Lighting

Equipment

Energy equilibrium applies, i.e.

Qsolar + Qfabric + Qpeople + Qlighting + Qequipment + Qventilation = 0


More temperature definitions

• The mean radiant temperature (MRT) = the uniform temperature of an imaginary enclosure in which the radiant

heat transfer from the human body is equal to the radiant heat transfer in the actual non-uniform enclosure.

• Operative temperature = Uniform temperature of an imaginary black enclosure in which an occupant would

exchange the same amount of heat by radiation and convection as in actual non-uniform environment.

Source: http://www.ides-edu.eu/wp-content/uploads/2013/04/2-thermal-comfort.pdf


Thermal comfort• People feel good within a certain

boundary of operative temperature and

this is in turn translated in a certain

space in the psychrometric chart.

• This space is objectively defined.

• But statistics help us find a common

space.

• Statistics are applied to people’s voting

using a predefined scale of comfort.

Heating only Cooling only

Heating + Humidify

Cooling + HumidifyHumidify

Dehumidify and

reheat if

necessary


Thermoregulatory system

• Humans are endothermic organizations, i.e. heat needed for vital needs stems from metabolic functions

• Humans are homeothermic organizations(or warm-blooded), i.e. body temperature is kept within certain bounds

• Human body uses homeostasis (i.e. preservation of relatively constant conditions), a highly complex control

system which takes place in the brain area called hypothalamus


• Homeostasis caters for preserving a stable body temperature, through energy homeostasis, i.e. energy

balancing, by

• adjusting metabolism i.e. the set of life-sustaining chemical transformations within the cells of living

organisms

• inaugurating positive/negative loop mechanisms (Positive feedback is a process that occurs in a feedback

loop in which the effects of a small disturbance on a system include an increase in the magnitude of the

perturbation. Negative is the opposite)


Thermoregulatory system

6 factors of thermal comfort

Metabolic rate Clothing

Air velocity

RH Air temperature

Mean radiant

temperature


Metabolic rate

• Increased work leads to increased heat production → type of activity influences heat produced by the human

body and is proportional to heart rate

• Metabolic rate = Energy/time = power

• Expressed as W/m2, i.e. power per surface area of the body (as per EN ISO 8996 “average” individual is 30

years-old, 70kg weight man of 1,8m2 and 60 kg weight woman of 1,6m2)

• Additional unit used met = 58,15 W/m2


Metabolic rate

• EN ISO 8996 defines methodology of calculating or measuring metabolic rate.

• Practically occupancy loads are taken from national/EU standard tables that define load per building space.

• In such cases it is important to remember that loads are expressed also in W/m2, but m2 usually is building area.

• Work can also be expressed in W/m2 or met units. For common light work is usually accounted as being 0.

• Metabolic rate influences evaporation (skin, respiration), thus adjusting for latent load.


Metabolic rate

ActivityMetabolic Rate

[W/m2]

Metabolic Rate

[met]

Seated, Relaxed 58 1.0

Shopping 93 1.6

Domestic work 116 2.0

Shivering 200 3.4

Source: EN ISO 8996:2004


Clothing principleOuter environment

Layer of still warmed fluid heated by human

body

Clothing layers

Clothing adjusts:

• Heat radiated

• Heat convected by passing of the air

though garments

• Evaporation cooling as sweat passes

through clothing fibers




Clothing

Clothing

• Clothing insulation (Icl) is the means of maintaining this still warm layer.

• As insulation is expressed in thermal resistance units, i.e. m2K/W or clo=0,155 m2K/W

• Evaporation cooling resistance (Re) provided is proportional to clothing permeability (material specific),

approached by permeability index (im).

• As per EN ISO 9920 Re = f(im, Icl).


Clothing

ClothingIcl

[m2K/W]

Icl

[clo]

Panties, T-shirt, shorts, light socks, sandals 0.050 0.30

Underpants, shirt with short sleeves, light trousers, light socks,

shoes0.080 0.50

Panties, shirt, trousers, jacket, socks, shoes 0.155 1

Icl continuum [clo] 0.2 0.6

Considered as nude Considered as clothed

0.5 1.0

Common summertime

design parameter

Common wintertime

design parameter


Temperatures

• Operative temperature is a function of mean radiant temperature (MRT) and air temperature

• MRT considers for heat transferred by radiation and is commonly measured by black globe thermometer

• Air temperature considers heat transferred by convection and is measured by typical thermometers


Air velocity

• Airflow in spaces is typically turbulent

• Turbulent flows enable greater heat transfer rates

• But also increased turbulence means increased discomfort

Source: Wikipedia, "False color image of the far field of a

submerged turbulent jet" by C. Fukushima and J. Westerweel,

Technical University of Delft, The Netherlands

Turbulent flow

Source: Wikimedia, By Instrueforme231 (Own work)

Both laminar and turbulent flow


Air velocity

• Humans show different sensibility on wind

direction

• Human body does not have a specialized

sensing for wind measurement. Wind is

indirectly determined by temperature

change


Air velocity

• Correlates to convection and evaporation heat transfer

• Difficult to measure accurately

• Fluid mechanics & heat transfer calculations are both knowledge and resource demanding

• Currently encountered either with simplistic assumptions leading to linear equations or CFD (computational fluid

dynamics) based on Navier Stokes equation (e.g. k-ω, k-ε etc)


Humidity

• Interacts with thermoregulatory system through:

• Gas diffusion

• Sweat evaporation

• Humidification of inhaled air

• It loosely affects skin temperature

• The amount of sweat remaining on the skin is a very good indicator of discomfort


Humidity

Measured ether by psychrometer or by hygrometer



Interdependability table

Table 1 - Main independent quantities involved in the analysis of the thermal balance between man and the thermal

environment

Elements in the thermal balance

Quantities

ta va pa Icl Rcl M W

Air

temperature

Mean radiant

temperature

Air

velocity

Absolute humidity of

the air (partial pressure

of water vapour)

Insulation

of clothing

Evaporative

resistance of

clothing

Metabolism External

work

Internal heat production, M-WX X

Heat transfer by radiation, RX X

Heat transfer by convection, C*X X X

Heat losses through evaporation:

- evaporation from the skin, E

- evaporation by respiration, Eres

X X

X

X

X

Convection by respiration, Cres

X X

* Heat transfer by convection is also influenced by body movements. The resultant air velocity at skin level is called relative air velocity (var). Heat conduction (surface

temperature) has only a limited influence on the thermal heat balance.



Some food for thought

Source: Wikipedia, "Dishdasha" by

Mary Paulose from Muscat, Oman -

Assorted Arabs.

Source: Wikipedia, "Civilian

Conservation Corps at an

experimental farm in

Beltsville, Maryland - NARA -

195831" by Unknown or not

provided - U.S. National

Archives and Records

Administration.

Source: Wikipedia,

"Chasseur sous-marin et son

équipement" by Calcineur -

Own work.

Arabs in thawb American workers Spare fisherman Farmer in Venezuela

Source: Wikipedia, "Campesino

Venezolano, Edo. Yaracuy crop" by The

Photographer - Own work


Adaptation

• Previous analysis pre-assumed that individuals act passively on environmental parameters.

• Is this the case or:

• When you feel hot you open the window?

• When you feel cold you wear your wool shirt?

• Isn’t adaptation the cornerstone for our evolutionary straggling?


Adaptation

• Thermoregulatory system is controlled by homeostasis system that produces stimuli.

• Thus, adaptation defined as:

the gradual decrease of the organism’s response to repeated exposure to a stimulus, involving all the actions

that make them better suited to survive in such an environment


AdaptationAdaptive opportunity

Good Low Inexistent

Time

Tem

pera

ture

Adaptive

opportunity

Thermal discomfortThermal discomfort

Thermal

discomfort

Thermal neutrality

Adapted from: Baker and Standeven, 1996


Adaptation

Adaptive model of thermal comfort “If a change occurs in the thermal environment which

tends to produce discomfort, people will respond in ways that tend to restore their comfort.”

(Humphreys, 1997).

Field studies and the adaptive model


Adaptation

The adaptive model

In buildings with HVAC systems, the comfort temperature adjust to EN ISO 7730 model.

In buildings without mechanical systems, the occupants adapt themselves in a way that EN

ISO 7730 does not predict.

Dear et al.

ASHRAE RP 885


Adaptation

The “adaptive” hypothesis

The three components of

adaptation to indoor climate

ASHRAE RP 884

Adaptation to

Indoor Climate

Adjustment

(behavioural/technological

changes to heat-balance)

Acclimatization

(long-term physiological

adaptation to climate)

Habituation

(psychological adaptation -

changing expectations)


Adaptation

The adaptive model

The types of action which can be taken to adapt to the indoor climate are:

– Modifying the internal heat generation: this can be achieved unconsciously with

raised muscular tension or, in a more extreme situation, the shivering reflex, or

consciously, for instance through jumping about in the cold to increase metabolic heat

or having a siesta in the warm to reduce it.

– Modifying the rate of body heat loss: achieved unconsciously through

vasoregulation or sweating: consciously by such actions as changing ones clothing,

cuddling up or by taking a cooling drink.

– Modifying the thermal environment: through lighting a fire, opening a window, or in

the longer term by insulating the loft or moving house.

– Selecting a different environment: within a room by moving closer to the fire or

catching the breeze from a window, between rooms in the same house with different

temperatures, or by moving house or visiting a friend.


