Midea Aqua Tempto Power Series, Manual, Page: 179 / 213

MCAC-ATSM-2014-09 Aqua tempo power series tropical air-cooled scroll chiller 50Hz
177
p
1
=absolute pressure at lower temp.,psia(kPa abs.)
p
2
=absolute pressure at higher temp.,paia(kPa abs.)
v
1
,v
2
=specific volume of water at lower and higher temp., respectively, ft
3
/lb(m
3
/kg)
α
=linear coefficient of thermal expansion; for steel,
α
=6.5x10
-6
in./in
·
o
F(1.2x10
-5
per
℃
); for copper,
α
=9.5x10
-6
in./in
·
o
F(1.7x10
-5
per
℃
)
In a chilled water system, the higher temp. T2 is the highest anticipated ambient temp. when the chilled water
system shuts down during summer. The lower temp. in a heating system is often the ambient temp. at fill
conditions(for example, 50
o
F or 10
℃
).
3.8 Selection and installation of the pump
(1)Selection of the pump
a. Select the water-flow of the pump
The rated water-flow must no less than the unit rated water-flow; in terms of multi-connect the units, that
water-
flow must no less than total units’ rated water-flow.
b. Select the head of the pump.
H=h1+h2+h3+h4
H: The head of the pump.
h1: Main unit water resistance.
h2: Pump water resistance.
h3: Water resistance of the longest water-
loop distance, includes: pipe resistance, different valve’s resistance,
flexible pipe resistance, pipe elbow and three-way resistance, two-way resistance or three-way resistance, as
well as filter resistance.
H4: the longest terminal resistance.
(2) Installation of the pump
a. The pump should be installed at the water inlet pipe, both of which sides must mount the soft connectors
for vibration-proof.
b. The backup pump for the system (recommended).
c. Units must with a main unit controls (Please see
“4.5 fielding wiring” for the controls diagram).