HVAC system equations

Question 1

Air Flow

Answer 1

AF1 = VCR*volume

Question 2

For certain engines

Answer 2

Minimum air flow (m^3/min) = kW/9.5 - 2.5

Question 3

TCA

Answer 3

Time to change air

Question 4

Air Flow for people

Answer 4

AF2 = 25*Number of persons

Question 5

Area of inlet

Answer 5

AF = v(speed of air)A3600(seconds in an hour)

Question 6

Area of inlet with considerations

Answer 6

AF = v3600turbulant and frictional losses(0.6)wind direction(0.866 at 30degrees)A/inlet and exhaust(2)

Question 7

Manipulated A

Answer 7

A1 = 0.0005*AF

Question 8

Engine Rooms, relationship between power and ventilation area

Answer 8

A(cm^2) = kW*2.6

Question 9

Fan output

Answer 9

Fan output = Rating - Losses

Question 10

Types of losses

Answer 10

Friction
Bends
Louvers and vents

Question 11

Typical losses in %

Answer 11

2% per feet length of ducting
10% per 90degree bends
10% per screen mesh
20% for clamshell and louver

Question 12

Diameter of fan

Answer 12

qv(VFR m^3/minute) = 55fanRPSd^3

Question 13

Diameter of fan

Answer 13

qv(VFR m^3/minute) = 55fanRPSd^3

Question 14

Below deck BTU

Answer 14

BTU = Volume*388

Question 15

Mid deck BTU

Answer 15

BTU = Volume*530

Question 16

Above deck BTU

Answer 16

BTU = Volume*600