DHE – Detector Head Electronics
Monsoon 80mm
Crate Heat Load
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
1
Crate Parts
60mm FAN (x2) on
MAIN PLENUM (at
both ends, only this
end shown here)
FAN power
supply is in
the middle (at
both ends)
HEAT EXCHANGERS connect in
series with ¼” copper tube
MONSOON CARDS (10)
plug in on this side
(6U x 160mm Eurocards)
HEAT EXCHANGER on
CHILLER PLENUM
(one at each end of main
MONSOON cards)
92mm FAN (x2) on FAN
PLENUM (one at each
end of transition cards)
2006 Oct. 19
TRANSITION CARDS (8)
(6U x 80mm)
DES Project -- Vaidas Simaitis, University of Illinois
2
Crate (without shield)
VICOR power supply
with built-in 80mm fan,
30cfm listed, pressure
drop unknown (x2)
POWER
SUPPLY
PLENUM
MAIN
PLENUM
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
3
Air Heat Load Diagram
30
30 CFM
30
30 CFM
30
FAN PS
8W
FAN
12 W
30
FAN 12
W
120 CFM
COLD
WATER
HEAT
EXCH
MAIN
PLENUM 1
2006 Oct. 19
-201 W
COLD PLENUM FAN PLENUM
FAN 9 FAN
W
9W
VICOR PS 80 mm
31 W
built in
VICOR PS
20 W
60
CFM
80 mm
built in
MONSOON
TRANSITION
CARDS
30 CFM
30 CFM
FAN PS FAN
8W
9W
60
CFM
50 W
120
CFM
MONSOON
MAIN
MODULES
205 W
30
30
120
CFM
COLD PLENUM FAN PLENUM
PWR SUPPLY PLENUM
FAN
12 W
30
FAN
12 W
30
FAN 9
W
COLD
WATER
120 CFM
HEAT
EXCH
MAIN
-205 W
PLENUM 2
DES Project -- Vaidas Simaitis, University of Illinois
4
Heat Exchanger Thermal
Performance for Water
The design uses a Lytron
M05-050 heat exchanger
For the target of 120 CFM air flow,
and ½ gpm water flow, the heat
removed is 24W for each °C
difference between the water in and
the air in
To remove 216W of heat, the water
must be 9°C colder than the air
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
5
Air Temperature Change Chart
For 200W at 120 CFM air flow, the air should rise about 3°C
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
6
Water Temperature Change Chart
For 200W at ½ GPM water flow, the rise is about 1.5°C
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
7
Heat Exchangers in Series
• To minimize the water flow needs, we can pipe the
heat exchanger water in series
• If we choose 12°C for the inlet water into the 1st heat
exchanger, it should be about 13.5°C into the 2nd
• If the input air into the 1st heat exchanger is 21°C,
then 216 watts of heat is removed, and exit air is 18°C
• The input air into the 2nd heat exchanger should be
21°C, 180 watts of heat removed, exit air is 18°C
• Equilibrium should be about 20°C for the electronics
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
8
Air Temperature Diagram
30
VICOR PS 80 mm
31 W
built in
30 CFM
30
30 CFM
30
30
120 CFM
FAN PS
8W
FAN
12 W
FAN 12
W
COLD
WATER
HEAT
EXCH
21°C
-180 W
21°C
COLD PLENUM FAN PLENUM
FAN 9 FAN
W
9W
VICOR PS
20 W
60
CFM
21°C
120
CFM
80 mm
built in
MONSOON
TRANSITION
CARDS
50 W
MONSOON
MAIN
MODULES
30 CFM
30 CFM
18°C
60
CFM
18°C
120
CFM
205 W
18°C
30
30
21°C
FAN PS FAN
8W
9W
COLD PLENUM FAN PLENUM
PWR SUPPLY PLENUM
FAN
12 W
30
FAN
12 W
30
FAN 9
W
COLD
WATER
120 CFM
HEAT
EXCH
18°C
-216 W
2006 Oct. 19 15°C 13.5°C DES Project -- Vaidas Simaitis, University of Illinois
12°C
9
Water Pressure Chart
The design uses a
Lytron M05-050
heat exchanger
At ½ GPM water
flow, the water
pressure drop is ½
PSI, or 1 PSI for
the 2 in series
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
10
Water Supply
According to COPPER.ORG :
“In general, the mains that serve fixture branches can be sized as
follows:
Up to three 3/8-inch branches can be served by a 1/2-inch main.
