Data Sheet for Product

Technical Instructions MVL661… Modulating Refrigerant Valves
Document Number 155-400 Valves with Magnetic Actuator
May 11, 2016
Page 12
Valve Sizing and
Correction Factor
The applications and tables on the following pages are designed for help with selecting
the valves. To select the correct valve, the following data is required:
 Application
 Expansion (see Use of the MVL661…as an expansion valve)
 Hot-gas (see Use of the MVL661…as a hot-gas valve)
 Suction throttle (see Use of the MVL661…as a suction throttle valve)
 Refrigerant type
 Evaporating temperature t
0
°F (°C)
 Condensing temperature t
c
°F (°C)
 Refrigeration capacity Q
0
(kW)
To calculate the nominal capacity, use the following formula:
 k
vs
[m³/h] = Q
0
[kW] / K...* *K… for expansion = KE
for hot-gas = KH
for suction throttle = KS
 CV = 1.156 × kvs
 The theoretical C
V
(kv) value for the nominal refrigeration capacity of the plant
should not be less than 50% of the C
V
(kvs) value of the selected valve.
 For accurate valve sizing, we recommend using the valve selection program
“Refrigeration VASP”.
Application
Examples
Use of the MVL661…
as an expansion
valve
Capacity optimization
The application examples below reflect principles only. They do not include installation-
specific details such as safety elements refrigerant collectors, and so on.
 Typical control range is 20 to 100%.
 Increased capacity through better use of the evaporator.
 The use of two or more compressors or compressor stages significantly increases
efficiency with low loads.
 Especially suitable for fluctuating condensing and evaporating pressures.
 For more information, see Engineering Notes.
Electronic superheat control is achieved by using additional control equipment.
Application example
Refrigerant R407C; Q
0
= 205 kW; t
o
= 25°F (–5°C); t
c
= 95°F (35°C)
The correct C
V
(k
vs
) value for the MVL661..-.. valve needs to be determined.
The important section of table KE for R407C (see Table 4 or Table 5) is the area around
the working point. The correction factor KE relevant to the working point should be
determined by linear interpolation from the four guide values.