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Author Topic: Hybrid ultra effective PC cooling system - Extreme sub-ambient temperatures  (Read 44740 times)

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Well, it looks like that global warming is getting more and more to our lives. Living in a country that can have temperatures more than 45 degrees C can be hard to be a server. Air-cooling is a nice old-fashioned cooling way but trying to chill out the CPU with an air of 45 or more degrees C is not always enough.

Water-cooling on the other hand is an efficient method of cooling because water is by far a better temperature conductor than air. It also carries the problem of high water temperature due to ambient temperature but with a big tank and radiator it can keep the CPU cooler than air. What I really do not like with the water-cooling is that the temperature inside the box and to all parts is not even. On the CPU and GPU that you place a heat exchanger plate, you get a good working temperature. But what about the rest of the parts? The HDD, the CD and DVD writers that suffers from high temperatures, the memory modules, the PSU, chipsets and not only. A server requires also a router and maybe a switch. These parts also may suffer from heat-stroke. Water cooling may be one way but alone is inefficient and if you try to cool all parts with water cooling, you will need a respectable amount of money to do this as you need heat exchanging plates for each end every part, and imagine having for example 6 HDD and 4 memory banks!!!

Bong cooler is an efficient way to achieve sub-ambient temperatures but I really hate this way of cooling. I cannot accept that this cooling way will not kill the computer because of the moisture. I get it out of the question.

The solution to these speculations? An air condition!!! Yes, an air condition. Imagine this, your server working day and night, summer and winter under 35 or LESS degrees C. Wouldn’t this be fantastic? Of course yes. No part would be stressed, the power consumption would be also less and the performance would always be on top. But an air condition is an energy-consuming device and hard to install it. But a hybrid 3-way cooling system is less energy consuming, more fancy and more fun because after all, you do it yourself. With no further ado, I present my idea and the way to make an efficient cooling system for a server or any 24/7-system working on countries with temperature range from –5 to +45 ore more.
« Last Edit: August 25, 2008, 18:32:04 PM by kam »


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Hybrid ultra effective PC cooling system - Overview
« Reply #1 on: August 24, 2008, 14:17:15 PM »
Hybrid 3-way cooling system. Fancy name but simple operation. It is a hybrid system because it uses both water, thermoelectric and air-cooling systems to achieve perfect operation. The server (or anything else) is placed into an airtight temperature isolated box. This box can be anything you like as long as it is isolated with Dow or other isolating material. I will use a classic wood made box with the blue Dow isolating material same as used in cement building construction. You can use whatever you like but this Dow thing is perfect as is cheap and has excellent temperature isolating characteristics.
Inside this box, there is a radiator with two 120mm fans. Within the radiator, cold water is flowing. The water is kept cold inside a water tank using peltier TE device. Using the fan, the air inside the box is kept in low temperatures and further more, no humidity and dust is entered inside the box, as is it airtight. The same air that exists in the box is recycled. Additional small fans are placed over the CPU and GPU, as normal pc air cooling configuration. All other parts do not need fans as the ambient temperature will be around 30 degrees (of course maniacs can put as many fans as they want).
What is the 3-way thing now? It is simple a way to preserve power when the outside ambient temperature is cold enough and no extra cooling is needed for the water in the tank. 3 way means that the system uses 3 different ways of cooling, each one seperated or all together combined. The first way is already described above, using peltier cooling, water cooling and air cooling system.
The second way is using water and air cooling. If for example the air temperature outside the house is 10 degrees and inside the house is 20, then an extra tank is placed outside the house keeping the water cold. A valve will switch so that the cold water is now flowing in the radiator. The peltier will be permanently turned off for the winter.
The third way is using only air cooling and is the most energy saving cooling way. If the room ambient temperature is low enough to maintain a good operating temperature (for example less than 22 degrees) the whole cooling system is turned off. Water is not circulating and the peltier is not working. Extra fans are used to circulate in the box fresh air taken from the room. There are of course filters to ensure as much as dust-free air can be. The intakes and outtakes of these extra fans open and close using special tamper air valves. So when the system runs in peltier mode or external tank mode, the tampers are kept closed and there is no heat loss because of the fan holes.

