HVAC Exam 2023 with complete and correct answers

Matter exists in what three forms? solid, liquid, gas What is temperature measured by? Quantity or intensity Intensity Define British thermal unit (Btu) Measure of heat energy - amount of energy needed to raise 1 lb of water 1 degree F How much heat is required to raise the temp of 100 lb or water from 70F to 120F Q=1000lb*(1btu / change of temp) so 1000*(1/ 50) = 50,000 If 750 Btu is supplied to 15lb of water at 72F what will be the resulting temperature? ... 1 Btu raises air 4.75F To melt 1lb of ice you need 144 Btu So to melt 2000 lbs of ice or 1 ton you need 288,000 Btu What is 1 ton of refrigeration? 288,000 Btu / 24 hrs = 12,000 Btu/Hr What is the hottest water can get? 212F 1 Btu raises 1 lb of water 1 degree F If 750 Btu is supplied to 15 lb. of water at 72F, what will be the resulting temperature? 750/15=50F 50F + 72F = 122F Latent heat cannot be measured on a thermometer. True or false? True - only sensible heat can be recorded- latent heat is a change in mass EX) vaporization, condensation, fusion, melting How much heat needs to be removed to drop the temperature of 1000 cfm of air from 70F to 55F. Q= 1.08CFMChange in Temp CFM cubic feet/min make sure it is given to you in CFM or convert it from seconds to min or hours to min The heat that changes the temperature of a substance is called Sensible heat The heat that changes the state of a substance is called Latent heat The heat that changes a liquid to a vapor is called the heat of Vaporization A ton of refrigerant is The amount of cooling a ton of ice can do in 24 hours 144 Btu = 1 lb of ice 2,000 lbs of ice (1 ton) = 288,000 288,000 Btu / 24 hrs = 12,000 Btu/Hr