Environmental Principles Week 3 Slideshow 2

Psychrometric Chart

A graphical representation of air properties at different temperatures and moisture levels.

Relative Humidity (RH)

Amount of moisture in the air relative to maximum capacity.

Dry Bulb Temperature

Regular air temperature.

Moisture Content

Measured in pounds of water per pound of dry air.

Comfort Zone

Defined by air temperature, relative humidity, air movement, and mean radiant temperature (MRT).

Winter Comfort Zone

The comfort zone that tends to be on the cooler side of the psychrometric chart with higher humidity.

Summer Comfort Zone

The comfort zone that tends to be on the warmer side of the psychrometric chart with lower humidity.

Natural Ventilation

Uses wind and pressure differences to improve indoor air quality and cooling.

Night-Time Ventilation

A cooling strategy that stores cool night air and releases it during the day.

Thermal Mass

Materials that absorb and store heat energy, used in passive design to regulate indoor temperature.

Direct Gain Systems

Systems where direct solar radiation heats interior surfaces for passive heating.

Lechner’s 6 Climate Zones

A classification dividing the U.S. based on thermal behavior.

Hot & Dry Climates

Characterized by large diurnal temperature swings, with hot days and cool nights.

Cold Climate Design Strategy

Maximize south-facing windows, avoid white exteriors, and use heavy mass for insulation.

Evaporative Cooling

Cooling process where sensible heat decreases and latent heat increases.

Example of Thermal Mass

Bruck Passive House Hotel, optimized for thermal mass efficiency.

Example of Direct Gain System

Rocky Mountain Institute, Colorado, which uses passive solar gain.