4.0 HEAT LOAD CALCULATION (OLD) Total heat calculation ( Btu/hr ) : 1) Measure your room or space area ( width x length ).Use a metric unit for measurement ( meter ).Multiply with 700 to get in Btu/hr • Room area = 4 meter x 3 meter = 12 m2 • Btu/hr = 12 x 700 = 8400 Btu/hr
2) Estimate occupant for this room. Multiply with 500 to get in Btu/hr • 1 peoples x 500 = 500 Btu/hr 3) Estimate the heat from electrical equipment .Refer wattage for equipment and multiply with 3.5 • Hair dryer = 100 watt, Computer : 200 watt, lighting : 64 watt,ceiling fan:49.25watt ; Total : 413.25watt • so 413.25 watt x 3.5 = 1446.375 Btu/hr 4) Total Btu/hr =8,400 Btu/hr + 500 Btu/hr + 1446.375 Btu/hr = 10346.375 Btu/hr 5) To get air-conditioner sizing, we must divide Total heat ( Btu/hr) with 9800 Btu/hr • 10346.375 / 9800 = 1.056 hp 6) From this answer we can estimate to choose a 1 Hp of air-conditioner for this room.
My room has a 1.5HP air conditioner , but in my head load calculation of remaining older electrical equipment, the result of calculation shows that 1.0hp is enough for this room.
4.1 HEAT LOAD CALCULATION (NEW) Total heat calculation ( Btu/hr ) : 1) Measure your room or space area ( width x length ).Use a metric unit for measurement ( meter ).Multiply with 700 to get in Btu/hr • Room area = 4 meter x 3 meter = 12 m2 • Btu/hr = 12 x 700 = 8400 Btu/hr 2) Estimate occupant for this room. multiply with 500 to get in Btu/hr
• 1 peoples x 500 = 500 Btu/hr 3) Estimate the heat from electrical equipment. Refer wattage for equipment and multiply with 3.5 • Hair dryer = 100 watt, Computer : 200 watt, lighting : 67 watt, ceiling fan:22watt ; Total : 389 watt • so 389 watt x 3.5 = 1361.5 Btu/hr 4) Total Btu/hr= 8,400 Btu/hr + 500 Btu/hr + 1361.5 Btu/hr = 10261.5 Btu/hr 5) To get air-conditioner sizing, we must divide Total heat ( Btu/hr) with 9800 Btu/hr • 10261.5 / 9800 = 1.047 hp 6) From this answer we can estimate to choose a 1 Hp of air-conditioner for our room.
After adding the wattage of new lightings into the calculation, it shows that 1.0HP is enough for the room . Although adding more lightings in the room , the calculation shows that 1.047HP is lower than the old heat load calculation of 1.056HP .
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