Mitsubishi Electric Lossnay series Technical Manual page 32

(2) Heating During Winter
Conditions:
•
Model LGH-F600RX
(at 60Hz, high speed)
•
Ventilation rate: 600 CFM
(Specific gravity of air ρ = 0.0749 Ib/ft
Dry bulb temperature
Absolute humidity
Relative humidity
Enthalpy
Total energy recovered
Ventilation load
Ventilation load ratio
Dry bulb
temperature
Indoor Unit
Absolute
of
humidity
Air Conditioner
Relative
humidity
Enthalpy
Calculation Example
•
Lossnay Unit
(Supply air diffuser temperature)
(Supply air diffuser enthalpy)
Heat recovered (11.3 – 2.0) × 0.0749 × 600
Ventilation load (16.6 – 11.3) × 0.0749 × 600
•
Sensible HRV Unit
(Supply air diffuser temperature) t
(Supply air diffuser enthalpy)
Heat recovered (7.9 – 2.0) × 0.0749 × 600
Ventilation load (16.6 – 7.9) × 0.0749 × 600
[Calculated enthalpy recovery efficiency 265.1 ÷ (265.1 + 391.0) × 100 = 40%]
•
Conventional Ventilator Unit
If a conventional ventilator is used, the supply air diffuser is the same
as the outdoor air and the exhaust is the same as the room air.
Thus the energy recovered is 0 kcal and the Ventilation load is
(16.6 – 2.1) × 0.0749 × 600 = 651.6 Btu/min = 11.5 kW
-E
5
3
)
Supply air
Lossnay Sensible HRV
Unit
(°F) 56.8
(Ib/Ib') 0.0047 0.0018
(%) 48.5
(Btu/Ib) 11.1
(kW) 7.1
(kW) 4.3
(%) 36
Room air
68°F
0.0073 Ib/Ib'
50%
16.6 Btu/Ib
t = (68°F – 32°F) × 0.69 + 32°F = 56.8°F
SA
h = (16.6 – 2.0) × 0.64 + 2.0
SA
= 11.3 Btu/Ib
= 417.9 Btu/min = 7.3 kW
= 238.2 Btu/min = 4.2 kW
= (68°F – 32°F) × 0.69 + 32°F = 56.8°F
SA
h = 7.9 Btu/Ib
SA
(from psychrometric chart)
= 265.1 Btu/min = 4.7 kW
= 391.0 Btu/min = 6.9 kW
•
CHAPTER 3 General Technical Considerations
•
Energy recovery efficiency table (%)
(For winter)
Lossnay
Unit
Temperature
69
(Sensible Heat)
Enthalpy
64
(Total Heat)
* Calculated volume under conditions below .
Conventional
Unit Ventilator Unit
56.8 32
0.0018
18.5 50
7.9 2.0
4.6 0
6.8 11.5
60 100
Winter Conditions
11.3
i
SA
2.0
i
OA
Sensible HRV Conventional
Unit Ventilator Unit
69
40*
Outdoor air
Dry bulb
temperature
Absolute
humidity
Relative
humidity
Enthalpy
16.6
i
RA
S
O
A
t t t
OA SA
32 56.8
Dry bulb temperature (°F)
–
–
Exhaust air
32°F
0.0018 Ib/Ib'
50%
2.0 Btu/Ib
R
X
RA 0.0073
X
SA 0.0047
X
OA 0.0018
RA
68
U-23