System Design & Load Calculation Flashcards
7 cards from real RSES practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 System Design & Load Calculation flashcards as text
Which formula correctly represents the heat transmission through an insulated panel?
Answer: Q = U × A × TD
Heat transmission is calculated as Q = U × A × TD, where U is the overall heat transfer coefficient, A is the surface area, and TD is the temperature difference.
What does the R-value of insulation represent?
Answer: The resistance to heat flow per unit of insulation thickness
R-value measures thermal resistance; a higher R-value means the insulation resists heat flow more effectively, reducing the transmission load.
When calculating infiltration load for a walk-in cooler, which factor has the greatest impact on the amount of heat entering through door openings?
Answer: The frequency and duration of door openings
Infiltration load is directly proportional to how often doors are opened and for how long, since warm outside air replaces the cold interior air each time.
In a refrigeration load calculation, what is the latent component of infiltration load caused by?
Answer: Moisture in the warm outside air that condenses or freezes inside
Latent infiltration load results from the moisture carried by warmer incoming air, which must be condensed and its latent heat of condensation removed by the refrigeration system.
What is the design temperature difference (TD) used for in evaporator coil selection?
Answer: To size the evaporator coil capacity relative to the refrigerant evaporating temperature
TD is the difference between the room air temperature and the refrigerant evaporating temperature, and it directly determines the evaporator coil size needed to handle the load.
For a low-temperature freezer application, how does required insulation thickness compare to a medium-temperature cooler operating at the same outdoor conditions?
Answer: Freezer insulation is thicker due to the greater temperature differential
Freezers maintain much lower interior temperatures, creating a larger temperature differential across walls and requiring thicker insulation to limit transmission load.
Which condition typically represents the peak (design) load for a refrigeration system?
Answer: Maximum outdoor temperature combined with heaviest expected product load
Systems must be sized for the worst-case scenario, which combines the highest outdoor ambient temperature with maximum product loading to ensure adequate capacity.