Adaptation strategies

Adaptation

Physiological Behavioral Psychological

Genetic

Acclimatization

Personal

Technological

Cultural

Reference


Genetic

• Change in natural characteristics

• Long term

Source: Wikipedia, "Sherpa" by

Original uploader was Gac at

it.wikipedia

A Tibetan family


Source:

Mother nature network

Acclimatization

• Habituation (stop in responding to a stimulus which is no longer biologically relevant)

• Metabolic adaptations

• Insulative adaptations


Source:

Ultimate everest

Behavioral

• Most common type of adaptation

• Personal (e.g. clothing, warm/chill drinks)

• Technological (e.g. turn air condition on/off)

• Cultural (e.g. siesta)

• But also contextually rearranging the above:

• Reactive (personal adjustment - e.g. it got hot so I revise

my clothing)

• Interactive (change the circumstances)


Source:

Discovering antartica

Psychological

• Naturalness (free of artificiality)

• Expectations (how environment should be)

• Experience

• Short term (memory related)

• Long term (schemata in mind related)

• Time of exposure (e.g. getting out of a warm car to enter a building in winter)

• Perceived control (control over a source of discomfort)

• Environmental stimulation


Flip-side of adaptive opportunity (i.e, the lack of...)

The flip-side of adaptive opportunity (i.e, the lack of...), is the analysis of constraints to thermal control. These

constraints may be gathered under five main headings (Nicol and Humphreys 1972, Humphreys 1994a):

a) Constraints due to climate.

b) Economic constraints.

c) Constraints due to social custom or regulation.

d) Constraints due to task or occupation.

e) Constraints due to design.


Adaptive thermal comfort model

Average outdoor temperature in Lisbon (12ºC; 23ºC)

21

Mean monthly outdoor air temperature, Tm, (ºC)

Ind

oo

r o

pe

rati

ve t

em

pe

ratu

re,

To

c,

(ºC

)

90% acceptability limits

80% acceptability limits

Toc = 17,8 + 0,31Tm

ASHRAE 55:2013

Portugal


Global vs local comfort

Imagine a space within thermal comfort boundaries.

• Under your perception between Mr. Black, Mr. Green and Mr. Red, who is supposed to

feel most comfortable?

air

Solar

irradiation


Global vs local comfort

• Thus local discomfort consists of exposing parts of body to conditions thermally uncomfortable.

Evaluating thermal

environmentGlobal comfort Local comfort= +


Radiant asymmetry

Source: Wikipedia, By Ernst Vikne (Watching the fireplace)

• Radiant temperature asymmetry leads to

discomfort

• Warm ceilings and cold windows cause

greater discomfort than cold ceilings and warm

walls


Vertical air temperature differences

• Unpleasant to be warm around head and cold around feet

• Temperature is measured at ankle and neck hot

cold


Draught

• Most common complaint

• Discomfort depends on air velocity and turbulence

air


Floor

• Depends on floor’s conductivity, floor’s thermal mass and

footwear

• Difference in conductivity and heat capacity makes cork floors

feel warm and marble floors feel cold

• Normal footwear makes floor influence minor

• Bathroom is an exemption since walking on bare feet is the

norm.Source: Wikipedia, "Fire Walking (1234969885)" by

Aidan Jones from Oxford, U.K. - Fire Walking


Natural ventilation

• Correlates to psychological adaptation, i.e. Naturalness, Environmental

stimulation

• Research is converging that natural ventilation makes individual feel

more thermally comfortable

• Depends on outside air velocity (impossible to control outside air, hard

to predict, may change as surroundings change)

• Natural sometimes also mean “natural” air born noise thus a thermally

comfortable environment may not be comfortable.

• Sometimes difficult to implement (e.g. renovation projects)


Adaptive thermal comfort model

Use of natural ventilation strategies

Adapted from: Jim Lambert, Natural Ventilation – capabilities and limitations (comfort and

energy efficiency in domestic dwellings), ATA Melbourne Branch presentation, April 2008

Thermal Comfort interval

Thermal Comfort interval with

a breeze (natural ventilation)

Te

mp

era

ture

(ºC

)

6h 12h 18h 24h 6h

30

20

10


Age

• As people get older:

• Metabolic rate probably falls

• Sweating normally reduces

• Thermoregulation becomes harder

• But apart from physical also psyco-socio-economical parameters are influenced:

• Income tends to decrease

• Usually spend more time indoors

• Perception of what is cold and hot may change


Gender

• Females tend to be more prone to express thermal discomfort than males

• Females are expected to have higher thermo-neutral temperature

• Differences are attribute to:

• Body fat

• Surface to mass ratio

• Regulatory hormones

• Clothing and clothing distribution across body


Temperature changes over time

• Changes of temperature within a day

• Temperature changes from day to day

• Seasonal changes in temperature


Correlation to climate change

Source: Wikipedia, "NSFmonsoonsandclimatesince200AD" by U.S. Government, National Science Foundation

(NSF)

Dynasties may fall and rise, but desire for thermal comfort remains unchanged.



Source: Wikipedia , "Mauna Loa Carbon Dioxide-en" by © Sémhur / Wikimedia Commons.


Temperature range

Health dangerous temperatures

Discomfort temperatures

Comfort temperatures


Thermal comfort and productivity

• Many researches have shown a positive correlation in business environment between lowering temperature

during cooling period and increase in productivity.

• 10-12 year old students have shown to have an improved performance by increasing ventilation rate and

lowering temperature. Ventilation rate had a positive impact of 8-14%, while cooling 2-4%.

Source: Thermco, 2009


What is the “discomfort cost”?

• In 2000 Fisk* estimated that for the U.S. improved indoor environment could:

• Save 6-14 b$/a from reduced respiratory disease

• Save 2-4 b$/a from reduced allergies & asthma

• Save 10-30 b$/a from reduced building syndrome symptoms

• Generate extra 20-160 b$/a due to improved personnel performance

• Nicol et.al.** claim that UK medical treatment cost due to poor housing is 2,5b₤/a out of which 700m₤/a stem

from poor energy efficiency/fuel poverty.

*Fisk W., REVIEW OF HEALTH AND PRODUCTIVITY GAINS FROM BETTER IEQ, Proceedings of Healthy Buildings 2000 Vol. 4

**Nicol, S., Roys, M., Davidson, M., Summers, C., Ormandy, D., Ambrose, P., Quantifying the Cost of Poor Housing. IHS BRE Press, Watford, 2010.


Heat stress

• Associated with the heat balance between human body and environment: it shows the load a human may be

exposed;

• Mild heat stress may cause discomfort or deterioration of performance;

• Above tolerated temperatures, heat related illness arise.


Thermal Comfort assessment procedures overview

Monitoring and evaluation

Empirical approach (surveys)

Analytical approach

Thermal comfort measurements. Sensors and equipment

Practical session with equipment

2.Measurements and Models

Thermal Comfort Assessment

Evaluation of the thermal environment

Qualitative

Quantitative

Thermal Comfort

Evaluation

Talking to and interviewing people

Observation

→ subjective judgement

Carry out measurements

→ Objective assessment



Validating the Thermal Environment


Validation Methods

In order to determine the thermal environments’ ability to meet the

defined criteria there are two methods that can be implemented

(ASHRAE 55):

• statistically determine occupant satisfaction through the

evaluation of survey results.

• technically establish comfort conditions through the

analysis of environment variables.



Measuring thermal comfort

A simple way of estimating the level of thermal comfort in a workplace or home is

to ask the workers or inhabitants.

If the percentage of workers/inhabitants dissatisfied with the thermal environment

is above a certain level it is necessary to take actions.

The use of a thermal comfort checklist helps to identify whether there may be a

risk of thermal discomfort to the occupants of a room.



Assessing thermal comfort

Read the descriptions for each

thermal comfort factor, and tick the

appropriate box.

If two or more ‘YES’ boxes are ticked

there may be a risk of thermal

discomfort and it is necessary to

carry out a more detailed

assessment.

Factor Description YES

Air temperature

Does the air feel warm or hot?

Does the temperature in the workplace fluctuate

during a normal working day?

Does the temperature in the workplace change a

lot during hot or cold seasonal variations?

Radiant temperature Is there a heat source in the environment?

Humidity

Is there any equipment that produces steam?

Is the workplace affected by external weather

conditions?

Are you wearing clothes or protection equipment

that is vapour impermeable?

Do you complain that the air is too dry?

Do you complain that the air is humid?

Air movement

Is cold or warm air blowing directly into the

workspace?

Are you or your colleagues complaining of

draught?

Metabolic rate

Is work rate moderate to intensive in warm or hot

conditions?

Are you or your colleagues sedentary in cool or

cold environments?

Changes to the

environment

Can you make individual alterations to your

clothing in response to the thermal environment?

What your thinkDo your think that there is a thermal comfort

problem?

Thermal comfort checklist

Adapted from: http://www.hse.gog.uk/temperature/thermal/measuringthermalcomfort.pdf



https://www.educate-sustainability.eu/kb/sites/www.educate-sustainability.eu.portal/files/OCCUPANT%20COMFORT%20SURVEY%20QUESTIONNAIRE.pdf

Subjective evaluations

Questionnaires



Survey Occupants

The occupants’ survey require a survey check sheet to be provided by the team responsible for

validating the thermal environment of the space.

The sheet shall have, as a minimum, the following data for the occupant to fill in:

• Occupants name, date & time;

• Approximate outside air temperature;

• Clear sky/ Overcast (if applicable);

• Seasonal conditions;

• Occupant’s clothing;

• Occupant’s activity level;

• Applicable equipment;

• General thermal comfort level;

• Occupant’s location.

In addition to the occupant’s data, space should be provided for the surveyor to:

• number the survey;

• summarize the results; and

• sign his/her name.





Source: ASHRAE 55:2013



EN 15251:2007 - Methodologies for subjective evaluations

Subjective questionnaires can be used to evaluate the indoor environment.

