HEATING, VENTILATION & AIR CONDITIONING

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• Q1: Define HVAC.
  Ans: HVAC stands for Heating, Ventilation, and Air Conditioning. It is a system used to control the temperature, humidity, and air quality in buildings.
• Q2: Define Heat.
  Ans: Heat is a form of energy that flows from a hotter object to a cooler one.
• Q3: Define Heating.
  Ans: Heating is the process of raising the temperature of a space or substance.
• Q4: Write the measuring unit of Heat.
  Ans: The measuring unit of heat is calorie (cal) or joule (J).
• Q5: Name the Heating systems in Buildings.
  Ans: The Heating systems are:

  • ➔ Local Heating System
  • ➔ Central Heating System
  • ➔ Partial Heating System
  • ➔ Combined Heating System
• Q6: Define Local Heating System.
  Ans: A local heating system heats only a small area or a single room in a building.
• Q7: Define Combined Heating System.
  Ans: A combined heating system uses more than one method to provide heating to different parts of a building.
• Q8: Define Central Heating System.
  Ans: A central heating system provides heat from a single central source to the entire building through pipes or ducts.
• Q9: Define Partial Heating System.
  Ans: A partial heating system heats only selected parts of a building rather than the whole area.
• Q10: Name the methods of Heating of Buildings.
  Ans: The methods of Heating of buildings are as follows:

  • ➔ Hot water method
  • ➔ Steam Heating method
  • ➔ Plenum Heating method
• Q11: Define the Hot Water method for heating a building.
  Ans: The hot water method heats a building by circulating hot water through pipes and radiators.
• Q12: Define Steam Heating method for heating a building.
  Ans: The steam heating method heats a building by circulating steam through pipes and radiators.
• Q13: Define Plenum Heating method for heating a building.
  Ans: The plenum heating method heats a building by blowing warm air through ducts into rooms.
• Q14: Define Ventilation.
  Ans: Ventilation is the process of supplying fresh air and removing stale air from a building.
• Q15: Define Ventilators.
  Ans: Ventilators are devices or openings in a building that allow air to enter or leave for ventilation.
• Q16: Write the importance of Ventilation in a building.
  Ans: Ventilation is important to provide fresh air, remove pollutants, control humidity, and maintain a comfortable temperature.
• Q17: Name 4 factors affecting the Ventilation.
  Ans: Some of the factors affecting the ventilation are as follows:

  • ➔ Size of doors and windows
  • ➔ Position of doors and windows
  • ➔ Number of occupants
  • ➔ Type of building construction
• Q18: Define Humidity.
  Ans: Humidity is the amount of water vapor present in the air.
• Q19: Define Temperature.
  Ans: Temperature is the measure of how hot or cold the air or an object is.
• Q20: Define Purity of Wind.
  Ans: Purity of wind refers to the cleanliness or freshness of the air entering a building.
• Q21: How does the size of doors and windows affect ventilation?
  Ans: Larger doors and windows allow more air to enter and exit, improving ventilation.
• Q22: How does the position of doors and windows affect ventilation?
  Ans: Properly positioned doors and windows create airflow paths and enhance cross ventilation in a building.
• Q23: Name the types of ventilation.
  Ans: The types of ventilation are:

  • ➔ Natural Ventilation
  • ➔ Artificial Ventilation
• Q24: Define Natural ventilation.
  Ans: Natural ventilation is the movement of fresh air into a building without using mechanical devices, usually through windows, doors, or vents.
• Q25: Define Artificial ventilation.
  Ans: Artificial ventilation is the use of fans or mechanical devices to supply fresh air or remove stale air from a building.
• Q26: Define Cross ventilation.
  Ans: Cross ventilation occurs when fresh air enters a building from one side and exits from the opposite side, creating airflow through the space.
• Q27: Define the Central Plant System in ventilation.
  Ans: A central plant system is a ventilation system where air is cooled, heated, or filtered at a central location and then distributed to different parts of a building.
• Q28: Define the Suction System in ventilation.
  Ans: A suction system is a ventilation system that removes air from a building by creating negative pressure and drawing fresh air from outside.
• Q29: Define the Air Conditioning.
  Ans: Air conditioning is the process of controlling the temperature, humidity, and quality of air in a room or building for comfort.
• Q30: Define the Air Circulation.
  Ans: Air circulation is the movement of air inside a room or building to maintain even temperature and freshness.
• Q31: What is the normal human body temperature?
  Ans: The normal human body temperature is 37°C (98.6°F).
• Q32: Define the Air Filtration.
  Ans: Air filtration is the process of removing dust, pollen, and other particles from the air using filters.
• Q33: Define the Air Pressure.
  Ans: Air pressure is the force exerted by the weight of air on a surface.
• Q34: Name the methods of Cooling the building.
  Ans: The methods of cooling the building are as follows:

