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A collection of basic hvac test questions and answers, covering fundamental concepts like heat transfer, refrigeration cycles, and common hvac components. It serves as a valuable resource for individuals seeking to understand the basics of hvac systems and prepare for introductory exams or assessments.
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The human body gives off heat by Ans: Convection, Radiation and Conduction How many BTU's are required to change five pounds of ice at 20º F to steam at 220º F Ans: 1,304 BTU/h How many BTU's must be removed from one pound of water at 200º F for it to end up as ice at 30º F? Ans: 313 BTU At Standard conditions on the Celsius scale, water will boil at Ans: 100º C The standard atmospheric pressure at sea level is Ans: 29.
Pure water boils at a temperature of 212º Fat which of the following standard conditions? Ans: 14. The temperature on the Fahrenheit scale where all molecular biology stops is Ans: - 460º F The temperature on the Celsius scale where all molecular activity stops is Ans: - 273º C As the temperature of a material increases, the molecules in the material Ans: travel faster PSIG indicates Ans: Pound per square inch gauge The amount of heat needed to change the temperature of a substance will vary with the type of substance. this heat quality is called Ans: Specific heat
Ans: Watt one watt of electrical energy is equal to Ans: 3.413 BTU how many watts of electrical power are equal to 1 horsepower Ans: 746 a helicopter is lifted an 800-pound unit at a rate of 200 feet per minute. how many horsepower of work energy is the helicopter using in the process? Ans: 4.848hp a solid material exerts a pressure or force Ans: downward only a liquid material exerts a pressure or force Ans: outward and downward a vapor material exerts a pressure or force Ans: in all directions
Refrigeration can be described as Ans: a process of removing heat from a place where its not wanted to a place that makes little or no difference The pressure in a refrigeration system is changed in the Ans: Compressor and expansion valve the refrigerant in a refrigeration system changes state Ans: Condenser and evaporator At what location or locations in a refrigeration system does the saturation pressure correspond to the saturation temperature Ans: Evaporator and condenser What happens when room temperature soda is poured into a glass of ice Ans: The ice melts because it is absorbing heat from the soda Ice melts in an icebox because
Good ventilation is important when working around Refrigeration equipment because modern refrigerants Ans: Are heavier than air and may displace oxygen around you The law requires technicians to recover refrigerant from a refrigeration system so that they Ans: Will not be released into the atmosphere May be used again May be reclaimed for future use all of the above When refrigerant enters the compressor it is a Ans: low pressure low temperature superheated vapor Where refrigerant leave the compressor it is a Ans: High-pressure high-temperature superheated vapor When water boils at 212 degrees Fahrenheit it is only absorbing latent heat Ans: True
Water boils at 212 degrees Celsius Ans: False The difference in the level of heat between two substances will determine the heat transfer rate between the substance Ans: True Regardless of water is in a solid, liquid, or vapor State, the heat per pound to change the temperature of the water is the same Ans: False A molecule is the smallest portion that an element or substance can be divided into Ans: True The law of conservation of energy states that energy is neither created nor destroyed Ans: True For the refrigeration system to operate correctly, because there's almost always be at a lower saturation temperature than the evaporator Ans: False
Ans: Refrigeration is the process of removing heat from a place where it's not wanted and transferring that he took place where it makes little or no difference BTU Ans: British thermal unit What is BTU Ans: Is the amount of heat energy that is required to raise the temperature of 1 pound of water to 1 degree Fahrenheit Sensible heat Ans: change in temperature of a substance Latent heat Ans: Change of state of a substance Specific heat Ans: The number of BTUs required to raise the temperature of 1 pound of a substance to one degree Fahrenheit
Superheat Ans: Is the point above boiling point of a substance Subcooled Ans: Is the point below condensing temperature of a substance 10°F- 15 °F in the liquid line Fusion Ans: when the state changes from solid to liquid Separation Ans: A mixture of vapor liquid at room temperature Refrigerant Ans: Liquid that can be made to evaporate at low temperature and pressure and condenses at high temperature and pressure Major components of the refrigeration system are Ans: Suction Line, compressor, condenser, metering device. Condenser