Here is a block diagram of the operation:

« Last Edit: August 25, 2008, 18:37:10 PM by kam »


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Hybrid ultra effective PC cooling system - Operation
« Reply #2 on: August 24, 2008, 19:40:28 PM »

There are two ways of operation modes, automatic and manual mode. In manual mode, the operator may choose the cooling method for the box. In automatic mode, the system will choose the best cooling method. The selection is made with the help of some parameters. Those parameters are:

[ATL]Ambient temperature low
[ATM]Ambient temperature max
[ETTL]External tank temperature low
[ETTM]External tank temperature max

The system will always try to choose the most economic way of cooling. This means that it will first check if is possible to use the room ambient temperature for cooling, then the external tank and if none of the above are efficient, then it uses the peltier for cooling. Check out the following flowcharts:

As seen above, there is a window that each cooling mode is to operate. The ambient air cooling mode will start to operate when the ambient temperature is below parameter [ATL] and will remain in operation until it becomes higher than [ATM]. The External tank cooling mode will start to operate if the external ambient temperature is below [ETTL] and will remain in operation until it becomes higher than [ETTM]. If there is no proper cooling mode available then the system will run on peltier cooling mode.
« Last Edit: August 24, 2008, 19:45:41 PM by kam »


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Re: Hybrid ultra effective PC cooling system - Electronic peripherals
« Reply #3 on: August 24, 2008, 21:31:17 PM »
In a glance our electronic peripherals to be used:

LCD diaplay will be used the 128 X 64 blue graphics LCD display with backlit and with controller KS0108B

We shall use the SHT 15 temperature and humidity sensor for measurements inside pc cabinet.

For the water return temperature, a PTC shall be used. It is water resistant and easily mounted between the hoses

For the rest of the temperature sensors we use the DS1621 IC.

For water flow control, we shall use a flow meter or indicator. Still not found

For tank selection valve, we shall use two ball valves with electromechanical actuators, possibly home made.

The thermoelectric element is a peltier with 136.8W power consumption, 12V, driven by mosfet IRFZ24N.

The water pump is an Eheim 230V 5W water pump controlled by relay HFD2

Instead of buttons for input we shall use touch sensors QT110

And here are all the datasheet for what shall we use:
The Blue graphic 128X64 LCD Display
LCD controller ks0108.pdf
Microchip PIC16F887 microcontroller
Temperature and humidity sensor sht15.pdf
Temperature sensor ds1621.pdf
Peltier thermoelement tec1_12709
Touch sensor qt110.pdf
Mosfet for controlling the TE irfz24n.pdf
Relay for controlling the pump and fans
Relay for controlling the tank select valve actuator
The pump and The pump characteristics
120mm Fans for PC box
Water flow control
Analog temperature sensor
The inbox radiator
8-bit PISO shift register - 74LS165
8-bit SIPO shift register - 74LS595
Power transistor 2N2222
General purpose diode 1N4001

« Last Edit: August 26, 2008, 05:32:52 AM by kam »


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Hybrid ultra effective PC cooling system - Inputs and Outputs
« Reply #4 on: August 24, 2008, 21:38:14 PM »
Here is a list of the inputs and outputs that the microcontroller should be equipped:

Temperature sensors for
External ambient
Internal ambient
Peltier tank
Peltier heat sink
Temperature and humidity sensor for PC Box2Digital
Temperature sensors for water return1Anaglog
Current drain1Analog
Keypad (4 key BCD + 1 long key press)5Digital
Memory module expansion2Digital
Reset1Master reset
16 bit Digital inputs from PISO:
0: PC functioning sensor
1: Pump thermal protection
2: Peltier protection overload
3: Valve actuator failure
4: Insufficient radiator air flow
5: Insufficient circulating air flow
6: Tank select valve to external
7: Tank select valve to Peltier
8: Air tamper open
9: Air tamper closed
10: Insufficient water flow
11: Water in tank low
12: Water in tank empty
13: Trap door closed

Peltier control1PWM
LCD data4Digital
Emergency trap door release1Digital
Emergency alarm contact set1Digital
Microcontroller watchdog reset1Digital
Communication with computer3Digital
16 bit Digital outputs for SIPO:
0: Pump motor
1: Tank selection valve to external
2: Box radiator fans
3: Box circulation fans
4: Air tampers close
5: Beeper
6: LCD Backlit
7: LCD Backlit luminosity bit:0
8: LCD Backlit luminosity bit:1
9: Operation LED
10: Alarm LED
11: Peltier fan

« Last Edit: August 26, 2008, 00:03:38 AM by kam »


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This is a first impression, a draft, of the LCD screen. Of course the actual size is much bigger.