  • ➔ Evaporative cooling
  • ➔ Well water cooling
  • ➔ Mechanical refrigeration
• Q35: Define the Evaporative Cooling.
  Ans: Evaporative cooling is a method of reducing air temperature by passing air over water, which absorbs heat as it evaporates.
• Q36: Define the Well Water Cooling.
  Ans: Well water cooling is a method of cooling a building by circulating cold water from a well through air cooling systems.
• Q37: Define Mechanical Refrigeration.
  Ans: Mechanical refrigeration is a method of cooling using a refrigerant and a compressor to remove heat from a space.
• Q38: Name the methods of the air conditioning system.
  Ans: The methods of air conditioning system are:

  • ➔ Unit Air Conditioning system
  • ➔ Central Air Conditioning system
  • ➔ Partial Central Air Conditioning system
  • ➔ Combined Air Conditioning system
• Q39: Define the Window air-conditioner.
  Ans: A window air conditioner is a compact air conditioning unit that is installed in a window or wall opening to cool a single room.
• Q40: Define the Split air conditioner.
  Ans: A split air conditioner is an air conditioning system with two separate units: an indoor unit that cools the room and an outdoor unit that dissipates heat.
• Q41: Define Unit Air Conditioning system.
  Ans: A unit air conditioning system is a system where all the components of the air conditioner are combined into a single unit.
• Q42: Define the Air conditioner.
  Ans: An air conditioner is a device that removes heat and moisture from a room to maintain a comfortable temperature and humidity.
• Q43: Name the components of the air conditioner.
  Ans: Some of the components of air conditioner are as follows:

  • ➔ Compressor
  • ➔ Condenser
  • ➔ Evaporator
  • ➔ Capillary tube
  • ➔ Fan
  • ➔ Capacitor
  • ➔ Thermostat
  • ➔ Starting relay
  • ➔ Selector switch
• Q44: Define Compressor.
  Ans: A compressor is a device that increases the pressure and temperature of the refrigerant gas in an air conditioning system.
• Q45: Define Condenser.
  Ans: A condenser is a device that removes heat from the refrigerant and changes it from a gas to a liquid.
• Q46: Define Evaporator.
  Ans: An evaporator is a device where the refrigerant absorbs heat from the room air and changes from a liquid to a gas.
• Q47: Define Capillary Tube.
  Ans: A capillary tube is a small tube that controls the flow of refrigerant from the condenser to the evaporator.
• Q48: Define Capacitor.
  Ans: A capacitor is an electrical device that stores and releases energy to help start and run the motor in an air conditioner.
• Q49: Define Selector Switch.
  Ans: A selector switch is a switch used to select different modes of operation in an air conditioner, such as cooling or fan mode.
• Q50: Define Thermostat.
  Ans: A thermostat is a device that senses the room temperature and switches the air conditioner on or off to maintain the desired temperature.
• Q51: Define Starting Relay.
  Ans: A starting relay is a device that helps the compressor motor to start by temporarily providing extra current.
• Q52: Name the methods of Heat transfer.
  Ans: The methods of heat transfer are as follows:

  • ➔ Conduction
  • ➔ Convection
  • ➔ Radiation
• Q53: Define Convection.
  Ans: Convection is the transfer of heat through the movement of fluids such as air or water.
• Q54: Define Radiation.
  Ans: Radiation is the transfer of heat in the form of electromagnetic waves without using any medium.
• Q55: Define Conduction.
  Ans: Conduction is the transfer of heat through a solid material from a hotter part to a cooler part.
• Q56: Name the methods of Body Heat Loss.
  Ans: The methods of Body heat loss are as follows:

  • ➔ Convection
  • ➔ Radiation
  • ➔ Evaporation
• Q57: Define Evaporation.
  Ans: Evaporation is the process in which a liquid changes into vapor at a temperature below its boiling point.
• Q58: On which factors does the rate of evaporation depend on?
  Ans: The rate of evaporation depends on:

