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--- hi:cooling:cooling:blmrackcooling [2023/02/01 13:48]
p.boutachkov
+++ hi:cooling:cooling:blmrackcooling [2023/02/01 21:10] (current)
p.boutachkov
@@ Line 25: / Line 25: @@
 {{:hi:cooling:cooling:ac25c-nim-crate-on.png?200|}}
 The period of oscillation changes. It is most likely related to outside temperature.
-  * Switched the Tek ~MSO44 scope. The temperature in the rack is __28.3 C__ but there are no more oscillation. Seems the AC is ON all the time
+  * Switched the Tek MSO44 scope. The temperature in the rack is __28.3 C__ but there are no more oscillation. Seems the AC is ON all the time
   * Switched the CAEN HV, no HV ON. The temperature in the rack is __31 C__
   * Switched the DAQ electronics ON. The temperature in the rack got up to __ 34.5 C __. During the night it went down to __ 33.6 C__
@@ Line 32: / Line 33: @@
 {{:hi:cooling:cooling:hvwithroog.jpg?200|}}
   * Removed the paper "roof" and turned off the HV. The temperature stabilized at __31.7 C__
   * Removed the HV main frame, the temperature dropped from __31 C__ to __26 C __
 {{:hi:cooling:cooling:hvremoved.jpg?200|}}
   * Installed the HV under the scope, above the DAQ. Turned it on. The temperature stabilized at __31.5 C __.
     * There is a possibility to measure the HVCardsTemperature. The temperature is __ 30 C__
 {{:hi:cooling:cooling:hvabovedaq.jpg?200|}}
   * Installed the HV under the DAQ in place of the NIM bin. The temperature stabilized at  __ 29.5 C__. The HV card temperature is __ 29 C__.
 {{:hi:cooling:cooling:hvinsteadofnim.jpg?200|}}
   * Installed the NIM bin above the HV and the DAQ above the NIM bin. everything is on now. The temperature stabilized at __ 29.1 C __.
@@ Line 52: / Line 57: @@
 {{:hi:cooling:cooling:secondsensorintherack.jpg?200|}}
 The temperature was the same for both sensors. Hence there is sufficient air mixing.
@@ Line 61: / Line 67: @@
 {{:hi:cooling:cooling:secondsensoroutsidetherack.jpg?200|}}
 The outside temperature is __ 23 C__.
-* Leave the CAEN HV on, turn off the DAQ, scope and NIM crate. The temperature stabilized at __ 28 C __
+  * Leave the CAEN HV on, turn off the DAQ, scope and NIM crate. The temperature stabilized at __ 28 C __
 Observations:
-* The maximum temperature in a close rack was reached with the paper roof on to of the HV: __ 35 C__.
+  * The maximum temperature in a close rack was reached with the paper roof on to of the HV: __ 35 C__.
-* The minimum temperature in a close rack was __ 26 C__. Reached with the HV removed from the rack. Note that the AC set points is __25 C __.
+  * The minimum temperature in a close rack was __ 26 C__. Reached with the HV removed from the rack. Note that the AC set points is __25 C __.
 Therefore the AC has sufficient cooling power to take care of the system without the HV. The HV is the main heat load.
@@ Line 73: / Line 80: @@
 {{:hi:cooling:cooling:heatingestimation.jpg?400|}}
-These are the parameters of the [[DEK15|files/BLM/RackTemperature/DEK15.pdf]] and more powerful units
-[[DEK20|files/BLM/RackTemperature/DEK20.pdf]] and [[DEK30|files/BLM/RackTemperature/DEK30.pdf]].
+These are the parameters of the {{ :hi:cooling:cooling:dek15.pdf | DEK15}} and more powerful units
+{{ :hi:cooling:cooling:dek20.pdf |DEK20}} and {{ :hi:cooling:cooling:dek30.pdf |DEK30}}.
 Based on the estimate we need of order of 1600-1700 W cooling power. So lets use 1750 W for the search.
-A ~DEC20 at __ 35 C __ ambient temperature should be able to cool down to __ 30 C __. This is a drop in replacement of a ~DEC15. It is 6 kg heavier than ~DEC15.
+A DEK20 at __ 35 C __ ambient temperature should be able to cool down to __ 30 C __. This is a drop in replacement of a DEK15. It is 6 kg heavier than DEK15.
+A DEK30 can cool bellow __ 20 C __ when operated at __ 35 C __ room temperature. But it requires more space and is 80 kg
+As extreme case lest take __ 40 C __ hall temperature. The the DEK20 should stabilize the rack temperature just bellow __ 35 C __. A DEK30 unit will no have problems keeping the temperature bellow __ 20 C __ even at __ 40 C __ ambient temperature.
-A ~DEC30 can cool bellow __ 20 C __ when operated at __ 35 C __ room temperature. But it requires more space and is 80 kg
+Therefore a DEK20 is the minimum suitable choice for the rack cooling. A DEK30 is to be considered if additional BLM will be operated from the same rack.
+====== Summary ======
+  * The main source of heat is the CAEN HV. The heat output of the rest is much lower.
+  * Placing the HV frame under the scope has the largest effect on the cooling efficiency in the rack.
+    * The optimum configuration is with the CAEN HV at the bottom. Speculation: there is a minimum space between the AC heat ducks and first heat generating unit above which the ordering of the units leads to small improvements.
+  * The cooling power needed to control the temperature in the rack is of order of 1700 W. I expect to add 4 more units, 2 LED drivers and 2 switching matrices. The will add of order of 40 W. Hence, I use 1750 W for the estimates
+  * A DEK15 unit operating in __ 35 C __ hall temperature will stabilize the rack temperature at around __ 40 C __.
+  * A DEK20 unit operating in  __ 35 C __ hall temperature will stabilize the rack temperature at around __ 30 C __. (Note: this is a drop in replacement of DEK15, it adds 6 kg to the roof load)
+  * A DEK30 unit can keep the rack temperature bellow __ 20 C __ even in __ 35 C __ hall.

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