Subjective scales are presented to the occupants at fixed time intervals (daily,

weekly, monthly, etc.).

The questionnaires should be filled out during middle morning or middle

afternoon. Not just after arrival or after a lunch break.

The results can be presented as average values and/or distributions.

Source: EN 15251:2007




Example of a Questionnaire (Based on ASHRAE 55 and EN15251)




At the design stage the thermal environment may be evaluated by

calculations.

Simple hand calculations and computer models and software of buildings and

systems are available for this purpose (see Training Module 2.4 section 6.2).

Temperature[ºC]

0

5

10

15

20

25

30

35

0:00 3:00 5:00 7:00 9:00 11:00 13:00 15:00 17:00 19:00 21:00 23:00

Hour

0

1

2

3

4

5

6

7

8

Heating and Cooling Energy Needs [kW/h]

21st Feb -Ext 21st Feb - Int 3rd Jun - Ext

3rd Jun - Int Heating needs [kW/h] Cooling needs [kW/h]

Comfort zone

Occupation period Occupation period



In existing buildings the thermal environment may be evaluated based on measurements

conducted during building operations.

Full scale laboratory testing may provide a more controlled validation.

http://www.healthyheating.com/Built

-to-code.htm#.VRwRR_zF_R8

IR survey



Measurement positions

Location of measurements

Measurements shall be made in occupied zones of the building at locations

where the occupants are known to or are expected to spend their time.

Locations might be workstation or seating areas, depending on the function of

the space.

Occupied rooms → measurements at a representative sample of occupant

locations spread throughout the occupied zone.

Unoccupied rooms → make a good faith estimate of the most significant

future occupant locations within the room and make appropriate

measurements.

www.testo.org/en/home/products/comfort_and

_indoor_air_quality/iaq_and_comfort_level.jsp

www.testo.org/en/home/products/comfort_and

_indoor_air_quality/iaq_and_comfort_level.jsp




Location of measurements

If occupancy distribution cannot be estimated, then the measurement locations shall be:

a) in the center of the room or zone;

b) 1.0 m inward from the center of each of the room's walls;

c) 1.0 m inward from the center of the largest window for exterior walls with windows.

1 m

1 m

1 m




Height above floor of measurements

http://www.blowtex-educair.it/

- 1.1 m (ta, va)

- 0.1 m (ta, va)

- 0.6 m (H, pa, ∆tpr)

- 0.1 m (ta, va)

- 1.1 m (H, pa, ∆tpr)

- 1.7 m (ta, va)



Measuring Conditions

To determine the effectiveness of the building system at providing the environmental

conditions specified in the ASHRAE 55 Standard, measurements shall be made under the

following conditions:

• Heating period (winter conditions) → measurements shall be made when the indoor-

outdoor temperature difference is not less than 50% of the difference used for design

and with cloudy to partly cloudy sky conditions.

If these sky conditions are rare and not representative of the sky conditions used for

design, then sky conditions representative of design conditions are acceptable.

• Cooling period (summer conditions) → measurements shall be made when the outdoor-

indoor temperature difference and humidity difference are not less than 50% of the

differences used for design and with clear to partly cloudy sky conditions.

If these sky conditions are rare and not representative of the sky conditions used for

design, then sky conditions representative of design conditions are acceptable.

• Test interior zones of large buildings → measurements shall be made with the zone

loaded to at least 50% of the design load for at least one complete cycle of the HVAC

system, if not proportionally controlled.

Simulation of heat generated by occupants is recommended.



Mechanical Equipment Operating Conditions

To determine appropriate corrective actions following the use of ASHRAE 55 Standard to

analyse the environment, the following operations of the mechanical system should be

measured concurrently with the environmental data:

• Air supply rate into the space being measured;

• Room/supply air temperature differential;

• Type and location of room diffuser or air outlet;

• Discharge air speed;

• Perimeter heat type, location and status;

• Return grille location and size;

• Type of air supply system;

• Surface temperatures of heated or cooled surfaces;

• Water supply and return temperatures of hydronic systems.




Define Criteria

After the definition of the comfort criteria, the validation team will evaluate the system’s ability to

meet and maintain the desired comfort level(s). The comfort criteria definition must outline at

least the following:

• Temperature (air, radiant, surface);

• Humidity;

• Air speed.

The environmental conditions must be specified as well to ensure

measurements taken correspond correctly to the design parameters.

Environmental conditions required are, but are not limited to:

• Outdoor temperature design conditions;

• Outdoor humidity design conditions;

• Clothing (seasonal);

• Activity expected.

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Documentation

The validation also involves ensuring a thoroughly documented process.

The process must be well documented and turned over to the design engineer and the owner

for approval and for their records.

When surveying the occupants of a building the survey method must be developed, written, and

turned over, with the sample survey sheets to the design engineer and the owner for review

and approval.

At the completion of the survey, the survey sheets and analysis of the data shall be turned over

to the design engineer and the owner for review and sign-off of the validation process.



Long-term evaluation of the general thermal comfort conditions

In order to evaluate the comfort conditions over time (season, year), a summation of parameters

must be made based on data measured in real buildings or dynamic computer simulations.

EN ISO 7730 Annex H lists five methods, each of which can be used for that purpose:

Method A: Calculate the number or percentage of hours during the hours the building is

occupied, the PMV or the operative temperature is outside a specified range.

Method B: The time during which the actual operative temperature exceeds the specified

range during the occupied hours is weighted with a factor which is a function of

how many degrees the range has been exceeded.

Method C: The time during which the actual PMV exceeds the comfort boundaries is

weighted with a factor which is a function of the PPD.

Method D: The average PPD over time during the occupied hours is calculated.

Method E: The PPD over time during the occupied hours is summed.



EN 15251:2007 - Inspections and measurement of the indoor environment in existing

buildings

Measurements shall be made where occupants are known to spend most of their time and under

representative weather condition of cold and warm season.

For the winter (heating season) measurements at or below mean outside temperatures for the 3

coldest months of the year.

For the summer (cooling season) measurements at or above statistic average outside temperatures

for the 3 warmest months of the year with clear sky.

The measurement period for all measured parameters should be long enough to be representative,

for example 10 days.

Air temperature in a room can be used in long term measurements and corrected for large hot or

cold surfaces to estimate the operative temperature of the room.



EN 15251:2007 - Long term evaluation of the general thermal comfort conditions

According to EN 15251 to evaluate the comfort conditions over time (season, year) a

summation of parameters must be made based on data measured in real buildings or

dynamic computer simulations.

EN 15251 Annex F lists the methods, which can be used for that purpose:

Method A: Percentage outside the range - Calculate the number or percentage of occupied

hours (those during which the building is occupied) when the PMV or the operative

temperature is outside a specified range.

Method B: Degree hours criteria - The time during which the actual operative temperature

exceeds the specified range during the occupied hours is weighted by a factor

which is a function depending on by how many degrees, the range has been exceeded.

Method C: PPD weighted criteria - The time during which the actual PMV exceeds the

comfort boundaries is weighted by a factor which is a function of the PPD.



Measuring instruments

Measured quantities

Main independent quantities involved in the analysis of the thermal balance between man and the thermal environment

Elements in the thermal balance

Quantities

ta va pa Icl Rcl M W

Air

temperature

Mean radiant

temperature

Air

velocity

Absolute humidity of the

air (partial pressure of

water vapour)

Insulation

of

clothing

Evaporative

resistance of

clothing

MetabolismExternal

work

Internal heat production, M-W X X

Heat transfer by radiation, R X X

Heat transfer by convection, C* X X X

Heat losses through evaporation:

- evaporation from the skin, E

- evaporation by respiration, Eres

XX

XX

X

Convection by respiration, Cres X X

* Heat transfer by convection is also influenced by body movements. The resultant air velocity at skin level is called relative air velocity (var). Heat conduction (surface

temperature) has only a limited influence on the thermal heat balance.

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high-end-vac-measuring-instrument

_

rt

Source: EN ISO 7726


Equipment and methods

Types of temperature sensor

a) Expansion thermometers:

1) liquid expansion thermometer (mercury);

2) solid expansion thermometer.

b) Electrical thermometers:

1) variable resistance thermometer

• platinum resistor;

• thermistor;

2) thermometer based on the generation of an electromotive force (thermocouple).

c) Thermom-anometers (variation in the pressure of a liquid as a function of temperature).



Precautions to be taken when using a temperature probe

Reduction of the effect of radiation

Care should be taken to prevent the probe from being subjected to

radiation from neighbouring heat sources.

Means of reducing the effect of radiation on the probe :

a) Reduction of the emission factor of the sensor;

b) Reduction in the difference in temperature between the sensor

and the adjacent walls.

c) Increasing the coefficient of heat transfer by convection.

Certain devices use the three means of protection simultaneously, which

results in small measuring errors.http://www.deltaohm.com/



The mean radiant temperature is the uniform temperature of an imaginary

enclosure in which radiant heat transfer from the human body is equal to

the radiant heat transfer in the actual non-uniform enclosure. The mean

radiant temperature is defined in relation to the human body.

The mean radiant temperature can be measured by instruments which allow

the generally heterogeneous radiation from the walls of an actual enclosure to

be "integrated" into a mean value.

The black globe thermometer is a device frequently used in order to derive

an approximate value of the mean radiant temperature from the observed

simultaneous values of the globe temperature, tg, and the temperature and the

velocity of the air surrounding the globe.

The spherical shape of the globe thermometer can give a reasonable

approximation of the shape of the body in the case of a seated person. An

ellipsoid-shaped sensor gives a closer approximation to the human shape

both in the upright position and the seated position.www.alphaomega-

electronics.com



Method for calculation of mean radiant temperature

Calculation from the temperature of the surrounding

surfaces

The mean radiant temperature can be calculated from

• the surface temperature of the surrounding

surfaces;

• the angle factor between a person and the

surrounding surfaces, a function of the shape,

the size and the relative positions of the surface

in relation to the person.

