Positioning Of The Supply/Exhaust Fans And The Air Transmission Rate (Excluding Moisture Resistant Total Heat Recovery Units) - Mitsubishi Electric Lossnay LGH-15RX3 Technical Manual

CHAPTER 5 G System Design Recommendations
8. Positioning of the Supply/Exhaust Fans and the Air Transmission
Rate (excluding moisture resistant total heat recovery units)
The following four methods can be used for when setting the Lossnay supply and exhaust fans around the Lossnay Core.
When using the LU and LUT models, methods a or b should be used in respect of both the Lossnay Core air leakage and
effective air ventilation. Use method c if air leakage to the RA or SA sides is not allowed such as in hospital air conditioning, or
transmission of the fan noise into the room must be suppressed by putting the Lossnay Core between the supply/exhaust fans
and room, and if a certain degree of air leakage is allowed between OA to EA.
a. Installing the supply fan (OA-SA) and exhaust fan
(RA-EA) for suction feed to the Lossnay Core
Outdoors
EA
Fan for exhaust air
OA
If the static pressure difference between SA and RA and
between EA and OA is 50mmAq, the air leakage rate will
be 2.5%, and 3.4%. This value is of no problem for most
standard uses.
c. Installing the supply fan (OA-SA) for force feed and
the exhaust fan (RA-EA) for suction feed
Outdoors
EA
Fan for exhaust air
Fan for supply air
OA
In this case, the positive/negative relation of the static
pressure will be the reverse of that in system d, and the air
leakage outside the room (leakage from OA to EA) will be
the same as system d. Thus, the effective volume of
ventilating air will be reduced by that rate.
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Indoors
SA
Fan for supply air
Lossnay
RA
Indoors
SA
Lossnay
RA
b. Installing the supply fan (OA-SA) and exhaust fan
(RA-EA) for forced supply to the Lossnay Core
Outdoors
EA
OA
Fan for supply air
The air leakage rate is the same as in system a.
d. Installing the supply fan (OA-SA) for suction feed
and the exhaust fan (RA-EA) for force feed
Outdoors Indoors
EA
Lossnay
OA
In this case, the intake side pressure (OA-SA) will be
negative, and the exhaust side pressure (RA-EA) will be
positive, so the amount of air leakage to the intake side will
be the greatest. If the static pressure difference between
OA and RA is 50 mmAq, the air leakage rate will be 10.5%,
and 13.0%.
This system can be used when an air leakage of 10% to the
intake side (OA-SA) is permitted, but should be avoided in
all other cases.
Indoors
SA
Lossnay
RA
Fan for exhaust air
SA
Fan for supply air
Fan for exhaust air
RA