This screen show the temperatures (external tank, cooling tank, computer box, room ambient and water return) and the state of the system. It shows (on the top right corner) wether it runs on external tank, on cooling tank or using ambient temperature. It also shows if it is in auto or manual mode, the humidity and the power consumption of the cooling system. The snow animation is just to confirm that the controller is working

This screen is the same as previous but in this case an alarm has occur. The operator may see the alarms using a touch button and from there he can reset them. The alarm might be failure in water circulation, failure in power suply or anything else.

« Last Edit: August 24, 2008, 23:02:18 PM by kam »


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Hybrid ultra effective PC cooling system - Some more operational parameters
« Reply #6 on: August 25, 2008, 16:28:49 PM »
Some more operational parameters

Some posts before we saw some parameters regarding the conditions that the system will choose (in automatic mode) the most efficient cooling method. Now we will see some more parameters:

[PTEOL]Peltier TE operation temperature low
[PTEOM]Peltier TE operation temperature max
[BOTL]Box operational temperature low
[BOTM]Box operational temperature max
[BAV]Box alarm value
[BSTV]Box shut down value
[WRTM]Water return temperature max
[PHSM]Peltier heat sink max temperature
[BLM]LCD Backlit mode
[BLL]LCD Backlit luminosity
[VCD]Tank selector valve change delay
[TCD]Air tamper change delay
[PFCD]Peltier fan off-delay
[AFK]Away from keyboard threshold
[SMPL]Sampling rate delay for taking measurements in 1/10 sec
[KTMI]Keyboard typematic initial delay in 1/10 sec
[KTMD]Keyboard typematic repeat delay in 1/10 sec

The parameters [PTEOL] and [PTEOM] will control the peltier operation, if of course the current cooling mode is using the peltier TE. When the temperature of the water in the cooling tank is above [PTEOM], the peltier will start cooling the water until it goes below [PTEOL].

The parameters  [BOTL] and [BOTM] are used to control the cooling system operation. If the temperature inside the box is above [BOTM], then the cooling system starts to work, until the temperature drops below [BOTL].

The parameter [BAV] if the maximum temperature that may be reached inside the box without the high temperature alarm to occur. If the box temperature exceeds the [BSTV], then the computer is forced to shut down for protection.

The [WRTM] parameter is the max temperature that the pc box can reach before sounding alarm

The [PHSM] is the max temperature that peltier heat sink can reach before putting it out of control.

The [BLM] parameters is to control the backlit of the LCD. If is 0, then the backlit does not work. If it is 1, then it is always on. If another value is inserted, then the backlit will turn on anytime a key is pressed, and this parameter will be the delay to turn the backlit off, measured in 1/10 sec.

The parameter [BLL] will control the luminosity of the backlit. Values can be from 0 to 3

The parameters [VCD] and [TCD] indicates the maximum delay accepted for completing the state change of the tank selector valve and the air tamper change before indicating a failure alarm., in 1/10 sec

[PFCD] is a parameter to control the delay to turn off the peltier fan after the peltier has stop operation in order to further cool the peltier hot surface, in 1/10 sec.

[AFK]: If this time is passed and no key is pressed, then it automatically goes to operation screen. The value is in 1/10 sec

[SMPL] will control the delay for the acquisition of sensor measurements and thus the delay for updating the values in the operation screen of the LCD

[KTMI] and [KTMD] control the keyboard typematic initial delay and repeat delay. Works like a normal computer keyboard.
« Last Edit: August 25, 2008, 23:47:59 PM by kam »


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Re: Hybrid ultra effective PC cooling system - A first impression
« Reply #7 on: August 25, 2008, 18:10:34 PM »
And here is another impression for the operating control panel screens:

The first screen (shown below) is the main menu that appears when touching the menu touch panel. Within this menu the operator may start the cooling system in auto mode, manual with external tank cooling or manual using the peltier cooling. The operator may also stop the cooling system. Attention: STOPPING THE COOLING SYSTEM DOES NOT MEAN THAT THERE WILL BE NO COOLING AT ALL. Stopping the cooling system means that the ambient air cooling fans will operate as long as the computer is turned on. The last menu is to change the operational parameter values.

The screen that will appear when the operator chooses to change the parameter values is the following.

From this screen he may choose which parameter to change. Then the following screen will appear:

And from this screen he may give the new parameter value.


