Design of 3WAY VRF SYSTEM
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1. Model Selecting and Capacity Calculator
<Heating>
Outdoor unit corrected heating capacity (5) =
Outdoor unit rated heating capacity × Correction coeffi cient for model ((1)
Page
2
-11) × Correction coeffi cient for outdoor temperature conditions ((2)
Page
2
-15) × Correction coeffi cient for tubing length and elevation difference
((3) Page
2
-14) × Correction coeffi cient for frosting/defrosting ((4) Page
2
-13)
* However, if the outdoor unit corrected heating capacity [5] is greater than 100%, then the outdoor unit corrected heating
capacity is considered to be 100%.
Corrected heating capacity of each indoor unit (5) = Rated heating capacity for that indoor unit × Correction coeffi cient for
indoor temperature conditions at that indoor unit ((2) Page
2
-14) × Distribution ratio based on tubing length and elevation
difference at that indoor unit.
However, the corrected heating capacity of each indoor unit is found as shown below.
If (2) < 100% and (2)
×
(3) > 100%: Corrected heating capacity for that indoor unit (5) = Rated heating capacity for that indoor unit
If (2) 100%: Corrected heating capacity for that indoor unit (5) = Rated heating capacity for that indoor unit
×
(2)
* Characteristic graphs are shown on the pages listed above next to each correction item. Find each correction coeffi cient
from the appropriate conditions.
4. Calculating the actual indoor unit capacity based on the indoor/outdoor corrected capacity ratio
Calculate the actual capacity of each indoor unit from the values (found in (3)) for the corrected outdoor unit capacity and the
corrected capacity of each indoor unit.
<Cooling capacity>
Corrected indoor/outdoor capacity ratio during cooling (Ruc) = Total corrected cooling capacity of all indoor units in that system /
Corrected outdoor unit cooling capacity
If the corrected outdoor unit cooling capacity is greater than or equal to the total corrected unit cooling capacity of all indoor units
in that system (Ruc 1), then:
Actual cooling capacity of each indoor unit (7) = Corrected cooling capacity of each indoor unit (5) (In other words, the cor-
rection coeffi cient (6), based on the corrected indoor/outdoor capacity ratios for each indoor unit, is 1.)
If the corrected outdoor unit cooling capacity is less than the total corrected unit cooling capacity of all indoor units in that sys-
tem (Ruc > 1), then:
(Actual cooling capacity of each indoor unit (7)) = (Corrected cooling capacity of each indoor unit (5)) × (0.25 × Ruc + 0.75)
/ Ruc
(In other words, the correction coeffi cient (6), based on the corrected indoor/outdoor capacity ratios for each indoor unit, is
the underlined part in the formula above.)
<Heating capacity>
Corrected indoor/outdoor capacity ratio during heating (Ruh) = Total corrected heating capacity of all indoor units in that system
/ Corrected outdoor unit heating capacity
If the corrected outdoor unit heating capacity is greater than or equal to the total corrected unit heating capacity of all indoor
units in that system (Ruh 1), then:
Actual heating capacity of each indoor unit (7) = Corrected heating capacity of each indoor unit (5)
(In other words, the correction coeffi cient (6), based on the corrected indoor/outdoor capacity ratios for each indoor unit, is 1.)
If the corrected outdoor unit heating capacity is less than the total corrected unit heating capacity of all indoor units in that sys-
tem (Ruh > 1), then:
(Actual heating capacity of each indoor unit (7)) = (Corrected heating capacity of each indoor unit (5)) × (0.1 × Ruh + 0.9) /
Ruh
(In other words, the correction coeffi cient (6), based on the corrected indoor/outdoor capacity ratios for each indoor unit, is
the underlined part in the formula above.)
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Summary of Contents for U-72MF1U9
Page 118: ...Section 8 TENTATIVE ...
