11
Source Side
vs.
Load Side
Application
Considerations
Source vs. Load
The model WPWD water-to-water
system contains two water to refrig-
erant heat exchangers. The two
heat exchangers enable the system
to be divided into a source and load
separation.
The “source side” heat exchanger
performs as in a standard water to
air heat pump system. The source is
typically supplied through a cooling
tower, boiler, closed loop, or open
well system. During the refrigeration
cycle, heat is transferred from the
source side heat exchanger to the
load side heat exchanger.
The “load side” heat exchanger
takes the place of a DX (direct ex-
pansion) air coil. It provides treated
fluid (hot or cold) to a mechanical
device. These mechanical devices
include designs such as radiant slab
heating, hydronic coils, or fresh air
ventilation units.
See Figure 9 for a basic schematic
of source side verses load side of a
water-to-water system.
Water-Out
(Source Side)
Water-In
(Source Side)
TO or FROM a cooling
tower, boiler, ground
loop or open well
system
(Load Side)
Water-In
(Load Side)
TO or FROM a
mechanical device
such as hydronic coil,
concrete slab, or flooring
Refrigeration
Circuit
Water-Out
Fluid traveling
Fluid traveling
Figure 9: Source/Load schematic
