Building Technology 2: Thermal Comfort Week 6

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Questions and Answers

What temperature range is generally considered suitable for human occupancy?

5 °C to 20 °C

20 °C to 35 °C

15 °C to 25 °C (correct)

10 °C to 30 °C

Which factors can influence human thermal comfort beyond temperature?

Lighting intensity

Air circulation (correct)

Color of walls

Furniture arrangement

What is the primary purpose of a bioclimatic diagram?

To analyze thermal comfort needs (correct)

To design aesthetically pleasing spaces

To determine maximum allowable occupancy

To choose building materials

What should designers consider when adapting indoor temperature ranges for seasonal changes?

The average thermal comfort temperatures Signup and view all the answers

Why is it difficult to address the thermal comfort needs of every person?

Because preferences differ widely Signup and view all the answers

Which method of heat transfer involves physical contact between surfaces?

Conduction Signup and view all the answers

What is the primary way heat is lost from the exterior of a building in winter?

To the exterior by conduction Signup and view all the answers

What type of material typically has a high thermal capacity?

Water Signup and view all the answers

Which of the following is NOT a method of heat transfer?

Convectional heating Signup and view all the answers

What does thermal resistance indicate in materials?

The rate at which heat is lost Signup and view all the answers

How does radiation differ from conduction in heat transfer?

Radiation transfers heat without direct contact Signup and view all the answers

Which is true about materials with high thermal resistance?

They are good insulators. Signup and view all the answers

What practical application is often associated with high thermal capacity materials?

Used as heat carriers in building systems Signup and view all the answers

What is the significance of a higher R-value in insulation?

It signifies greater thermal resistance. Signup and view all the answers

What are potential effects of high humidity indoors?

Growth of mold and bacteria Signup and view all the answers

Who plays a key role in the design of temperature regulating systems in buildings?

Architects and Engineers Signup and view all the answers

What is a primary cause of indoor air pollution?

Synthetic building products Signup and view all the answers

Why is moisture control critical in indoor environments?

It helps inhibit mold growth and supports air quality. Signup and view all the answers

What is an essential component for improving indoor air quality in energy-efficient buildings?

Designing a balanced ventilation system Signup and view all the answers

In which type of building is infiltration traditionally used to supply fresh air?

Small residences Signup and view all the answers

What is a reason for needing well-designed ventilation systems in modern buildings?

Tight building envelopes can trap air pollutants. Signup and view all the answers

What best defines thermal comfort?

A state of mind expressing satisfaction with the thermal environment. Signup and view all the answers

Which factor is NOT considered a personal factor affecting thermal comfort?

Indoor temperature Signup and view all the answers

According to ASHRAE Standard 55, what percentage of sedentary or slightly active persons need to find the environment thermally acceptable?

80% Signup and view all the answers

Which of the following is considered an environmental factor affecting thermal comfort?

Humidity Signup and view all the answers

What is the primary input energy for the human body's heat generation?

Food Signup and view all the answers

Which of the following is least likely to influence an individual's thermal comfort?

Economic status Signup and view all the answers

Which personal factor is specifically related to the biological and physiological characteristics of the individual?

Metabolic rate Signup and view all the answers

What does the term 'thermal comfort' suggest regarding body temperature?

Body temperature should be stabilized without excess heat and moisture loss. Signup and view all the answers

Which factor is NOT typically considered when assessing thermal comfort?

Color of interior walls Signup and view all the answers

What does the ANSI / ASHRAE Standard 55 address?

Thermal comfort calculations Signup and view all the answers

Which organization provides a tool for thermal comfort calculations according to ASHRAE standards?

Center for the Built Environment Signup and view all the answers

What is a primary challenge in determining thermal comfort for a group of individuals?

Variability in personal preferences Signup and view all the answers

What is the bioclimatic design approach primarily concerned with?

Using nature’s energies for design Signup and view all the answers

Which of the following is an example of a standard similar to ASHRAE Standard 55?

EN 15251 Signup and view all the answers

Which factor can vary with time but is accounted for in thermal comfort studies?

Air movement Signup and view all the answers

What is the objective of the Center for the Built Environment?

To improve environmental quality and energy efficiency Signup and view all the answers

What percentage of people exposed to indoor air should not express dissatisfaction according to ASHRAE Standard 62.1.2013?

80% Signup and view all the answers

Which of the following is a reason for poor indoor air quality in office buildings?

Poorly designed ventilation systems Signup and view all the answers

What is the preferred strategy for dealing with indoor air quality issues?

Choosing materials that limit pollution at the source Signup and view all the answers

How can interior designers contribute to improving indoor air quality?

By specifying materials that do not contribute to indoor air pollution Signup and view all the answers

What challenge complicates the diagnosis of illnesses caused by indoor air contaminants?

Subjective definition of comfort and health Signup and view all the answers

What is the indoor air quality definition provided by ASHRAE Standard 62.1.2013 focused on?

Absence of contaminants at harmful concentrations Signup and view all the answers

Why is maintaining a clean building and equipment important for indoor air quality?

It limits sources of indoor air pollution Signup and view all the answers

What significant impact has research shown regarding improved indoor air quality?

Increased health and productivity Signup and view all the answers

Study Notes

Building Technology 2: Mechanical & Safety Systems - Week 6

Course: INTD 3007
Instructor: Claudina Sula
Week: 6
Topic: Thermal Comfort & Air Quality

Thermal Comfort & Air Quality

The topic is about creating comfortable interior spaces using HVAC systems
Heating is governed by OBC (Office Building Code)
Key reading material: Binggeli, chapters 12-14
Includes principles of:
- Thermal comfort
- Heat transfer in buildings
- Humidity
- Indoor air quality

What is Thermal Comfort?

