Lossnay Energy Recovery Calculation - Mitsubishi Electric Lossnay series Technical Manual

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CHAPTER 2 Lossnay Construction and Technology

5. Lossnay Energy Recovery Calculation

The following diagram shows the various air conditions when ventilation air is introduced through the Lossnay Core. If a
conventional sensible energy recovery unit is used alone and is assumed to have the same energy recovery efficiency as
Lossnay, the condition of the air supplied to the room is expressed by Point A in the figure. Point A shows that the air is very
humid in summer and very dry in winter.
The air supplied to the room with Lossnay is indicated by Point S in the figure. The air is precooled and dehumidified in the
summer, and preheated and humidified in the winter before it is introduced to the room.
i
SA
i
OA
The quantity of heat recovered by using the Lossnay Core can be calculated with the formula below:
Total heat recovered:
Where <US unit>
γ = Specific weight of the air
under standard conditions 75 (Ib/ft
Q = Treated air volume (CFM)
t = Temperature (°F)
x = Absolute humidity (Ib/Ib')
i = Enthalpy (Btu/Ib)
η = Energy recovery efficiency (%)
OA : Outdoor air
RA : Return air
SA : Supply air
U-20
i
RA
O
t
OA
= γ × Q × (i
q - i ) [W]
T OA SA
= γ × Q × (i ) × ηi
- i
OA RA
3
i
OA
i
SA
i
RA
R
S
A
t t
SA RA
Dry bulb temperature (°F, °C)
<SI unit>
γ = Specific weight of the air
) under standard conditions 1.2 (kg/m
Q = Treated air volume (m
t = Temperature (°C)
x = Absolute humidity (kg/kg')
i = Enthalpy (kJ/kg)
η = Energy recovery efficiency (%)
OA : Outdoor air
RA : Return air
SA : Supply air
A O
X
OA
S
X
SA
R
X
RA
X
RA
X
SA
X
OA
t t t
RA SA OA
3
/h)
3
)