As most building materials have a high emissivity (e), it

is possible to disregard the reflection i.e. to assume that

all the surfaces in the room are black.

Mean value of angle factor

between a seated person and a

vertical rectangle (above or below

his centre) when the person is

rotated around a vertical axis. (To

be used when the location but not

the orientation of the person is

known).

Mean value of angle factor

between a seated person and a

horizontal rectangle (on the ceiling

or on the floor) when the person is

rotated around a vertical axis. (To

be used when the location but not

the orientation of the person is

known.)

Source: ISO

7726




Calculation from the temperature of the surrounding surfaces

The angle factors (Fp-n) can also be calculated from the equation:

Where:

Source: ISO 7726

Fmax A B C D E

Seated Person

Vertical surfaces: Wall, Window0.18 1.216 0.169 0.717

0.0870.052

Seated Person

Horizontal surfaces: Floor, Ceiling0.116

1.396 0.130 0.951 0.080 0.055

Standing Person

Vertical surfaces: Wall, Window0.120 1.242 0.167

0.616 0.082 0.051

Standing Person

Horizontal surfaces: Floor, Ceiling

0.116 1.595 0.128 1.226 0.046 0.044




Calculation from the plane radiant temperature

The mean radiant temperature may be calculated from:

• the plane radiant temperature, tpr, in six directions;

• the projected area factors for a person in the same

six directions.

The projected area factors for a seated or standing person are

given in the table for the six directions: up (1), down (2), left (3),

right (4), front (5), back (6).

The mean radiant temperature can be calculated by multiplying

the six measured values by the relevant projection factors given

in the table adding the resultant data and dividing the result by

the sum of the projected area factors.

Where the orientation of the person is not fixed, the average of

the Right/Left and Front/Back projected area factors is used.

Projected area factorsUp/down Left/right

Front/bac

k

Standing Person

Ellipsoid

Sphere

0.,08

0.08

0.25

0.23

0.28

0.25

0.35

0.28

0.25

Seated Person

Ellipsoid

Sphere

0.18

0.18

0.25

0.22

0.22

0.25

0.30

0.28

0.25

Source: EN ISO 7726



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The plane radiant temperature and radiant temperature asymmetry can be

measured using :

• a net radiometer;

• a heated sensor consisting of a reflective disc, and an absorbing disc;

With a net radiometer it is possible to determine the plane radiant

temperature from the net radiation exchanged between the environment

and the surface element and the surface temperature of the radiometer.

A radiometer with a sensor consisting of a reflective disc (polished) and an

absorbent disc (painted black) can also be used.



Method for calculation of plane radiant temperature

The plane radiant temperature can be calculated from:

• the surface temperature of the surrounding surfaces;

• the angle factor between a small plane element and the surrounding surfaces, a function

of the shape, the size and the relative position of the surface in relation to a person.

The radiant temperature asymmetry is estimated as the difference between the plane radiant

temperature in two opposite directions.

As most building materials have a high emittance (e), it is possible to disregard the reflections, i.e. to

assume that all the surfaces in the room are black.

The plane radiant temperature is calculated as the mean value of the surface temperatures

weighted according to the magnitude of the respective angle factors.

Analytical formula relating to the calculation of the

shape factor in the case of a small plane element

perpendicular to a rectangular surface

Analytical formula relating to the calculation of the

shape factor in the case of a small plane element

parallel to a rectangular surface

Source: ISO 7726



Method for calculation of plane radiant

temperature

Chart for the calculation of the shape factor in

the case of a small plane element perpendicular

to a rectangular surface

Chart for the calculation of the shape factor in the

case of a small plane element parallel to a

rectangular surface

Source: ISO 7726



The absolute humidity can be determined:

• Directly:

- dew-point instruments;

- electrolytic instruments; or

• Indirectly by the measurement of several quantities

simultaneously:

- relative humidity and temperature of the air;

- psychrometric wet temperature; and

- temperature of the air.

http://www.dpi.nsw.gov.au/agriculture/h

orticulture/greenhouse/structures/evap-

cooling

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Measurement of the absolute humidity using psychrometry

Description and principle of operation

A psychrometer consists of two thermometers and a device to ensure ventilation of the

thermometers at a minimum air velocity.

The first thermometer is an ordinary thermometer indicating the air temperature, ta, the "dry"

temperature of the air.

The latter consists of a thermometer surrounded by a wet wick

generally made from close-meshed cotton. The end of the wick lies in a

container of water.



Direct determination of the thermo-hygrometric

characteristics of humid air using a

psychometric chart

The main characteristics of humid air are usually grouped

together in a chart known as a psychometric chart. The

coordinates of this chart are as follows:

• on the x-axis → the air temperature, ta (ºC);

• on the y-axis → the partial pressure of water vapour, pa, of

the air (kPa).

Psychrometric chart

Source: ISO 7726



The air velocity is a quantity defined by its magnitude and direction.

The quantity to be considered in the case of thermal environments is the speed of the air, i.e. the

magnitude of the velocity vector of the flow at the measuring point considered.

The following factors must be considered for accurate velocity measurements:

a) the calibration of the instrument;

b) the response time of the sensor and the instrument;

c) the measuring period.

Types of anemometers

The air velocity, Va, can be determined:

• either by the use of an omnidirectional probe which is sensitive to the magnitude of the

velocity whatever its direction (hot-sphere sensor);

• or by the use of three directional sensors which allow the components of the air velocity to

be measured along three perpendicular axis (cosine law).

In practice it is very difficult to measure accurately in one direction.

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The surface temperature can be measured by the method given in

EN ISO 7726 Annex F, including:

• contact thermometer, where the sensor is in direct contact

with the surface.

• infrared sensor, where the radiant heat flux from the surface

is measured and converted to a temperature. This may be

influenced by the emissivity of surface.

http://www.deltaohm.com



Characteristics of measuring instruments

Characteristics of instruments for measuring the basic quantities

Class C (Comfort) Class S (thermal stress)

CommentsMeasuring

range

Accuracy Response time

(90%)

Measuring

range


(90%)

10ºC to

40ºC

The shortest

possible. Value

to be specified

as characteristic

of the measuring

instrument.

-40ºC to

+120ºC

The shortest

possible. Value

to be specified

as characteristic

of the measuring

instrument.

The air temperature

sensor shall be

effectively protected

from any effects of the

thermal radiation

coming from hot or

cold Wall. Na

indication of the mean

value over a period of

1 min is also desirable

Characteristics of measuring instruments – Air temperature (ta)

Source: EN ISO 7726






CommentsMeasuring

range


(90%)

Measuring

range


(90%)

10ºC to

40ºC

Required: ± 2ºC

Desirable: ± 0.2ºC

These levels are

difficult or even

impossible to achieve

in certain cases with

the equipment

normally available.

When they cannot be

achieved, indicate the

actual measuring

precision.

The shortest

possible. Value

to be specified

as

characteristic of

the measuring

instrument.

-40ºC to

+150ºC

The shortest

possible. Value

to be specified

as

characteristic of

the measuring

instrument.

When the

measurement is

carried out with a

black sphere, the

inaccuracy relating to

the mean radiant

temperature can be

as high as ± 5ºC for

class C and ± 20ºC

for class S according

to the environment

and the inaccuracy

for Va, ta and tg.

Source: EN ISO 7726





Characteristics of measuring instruments – Plane radiant temperature (tpr)


CommentsMeasuring

range


(90%)

Measuring

range


(90%)

0ºC to

50ºC

The shortest

possible.

Value to be

specified as

characteristic of

the measuring

instrument.

0ºC to

200ºC

The shortest

possible. Value

to be specified

as characteristic

of the measuring

instrument.

Source: EN ISO 7726





Characteristics of measuring instruments – Air Velocity (Va)


CommentsMeasuring

range


(90%)

Measuring

range


(90%)

0.05 m/s

to 1.0

m/s

Required: ± (0.05 +

0.05Va) m/s

Desirable: ± (0.02 +

0.07Va) m/s

These levels shall be

guaranteed whatever the

direction of flow within a

solid angle (:) = 3 sr

Required: 0.5 s

Desirable: 0.2 s

0.2 m/s to

20.0 m/s

Required: ± (0.1 +

0.05Va) m/s

Desirable: ± (0.05 +

0.05Va) m/s

These levels shall be

guaranteed whatever

the direction of flow

within a solid angle

(:) = 3 sr

The shortest

possible. Value

to be specified

as characteristic

of the measuring

instrument.

For measuring

the degree of

turbulence a

small response

time is needed.

Except in the case of

a unidirectional air

current, the air velocity

sensor shall measure

the velocity whatever

the direction of the air.

An indication of the

mean value and

standard deviation for

a period of 3 min is

also desirable.

Source: EN ISO 7726





Characteristics of measuring instruments – Absolute humidity expressed as partial pressure of water

vapour (pa)


CommentsMeasuring

range


(90%)

Measuring

range


(90%)

0.5 kPa to

3.0 kPa

The shortest

possible. Value

to be specified

as characteristic

of the measuring

instrument.

0.5 kPa to

6.0 kPa

The shortest

possible. Value

to be specified

as characteristic

of the measuring

instrument.

Source: EN ISO 7726





Characteristics of measuring instruments – Surface temperature (ts)


CommentsMeasuring

range


(90%)

Measuring

range


(90%)

0ºC to

50ºC

Required: ± 1ºC

Desirable: ± 0.5ºC

The shortest

possible. Value

to be specified

as characteristic

of the measuring

instrument.

