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CHAPTER 2
Lossnay Construction and Principle
3. Calculation of the Total Heat Recovery Efficiency
The Lossnay Core's heat 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 heat recovery effect can be calculated if two of the above
efficiencies is known. (The temperature and enthalpy efficiencies
are indicated in the applicable catalogue.)
Each recovery efficiency can be calculated with the formulas
given below.
When the supply air volume and exhaust air volume are equal,
the heat recovery efficiencies on the supply and exhaust sides
are the same.
When the supply air volume and exhaust air volume are not
equal, the total heat recovery efficiency is low if the exhaust
volume is lower, and high if the exhaust volume is higher.
Refer to the Heat Recovery Efficiency Correction Curve in the
applicable catalogue for more details.
Item
Temperature recovery
efficiency (%)
Enthalpy recovery
efficiency (%)
Calculation of air conditions after passing through Lossnay
If the Lossnay heat 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.
Temperature
Enthalpy
18
Formula
ηt = t (
) - t (
) × 100
OA
SA
t (
) - t (
)
OA
RA
ηi = i (
) - i (
) × 100
OA
SA
i (
) - i (
)
OA
RA
Supply side
t
= t
- (t
- t
) · ηt
SA
OA
OA
RA
i
= i
- (i
- i
) · ηi
SA
OA
OA
RA
SA
Indoors
Supply air
(Fresh cold or warm air)
RA
Return air
(Stale cold or warm air)
η: Efficiency (%)
t : Dry bulb temperature (°C)
i : Enthalpy (kJ/kg)
Exhaust side
t
= t
+ (t
- t
) · ηt
EA
RA
OA
RA
i
= i
+ (i
- i
) · ηi
EA
RA
OA
RA
EA
Outdoors
Exhaust air
(Stale air)
OA
Outdoor air
(Fresh air)
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