Load Calculation and System Design Flashcards
6 cards from real HVAC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Load Calculation and System Design flashcards as text
What is a zoning system in HVAC design?
Answer: A system that independently controls temperature in different areas of a building using dampers and multiple thermostats
An HVAC zoning system uses motorized dampers and multiple zone thermostats to independently control temperature in different areas of a building from a single HVAC unit.
What is a ground-source (geothermal) heat pump and what makes it efficient?
Answer: A heat pump that exchanges heat with the stable-temperature ground or groundwater instead of outdoor air
Ground-source heat pumps exchange heat with the earth or groundwater, which maintain more stable temperatures year-round than outdoor air, enabling higher efficiency than air-source heat pumps.
What does 'total equivalent length' mean when designing a duct system?
Answer: The actual straight duct length plus the equivalent straight-duct resistance of all fittings and transitions
Total equivalent length accounts for friction losses in both actual duct lengths and fittings by expressing fitting resistance as an equivalent length of straight duct.
What is the purpose of Manual S in residential HVAC design?
Answer: To select properly sized HVAC equipment based on the Manual J load and equipment performance data
Manual S provides criteria and procedures for selecting heating and cooling equipment whose performance characteristics match the calculated loads from Manual J.
What is a cooling tower used for in large commercial HVAC systems?
Answer: To reject heat from a water-cooled chiller's condenser water to the atmosphere
A cooling tower uses evaporative cooling to reject heat from the condenser water loop of a water-cooled chiller, expelling the building's unwanted heat to the atmosphere.
What does a building energy model (BEM) provide that a Manual J calculation does not?
Answer: Annual energy consumption predictions and comparison of design alternatives over time
A building energy model simulates hour-by-hour energy consumption throughout the year, allowing comparison of design alternatives and prediction of annual utility costs, while Manual J only calculates peak design loads.