-40ºC to

+120ºC

Required:

< -10ºC: ± [1+0.05(-ts-

10)]

-10ºC to 50ºC: ± 1ºC

> 50ºC: ± [1+0.05(ts-

50)]

Desirable:

required accuracy / 2

The shortest

possible. Value

to be specified

as characteristic

of the measuring

instrument.

Source: EN ISO 7726



Characteristics of measuring instruments for measuring the basic quantities

The standard environmental conditions specified shall be used as a reference except where this

contradicts the principle for measuring the quantities under consideration.

Standard environmental conditions for the determinations of time constants of sensors

Quantities of the standard

environment

Measurement of the

response time of sensors for

ta pa va

Air temperature = ta Any < 0.15 m/s

Mean radiant temperature Any < 0.15 m/s

Absolute humidity = 20ºC = ta To be specified according to the measuring method

Air velocity = 20ºC = ta Any

Plane radiant temperature = 20ºC = ta Any < 0.15 m/s

Surface temperature = 20ºC = ta Any < 0.15 m/s

Source: EN ISO 7726



Specifications relating to measuring methods

The methods for measuring the physical characteristics of the environment shall take account of the

fact that these characteristics vary in location and time.

The thermal environment may vary with the horizontal location, and then account has to be taken of

how long a time a person is working at the different locations.

The environment may also vary in the vertical direction.




Specifications relating to variations in the physical quantities within the space surrounding

the subject

When the environment is too heterogeneous, the physical quantities shall be measured at

several locations at or around the subject and account taken of the partial results obtained in

order to determine the mean value of the quantities to be considered in assessing the comfort or

the thermal stress.

Previous analyses of the thermal stress of the work places being studied or of work places of a

similar type may provide information which is of interest in determining whether certain of the

quantities are distributed in a homogeneous way.

In the case of poorly defined rooms or work places consider only a limited zone of occupancy

where the criteria of comfort or thermal stress shall be respected.

In case of dispute in the interpretation of data, measurements carried out presuming the

environment to be heterogeneous shall be used as a reference.




Specifications relating to variations in the physical quantities within the space surrounding

the subject

The sensors shall be placed at the heights where the person normally carries out his activity.

Location of

the sensors

Weighting coefficients for measurements for calculation

mean values Recommended heights

(guidance )Homogeneous environment Heterogeneous environment

Class C Class S Class C Class S Sitting Standing

Head level 1 1 1.1 m 1.7 m

Abdomen level 1 1 1 2 0.6 m 1.1 m

Ankle level 1 1 0.1 m 0.1 m

Measuring heights for the physical quantities of an environment

Plane radiant temperature, mean radiant temperature and absolute humidity are normally only measured

at the centre height.

Source: EN ISO 7726



Source: EN ISO 7726

Specifications relating to measuring

methods

Specifications relating to the variations in

the physical quantities with time

An environment is said to be stationary in

relation to the subject when the physical

quantities used to describe the level of

exposure are practically independent of the

time, i.e. for instance when the fluctuations in

these parameters in relation to their mean

temporal value do not exceed the values

obtained by multiplying the required measuring

accuracy by the corresponding factor X.


CommentsMeasuri

ng

range

Accuracy Response

time (90%)

Measurin

g range

Accuracy Response

time (90%)

10ºC to

40ºC

The shortest

possible.

Value to be

specified as

characteristi

c of the

measuring

instrument.

-40ºC to

+120ºC

The shortest

possible.

Value to be

specified as

characteristi

c of the

measuring

instrument.

The air

temperature

sensor shall be

effectively

protected from

any effects of the

thermal radiation

coming from hot

or cold Wall. Na

indication of the

mean value over

a period of 1 min

is also desirable

Elements in the thermal balanceClass C (comfort)

Factor x

Class S (thermal stress)

Factor x

Air temperature 3 4

Mean radiant temperature 2 2

Radiant temperature asymmetry 2 3

Mean air velocity 2 3

Vapour pressure 2 3

Note: Deviation between each individual quantity and their mean value shall be less than that

obtained multiplying the required measuring accuracy by the appropriate factor x listed

here.



Operative temperature (to) is defined as the uniform temperature of an enclosure in which an

occupant would exchange the same amount of heat by radiation plus convection as in the

existing non-uniform environment.

Where:

ta – air temperature 𝑡𝑟 – mean radiant temperature

hc – heat-transfer coefficient by convection

hc – heat-transfer coefficient by radiation.

In general:

hr = 4,9 w/m2k

hc = 2,9 w/m2k

If :

- surfaces with very different temperatures - hr = 𝑡𝑟;

- high air velocities (var >0.2 m/s) - hc = (10. var ) 1/2.

𝑡𝑜 =ℎ𝑐 . 𝑡𝑎 + ℎ𝑟 . 𝑡𝑟

ℎ𝑐 + ℎ𝑟



Working procedure:

1. Identification of the problem, which causes complaints.

2. What is the reason?

3. Identification of values that will support the assumption.

4. Taking measurements.

5. Evaluation of data obtained.

6. Making conclusion and draft of measures to solve detected problems.

7. Final report.

http://www.healthyheating.com/Ther

mal-Comfort-Survey/Thermal-

comfort-survey.htm#.VR0uBfzF_R8


Assessment procedures overview

Complete plans, descriptions, component literature, and operation and maintenance instructions for

the building systems should be provided and maintained.

https://www.energystar.gov/index.cfm?c=next_generation.ng_thermal_enclosure_sys



The information should include, but not be limited to, building system design specifications

and design intent as follows:

1. The design criteria of the system in terms of indoor temperature and humidity,

including any tolerance or range, based on stated design outdoor ambient conditions

and total indoor loads, should be stated. Values assumed for comfort parameters,

including clothing and metabolic rate, used in calculation of design temperatures,

should be clearly stated.

2. The system input or output capacities necessary to attain the design indoor

conditions at design outdoor ambient conditions should be stated, as well as the full

input or output capacities of the system as supplied and installed.

3. The limitations of the system to control the environment of the zone (s) should be

stated whether based on temperature, humidity, ventilation, time of week, time of day,

or seasonal criteria.



4. The overall space supplied by the system should be shown in a plan view layout,

with individual zones within it identified. All registers or terminal units should be

shown and identified with type, flow, or radiant value.

5. Significant structural and decor items should be shown and identified if they

affect indoor comfort. Notes should be provided to identify which areas within a

space, and what locations relative to registers, terminal units, relief grills, and control

sensors should not be obstructed as this would negatively affect indoor comfort.

6. Areas within any zone that lie outside the comfort control areas, where people

should not be permanently located, should be identified.





7. Locations of all occupant adjustable controls should be identified, and each should

be provided with a legend describing what zone(s) it controls, what function(s) it

controls, how it is to be adjusted, the range of effect it can have, and the

recommended setting for various times of day, season, or occupancy load.

8. If more than one comfort level is available for any zone(s), they should be identified as

A, B, C etc., with A being the narrowest range (highest comfort), and the specifications

as above should be provided for each, along with the relative seasonal energy usage

for each at 80 % of design ambient.





9. A control schematic should be provided in block diagram with sensors, adjustable

controls, and actuators accurately identified for each zone. If zone control

systems are independent but identical, one diagram is sufficient if identified for which

zones it applies. If zones are interdependent or inter-active, their control diagram

should be shown in total on one block diagram with the point(s) of interconnection

identified.

10. The general maintenance, operation and performance of the building systems

should be stated, followed by more specific comments on the maintenance and

operation of the automatic controls and manually adjustable controls, and the response

of the system to each. Where necessary, specific seasonal settings of manual controls

should be stated, as also major system changeovers that are required to be performed

by a professional service agency should be identified.





11. Specific limits in the adjustment of manual controls should be stated.

Recommendations for seasonal setting on these should be stated along with the

degree of manual change that should be made at any one time, and the waiting time

between adjustments, in trying to fine tune the system. A maintenance and

inspection schedule for all thermal environmental related building systems

should be provided.

12. Assumed electrical load for lighting and equipment in occupied spaces (including

diversity considerations) used in HVAC load calculations should be documented,

along with any other significant thermal and moisture loads assumed in HVAC load

calculations and any other assumptions upon which HVAC and control design is

based.





EN ISO 7730:2005

EN 15251:2007

ASHRAE 55:2010

Thermal Comfort Predictive Models

Standards


EN ISO 7726:2001 - Ergonomics of the thermal environment - Instruments and methods for

measuring physical quantities;

EN ISO 7243:1989 - Hot environments - Estimation of the heat stress on working man, based

on the WBGT-index (wet bulb globe temperature);

ISO 7933:2004 - Ergonomics of the thermal environment - Analytical determination and

interpretation of heat stress using calculation of the predicted heat strain;

ISO 11079:2007 - Ergonomics of the thermal environment - Determination and interpretation of

cold stress when using required clothing insulation (IREQ) and local cooling effects.

Standards



Air Temperature

Me

an

Ra

dia

nt

Te

mp

era

ture

Air Velocity

Re

lati

ve

Hu

mid

ity

Clothing Insulation

Me

tab

olic R

ate



Air Temperature

Me

an

Ra

dia

nt

Te

mp

era

ture

Air VelocityR

ela

tive

Hu

mid

ity

Clothing Insulation

Me

tab

olic R

ate

EN ISO 7730:2005

Ergonomics of the thermal environment

Analytical determination and interpretation of thermal

comfort using calculation of the PMV and PPD indices

and local thermal comfort criteria



EN ISO 7730:2005

http://sustainabilityworkshop.autodesk.com/buildings/controls-lighting-and-daylighting

Presents methods for predicting the general thermal sensation and degree of discomfort

(thermal dissatisfaction) of people exposed to moderate thermal environments.

