Mitsubishi Electric Lossnay LGH-15RX3 Technical Manual page 26

(2) Heating during winter
Conditions:
G
Model LGH-50R type
(at 50Hz, high speed)
G
Ventilation rate: 500 m
(Specific gravity of air ρ = 1.2 kg/m
Dry bulb temperature
Absolute humidity
Relative humidity
Enthalpy
Total heat recovered
Outdoor air load
Outdoor air load ratio
Dry bulb
Air temperature
conditioner
Absolute
humidity
Relative
humidity
Enthalpy
Calculation example
G Lossnay
(Supply air diffuser temperature) t
(Supply air diffuser enthalpy)
Heat recovered (27.4 – 5.0) × 1.2 × 500
Outdoor air load (38.5 – 27.4) × 1.2 × 500
G Sensible HRV
(Supply air diffuser temperature) t
(Supply air diffuser enthalpy)
Heat recovered (19.8 – 5.0) × 1.2 × 500
Outdoor air load (38.5 – 19.8) × 1.2 × 500
[Calculated enthulpy recovery efficiency 8,880 ÷ (8,880 + 11,200) × 100 = 44.2]
G Conventional ventilator
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 heat recovered is 0 kcal and the outdoor air load is
(38.5 – 5.0) × 1.2 × 500 = 20,100 kJ/h = 5.6 kW (4,802 kcal/h)
3
/h
3
)
Supply air
Lossnay Sensible HRV
(°C) 15.4
(g/kg') 4.6
(%) 43
(kJ/kg) 27.4
(kcal/kg') (6.5)
(kW) 3.7
(kcal/h) (3,211) (2,121)
(kW) 1.9
(kcal/h) (1,591) (2,680)
(%)
33
Room air
20°C
7.2 g/kg'
50%
38.5 kJ/kg
(9.2 kcal/kg')
= (20°C – 0°C) × 0.77 + 0°C = 15.4°C
SA
= (38.5 – 5.0) × 0.67 + 5.0
h
SA
= 27.4 kJ/kg
= 13,440 kJ/h = 3.7 kW (3,211 kcal/h)
= 6,660 kJ/h = 1.9 kW (1,591 kcal/h)
= (20°C – 0°C) × 0.77 + 0°C = 15.4°C
SA
h = 19.8 kJ/kg (4.7 kcal/kg')
SA
(from psychrometric chart)
= 8,880 kJ/h = 2.5 kW (2,121kcal/h)
= 11,200 kJ/h = 3.1 kW (2,681 kcal/h)
CHAPTER 3 G General Technical Considerations
G
Heat recovery efficiency table (%)
(For winter)
Lossnay
Temperature
77
(sensible heat)
Enthalpy
67
(total heat)
* Calculated volume under below conditions.
Conventional
ventilator
15.4 0
1.8 1.8
17 50
19.8 5.0
(4.7) (1.2)
2.4
0
3.2 5.6
(4,802)
57 100
Winter conditions
27.4
5.6
i
OA
Sensible HRV
77
44.2*
Outdoor air
Dry bulb
temperature
Absolute
humidity
Relative
humidity
Enthalpy
38.5
h
RA
h
SA
S
O
A
t t
OA SA
0 15.4
Dry bulb temperature (°C)
Conventional
ventilator
–
–
Exhaust air
0°C
1.8 g/kg'
50%
5.0 kJ/kg
(1.2 kcal/kg')
R
X
RA 0.0072
X
SA 0.0046
X
OA 0.0018
t
RA
20
23