HVAC Exam 1 Questions And Answers Already Passed!!

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=50F50F + 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= 1.08*CFM*Change in Temp