Also specifies how to predict the percentage dissatisfied owing to local discomfort

parameters.



A human being's thermal sensation is mainly related to the thermal balance of his or her body as a

whole.

EN ISO 7730:2005

• PMV (predicted mean vote)

• PPD (predicted percentage

of dissatisfied)

• Local thermal comfort

criteria

• physical activity

• clothing

• air temperature

• mean radiant temperature

• air velocity

• air humidity

estimated or measured



EN ISO 7730:2005

+ 3 → Hot

+ 2 → Warm

+ 1 → Slightly warm

0 → Neutral

− 1 → Slightly cool

− 2 → Cool

− 3 → Cold

PMV

Seven-point thermal sensation scale:



EN ISO 7730:2005



EN ISO 7730:2005

Where:

𝑀 is the metabolic rate (W/𝑚2);

𝑊 is the effective mechanical power (W/𝑚2);

𝐼𝑐𝑙 is the clothing insulation (𝑚2⋅K/W);

𝑓𝑐𝑙 is the clothing surface area factor;

𝑡𝑎 is the air temperature (°C);

𝑡𝑟 is the mean radiant temperature (°C);

𝑣𝑎𝑟 is the relative air velocity (m/s);

𝑝𝑎 is the water vapour partial pressure (Pa);

ℎ𝑐 is the convective heat transfer coefficient [W/(𝑚2⋅ K)];

𝑡𝑐𝑙 is the clothing surface temperature (°C).



The PMV index should be used only for values of PMV between −2 and +2, and when the six main

parameters are within the following intervals:

M - 46 W/m2 to 232 W/m2 (0,8 met to 4 met);

Icl - 0 m2 ⋅ K/W to 0,310 m2⋅K/W (0 clo to 2 clo);

ta - 10 °C to 30 °C;

tr - 10 °C to 40 °C;

var - 0 m/s to 1 m/s;

pa - 0 Pa to 2 700 Pa.

EN ISO 7730:2005

1 metabolic unit = 1 met = 58,2 W/m2;

1 clothing unit = 1 clo = 0,155 m2 ⋅ °C/W.



Predicted percentage dissatisfied (PPD)

With the PMV value determined, calculate the PPD:

EN ISO 7730:2005

Where:

PMV - predicted mean vote

PPD - predicted percentage dissatisfied (%)

The PPD predicts the number of thermally

dissatisfied persons among a large group of people.

The rest of the group will feel thermally neutral,

slightly warm or slightly cool.

𝑃𝑃𝐷 = 100 − 95 ∗ exp(−0.03353 ∗ 𝑃𝑀𝑉4 − 0.2179 ∗ 𝑃𝑀𝑉2)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

-3 -2 -1 0 1 2 3

PMV

PP

D

T = Tair - Tair comfortable

-8º -6 -4 -2 0º +2 +4 +6 +8º

-3 -2 -1 0 +1 +2 +3

Cold Cool slightly Neutral slightly Warm Hot cool warm



The PMV and PPD express warm and cold discomfort for the

body as a whole.

Thermal dissatisfaction can also be caused by unwanted

cooling or heating of one particular part of the body → local

discomfort.

The most common local discomfort factors are:

• draught (local cooling of the body caused by air

movement);

• radiant temperature asymmetry (cold or warm surfaces);

• vertical air temperature difference (between the head

and ankles); and

• cold or warm floors.

EN ISO 7730:2005

http://www.blowtex-educair.it/

Local thermal discomfort




Draught

The discomfort due to draught may be expressed as the percentage of

people predicted to be bothered by draught. The draught rate (DR):

EN ISO 7730:2005

Where:

ta,I - local air temperature, in degrees Celsius, 20 °C to 26 °C;

𝑣𝑎,𝐼 - local mean air velocity, in metres per second, < 0,5 m/s;

Tu - local turbulence intensity, in percent, 10 % to 60 % (if unknown, 40% may be used).

𝐷𝑅 = 34 − 𝑡𝑎.𝐼 . 𝑣𝑎,𝐼 − 0.050.62

. 0.37. 𝑣𝑎,𝐼 . 𝑇𝑢 + 3.14

𝐹𝑜𝑟 𝑣𝑎,𝐼 < 0.05 𝑚/𝑠 𝑢𝑠𝑒 𝑣𝑎,𝐼 = 0.05 𝑚/𝑠

For DR > 100% use DR=100%

The model applies to people at light, mainly sedentary activity with a thermal sensation for the whole

body close to neutral and for prediction of draught at the neck. At the level of arms and feet, the

model could overestimate the predicted draught rate. The sensation of draught is lower at activities

higher than sedentary (> 1,2 met) and for people feeling warmer than neutral.




Vertical air temperature difference

EN ISO 7730:2005

PD - percentage dissatisfied (%)

ta,v - vertical air temperature

difference between head and

feet (°C)

Local discomfort caused by vertical air temperature

difference, when the temperature increases

upwards

25 oC

19 oC


Warm and cool floors

Local thermal discomfort caused by warm or cold floors


tf - floor temperature (°C)




Radiant asymmetry

Source: EN 7730:2005

Local thermal discomfort caused by radiant temperature

asymmetry

Warm ceilingCool wall

Cool ceiling

Warm wall


tpr - radiant temperature asymmetry (°C)



Categories of thermal environment

The desired thermal environment for a space may be selected from among the three categories, A,

B and C. All the criteria should be satisfied simultaneously for each category.

EN ISO 7730:2005

Categories of thermal environment

Category

Thermal state of the body

as a whole Local discomfort

PPD

(%)PMV

DR

(%)

PD

(%)

caused by

vertical air temperature

difference

warm or

cool floor

radiant

asymmetry

A < 6 - 0.2 < PMV < + 0.2 < 10 < 3 < 10 < 5

B < 10 - 0.5 < PMV < + 0.5 < 20 < 5 < 10 < 5

C < 15 - 0.7 < PMV < + 0.7 < 30 < 10 < 15 < 10




Operative temperature range

For a given space there exists an optimum operative temperature corresponding to PMV = 0,

depending on the activity and the clothing of the occupants.

EN ISO 7730:2005

Category A: PPD < 6 % Category B: PPD < 10 % Category C: PPD < 15 %

Optimum operative temperature as function of clothing and activity

Clothing

Activity

Clothing

Activity

Clothing

Activity

PPD - Predicted percentage dissatisfied (%)

X - Basic clothing insulation (clo)

X′ - Basic clothing insulation (m2⋅°C/W)

Y - metabolic rate (met)

Y′ - metabolic rate (W/m2)




Extreme environmental conditions

ISO 7243, ISO 7933 and ISO/TR 11079

Specify methods for the measurement and evaluation of the extreme thermal environments to

which human beings are exposed.



ASHRAE 55 specifies thermal environmental conditions acceptable

Healthy adults at atmospheric pressure equivalent to altitudes up to

3000 m in indoor spaces designed for human occupancy

periods not less than 15 minutes.

The selected design criteria will influence the HVAC-system design

and may also influence the building design.

ASHRAE Standard 55:2013



Operative Temperature

For given values of humidity, air speed, metabolic rate, and clothing insulation, a comfort zone

may be determined.

The comfort zone is defined in terms of:

- a range of operative temperatures that provides acceptable thermal environmental

conditions; or

- the combinations of air temperature and mean radiant temperature that people find

thermally acceptable.

Applied to spaces where:

- occupants activity levels’ result in metabolic rates between 1.0 met and 1.3 met;

- clothing thermal insulation between 0.5 clo and 1.0 clo.




Graphical method for typical indoor environments


Class B thermal environments

Var < 0.2 m/s

Acceptable range of operative temperature and humidity

Source: ASHRAE 55: 2013



PMV and PPD

ASHRAE standard also defines three classes of thermal comfort based on the PPD allowed.


Category PPD

(%)PMV

A < 6 - 0.2 < PMV < + 0.2

B < 10 - 0.5 < PMV < + 0.5

C < 15 - 0.7 < PMV < + 0.7

Three classes of acceptable thermal

environment for general comfort

Predicted percentage dissatisfied (PPD) as a function

of predicted mean vote (PMV)


𝑃𝑃𝐷 = 100 − 95 ∗ exp(−0.03353 ∗ 𝑃𝑀𝑉4 − 0.2179 ∗ 𝑃𝑀𝑉2)




The local thermal discomfort caused by:

• a vertical air temperature difference between the feet and the head,

• an asymmetric radiant field,

• by a local convection cooling (draft), or

• contact with a hot or cold floor.

must be considered in determining conditions for acceptable thermal comfort.

People are more sensitive to local discomfort when the whole body is cooler than neutral and

less sensitive to local discomfort when the whole body is warmer than neutral.






Radiant temperature asymmetry

The thermal radiation field about the body

may be non-uniform due to hot and cold

surfaces and direct sunlight.

This asymmetry may cause local discomfort

and reduce the thermal acceptability of the

space.Local thermal discomfort caused by radiant asymmetry





Draft

Allowable mean air speed as a function of air temperature and turbulence intensity

for Class A and Class B thermal environments. Class C is the same as Class B

Based on sensitivity to draft in

the head region with airflow

from behind.

May be conservative for some

locations on the body and for

some directions of airflow.






Vertical air temperature difference

Local thermal discomfort caused by vertical

temperature differences

Thermal stratification that results in the air temperature at the head level being warmer than at the

ankle level may cause thermal discomfort.

Allowable vertical air temperature difference between

head and ankles for the three classes of thermal

environment

ClassVertical air temperature difference

(°C)

A < 2

B < 3

C < 4






Floor surface temperature

Occupants may feel uncomfortable due to contact with floor surfaces that are too warm or too

cool. The temperature of the floor, rather than the material of the floor covering, is the most

important factor for foot thermal comfort for people wearing shoes.

