Technical information

25
Table 11. Gumming coefficients
cable, conditions will be as follows:
Cooling capacity: 119 kW
Power consumed: 40 kW
Water temperature: 13°C to 7°C (Dt = 6)
119 x 860
Water flow: =17 056 l/h
6
Available pressure in hydraulic circuit of a unit with pack
(kit).
- From Table 6 we infer that the YLCA 120 TP, with a 17 052 l/h
flow, has an available pressure of 279 kPa.
Pressure drop in hydraulic circuit of a unit without pack
(kit).
- From Table 7 we infer that the YLCA 120 T, with a 17 056 l/h
flow, has a pressure drop of 23 kPa.
Pressure drop in filter.
- From Table 8, 2 ½" filter, we infer that with a 17 056 l/h flow,
said filter has a pressure drop of 2.4 kPa.
YLHA selection method
1. Determine the correct size of the YLHA unit by selecting a
model from Tables 3, 4 and 5 that is closest to the cooling
and heating capacities required in the design conditions
of the water outlet and air intake temperatures.
2. Apply gumming correcting factors (Table 11) and altitude
(Table 12) to the capacity and power values that appear
in the corresponding capacity tables in cool and heat.
Make sure the corrected capacity is still sufficient for your
needs.
3. Using the corrected capacities of the unit, select the de-
sign temperature differential, or the flow.
4. Check to make sure that these selections are within the
YLCA/YLHA operating limits.
YLHA selection example
A YLHA heat pump operating at a 35°C ambient temperature
should chill water from 13°C to 7°C, with a 112 kW cooling
capacity.
A 110 kW heating capacity is required in 5°C design ambient
temperature and a hot water output temperature of 45°C.
The gumming coefficient is 0.044 m² °C/kW, with the unit
operating at sea level (no corrections).
With a quick glance of capacity Tables 3 and 5, we see that
a YLHA 120 heat pump gives the approximate required
capacities of:
Cooling capacity = 114 kW
Total unit absorbed power = 43.2 kW
Cold water temperature = 13°C to 7°C (
Dt = 6°C)
Hot and cold water flow = 16 340 l/h
Heating capacity = 116.3 kW
Total unit absorbed power
in heat mode = 39.3 kW
Hot water output temperature = 45°C
Evaporating unit
Gumming coefficient
m² °C/kW
Capacity factor Comp. ab. power coef.
0.044 1.000 1.000
0.088 0.987 0.995
0.176 0.964 0.985
0.352 0.926 0.962
Altitude (m.) Capacity factor Comp. ab. power coef.
0 1.000 1.000
600 0.987 1.010
1 200 0.973 1.020
1 800 0.958 1.029
2 400 0.943 1.038
Table 12. Altitude coefficients
Selection guide (YLCA/YLHA)
Necessary information
The following information is needed to select a YLCA/YLHA
water chiller:
1. Cooling capacity needed.
2. Design cold water input and output temperatures.
3. Design water flow, if any of the temperatures in above
point 2 is unknown.
4. Design input temperature of air to the condensing unit.
Normally, this will be the design ambient temperature of
summer air, unless influenced by the situation or other
factors.
5. Altitude above sea level.
6. Design gumming coefficient of the evaporating unit.
Note: Points 1, 2 and 3 should be related by means of the
following formulae:
l/h cold water x °C differential
Cooling capacity kW =
860
Selection example
A chiller is required to chill water from 13°C to 7°C, with a
cooling capacity of 117 kW.
Here are other design conditions AS WELL:
Ambient air entering the condensing unit: 35°C
Gumming coefficient: 0.044m² °C/kW
Altitude: At sea level
Taking a quick look at Table 1 we can see that a YLCA 120
unit gives an approximate required capacity of 117 kW.
As the factors appearing in Tables 11 and 12 are not appli-