Total Energy Recovery Efficiency Calculation - Mitsubishi Electric Lossnay series Technical Manual

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CHAPTER 2 Lossnay Construction and Technology

3. Total Energy Recovery Efficiency Calculation

The Lossnay Core's energy recovery efficiency can be considered
using the following three transfer rates:
(1) Temperature (sensible heat) recovery efficiency
(2) Humidity (latent heat) recovery efficiency
(3) Enthalpy (total heat) recovery efficiency
The energy recovery effect can be calculated if two of the above
efficiencies are known.
•
Each energy efficiency can be calculated with the formulas in the
table.
•
When the supply and exhaust air volumes are equal, the energy
recovery efficiencies on the supply and exhaust sides are the
same.
•
When the supply and exhaust air volumes are not equal, the total
energy recovery efficiency is low if the exhaust volume is lower,
and high if the exhaust volume is higher.
Item
Temperature recovery
efficiency (%)
Enthalpy recovery
efficiency (%)
Calculation of Supply Air Condition After Passing Through Lossnay
If the Lossnay energy recovery efficiency and the conditions of the room and outdoor air are known, the conditions of the air
entering the room and the air exhausted outdoors can be determined with the following formulas in the following table.
Temperature
Enthalpy
U-18
Formula
t - t
OA SA
ηt =
×100
t - t
OA RA
i - i
OA SA
ηi =
× 100
i - i
OA RA
Supply Side
) × ηt
t = t - (t - t
SA OA OA RA
) × ηi
i = i - (i - i
SA OA OA RA
SA
Indoors
Fresh air exhaust
(Fresh heating/cooling air)
RA
Stale air induction
(Dirty heating/cooling air)
η : Efficiency (%)
t : Dry bulb temperature (°F, °C)
i : Enthalpy (Btu/Ib, kJ/kg)
Exhaust Side
) × ηt
t = t + (t - t
EA RA OA RA
) × ηi
i = i + (i - i
EA RA OA RA
EA
Outdoors
Exhaust air
(Stale air)
OA
Fresh air
induction
(Fresh air)