COIL PERFORMANCE ( HVAC )

 

COIL PERFORMANCE

Ø  IDEALLY, WATER SIDE CAPACITY SHOULD BE EQUAL TO AIR SIDE CAPACITY

Q = U X A X LOG MEAN TEMPERATURE DIFFERENCE.

U = DEPENDS ON GEOMETRY, FIN SPACING/TYPE, WATER CIRCUIT/VELOCITY, AIR VELOCITY OVER COIL,

U INCREASES WITH INCREASE IN WATER VELOCITY & AIR FACE VELOCITY.

Ø  TOTAL SURFACE AREA DEPENDS ON FINNED LENGTH, FINNED WIDTH, ROWS DEEP, NO. OF FINS/INCH

Ø  FACE AREA: DEPENDS ON FINNED LENGTH AND   FINNED HEIGHT.

Ø  FACE VELOCITY: AIR QUANTITY / FACE AREA

Ø  WATER CIRCUITS: 2 TUBES PER CIRCUIT, 4 TUBE PER CIRCUIT, 6 TUBES PER CIRCUIT, 8 TUBES PER CIRCUIT ETC.

Ø  INCREASE IN CAPACITY WITH INCREASE IN WATER PRESSURE DROP.

Ø  HIGHER THE FINS/INCH, HIGHER THE TURBULENCE, HIGHER THE AIR PRESSURE DROP & LOWER IS THE BY PASS FACTOR.

Ø  COOLING CAPACITY = SENSIBLE + LATENT

Ø  SENSIBLE CAPACITY CAN BE ENHANCED BY INCREASING FACE AREA.(GENERALY 4 ROWS DEEP)

Ø  LATENT CAPACITY CAN BE ENHANCED BY INCREASING ROW DEEP (GENERALLY 6,8 ROWS)

Ø  LOWERINGCOOLANT TEMPERATURE WILL INCREASE BOTH SENSIBLE AND LATENT CAPACITY.

Ø  HOT WATER COIL NORMALLY HAS MAXIMUM 2 ROWS DEEP COIL.