Specifications
SELECTION PROCEDURE (WITH EXAMPLE)
I DETERMINE THE TYPE OF FAN COIL WHICH BEST
SUITS THE APPLICATION (REFER TO SYSTEMS
INDEX TABLE ON PAGE 26).
Duct-free split systems have 3 types of fan coils with over-
lapping capacities to choose from. Select the system type
which best meets the job conditions. This example uses a
2-ton ceiling-suspended fan coil (assume wall space is not
available for a wall-mounted unit).
II DETERMINE COOLING AND HEATING LOAD RE-
QUIREMENTS AT DESIGN CONDITIONS.
Required Load Conditions:
Required Cooling Capacity (TCG) ........24,500 Btuh
Sensible Heat Capacity (SHC) ...........16,800 Btuh
Temperature Air Entering
Condensing Unit ..........................95F
Temperature Air Entering
Indoor Unit (EAT) ................82Fdb/68 F wb
Required Heating Capacity ...............8,500 Btuh
Indoor Heating Design Conditions ..............68F
Outdoor Heating Design Conditions .............0°F
db — dry bulb
wb — wet bulb
III SELECT SYSTEM THAT SATISFIES LOAD
REQUIREMENTS.
Enter the Systems Index table on page 26 at ceiling-
suspended system for 24,000 Btuh, and select the system
that best approximates cooling and heating requirements.
System no. 6, with a nominal net capacity of 24,000 Btuh
cooling and 12,500 Btuh heating (at 17 F), is the system
selected. The system consists of a 538B024 outdoor unit
matched with one 619C024 indoor unit.
IV DETERMINE IF SYSTEM SELECTED SATISFIES
COOLING REQUIREMENTS.
Enter Cooling Capacities table on page 32 at high speed
and 95 F outdoor entering air temperature (air entering
condenser). By interpolation, at 68 F EAT, the system
gross capacity is 24,900 Btuh cooling [(26,500 – 24,500) x
(1/5) + 24,500], and 15,740 Btuh SHG (gross sensible ca-
pacity). Adjust the SHG in accordance with Note 2 of the
Combinations Ratings table, using the correction factor
for an 82 F edb (air entering dry bulb), and an 0.03 BF
(bypass factor). The result is an adjusted SHG of
16,877 Btuh. The total gross cooling capacity of 24,900
Btuh and the sensible heat capacity of 16,877 Btuh satisfy
stipulated cooling load requirements.
V DETERMINE IF SYSTEM SELECTED SATISFIES HEAT-
ING REQUIREMENTS.
Enter Instantaneous and Integrated Heating Ratings table
for System 6 on page 48 at 0° F outdoor db. By inter-
polation, the system capacity is between 65 and 70 F for
integrated heating [−(7320 − 7710) x (2/5) + 7320 = 7476].
This is the value which reflects the net room effects after
defrost energy. This value is short of the required heating
capacity, however, the 619C units have a standard electric
heater which will work in conjunction with heat pump heat-
ing (booster heat mode).
The 619C units havea2kWheater which will add a total
of 6824 kW to the room (2 x 3412) or 6284 Btuh for a total
heating capability of 13,760 Btuh at design heating condi-
tions. This will satisfy the required heating load.
VI DETERMINE NET COOLING CAPACITY AND SYSTEM
ENERGY EFFICIENCY RATIO.
Determine net cooling capacity (refer to Cooling Capacity
table for System 6 on page 26). Net total cooling capacity
must be interpolated as follows:
(26,000 - 24,000) x (1/5) + 26,000 = 26,400 Btuh
To determine the energy efficiency ratio (EER), system kW
must be interpolated from the Cooling Capacity table for
System 6 in the same manner:
(2.47 - 2.40) x (1/5) + 2.40 = 2.41 kW
Then calculate EER:
Net Cooling Capacity
EER =
kW x 1000
26,400
= 10.95 EER
2.41 x 1000
NOTE: The SEER (Seasonal Energy Efficiency Ratio)
CANNOT be calculated for this system. SEERs can only
be found as a direct result of testing at specified ARI con-
ditions. See ARI Capacities table on page 6.
VII DETERMINE COP (COEFFICIENT OF PERFORMANCE)
AT THE DESIGN POINT.
To calculate the COP at the design point, interpolate
capacity as in Step V to arrive at a capacity of 7476.
Interpolate the kW between 1.63 and 1.62 to be 1.625.
7476
COP = ÷ 1000 = 1.48
1.625 × 3.412
NOTE: The HSPF (heating seasonal performance factor)
CANNOT be calculated for this system. HSPFs can only
be found as a direct result of testing at specified ARI con-
ditions. See ARI Capacities table on page 6.
VIII DETERMINE THE RECOMMENDED LIQUID AND VA-
POR LINE SIZES.
Refer to Refrigerant Lines section on page 65.
NOTE: With long-lines applications, it may be necessary
to adjust cooling capacity. See Refrigerant Lines section
on page 65 for more details.
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