Thermal comfort involves providing and achieving satisfaction with save and comfortable interior environments for human beings.
It is about the provision of a stable, normal body temperature that results in satisfying the environment.
This is subjective and assessed through evaluation (ANSI/ASHRAE Standard 55).

Thermal Comfort Factors - Personal Factors

Occupants need to be considered for proper thermal comfort
These factors include:
- Metabolic rate
- Clothing levels
- Activity levels
- Age
- Gender
- Adaptation
- Circadian rhythms
- Cultural influences
- Stress level

Thermal Comfort Factors - Environmental Factors

Factors relating to the thermal environment include:
- Air temperature
- Temperature of surrounding surfaces (mean radiant temperature)
- Humidity levels
- Air movement (natural ventilation)
- Non-uniformity of environment
Standards usually refer to a steady state to study thermal comfort, and accommodate limited temperature variations.

Thermal Comfort Standards

CBE Thermal Comfort Tool: can be used to calculate comfort according to standards such as ANSI/ASHRAE Standard 55, EN 15251, and ISO 7730.

Thermal Comfort Conditions

There is a range of variability in thermal comfort based on physiological and psychological factors.
Lab and field data are used to define optimal conditions for a specified percentage of occupants.

Bioclimatic Design

An integrated approach to architectural regionalism.
Integrates design and performance architecture.
Employs natural energies to harmonize buildings with their local conditions, including solar radiation and wind convection.
Revolves around four interconnecting circles: Biology, Climatology, Technology, and Architecture

Thermal Comfort - Bioclimatic Index

Bioclimatic diagram: based on maximum and minimum average registers, minimum and maximum average of dry bulb temperature and relative humidity.
Important to consider the 'comfort zone' versus 'comfort point' to create a space conducive for thermal satisfaction for many people.

Thermal Comfort Values

The suitable temperature range for human occupancy is 15 °C (59 °F) to 25 °C (77 °F).
Factors such as humidity, air circulation, can influence and extend this range.
Winter comfort temperature: 20-24 °C (68-75.2 °F)
Summer comfort temperature: 23-26 °C (73.4-78.8 °F)

How to convert Celsius to Fahrenheit

°C to °F Conversion: T(°F) = T(°C) × 1.8 + 32

Human Comfort: Natural vs Mechanical

Proper thermal comfort is supported by proper HVAC systems (Heating, Ventilation, and Air Conditioning) in interior spaces and protects structures and contents.
HVAC system design is not enough for comfort, and material selection & space planning are also key to comfort.

Principles of Heat Transfer

Heat always moves from warmer to cooler spaces or surfaces.
Thermal equilibrium occurs when there is no temperature difference between adjacent spaces or surfaces.
The greater the temperature difference, the faster heat moves.

Heat Transfer Methods

Heat transfer occurs in various ways including conduction, convection, and radiation.

Heat Transfer Methods - Conduction

Heat transfer through physical contact between molecules, surfaces.

Heat Transfer Methods - Radiation

Heat transfer without direct contact through electromagnetic waves.
Example of the heat reaching Earth from the Sun.

Heat Transfer Methods - Convection

Heat transfer through the movement of fluids (air).

Heat Transfer - Terminologies

Thermal capacity: ability of a material to store heat, proportional to mass.
Thermal resistance: opposite concept to thermal capacity, materials with higher thermal resistance result in slower heat loss.
R-value: a measure of thermal resistance, higher value means greater heat resistance of that material.

Thermal Comfort - Humidity

High humidity can cause issues in the interior environment, including mold growth and warping of materials, and irritation to occupants.
Low humidity can cause dry skin, nose, and throat irritation, and discomfort for occupants.

Indoor Air - Introduction

Most of human time is spent indoors.
Indoor Environments are susceptible to a wide array of air pollutants typically emitted from building products, equipment and cleaning products.
Limiting sources, moisture control, and proper ventilation are important for healthy indoor environments.

Indoor Air Quality

Consideration of indoor air quality is increasing due to tightly controlled building environments.
Presence of indoor air pollution sources, poorly designed ventilation, and unanticipated uses of buildings contribute to poor IAQ.
Designing for good IAQ involves selecting materials and equipment that limit pollution, isolating unavoidable sources, and using effective ventilation/filtration/cleaning systems of the built environment.

Indoor Air Quality - Illnesses

Poor IAQ can lead to illnesses.
Building codes are balancing energy efficiency needs with good IAQ.

Indoor Air Quality - Sources of Pollution

Key indoor pollutants include carbon dioxide, carbon monoxide, ozone, VOC's, some bacteria and fungi, including radon.
Control strategies for each type of indoor air pollution are recommended.

Indoor Air Quality - Volatile Organic Compounds (VOCs)

VOCs are chemical compounds that evaporate from surfaces at room temperature.
They are off-gassed by various materials.
VOC levels can increase in places where new furnishings, materials, etc., have been installed.

Indoor Air Quality - Equipment

HVAC systems are crucial in managing indoor air quality.
Air cleaning equipment, such as filters, cleans and efficiently circulates air.
Appropriate equipment size matches the size of the building/space.

Relevant Resources

Relevant external website resources for further research.

Studying That Suits You

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Description

Explore the principles of thermal comfort and indoor air quality in the context of HVAC systems. This quiz covers key factors such as heat transfer, humidity, and personal factors impacting comfort as per the relevant building codes. Enhance your understanding based on Binggeli's readings, chapters 12-14.