Thermal Comfort and Its Factors

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Questions and Answers

What primarily affects the thermal comfort of an individual?

The psychological perception of temperature

The surrounding air pressure

The amount of sunlight received indoors

The balance between heat production and dissipation (correct)

Which personal factor has the most direct impact on heat emission from the body?

Choice of surrounding furniture

Level of physical activity (correct)

Clothing insulation

Age of the individual

How does excessive cooling affect human thermal comfort?

It can lead to thermal discomfort (correct)

It prevents heat-related illnesses

It enhances overall productivity

It increases the energy efficiency of the body

In what way does solar heat gain influence indoor thermal conditions?

It causes thermal discomfort if not managed Signup and view all the answers

Which of the following best describes the effect of humidity on thermal comfort?

High humidity can impede the body's ability to cool itself Signup and view all the answers

What is the ideal range for air temperature to achieve thermal comfort?

24 to 26 °C Signup and view all the answers

At what relative humidity percentage would individuals likely feel oppressive conditions?

Above 70% Signup and view all the answers

Which air movement speed is considered too high for maintaining thermal comfort?

Above 0.2 m/s Signup and view all the answers

Why do women, older people, and young children usually require higher air temperatures?

They are generally more sensitive to temperature. Signup and view all the answers

If the air change per hour requirement is a minimum of 1.0, what could be a potential effect of inadequate air exchange?

Accumulation of indoor pollutants Signup and view all the answers

What condition might individuals find comfortable while exposed briefly, though it may not be ideal for long durations?

Direct hot sun on the beach Signup and view all the answers

What might occur if the relative humidity drops too low, below the recommended range?

Dryness of skin and throats Signup and view all the answers

How does the surface temperature of surrounding elements affect thermal comfort?

It influences the heat radiated from a person. Signup and view all the answers

What occurs when warm moist air meets a surface that is at or below the dew-point temperature of that air?

Condensation Signup and view all the answers

Which of the following factors does NOT affect the heat gained in a building from solar radiation?

Number of occupants Signup and view all the answers

In a psychrometric chart, if the dry-bulb temperature and relative humidity are known, which of the following properties can also be determined?

Moisture content Signup and view all the answers

What does a relative humidity (RH) of 100% indicate?

Air has reached its maximum moisture capacity Signup and view all the answers

Which temperature is measured by a thermometer with its bulb covered by a wetted wick?

Wet-bulb temperature Signup and view all the answers

Which factor contributes most to creating uncomfortable thermal conditions in a building in Singapore?

High intensity of solar radiation Signup and view all the answers

What is another term for the actual weight of water in the air expressed in a unit volume?

Specific humidity Signup and view all the answers

What strategy involves measuring the angles between rays of the sun and building surfaces to control solar heat gain?

Solar shading Signup and view all the answers

Study Notes

Thermal Comfort

Thermal comfort involves understanding various thermal conditions necessary for human well-being, including solar heat gain and psychrometric principles.
Achieving thermal comfort contributes to overall health, well-being, mental health, and productivity by preventing heat-related illnesses.
The human body maintains a constant temperature by balancing heat production and dissipation (radiation, convection, and evaporation).
Environmental conditions (air temperature, humidity, air movement, surface temperature) affect thermal comfort and human ability to regulate body temperature.

Factors Affecting Thermal Comfort

Personal Factors: Individual factors such as clothing, activity level, personal preferences, age, and body differences influence thermal comfort.
- Heat emission increases with higher activity.
  - Sleeping: ~70 W
  - Office work: ~140 W
  - Factory assembly work: ~265 W
  - Heavy lifting work: ~440 W
Physical Factors: Environmental factors impacting thermal comfort include air temperature, relative humidity, air movement, and surface temperatures.
- Appropriate air temperature range and humidity is crucial for comfort.
- Air movement should be between 0.05 and 0.2 m/s and humidity levels should be between 50%-70%.

Criteria for Ideal Thermal Comfort

Ideal thermal comfort involves maintaining a constant air temperature of 24-26°C, relative humidity between 50-70%, and air movement not exceeding 0.2m/s or below 0.05m/s

Effects of Solar Radiation

Solar radiation significantly impacts building thermal comfort, affecting the building's interior temperatures.
Factors like geographic latitude, season, cloud conditions, solar angles, and window types influence solar heat gain.
Singapore's location near the equator results in high solar radiation levels, significant heat transfer into buildings.

Principles of Psychrometry

Basic Terms: Explains key concepts related to measuring and controlling humidity, temperature, and moisture content in the air.
- Dry-bulb temperature (DBT): The temperature measured by a standard thermometer.
- Relative humidity (RH): The amount of water vapor in the air as a percentage of the maximum amount the air can hold at that temperature.
- Wet-bulb temperature (WBT): The temperature measured by a thermometer with a wet wick, used to measure the moisture content in the air.
- Dew-point temperature: The temperature at which air will be saturated and condensation will occurs.

Psychrometric Chart

A psychrometric chart is a graphical representation of the thermodynamic properties of humid air.
It displays relationships between dry-bulb temperature, wet-bulb temperature, relative humidity, and moisture content (used for design projects).
The chart can be used to determine various conditions and how they affect humidity.

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Description

This quiz explores the concept of thermal comfort, focusing on the environmental and personal factors that influence it. It discusses how conditions such as temperature, humidity, and individual differences affect human well-being and productivity. Understanding thermal comfort is crucial for preventing heat-related illnesses and promoting mental health.