Allowable range of the floor temperature for the three

classes of the thermal environment

ClassRange of surface temperature of the

floor (°C)

A 19 – 29

B 19 - 29

C 17 - 31

Local discomfort caused by warm and cool floors




Method for determining acceptable thermal conditions in naturally conditioned spaces


Occupant-controlled naturally conditioned spaces → spaces where the thermal

conditions of the space are regulated primarily by the occupants through opening and

closing of the windows.

Occupants’ thermal responses in occupant-controlled naturally conditioned spaces

depends in part on the outdoor climate, and

may differ from thermal responses in buildings with centralized HVAC systems primarily

because of the different thermal experiences, changes in clothing, availability of

control, and shifts in occupant expectations.





This optional method applies only to spaces where the occupants may freely adapt their

clothing to the indoor and/or outdoor thermal conditions.

Acceptable operative temperature ranges for naturally conditioned spaces

Source: ASHRAE 55, 2013




Portuguese Adaptive Thermal Comfort Model Based on ASHRAE Standard 55:2010

In Portugal Luís Matias performed a experimental study at national level, evaluating in situ the

thermal comfort parameters and surveying the occupants of schools, offices, elderly houses

and residential buildings.

Based on the field results the National Civil Engineering Laboratory (Laboratório Nacional de

Engenharia Civil, LNEC) defined a adaptive thermal comfort model to be used in the

assessment of the thermal conditions of the occupants of the Portuguese building stock.

Adaptive Thermal Comfort Models at National Level - Portugal





Two comfort temperatures were defined, Tconf:

- one to be used on spaces with the HVAC systems activated ;and

- other to be used on non-acclimatized spaces (without HVAC systems or when the systems

are turned off).

The thermal comfort temperatures is obtained based on the outdoor exponentially weighted

temperature, Tmp:

8,3

)T2,0T3,0T4,0T5,0T6,0T8,0T(T 7n6n5n4n3n2n1n

mp

where:

Tmp – outdoor exponentially weighted temperature(ºC) ;

Tn-i – average outdoor temperature of previous day (i) (ºC);




Portuguese Adaptive Thermal Comfort Model

Thermal comfort zone for a 90% acceptability level

defined as the thermal comfort temperature 3ºC

HV

AC

syste

m:

Off

HV

AC

syste

m:

On

Outdoor exponentially weighted temperature, Tmp, (ºC)

Th

erm

al C

om

fort

te

mp

era

ture

, T

co

mf, (

ºC)

35

30

25

20

15

10

0 5 10 15 20 25 30 35

І І І І І І І

_

_

_

_

_

Adapted from: Matias, 2010






EN 15251:2007

EN 15251 standard gives the indoor environmental parameters for design and

assessment of energy performance of buildings.

EN 15251 also specifies:

• the indoor environmental parameters which have an impact on the

energy performance of buildings;

• how to establish indoor environmental input parameters for building

system design and energy performance calculations;

• methods for long term evaluation of the indoor environment obtained as

a result of calculations or measurements;

• criteria for measurements which can be used if required to measure

compliance by inspection;

• identifies parameters to be used by monitoring and displaying the

indoor environment in existing buildings; and

• criteria for indoor environment are set by human occupancy and where

the production or process does not have a major impact on indoor

environment.



EN 15251:2007

EN 15251 standard divides indoor climate for different categories (ICC):

I - High level of expectation and is recommended for spaces occupied by very

sensitive and fragile persons with special requirements like handicapped, sick,

very young children and elderly persons.

II - Normal level of expectation and should be used for new buildings and

renovations.

III - An acceptable, moderate level of expectation and may be used for existing

buildings.

IV - Values outside the criteria for the above categories. This category should only be

accepted for a limited part of the year.



Adaptation:

Physiological, psychological or behavioural adjustment of building occupants to the

interior thermal environment in order to avoid discomfort.

In naturally ventilated buildings these are often in response to changes in indoor

environment induced by outside weather conditions.

EN 15251:2007



In Mechanically heated and/or cooled buildings the criteria for the thermal environment

shall be based on the thermal comfort indices PMV-PPD (predicted mean vote - predicted

percentage of dissatisfied) with assumed typical levels of activity and thermal insulation for

clothing (winter and summer).

EN 15251:2007

CategoryThermal state of the body as a whole

PPD PMV

I < 6% - 0.2 < PMV < + 0.2

II < 10% - 0.5 < PMV < + 0.5

III < 15% - 0.7 < PMV < + 0.7

Examples of recommended categories for design of mechanical

heated and cooled buildings

Source: EN 15251:2007



EN 15251:2007

Examples of recommended design values of the indoor temperature for design of buildings and HVAC

systems

Type of building/ space Category

Operative temperature (ºC)

Minimum for heating

(winter season) (1.0 clo)

Maximum for cooling

(summer season) (0.5 clo)

Residential buildings: living

spaces (bedrooms, drawing

room, kitchen etc.)

(1.2 met)

I 21.0 25.5

II 20.0 26.0

III 18.0 27.0

Residential buildings: other

spaces (storages, halls etc.)

(1.6 met)

I 18.0

II 16.0

III 14.0

Mechanically heated and/or cooled buildings

Source: EN 15251:2007



EN 15251:2007

Buildings without mechanical cooling

This method only applies to spaces where :

• the occupants are engaged in near sedentary physical activities (1.0 to 1.3 met);

• strict clothing policies inside the building are avoided, in order to allow occupants to freely adapt their

clothing insulation.

In order for this method to apply:

• the spaces must be equipped with operable windows which open to the outdoors and which can be

readily opened and adjusted by the occupants of the spaces;

• there must be no mechanical cooling in operation in the space;

• mechanical ventilation with unconditioned air (in summer) may be utilized, but opening and closing of

windows must be of primary importance as a means of regulating thermal conditions in the space;

• there may in addition be other low-energy methods of personally controlling the indoor environment

such as fans, shutters, night ventilation etc..

The spaces may be provided by a heating system, but this optional method does not apply during times of the

year when the heating system is in operation.



EN 15251:2007


Acceptable “summer” indoor temperatures (cooling season) for

buildings without mechanical cooling systems

To I = 0,33 Trm + 18,8 - 2

To III = 0,33 Trm + 18,8 + 4

Op

era

tive

Te

mp

era

ture

, T

o(º

C)

Outdoor Running mean temperature, Trm (ºC)

To II = 0,33 Trm + 18,8 -

3

To II = 0,33 Trm + 18,8 + 3

To III = 0,33 Trm + 18,8 -

4

To I = 0,33 Trm + 18,8 + 2

Trm - running mean outdoor temperature.

These limits apply:

- upper limit →10 ºC < Trm < 30 ºC

- lower limit → 15 ºC < Trm < 30 ºC

Above 25 ºC the graphs are based on a

limited database

Source: EN 15251:2007



EN 15251:2007


The external running mean temperature - Trm - is the exponentially weighted running

mean of the daily outdoor temperature.

Trm = (1- ).{ Ted -1 + . Ted -2 + 2 Ted -3…..}

This equation can be simplified to:

Trm = (1- )Ted -1 + . Trm-1

Where:

Trm - Running mean temperature for today

Trm-1 - Running mean temperature for previous day

Ted-1 - Daily mean external temperature for the previous day

Ted -2 - Daily mean external temperature for the day before and so on.

- Constant between 0 and 1. Recommended to use 0.8



EN 15251:2007

Buildings without mechanical coolingThe external running mean temperature - Trm

Where records of daily mean external temperature are not available:

8,3

)2,03,04,05,06,08,0( 7654321 ededededededed

mp

TTTTTTTT

Where:

Trm - Running mean temperature for today

Ted-1 - daily mean external temperature for the previous day

Ted -2 - daily mean external temperature for the day before and so on.



EN 15251:2007

Temperature ranges for hourly calculation of cooling and heating energy in three categories of indoor

environment

Type of building/ space Category

Operative temperature (ºC)

Minimum for heating

(winter season) (1.0 clo)

Maximum for cooling

(summer season) (0.5 clo)

Residential buildings: living

spaces (bedrooms, living room

etc.)

(sedentary activity - 1.2 met)

I 21.0 – 25.0 23.5 – 25.5

II 20.0 – 25.0 23.0 – 26.0

III 18.0 – 25.0 22.0 – 27.0

Residential buildings: other

spaces (kitchen, storages etc.)

(standing walking activity - 1.5

met)

I 18.0 – 25.0

II 16.0 – 25.0

III 14.0 – 25.0


Source: EN 15251:2007



PMV calculators

A Computer Program for Calculation of

PMV-PPD is presented in both EN ISO

7730 and ASHRAE 55.



Simulation Tools

PMV calculators

EN ISO 7730 also provides tables for determination of

predicted mean vote (PMV)

Activity level: 46,4 W/m2 (0,8 met)



Simulation Tools

PMV calculators

A set of spreadsheets, developed in Microsoft Excel, to calculate the thermal comfort indices,

using the Fanger’s method proposed in EN ISO Standard 7730 are available online:

http://www.lumasenseinc.com/EN/products/thermal-comfort/pmv-calculation/

http://www.ddcode.com/mobile/th/thermal-comfort-pmv-calculator.html


Simulation Tools

http://www.ddcode.com/mobile/th/thermal-comfort-pmv-calculator.html

PMV/PPD calculation

Excel files


Simulation Tools

Excel files


Simulation Tools

PMV/PPD Calculation

http://sustainabilityworkshop.autodesk.com/buildings/human-thermal-comfort

Apps

https://itunes.apple.com/us/app/pmv/id408246562?mt=8


Simulation Tools

ASHRAE 55

Simulation tools

ASHRAE's Thermal Comfort Tool

software provides a user-friendly interface

for calculating thermal comfort

parameters and making thermal comfort

predictions using several existing thermal

comfort models.

