Engineered Comfort Fan Coil Controller EZstat Especificaciones descargar pdf (Pagina 5)

7-11-07

FAN COIL UNIT CONTROLS

Airflow can be lowered by approximately 18%, reducing the

fan energy consumption by 20 to 50%, depending on

setpoint, in addition to the input savings. (See Table 1.)

5. Lower humidity levels at part load conditions:

If the air volume is modulated to maintain the discharge air

temperature at all room conditions, the perceived comfort

level in the space stays constant and the noise levels

decrease. Also, the relative humidity is greatly decreased

when compared to what happens without modulated air at

part load conditions. See line ABʼ on the psychrometric

chart. Under part load conditions, without controlled

discharge air temperature, the relative humidity levels in

the space can rise to as much as 70% because of reduced

run time or lowered discharge air temperatures on the

dehumidifying equipment. This would cause the room set

points to be greatly reduced to satisfy occupant comfort,

which increases operating costs at part load conditions. At

these reduced set points, the room will feel clammy and

mold growth potential increases.

MAXIMUM

COOLING

MAXIMUM

HEATING

4ºF (2.2ºC)

PROPORTIONAL BAND

(ADJUSTABLE)

SET POINT

ROOM TEMPERATURE INCREASE



AIRFLOW INCREASE



HEATER

ON/OFF

COOLING

VALVE

ON/OFF

DEAD BAND

MOULATING

ChW VALVE

Chart 3: Psychrometric Chart

Example 1:

ΔT

= 74 – 55 = 19 ΔT

= 76 – 52 = 24

CFM

= CFM

x 0.79

(

)

Example 2:

ΔT

= 78 – 55 = 23 ΔT

= 79 – 52 = 27

CFM

= CFM

x 0.85

(

)

Average =

0.79 + 0.85

= 0.82

Average CFM

= CFM

x 0.82

(

0.72 + 0.85

)

Std. FCU (CFM

) = 300 400 600 800 1000 1200

EPIC FCU (CFM

) = 246 328 492 656 820 984

Table 1. Airflow Reduction Comparisons

Figure 2. EPIC Fan Coil Unit Sequence of Operation

1 2 3 4 5 6 7 8 9 10 ... 19 20

Comentarios a estos manuales

Sin comentarios

Engineered Comfort Fan Coil Controller EZstat Especificaciones Pagina 5

Comentarios a estos manuales