YORK ® AIR-CONDITIONING PRODUCTS
Air-cooled VSD screw chiller
with integrated Free-cooling
YVFA
Saving energy is simple in every situation
Condenser
1
Condenser
Cooling
Coil
Condenser
Closed-loop Configuration
Flash Tank
(optional)
Closed
Glycol Loop
Compressor
with Unit
Mounted
Pump
Flash Tank
Free
Cooling
Coil
Condenser
Open-loop Configuration
Brazed Plate
Heat Exchanger
Flash Tank
Free
Cooling
Coil
Condenser
Free
Cooling
Condenser
Coil
Compressor
Evaporator
Automatic Liquid
Control Valve
Compressor
Evaporator
Flash Tank
Automatic Liquid
Control Valve
Condenser
2
Cooling
Coil
Free
Cooling
Condenser
Coil
Flash Tank
Free
Cooling
Coil
Condenser
Closed-loop Configuration
Flash Tank
(optional)
Closed
Glycol Loop
with Unit
Mounted
Compressor
Pump
Evaporator
Automatic Liquid
Open-loop Configuration
Control Valve
Brazed Plate
Heat Exchanger
Compressor
Free
Condenser
Cooling
Coil
Evaporator
Flash Tank
Automatic Liquid
Control Valve
Compressor
Flash Tank
Free
Cooling
Condenser
Coil
Evaporator
Automatic Liquid
Control Valve
Condenser
3
Free
Compressor
Cooling
Flash Tank
Free
Cooling
Coil
Free
Cooling
Coil
Automatic Liquid
Control Valve
Hybrid Cooling Mode
When ambient temperatures permit, liquid
flow through the free-cooling coils is enabled.
This pre-cooling reduces energy use while
the compressors deliver final cooling to
meet setpoint. Thanks to YORK ® VSD
Screw technology, at reduced ambient the
compressors may draw less power than the
fan motors required to move air through the
free-cooling coils. Advanced controls provide
the most efficient operation rather than simply
shutting off compressors as quickly as possible.
The Annual Energy Cost Report demonstrates
the benefit of this intelligent control.
Compressor Free
Evaporator
Flash Tank
Automatic Liquid
Control Valve
Mechanical Cooling Mode
When it’s too warm to use ambient air for
cooling, the YVFA performs as a standard
chiller. The automatic flow-control valve in the
open-loop configuration bypasses the free-
cooling coils to reduce pump energy. When
either cooling load or ambient temperature are
less than full design condition, the variable-
speed screw compressors and condenser fans
modulate to optimize energy use. In a closed-
loop configuration, the free-cooling coils are
also bypassed.
Compressor Free
Coil
Evaporator
Closed
Glycol Loop LD19976c
with Unit
Mounted
Pump
Flash Tank
Closed-loop Configuration
(optional)
Evaporator
Flash Tank
Automatic Liquid
Open-loop Configuration
Control Valve
Brazed Plate
LD19976c
Heat Exchanger
Evaporator
Automatic Liquid
Control Valve
LD19976c
Manufacturer reserves the rights to change specifications without prior notice.
41
Free Cooling Mode
At lower ambient temperatures, full cooling
load can be most efficiently delivered by the
free-cooling coils. Compressors are shut off and
the VSD fans are modulated to meet the cooling
setpoint.