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Re: Hybrid ultra effective PC cooling system - Error messages
« Reply #8 on: August 25, 2008, 21:54:27 PM »
the error messages and error levels

The error messages are the followings:

A0No water flow
A1Peltier overload
A2Water return temperature high
A3Peltier heat sink high temperature
A4Pump thermal protection
A5Valve actuator failure
A6Insufficient radiator air flow
A7Water in tank empty
I0Water in tank low
B0Insufficient circulating air flow
B1Air tamper failure
E0Box temperature too high

As seen, there are 4 different levels of alarms. Each level will have a different effect to the operation of the cooling system:

In any case that an Ax error occur, the system will indicate alarm and switch automatically to air circulation

In any case that a Bx error occur, the system will indicate alarm and switch automatically to external tank or peltier cooling mode

If both Ax and Bx error occur, the system will indicate alarm and release the box trap cover to allow air circulation, and will set the emergency alarm contact set.

Ix error messages are only to indicate. The alarm will not sound but error message led will lit.

In any case that Ex error occur, the system will indicate alarm and release the box trap cover to allow air circulation and will set the emergency alarm contact set. The system will stop.


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Re: Hybrid ultra effective PC cooling system - The program variables
« Reply #9 on: August 29, 2008, 01:05:37 AM »
The program variables

The program will be written in assembly. I prefer using assembly rather than C because I feel more free, the code is less messy and smaller and of course much faster.
The first thing to do is to declare the variables. The microprocessor that we will use, provide us 368 bytes of Ram to declare our variables, far enough for this project.

NameDescriptionLength (bits)
cur_opThe current cooling mode:0=Off, 1=Air, 2=Water 3=Peltier1
retfie_push_wContext saving for interrupt return – W register1
retfie_push_statusContext saving for interrupt return – Status register1
ani_icon_posWill hold the position of the animated icon bottom right of screen1
tmp_etExternal temperature placeholder1
tmp_ptPeltier tank temperature placeholder1
tmp_phPeltier heat sink temperature placeholder1
tmp_raRoom ambient temperature placeholder1
tmp_pcPC Box temperature placeholder1
tmp_phPC Box humidity placeholder1
tmp_wrWater return temperature placeholder1
lcd_screenThe screen to appear:
0000 = Splash screen
0001 = Main menu
0010 = operation
0011 = Alarms
0100 = parameter selection
0101 = edit parameter
lcd_ parIf lcd_screen 0:3 >= 4 then shows the current par selection.1
lcd_tmp_valWhen editing a par value, this holds the current new value1
lcd_tmp_minWhen editing a par value, this holds the lower limit1
lcd_tmp_maxWhen editing a par value, this holds the higher limit1
output_buffer16 bit output buffer to SIPO2
input_buffer16 bit input buffer from PISO2
a_level_alarmsThe A level alarm register1
i_level_alarmsThe I level alarm register1
b_level_alarmsThe B level alarm register1
e_level_alarmsThe E level alarm register1
rtc_counterThe real time counter, counting 1/10 sec4
rtc_counter_e8 bits to indicate if an rtc counter is enabled and needs attention1
rtc_0LCD backlit turn off delay RTC counter4
rtc_1Peltier fan off-delay in seconds RTC counter4
rtc_2Air tamper change delay in seconds RTC counter4
rtc_3Tank selector valve change delay in seconds RTC counter4
rtc_5Sensor sampling4
rtc_6Key typematic delay4
key_inputThe current key state read1
last_key_inputThe last current key state for comparison check1
tmp1_varGeneral temporary variable 11
tmp2_varGeneral temporary variable 21
tmp3_varGeneral temporary variable 31
tmp4_varGeneral temporary variable 41
« Last Edit: August 29, 2008, 01:08:32 AM by kam »


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Re: Hybrid ultra effective PC cooling system - Extreme sub-ambient temperatures
« Reply #10 on: September 01, 2008, 21:58:05 PM »
I really want to see where will you come up at last... I am really curious.

I say i do not have yet read all this staf, but i will...


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Re: Hybrid ultra effective PC cooling system - Extreme sub-ambient temperatures
« Reply #11 on: September 01, 2008, 22:25:16 PM »
It will come to a nice cooling system with a large dose of mad science on it! 

And a question, when in internal air loop all seems ok, when you get air from outside wouldn't moisture come along?
« Last Edit: October 01, 2008, 23:51:16 PM by spic0m »


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Re: Hybrid ultra effective PC cooling system - Extreme sub-ambient temperatures
« Reply #12 on: September 15, 2008, 21:56:54 PM »
F#K%N COOL MAN  8) 8) 8) 8) 8) 8) 8) 8)


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Re: Hybrid ultra effective PC cooling system - Extreme sub-ambient temperatures
« Reply #13 on: September 21, 2008, 13:10:06 PM »


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Ya sure, first you turn us up and then... cold shower.  :P