  • ➔ Temperature
  • ➔ Surface area
  • ➔ Humidity
  • ➔ Air movement
• Q59: Define Oxidation.
  Ans: Oxidation is a chemical reaction in which a substance combines with oxygen and may produce heat or rust.
• Q60: Define ASTM.
  Ans: ASTM stands for American Society for Testing and Materials. It is an organization that develops standards for materials, products, and systems.
• Q61: Name 4 fittings of steel pipe.
  Ans: The fittings of steel pipe are as follows:

  • ➔ Elbow
  • ➔ Tee
  • ➔ Union
  • ➔ Coupling
  • ➔ Bushing
• Q62: Name 4 types of valves.
  Ans: The types of valves are as follows:

  • ➔ Needle
  • ➔ Ball
  • ➔ Angle
  • ➔ Globe
  • ➔ Butterfly
• Q63: Define Valve.
  Ans: A valve is a device used to control the flow of liquids or gases in a system.
• Q64: Define Check Valve.
  Ans: A check valve is a valve that allows fluid to flow in only one direction and prevents backflow.
• Q65: Define Ducts.
  Ans: Ducts are passages or tubes used to carry air from one place to another in a ventilation or air-conditioning system.
• Q66: Define SMACNA.
  Ans: SMACNA is an organization that sets standards for the design, fabrication, and installation of HVAC duct systems. It stands for Sheet Metal and Air Conditioning Contractors’ National Association.
• Q67: Define Fans.
  Ans: Fans are devices that move air by using rotating blades.
• Q68: Name the types of fans.
  Ans: The two main types of fans are:

  • ➔ Centrifugal Fans
  • ➔ Axial Flow fans
• Q69: Define Insulation.
  Ans: Insulation is a material used to reduce heat transfer, control temperature, and save energy in a system.
• Q70: Define Pipe insulation.
  Ans: Pipe insulation is a material used to cover pipes to prevent heat loss, condensation, and freezing.
• Q71: Define Duct insulation.
  Ans: Duct insulation is the covering of air ducts to reduce heat loss, prevent condensation, and improve energy efficiency.
• Q72: Define Heating Load.
  Ans: Heating load is the amount of heat needed to keep a room or building warm.
• Q73: Define Cooling Load.
  Ans: Cooling load is the amount of heat that must be removed to keep a room or building cool.
• Q74: Name 4 factors affecting Heating Load.
  Ans: The factors affecting Heating load are as follows:

  • ➔ Outside temperature
  • ➔ Size of the room
  • ➔ Insulation quality
  • ➔ Number of windows and doors
• Q75: Name 4 factors affecting Cooling Load.
  Ans: The factors affecting Cooling load are as follows:

  • ➔ Sunlight entering the room
  • ➔ Number of people in the room
  • ➔ Heat from lights and appliances
  • ➔ Room ventilation
• Q76: Name the types of Cooling Load.
  Ans: The types of Cooling load are as follows:

  • ➔ Sensible cooling load
  • ➔ Latent cooling load
• Q77: Define Sensible Cooling Load.
  Ans: Sensible cooling load is the heat removed to lower the air temperature in a room.
• Q78: Define Latent Cooling Load.
  Ans: Latent cooling load is the heat removed to reduce the moisture or humidity in the air.
• Q79: Define Ventilation Heat Load.
  Ans: Ventilation heat load is the heat gained or lost due to fresh air entering the room.
• Q80: Define Infilteration Heat Load.
  Ans: Infiltration heat load is the heat gained or lost when outside air enters the room through gaps and cracks.
• Q81: Draw Heat Flow Diagram.
  Ans:
• Q82: Name Room Heat gain components.
  Ans: Some of the Room Heat gain components are as follows:

  • ➔ Heat from walls
  • ➔ Heat from windows
  • ➔ Heat from people
  • ➔ Heat from appliances
• Q83: Define Human Comfort.
  Ans: Human comfort is the condition in which a person feels comfortable with the temperature, humidity, and airflow in a room.
• Q84: Name 4 factors to be kept in mind while selecting a Room Air Conditioner.
  Ans: Following factors should be kept in mind while selecting an Air Conditioner:

  • ➔ Size of the room
  • ➔ Cooling capacity of the AC
  • ➔ Energy efficiency
  • ➔ Budget and maintenance needs
• Q85: Define Solderning.
  Ans: Soldering is the process of joining two metal parts using a melted filler metal called solder.