Thermal environment

In its broadest sense, the term ‘environment’ refers to all of the things around a certain point. The thermal environment refers to the things that can affect heat transfer at that point.

Heat transfer is the process of thermal exchange between different systems. Generally there will be a net heat transfer from a hotter system to a cooler system.

Very broadly, the mechanisms of heat transfer can be described as:

• Conduction.
• Convection.
• Radiation.
• Phase change.

For more information see: Heat transfer.

Aspects of the thermal environment that can affect heat transfer by these mechanisms include:

• Air temperature.
• Radiant temperature (long wave infrared radiation (surface temperatures) and short wave infrared radiation (solar radiation)).
• Air velocity.
• Humidity.
• The presence of surface water.
• The temperature of contacting objects.

There are a number of measures that can be used to approximate the total affect of these aspects at a single point. For more information see: Temperature.

The experience people have of the thermal environment that surrounds them will also be affected by personal factors such as:

• Clothing.
• Metabolic heat.
• Wellbeing and sickness.

This is a personal experience that cannot be accurately measured, but it may be represented approximately by standards such as Predicted Mean Vote (PMV) and Percentage People Dissatisfied (PPD).

For more information see: Thermal comfort.

Temperatures in the workplace are governed by the Workplace (Health, Safety and Welfare) Regulations 1992, which oblige employers to provide a reasonable temperature in the workplace.

For more information see: Maximum and minimum workplace temperatures.

Within the built environment, the thermal environment can be influenced by:

• Passive building design (such as shading, windows, insulation, thermal mass, natural ventilation and so on).
• Active building systems (such as heating, cooling and air conditioning).
• Personal behaviour (such as removing clothing, reducing activity and so on).

For more information see: Passive building design and Building services.

[edit] Related articles on Designing Buildings Wiki

• Building services.
• Built environment.
• Environment.
• External environment.
• Heat transfer.
• Indoor environmental quality.
• Internal environment.
• Maximum and minimum workplace temperatures.
• Natural environment.
• Passive building design.
• Sustainability.
• Temperature.
• Thermal comfort.
• Thermal indices for the built environment.
• Thermal pleasure in the built environment.
• Wellbeing.