The latest version focuses on the Adaptive

and Predicted Mean Vote (PMV) Models and

has an updated user interface. Available:

https://www.ashrae.org/resources--

publications/bookstore/thermal-comfort-tool


Simulation Tools

CBE Thermal Comfort Tool

Available at:

http://smap.cbe.berkeley.edu/comforttool

PMV Method

Video tutorials available online at: cbe.berkeley.edu/research/thermal-tool


Simulation Tools

http://www.cbe.berkeley.edu/research/thermal-tool.htm

CBE Thermal Comfort Tool

Adaptive Method

http://smap.cbe.berkeley.edu/comforttool/comforttool_static/html/help.html


Simulation Tools

Fraunhofer IBP Thermal Comfort Tool

Source: Fraunhofer IBP


Simulation Tools

Thermal performance software

EnergyPlus includes a building thermal

analysis tool allowing to determine whether

the environmental control strategy will be

sufficient for the occupants to be thermally

comfortable.

DesignBuilder allows the assessment of

the thermal comfort based on the Fanger

comfort indicators PPD and PMV.

http://www.designbuilder.co.uk/helpv4.3/Content/ThermalComfortCalculator.htm


Simulation Tools

PMV/PPD Calculation

Excel files

Thermal Comfort Simulation

Tools at National Level - Portugal


Simulation Tools

Source: EN 15251:2007

3.Building Regulations

European Standard Complex

EPBD Ergonomics

• EN ISO 7726 - Ergonomics of the thermal environments - Instruments for measuring

physical quantities

• EN ISO 7730 - Ergonomics of the thermal environment - Analytical determination and

interpretation of thermal comfort using calculation of the PMV and PPD indices and local

thermal comfort criteria

• EN ISO 8996 - Ergonomics of the thermal environment - Determination of metabolic rate

• EN ISO 27243 - Hot environments - Estimation of the heat stress on working man, based

on the WBGT-index (wet bulb globe temperature)

• EN ISO 9886 - Ergonomics - Evaluation of thermal strain by physiological measurements

• EN ISO 9920 - Ergonomics of the thermal environment - Estimation of thermal insulation

and water vapour resistance of a clothing ensemble

• EN ISO 7933 - Ergonomics of the thermal environment - Analytical determination and

interpretation of heat stress using calculation of the predicted heat strain



• Thermal comfort is part of EPBD

• Member states follow different policies, thus making a pan European approach not possible yet.

• Standardization connection between comfort and achieving EPBD energy rating has accepted criticism

throughout EU.



A. Environmental criteria for

building and HVAC

EN 12831, EN 15243

B. Values for indoor environment

during occupancy

EN ISO 13790, EN 15255, EN

15265

Output to

C. Evaluation of annual

performance

EN 15203

Input from

D. Temperature calculations

EN ISO 13791, EN ISO 13792

E. Measurement of the indoor

environment and HVAC inspection

EN 15240, EN 15239, EN 15378

Method for

F. Categorization of indoor

environment

EN 15217


Connection of

EN 15251 to others

Major EU standardization issues

• Natural ventilation is not adequately covered

• Demand controlled ventilation does not follow choice of occupants

• Overheating needs to be more adequately approached


Decree-Law 118/2003, related Ordinances and

Mandamus – Portuguese Energy Certification System;

Regulation on the Energy Performance of Residential

Buildings; Regulation on the Energy Performance of Office

Buildings (sets the minimum quality of the envelope and

indoor reference ambient temperatures to ensure the

conditions for thermal comfort).

Portuguese Adaptive Thermal Comfort Model – Adaptive

Thermal Comfort Model based on the ASHRAE 55:2010

model adjusted to Portuguese conditions (LNEC, 2010).

Standards, Regulations and Methodologies at National Level -

Portugal


Portugal context – Thermal regulation

Portugal context – Thermal regulation

Decree-Law 118/2013 and related ordinances and mandamus define:

1. Ventilation

Winter air change rate: 0.4 h-1

Summer air change rate: 0.6 h-1

2. Temperature

Winter: 18ºC

Summer : 25ºC


Lighting

Equipment

Energy equilibrium applies, i.e.

Qsolar + Qfabric + Qpeople + Qlighting + Qequipment + Qventilation = 0

4.Impact of renovation solutions

Remember heat sources

So fabric or envelope….

• ….is a major aspect defining

• How heat is exchanged between indoor and outdoor environment.

𝑄1

𝑄2


Example

Thermal and normal image of office building in Athens on a cold winter day during occupancy

period (office spaces conditioned)

Courtesy: Extra Mile


Analogy 1

Analogous formulation

• Imagine that you have a tank of water with 100L

capacity and a tap of water which you can control.

• Also, that you feel comfortable to see it has

between 30-50L of water in it.

• But this tank has a hole in its bottom, so water

flows away…..

𝑄𝑖𝑛

𝑄𝑜𝑢𝑡

Qcomfortable


Analogy 2

Analogous formulation

• Same as Analogy 1 but

• There are two taps. dQin1/dt is controlled by

someone else based on a known profile and

dQin2/dt is controlled by you at your own will

• also, you can only control dQout /dt only once.

𝑄𝑖𝑛1

𝑄𝑜𝑢𝑡

Qcomfortable

𝑄𝑖𝑛2


And how this hole is formulated? Opaque element

Transparent element

𝑞 =𝑘 ∗ 𝐴 ∗ ΔΤ

𝐿= 𝑈 ∗ ΔΤ

U = thermal conductance (W/m2*oK)

R = thermal resistance (m2*oK/W)

𝑈 =1

ΣRq = the resultant heat flow (W)

k = the thermal conductivity of the material (W/m*oK).

A = the surface area through which the heat flows (m²)

∆T = the temperature difference between the warm and cold sides of the material (oK)

L = the thickness / length of the material (m)


Thermal capacity

• And since fabric participates in heat transfer

physical laws apply.

• Fabric elements store heat

• The amount of storage is analogues to:

• Density (because m=ρ*V)

• Material (because of cp)

Fabric = energy buffer


What is the difference?

Formulation

• Two fabric elements:

• of identical dimensions

• of identical U values

• of different densities, i.e. ρ1<ρ2

• Of different cp, i.e. cp1<cp2

• One side at T1

• At t=0 T2=T3 < T1

What will happen and when?

T1

T1

T2

T3

m1

m2


Thermal lag & comfort

Thermally

comfortable

temperatures

Temperature

time

Case 1

Lag 1

Lag 2


Mediterranean thermal lag traditions

Source: Wikipedia, "La migdiada" by Ramon Martí

Alsina

Siesta High mass stone walls

Courtesy: Antonis Gerogiannakis


Radiant temperature

Does Mr. Black feel more comfortable than Mr. Green and why?


But nothing is perfect…..

• There are always unwanted gaps in building envelope enabling air to pass through.

• Remember that the more the gaps the more the “hole” will be.

• Infiltration contributes to both sensible & latent loads.


High humidity

• High relative humidity leads to indoor dampness and mould formation.

• According to WHO*:

• Houses in Europe experience indoor dampness in a percentage between 5-20%

• Houses in Europe experience mould formation in a percentage between 1,2-5%

• 12% of children living in houses with mould formation and 15% of that living in damp houses are expected

to suffer from asthma.

* World Health Organization. Regional Office for Europe, Environmental burden of disease

associated with inadequate housing, 2012


Low humidity

• RH < 15-20% can lead to dryness and irritation of

eyes and of other organs belonging to the

respiratory track.

Courtesy Extra Mile



A prefabricated modular approach to renovationMore-Connect Case study

Parameter Unit Data Parameter Unit Data

Implantation area m2 582.18 U-value wall W/(m2*

K)

0.96

Wall area (excl.windows) m2 2712.2 U-value attic floor W/(m2*

K)

0.91

Roof area (pitched) m2 514 U-value ceiling of cellar W/(m2*

K)

0.78

Area of ceiling of cellar m2 514 U-value windows W/(m2*

K)

3.60

Area of windows to North m2 0 g-value windows Factor 0.78

Area of windows to East m2 21.5 Energy need for cooling kWh/m2 2.20

Area of windows to South m2 0 Energy need for hot water kWh/m2 29.6-

Area of windows to West m2 10.6 Energy need for heating kWh/m2 53

Coretech®

Wood frame

Polyurethane foam

Coretech®


A prefabricated modular approach to renovationMore-Connect Case study

Example of designed connection

between modules in exterior wall

corners


between modules in interior wall

corners


between modules and concrete

slabs (top view)

Cost optimal renovation solutions in Portugal

A prefabricated modular approach


Cost optimal renovation solutions in Portugal

A prefabricated modular approach


0

20

40

60

80

100

120

140

160

180

200

REF M1 M2 M3 M4 M5 M6 M7 M8 M9 M10

NT

C (

KW

H/M

2.Y

)

Selected Renovation PackagesPrimary Energy Needs

REFERENCECONVENTIONALMULTISPLIT+GAS HEATERHEAT PUMP

System % in relation

to REF

Conventional 36%

MULTISPLIT+

GAS HEATER

70%

HEAT PUMP 73%

BIOMASS+

NO COOLING

97%

Percentage of Decrease of Ntc

MC Panel in relation to systems

Thank you for your attention!

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temperature)

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thermal comfort

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the predicted heat strain

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ISO 9888, Evaluation of thermal strain by physiological measurements

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