[3dem] cooling water supply

Fang Zhao fang.zhao at helsinki.fi
Sun Sep 27 23:05:42 PDT 2009


You have three options:

1. The air-cooled water chiller, which discharge all heat dissipated from
your EM, plus heat produced by the chillers itself (its motor, compressor)
into the room, if located inside the EM room, make the EM room very
uncomfortable: warm or hot, noisy environment. It may have problem like
Reinhard mentioned, although I have not encountered here in Helsinki. Avoid
this as much as possible.

2. In-house circulated cooling system: this would be the most convenience
choice if it is available. Be aware of the pressure in the system, the
temperature of the system (too cold water in summer causes condensation
within EM), and most important, the water quality of the system. In many
case the in-house cooling circulation system is for central air conditioning
which does not care about water quality. In worst case, the water comes
totally black like water in the sink. In one of my system, I have to add
consecutive two in-line filters before the water-in of the EM.

3. Water-cooled water chiller, this would be the best, but most expensive
option. By this device, you have control on pressure, temperature of the
water towards your EM. This device still need in-house circulated water to
cool down the condenser of the chiller, which eventually take the heat
dissipate from your EM to the house cooling system, avoid the problem that
the heat is discharged into the room air like the air cooled condenser does,
avoid occasionally heat wave problem in summer that make air-cooled chiller
incompetent like Reinhard mentioned. Be aware, if located within EM room,
there is still heat discharged into the room which comes from the chiller
itself (motor, compressor, etc) and produce noise. The small amount of heat
is negligible if the room is big enough, but the noise is the big problem.
It will drive you mad if you stay there all the day. Try to install it in a
small room or isolated cabin beside EM room where no people work in it.
Since it use in-house cooling water, still be aware of the water quality
that can clog your chiller's condenser.

I have all these three system in use for different EM, these are just my
experience and some painful lessons. Hope it helps you to make right choice
suitable in your situation.

Best regards,

Fang
--------------------------------------------------------
Fang Zhao, MD. PhD.
Advanced Microscopy Unit (AMU)
Haartman Institute 
Haartmaninkatu 3
PO Box 21, 00014 University of Helsinki
Finland
Tel. +358 9 1912 6261
E-mail: fang.zhao at helsinki.fi
Web: http://www.hi.helsinki.fi/amu


-----Original Message-----
From: 3dem-bounces at ncmir.ucsd.edu [mailto:3dem-bounces at ncmir.ucsd.edu] On
Behalf Of reinhard rachel
Sent: Friday, September 25, 2009 6:25 PM
To: 3dem at ncmir.ucsd.edu
Subject: [3dem] cooling water supply

Some years ago, we had to replace the first water chiller for our TEM (FEI)
by a new one, and we choose an air-cooled version. Later, we found this not
to be sufficient for periods of really hot summer days (rare, but can happen
even in Germany). The air-cooled system was, at that time, not located in a
room with AC. At above 29 or 30 C ambient temperature, it does not cool any
more. We had to shut down the scope for > 2 weeks. 
Later, the air-cooled system was modified and equipped with external water
cooling, which is cooled by an in-house (perfectly reliable, in our case)
water supply, in fact cooling water, which is too cold to directly run thru
the scope. 
Since then, everything is fine. 
Therefore, if possible, I would recommend a water-cooled system. 
Kind regards,
Reinhard Rachel


-- 

PD Dr. Reinhard Rachel
Universitaet Regensburg
Centre for EM - NWF III - 
@Institute for Anatomy
Universitaetsstr. 31
D-93053 Regensburg - Germany
tel +49 941 943 2837, 1720
fax +49 941 943 2868
mail reinhard.rachel at biologie.uni-regensburg.de
office: VKL 3.1.29 

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