Environmental Systems Test 2

System parts (elements, interconnections, purpose)

elements = parts, interconnections = relationships, purpose = overall function/goal

Stock

quantity of something stored in a system

Flow

rate at which stock changes

Dynamic equilibrium

system stays stable over time despite ongoing changes

Balancing feedback system

counteracts change to maintain stability

Reinforcing feedback system

amplifies change (growth or decline)

Resilience

ability of a system to recover after disturbance

Linear relationship

proportional, straight-line change

Non-linear relationship

irregular or exponential change

System boundaries

limits defining what is inside vs outside a system

System delays

time lag between action and effect

Bounded rationality

decision-making with limited info/time

Tragedy of the commons

shared resources get overused and depleted

Drift performance

gradual decline in system effectiveness over time

Escalation

actions intensify due to reinforcing feedback

Sensible heat

heat that changes temperature and can be felt/measured

Radiation

heat transfer through electromagnetic waves

Conduction

heat transfer through direct contact

Convection

heat transfer through air/fluid movement

Latent heat

heat involved in phase change (like evaporation)

Thermal comfort

condition where people feel neither too hot nor cold

CLO

measure of clothing insulation

Metabolic rate

rate the body produces heat

Dry-bulb temperature

actual air temperature

Wet-bulb temperature

temperature including evaporative cooling effect

Relative humidity

percentage of moisture in air compared to max possible

Dew point

temperature where air becomes saturated and condensation forms

Psychrometric chart

graph showing relationships of air temperature, humidity, and energy

Predicted Mean Vote (PMV)

predicted average comfort level (-3 cold to +3 hot)

Predicted Percentage of Dissatisfied (PPD)

percent of people uncomfortable

Comfort zone

range of conditions where most people feel comfortable

Mean radiant temperature (MRT)

average temperature of surrounding surfaces

Radiant asymmetry

uneven radiant heat from different directions

Operative temperature (mechanical)

average of air temp and MRT in conditioned spaces

Operative temperature (natural)

influenced by air temp, MRT, and air movement

Standards

guidelines (not legally required)

Codes

legally enforceable rules

Prescriptive

specifies exact requirements (how to do it)

Performative

specifies performance outcome (what it must achieve)

Passive systems

use natural energy (no mechanical systems)

Active systems

use mechanical/electrical energy

Sustainable

meets present needs without harming future

Carbon neutral

net-zero carbon emissions

Regenerative

improves and restores environmental systems

Hydrologic cycle

continuous movement of water on Earth

Embodied energy

total energy used to make a material

Environmental footprint

total environmental impact of a system/person

Internal load dominant (ILD)

heat gains mainly from internal sources

Skin load dominant (SLD)

heat gains/losses mainly through envelope

Climate

long-term weather patterns

Microclimate

localized climate conditions

Sun chart

diagram showing sun position by time/location

Latitude

position north/south of equator

Longitude

position east/west

Equinox

equal day and night

Solstice

longest or shortest day

Altitude

sun height angle

Azimuth

sun horizontal direction

Direct gain

sunlight enters and heats interior directly

Indirect gain

heat collected then transferred inside

Greenhouse effect

heat trapped by atmosphere or glass

Heat island effect

urban areas are hotter than surroundings

Heat loss

heat leaving a building

Cooling load

amount of heat to remove

Resistance

material’s ability to resist heat flow

Conductance

ability to transfer heat

Thermal properties

how materials respond to heat

R-value

resistance to heat flow (higher = better insulation)

U-value

rate of heat transfer (lower = better insulation)

Material thermal capacity

ability to store heat (density × specific heat)

Time lag

delay in heat passing through material

Vapor barrier

prevents moisture movement

Solar heat gain coefficient (SHGC)

amount of solar radiation entering through glass

Infiltration

uncontrolled air leakage

Ventilation

controlled air exchange

ACH method

air changes per hour calculation

Crack method

calculates air leakage through gaps

Fenestration

windows and openings in a building

Building form

overall shape of a building

Building envelope (skin)

outer shell separating inside/outside

Indigenous architecture

building adapted to local climate/culture

Polar climate

very cold, minimal sun

Temperate climate

moderate seasons

Sub-tropical climate

hot, humid summers

Tropical climate

consistently hot and humid

Passive heating (direct gain)

sunlight heats interior mass

Thermal mass

material that stores heat

Roof ponds

water on roof stores/releases heat

Passive heating (indirect gain)

heat collected in wall then transferred

Trombe wall

thick wall that stores solar heat

Passive heating (isolated gain)

separate solar space transfers heat

Sunspace

enclosed solar room

Geothermal

uses earth’s constant temperature

Cross ventilation

air flows across space

Stack ventilation

warm air rises and exits, pulling in cool air

Night ventilation (thermal mass)

cool night air removes stored heat

Night flush

flushing building with cool air at night

Evaporative cooling

cooling via water evaporation

Cooling towers

use evaporation to cool air

Roof ponds (cooling)

absorb heat during day, release at night