Absa 4B Power Engineering

ABSA 4B POWER ENGINEERING EXAM QUESTIONS WITH CORRECT VERIFIED ANSWERS | 100% PASS (A+ CERTIFIED) To ensure effective heat transfer which of the following is the most vital element? a) The fin must be crimped b) Highly conductive material used in fins c) A good bond must exist between the tube and fin d) High fin spacing e) Low fin spacing Answer C Which of the following is a limiting factor for the number of fins that can be used? a) Temperature of steam in coils b) Temperature of chilled water in the coils c) Fin material d) Resistance to airflow e) Face velocity Answer D Finned tube coils in air handling systems are often called a) fish coils b) bare tube coils c) extended surface coils d) cooling coils e) heating coils Answer C Fin surface area is called a) primary surface area b) secondary surface area c) tube surface area d) heater surface area e) none of the above Answer B Two types of modern coils used for heating and cooling services in air handling systems are a) the continuous-plate finned surface and the spiral-finned surface b) the bare tube and the spiral-finned surface c) the continuous-plate finned surface and the bare tube d) the bare tube and the insulated tube e) none of the above Answer A Flat-finned surface type coils are normally used for a) steam heating purposes b) water heating purposes c) high temperature application d) low temperature application where ice may form e) greater turbulence of air at the fin surface Answer D Rippled-finned surface type coils a) are often used for low temperature application where ice may form b) decrease the heat transfer efficiency c) increase the heat transfer efficiency by creating more turbulence at fin surfaces d) have no effect on heat transfer efficiency e) are not used in air handling systems Answer C Face velocity is the a) velocity of the supply water to the coil b) velocity of the air before it enters the coil c) velocity of the air after it leaves the coil d) average velocity of the air flowing over the face area of the fin surface e) velocity of the return water from the coil Coil Operation Answer D To prevent freezing of downstream equipment in a coil handling a large amount of outdoor air, which of the following is required? a) A long coil length b) A vacuum breaker c) A preheat coil d) An oversized coil e) Two-position damper motor Answer