Thermal Comfort in Architecture

Ommid Saberi

[1], Parisa Saneei [2] Amir Javanbakht [3]

1. Ph.D. Student (Architecture & Energy) in Shahid Beheshti Uni. Tehran Iran

e: omid_saberi@yahoo.com 2. Architect and Researcher Tehran Iran e:p_saneei@yahoo.com

3. Architect and Researcher (Iranian Fuel Conservation Org.) Tehran Iran

e:amir_javanbakht@yahoo.com

Abstract

One of the main goals of building design is to provide a comfortable space for living.

This was the reason of creation a new field in science called “

thermal comfort Models should be able to best, help the architects and other building

engineers in design process. The question is: How much comfort models up to now

could do this responsibility? Different models like Fanger and Adaptive are mostly for

defining the comfort zone; either it is static or dynamic. But how an architect could

adjust his building to these zones? Is it possible to make a new model with definition

of comfort zone in different climates simultaneously to give well advises for climatic

design process?

This paper is trying to discuss the above questions.

Thermal Comfort”. So

Key words:

Thermal comfort, Architecture, Climatic design,

1. Why Thermal Comfort?

Comfort has been defined as 'the condition of mind which expresses satisfaction with

the... environment’. The indoor environment should be designed and controlled so that

occupants' comfort and health are assured. [1] Most of the time of people now is spent in

buildings or urban spaces. Although comfort models mostly talks about indoor climate

but both indoor and outdoor climate should be taken into consideration not only in urban

design but also in buildings. So both indoor and outdoor comfort is a matter of attention

for architects and urbanists.

Looking back to the History of thermal comfort and climatic design shows that there

is a definite relation between them, because scientists need to know answers to these

two questions:

1. What are comfort conditions?

2. How buildings could adjust themselves to these conditions?

2. Architectural Design Process

Architectural design process itself is very complicated. Still in many schools there is

not a clear method which could lead tutors to teach architectural design trough it.

Even experienced architects could not easily clarify what exactly happens in creating

a new building. But in few words table (1) shows some steps in design

Table (1) shows the steps in architectural design process

Architectural Design Process

1. Study 2. Sketch Design

(giving Alternatives)

3. Design

Scale: 1:100

4. Detail design

Scale: 1:50-1:1

Concepts and Ideas

Site

Concepts and Ideas

Choosing one of

alternatives and giving

exact plans on different

levels

Climate and comfort

diagrams

Facades

Function Orientation Sections

Detail design of:

Architectural

Mechanical

Electrical

And structural systems

Circulation Volume Perspectives Cost estimation

Culture Plans Model Perspectives

Structure Facades exact models

Mechanical systems Site layout

Electrical systems Simple models

Primary decisions

about mechanical,

structural and electrical

systems

Functional 2d and 3d

The drawings should be

ready to built without

any more description

In this process climate studies are on the first step, in which architect needs to study

climate of the area using mostly metrological stations data outside or in the

boundaries of the city. Almost the information is average monthly data. Usually daily

or hourly data is not used because of very much time they need to be processed. Then

climate responsive architects analyze this data using some approximate comfort data

(winter and summer comfort zones). At the same time looking at passive

heating/cooling strategies, they combine these strategies to design in sketch and other

steps, if other issues such as economical and/or aesthetical considerations allow them.

To simplify architectural design process, after this, all other considerations rather than

comfort and climate omitted to show how they could be utilized in building design.

3. Architects’ needs/problems in climatic design

In comfort and climate study there are some problems that architect face and for

designing a successful model it is best to know them:

3.1. Undefined conditions of buildings

3.1.1. Human factors

In many cases architects could not exactly find a real definition of building occupants

during design. He or she could only come to an approximate assumption of clothing,

activities, behaviors, cultures and other human factors. For instance in a residential

complex of 1000 residents, practically it is not possible to exactly get all human

factors, knowing that even first occupants may alter during time. Or even the same

could happen for a small office building.

factors.

So architects could not get exact human

3.1.2. Climatic factors

Still in many countries getting correct climatic data of a region is not easy. As an

example unless Iran is a developing country but there are many cities without

metrological station, in such condition one might use nearer station data, sometime

100 km away.

Even if there is a station most of the time the station is in different microclimate from

the design site (Open space vs. urban dense space). As Givoni in his book “climatic

considerations in building and urban design” mentioned there are many factors

3

effecting urban climate such as urban density, streets, parks, traffic and… which are

not countable yet.

Also surrounding elements of a building such as materials, colors, water surfaces,

green spaces etc. could have considerable effect, creating small special microclimates,

hard to define.

So it is not easy to obtain climatic conditions near the building.

3.1.3. Building factors:

Although maybe in developed countries architects could have access to building

materials characteristics easily or the producers give this information, but in many

cases there is not exact data about materials properties such as U-value. So these

properties gained from some reference books like ASHREA or CIBSE. But is the Uvalue

for brick mentioned in these books is the same with brick produced in other

countries?

Above points shows a story about the approximate data available for architects and

building designers. So if a comfort or climatic model wants to be useful for architects

then it might consider these facts.

Some points help a comfort models to fit architects’ needs are mentioned below:

A. Easy process (comfort zone + climate analyses)

B. No long calculation

C. giving direct design guidelines for different steps of design instead of numbers

D. giving knowledge instead of just data

Understanding above points and simplifying design process together with looking to

most known comfort models, it is tried, in following parts, to find a solution.

4. Simplified design procedure (climate/comfort)

To define climatic design process according to comfort zone, it could be divided to

four main parts:

A. Study of the design subject (climate-activities-clothing-etc.)

B. Defining the comfort zone (monthly-daily)

C. Gathering the climatic design advices (shading-thermal mass-evaporative

cooling-thermal insulation-suitable orientation-…)

D. Designing the project (a climatic building)

In part (A) designer should be able to fully understand the climate and comfort needs

as well as all architectural main issues related to the project. Secondly (B) according

to information of 1

then (C) some clear

directions for each issue in building such as site design, form, ventilation, solar gains,

window sizing, thermal mass, passive heating and cooling, materials and etc.. Finally

(D) architect can be able to form a climatic building. The figure (1) shows the

process:

Figure (1) Climatic design process

Parts A and D would be done by architect, but B and C can be covered with a good

st part the monthly or daily comfort zone should be defined anddesign advices could be derived from previous studies to giveclimatic design model.