Load Calculation and Blueprints Flashcards

In residential load calculations, what climate data is used to determine outdoor design conditions?

Answer: ASHRAE Fundamentals Handbook design weather data for the local region

ASHRAE design weather data provides the 99% or 99.6% heating and 1% cooling design temperatures used for load calculations.

What is a 'Manual D' calculation used for in residential HVAC design?

Answer: Duct system design and sizing

ACCA Manual D provides the methodology for designing and sizing residential duct systems based on airflow requirements.

Which symbol on a blueprint typically represents a thermostat?

Answer: A circle with the letter T inside

Thermostats are commonly shown as a circle with the letter T on mechanical and electrical plans.

What does 'EWT' stand for in HVAC load and equipment performance documentation?

Answer: Entering Water Temperature

EWT stands for Entering Water Temperature, which is the temperature of water entering a coil or heat exchanger, used in equipment performance ratings.

On a blueprint legend, which line type typically indicates a low-voltage control wiring run for the thermostat?

Answer: Dashed or dotted line, often labeled 'LV' or 'control'

Low-voltage control wiring is usually shown as a dashed or dotted line and labeled 'LV' or 'control wiring' in the legend.

Which factor does NOT directly affect the calculated cooling load for a residential space?

Answer: The color of the homeowner's furniture

Furniture color has no significant impact on the calculated cooling load; loads are driven by envelope, occupants, solar gain, and internal equipment.

What does 'grains of moisture per pound of dry air' measure in psychrometric terms?

Answer: Specific humidity or humidity ratio

Grains per pound of dry air is the unit for specific humidity (humidity ratio), representing the actual mass of water vapor present per unit of dry air.