Room cooling
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Dear List,
Advice please. We have an imaging room containing several imaging systems, each of which has the potential to generate a significant amount of heat. Cooling in the room is regulated by chilled air (supplied to the whole building) which is vented into the room from the ceiling on one side of the room, and extracted out of the ceiling on the other side of the room. If the cooling capacity of this air is exceeded then a fan coil cooler kicks in. Unfortunately this has the effect of blowing an artic gale across the room causing microscope stages to vibrate and users to freeze. Has anyone encountered a similar problem to this and found an ingenious solution? My initial thoughts are to hang some kind of diffuser curtains around the ceiling vents where the air comes out, but I am worried this will affect the flow of cold air across the room. Any suggestions very welcome. Thanks in advance. Simon |
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There exist things called "Duct Socks"--basically a fabric diffuser tube
that goes along one edge of the room, connected to the duct(s). A good HVAC engineer should be able to help. Julian Simon Walker wrote: > Dear List, > > Advice please. We have an imaging room containing several imaging systems, > each of which has the potential to generate a significant amount of heat. > Cooling in the room is regulated by chilled air (supplied to the whole building) > which is vented into the room from the ceiling on one side of the room, and > extracted out of the ceiling on the other side of the room. If the cooling > capacity of this air is exceeded then a fan coil cooler kicks in. Unfortunately > this has the effect of blowing an artic gale across the room causing > microscope stages to vibrate and users to freeze. > > Has anyone encountered a similar problem to this and found an ingenious > solution? My initial thoughts are to hang some kind of diffuser curtains around > the ceiling vents where the air comes out, but I am worried this will affect the > flow of cold air across the room. > > Any suggestions very welcome. > Thanks in advance. > Simon > > -- Julian P.S. Smith III Director, Winthrop Microscopy Facility Dept. of Biology Winthrop University 520 Cherry Rd. Rock Hill, SC 29733 803-323-2111 x6427 (vox) 803-323-3448 (fax) 803-524-2347 (cell) |
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In reply to this post by simon walker (BI)
HI Simon
When designing our facility air flow was a concern especially in the ultra-microtome room. I found there is a large variety of hard and flexible diffusers available for both intake and supply that reduce or almost eliminate air flow currents. As suggested by a previous responder check with your HVAC people and explain your needs. Rick, Richard Harris, Manager - Imaging and Data Systems The Biotron - Experimental Climate Change Research University of Western Ontario, London Ontario, CANADA. N6A 5B7 Ph. 519-661-2111 ext. 86780 Fax 519-661-3935 e-mail [hidden email] web: www.biotron.uwo.ca -----Original Message----- From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Simon Walker Sent: Tuesday, March 10, 2009 9:45 AM To: [hidden email] Subject: Room cooling Dear List, Advice please. We have an imaging room containing several imaging systems, each of which has the potential to generate a significant amount of heat. Cooling in the room is regulated by chilled air (supplied to the whole building) which is vented into the room from the ceiling on one side of the room, and extracted out of the ceiling on the other side of the room. If the cooling capacity of this air is exceeded then a fan coil cooler kicks in. Unfortunately this has the effect of blowing an artic gale across the room causing microscope stages to vibrate and users to freeze. Has anyone encountered a similar problem to this and found an ingenious solution? My initial thoughts are to hang some kind of diffuser curtains around the ceiling vents where the air comes out, but I am worried this will affect the flow of cold air across the room. Any suggestions very welcome. Thanks in advance. Simon |
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In reply to this post by simon walker (BI)
Simon,
in one of our imaging rooms, the cooling (at the ceiling) extracts air just be´neath the ceiling (and, in addition, at the exhaust of laser chillers) and releases the chilled air via a pipe system at the room side walls just above floor level. This works works well, and convection is substantially reduced. Flat, broad pipes distributing output across a big cross-sectional area further help to minimize turbulences and convection. One drawback: some users may feel a little bit uncomfortable at their feet. Your chilled air may be redirected this way to the floor level. Best, Guenter ------------------------------------------ Dr. Guenter Giese Light Microscopy Facility Manager Dept. of Biomedical Optics MPI fuer Medizinische Forschung Jahnstr. 29 D-69120 Heidelberg, Germany Phone (+49) 6221-486-360 (Fax: -325) e-mail: [hidden email] > -----Ursprüngliche Nachricht----- > Von: Confocal Microscopy List > [mailto:[hidden email]] Im Auftrag von Simon Walker > Gesendet: Dienstag, 10. März 2009 14:45 > An: [hidden email] > Betreff: Room cooling > > Dear List, > > Advice please. We have an imaging room containing several > imaging systems, each of which has the potential to generate > a significant amount of heat. > Cooling in the room is regulated by chilled air (supplied to > the whole building) which is vented into the room from the > ceiling on one side of the room, and extracted out of the > ceiling on the other side of the room. If the cooling > capacity of this air is exceeded then a fan coil cooler kicks > in. Unfortunately this has the effect of blowing an artic > gale across the room causing microscope stages to vibrate and > users to freeze. > > Has anyone encountered a similar problem to this and found an > ingenious solution? My initial thoughts are to hang some kind > of diffuser curtains around the ceiling vents where the air > comes out, but I am worried this will affect the flow of cold > air across the room. > > Any suggestions very welcome. > Thanks in advance. > Simon > |