Up to three 1/2-inch branches can be served by a 3/4-inch main.
Up to three 3/4-inch branches can be served by a 1-inch main.”
The M05-050 uses 3/8-inch copper tubes, so we need
a ½-inch main for the supply, with a flow of 2 CFM
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
11
Pressure Loss in Piping
Pressure Loss of Water Due to Friction in Types K, L and M
Copper Tube
(psi per linear foot of tube)
Nominal or standard size, inches
1/4
3/8
1/2
3/4
Flow
GPM
K
L
M
K
L
M
K
L
M
K
L
M
1
0.138
0.118
N/A
0.036
0.023
0.021
0.010
0.008
0.007
0.002
0.001
0.001
2
N/A
0.130
0.084
0.075
0.035
0.030
0.024
0.006
0.005
0.004
3
N/A
0.275
0.177
0.159
0.074
0.062
0.051
0.014
0.011
0.009
4
N/A
0.125
0.106
0.086
0.023
0.018
0.015
5
N/A
0.189
0.161
0.130
0.035
0.027
0.023
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
12
Pressure Loss in Fittings
Pressure Loss
in Fittings and
Valves
Expressed as
Equivalent
Length of
Tube, feet
Fittings
Valves
Nominal
or
standard
size,
inches
90°
45°
Side
branch
Straight
run
3/8
.5
–
1.5
–
1/2
1
.5
2
5/8
1.5
.5
3/4
2
1
Standard Ell
90° Tee
Coupling
Ball
Gate
Btfly
Check
–
–
–
–
1.5
–
–
–
–
–
2
2
–
–
–
–
–
2.5
.5
3
–
–
–
–
–
3
2.5
1
4.5
–
–
.5
–
–
4.5
1-1/4
3
1
5.5
.5
.5
.5
–
–
5.5
1-1/2
4
1.5
7
.5
.5
.5
–
–
6.5
2
5.5
2
9
.5
.5
.5
.5
7.5
9
2-1/2
7
2.5
12
.5
.5
–
1
10
11.5
3
9
3.5
15
1
1
–
1.5
15.5
14.5
3-1/2
9
3.5
14
1
1
–
2
–
12.5
4
12.5
5
21
1
1
–
2
16
18.5
5
16
6
27
1.5
1.5
–
3
11.5
23.5
6
19
7
34
2
2
–
3.5
13.5
26.5
8
29
11
50
3
3
–
5
12.5
39
NOTES: Allowances are for streamlined soldered fittings and recessed threaded fittings.
For threaded fittings, double the allowances shown in the table. The equivalent lengths
presented above are based upon a C factor of 150 in the Hazen-Williams friction loss
formula. The lengths shown are rounded to the nearest half foot.
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
13
Pressure Loss for Gravity
Pressure will be lost in lifting the water to the highest point
in the system.
To account for this, multiply the elevation of the highest
point, in feet, by the factor 0.434, the pressure exerted by a
1-foot column of water.
This will give the pressure in psi needed to raise the water to
that level.
For DES, the difference in height of about 40 feet reduces
the available pressure by 18 psi (40 x 0.434 = 17.36).
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
14
Pressure Loss Total
Approximately 10 3/8” elbows and connectors per heat
exchanger is equivalent of 5 ft. of tubing. This is only
about a 0.2 psi loss, but allow 1.0 psi.
The camera is at least 40 feet from the ground, so allow
about 100 feet of 1/2” tubing (each way) to the refrigeration
unit. This is about a 7.0 psi loss, but recalculate for 3/8”
tubing to allow for thicker walls, so use 26 psi.
The pressure loss from gravity is 18 psi. (But may be
recovered on the return trip?)
Worst case loss should be about 45 psi.
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
15
CONCLUSION
• The calculations above are for water, but we
will need a water-alcohol mixture to avoid
freezing.
• We will need a refrigeration unit which can
dissipate 1500 W at a flow of 2 GPM and
output 45psi at 10°C.
2006 Oct. 19
DES Project -- Vaidas Simaitis, University of Illinois
16