A btu british thermal unit is the amount of heat needed to raise one pound of water one degree fahrenheit. Hvac design thumb rules air conditioning heating, ventilating. Book download link provided by engineering study material esm. Central airconditioning chilled water systems with outdoor water cooled condenser capacity ranges 20 to 2000 tr, suitable for an area of 4000 sqft and higher. Correction for the density is not needed however in air conditioning cooling or applications, if the temperature is between 40f to 100f and up to ft. Rules of thumb are abbreviated short cuts, time savers, and. This rule of thumb states that the max heating capacity required for your comfort cooling application is 1.
Useful collection of handy thumb rules for quick assessment of hvac systems. Heating and cooling loads are imposed primarily by the envelope, so lets start there. Central airconditioning chilled water system with air cooled condensers capacity ranges of 20 to 400 tr, suitable for an area of 4000 sqft and higher 5. Design guide for heating, ventilating, and air conditioning systems. Also, if youre interested in learning even more, heres a free download for you. Remember, when hvac contractors use rules of thumb to size air. They are only typical values, which should be verified for each application. In addition, the experienced engineer or designer may find this manual useful as a quick design reference guide. Hvac rule of thumb calculator engineering pro guides. Christopherson is an hvac instructor at san jose city college, san jose, ca. Coordination of hvac and fire detection and alarm system 74. The heating, ventilation, and air conditioning hvac equations, data, rules of thumb, and other information contained within this reference manual were assembled to aid the beginning engineer and designer in the design of hvac systems.
For example, if the cooling required is 30 tons 360,000 btus, then the max heating capacity required would be 612,000 btus 1. A ton of cooling load is actually 12,000 btu per hour heat extraction equipment. Hvac equations data and rules of thumb third edition pdf download. Hvac equations, data and rules of thumb by arthur a. If you have multiple floors, then add up all the air conditioned area for all floors and insert a single number for the hvac building area value. Hvac equations, data and rules of thumb by arthur a bell. Rules and rules of thumb for duct systems educated guesses and past experience with trial and error apply when using rules of thumb. Hvac equations data and rules of thumb third edition pdf. Designing heat pump duct systems with correct velocity and. The final load is than used to size the hvac equipment.
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