Mitsubishi Electric GUG-01SL-E, Техническое руководство

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52
CHAPTER
9
Model selection and capacity calculation
II: Calculate Dx-coil inlet air (Lossnay outlet air) condition
See the calculations and table in STEP1-III.
31.7 kJ/kg(DA)
49.7 kJ/kg(DA)
6.0 kW
IV: Calculate the supply air conditions from Dx-coil unit
Enthalpy of supply air from Dx-coil : h
o
= C
a
/ ( ρ x Q
f
/ 3600)+h
i
[kJ/kg(DA)]
Enthalpy of supply air from Dx-coil :
h
i
: Enthalpy of Dx-coil inlet air
(equal to Lossnay outlet air) [kJ/kg(DA)]
C
a
: Capacity of Dx-coil unit [kW]
h
o
= C
a
/ (
ρ
x Q
f
/ 3600)+h
i
[kJ/kg(DA)]
= 6.0 / (1.2 x 1000 / 3600)+31.7
Absolute humidity, the ratio of water weight
against the unit weight of dry air, is unchanged
during heating.
Supply air condition from Dx-coil can be read out
by the psychrometric chart.
Supply Air from Dx-coil unit
Dry-bulb temperature [°C] 34.5
Wet-bulb temperature [°C] 17.8
Absolute humidity [kg/kg(DA)] 0.0058
Relative humidity [%] 17
Enthalpy [kJ/kg(DA)] 49.7
7.5 m
8.1 kW
1.0
6.0 kW
(3) Corrected refrigerant pipe length factor
Read out the refrigerant pipe length factor C
3
using the capacity correction ratio curve on the page 63.
(A) Refrigerant pipe length
(B) Refrigerant pipe length factor C
3
(4) Adjusted Dx-coil unit capacity
(A) Dx-coil unit cooling capacity on the specification
(B) Adjusted Dx-coil unit cooling capacity
= (A) x C
1
x C
2
x C
3
= 8.1 x 1.0 x 0.74 x 1.0
1000 m 3 /h
1.0
1.0
1000 m
3
/h
III: Calculate the capacity of Dx-coil unit
(1) Air volume factor
(A) Designing air volume
(B) Related air volume of Lossnay unit at fan speed 4
(C) Air volume ratio = (A) / (B)
(D) Air volume factor C
1
(Find C
1
from the graph on page 62. )
(2) Air condition difference factor
Specification condition
(A) Air condition difference factor C
2-1
Designing condition
(B) Outdoor air wet-bulb temperature
(C) Lossnay outlet air dry-bulb temperature
(D) Air condition difference factor C
2-2
(Find C
2-2
from the graph on page 62. )
(E) Total air condition difference factor C
2
= C
2-2
/C
2-1
= (D) / (A) = 0.75/1.02
1.02
– 1 ˚CWB
16.8 ˚CDB
0.75
0.74
For the quick reference of air condition difference factor C
2
, see the page 63.
STEP4. Comparison of L Dx-coil unit capacity with required capacity
By calculations from STEP 1 to 3, the capacity of L Dx-coil unit is summate as shown below.
Capacity calculation result
(A) Required heating capacity
(B) Lossnay energy recovery
(C) Dx-coil heating capacity
(D) L DX-coil unit system heating capacity
= (B) + (C)
8.0 kW
6.0 kW
13.8 kW
14.0 kW
As a result, (D) is bigger than (A).
Therefore, under this example condition, L Dx-coil unit system has enough capacity as all-in-one air-conditioning system.