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In reply to this post by simon walker (BI)
Ignoring the relatively minor issue of user comfort, we found that changes
in temperature caused microscope stage drift as various components heat up or cool down at different rates - the microscope as a very expensive thermometer. You need to stop the heat generating equipment from warming the whole room, or a least not heating the microscopes - ideally stick the heat generating equipment (Lasers, Hg lamps etc) in another room. -or, failing this, box in the heat sources and connect the box to the venting ducts (both air flow into and out of the room), thereby keeping the heat out of the room. You could also insulate the box plus ducting or vent the warm air into a corridor. - environmental chambers also protect the microscopes from fluctuations in room temperature, look for chambers that enclose as much as possible of the microscope but exclude heat sources. As suggested by previous posts, diffusers will reduce the local air flow. Jeremy Adler F451a Cell Biologi Wenner-Gren Inst. The Arhenius Lab Stockholm University S-106 91 Stockholm Sweden tel +46 (0)8 16 2759 -----Original Message----- From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Simon Walker Sent: den 10 mars 2009 14:45 To: [hidden email] Subject: Room cooling Dear List, Advice please. We have an imaging room containing several imaging systems, each of which has the potential to generate a significant amount of heat. Cooling in the room is regulated by chilled air (supplied to the whole building) which is vented into the room from the ceiling on one side of the room, and extracted out of the ceiling on the other side of the room. If the cooling capacity of this air is exceeded then a fan coil cooler kicks in. Unfortunately this has the effect of blowing an artic gale across the room causing microscope stages to vibrate and users to freeze. Has anyone encountered a similar problem to this and found an ingenious solution? My initial thoughts are to hang some kind of diffuser curtains around the ceiling vents where the air comes out, but I am worried this will affect the flow of cold air across the room. Any suggestions very welcome. Thanks in advance. Simon |
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In reply to this post by simon walker (BI)
G'day Simon,
By ducting the cooling fan from an Argon ion laser through the false ceiling we were able to avoid such problems. Other sources such as Hg lamp, and HeNe lasers were insignificant compared to the 100W Argon ion. You need to make a small "chimney" that rises a little above the false ceiling, so that building rubble etc does not fall back into your laser housing.
Cheers
Stephen Cody
2009/3/11 Simon Walker <[hidden email]> Dear List, -- Stephen H. Cody Consulting Microscopist |
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We had all sorts of similar problems [our
confocal rooms were a large lab subsequently walled up into 3 separate rooms
with the air-conditioning ceiling air-in and air-out ducts ending up in separate
rooms]. The Bio-Rad Radiance 2000 confocal room frequently chilled to below 16oC
causing the [old style] Zeiss immersion oil to go into a cloudy lump. The
exhaust from the Bio-Rad vented through a wall into the next room heating that
up and sending the air chillers into a frenzy. Despite our buildings manager
saying it was impossible, a visiting air-con engineer did rebalance the air-conditioning
to raise the temp to a nominal 24oC [from 22oC] and that helped a great deal.
You can also pay a £1,000 or so to get the main air temp control ‘upgraded’
to a better system than the basic office one normally installed [was just a bit
more electronics on the control bit] – air con guys still haven’t
discovered the Victorian thermostat though, it’s all that air flow balance
stuff. Even with the room temp raised it did get very chilly by the Bio-Rad confocal
and the OpenLab time-lapse Axiovert 100 that sat on the other side of the room.
These two microscopes both had large stage 37oC incubators that fought against
the Arctic wind as well. When the cold air hit the microscope, temp regulation and/or
focus/stage drift suffered. I fitted large card right angle shields [~12”
drop] to the sides of the ceiling air in vent which forced the cold air
vertically down into the centre of the room, and prevented it blowing on the microscope
stage [or the person sitting by the microscope, although we were less concerned
about them]. Prior to that, the stages couldn’t maintain 37oC. In addition
we fitted a 1kW thermostatic wall electric fan heater to raise the temp of the
room and help the incubators overnight. Plus the large stage 37oC incubators
had bubble wrap Sellotaped on the outside, and additional mini ‘always on’
heaters inside, to help the [underpowered] incubator air heaters to cope. When the Leica SP2 was going into a new
room I insisted on a proper exhaust vent that took the laser cooling air off
into the ceiling and into an air-con duct of some sort. The room was in a new
building and I couldn’t access it when it was being built. Walked in when
it was almost completed and saw that they had placed the cold air ceiling out vent
right over where the microscope would have to go [nobody ever thinks to ask]. We
had to seal off a lot of the cold air-out vent with tough tape stuff on the
inside [so you couldn’t see it] to block of the air flow to the microscope/air-table
area. This was the room that then had the additional £1,000 upgrade on the
air-con temp control. The Bio-Rad confocal was moved next door to the Leica and
an exhaust tube fitted to take the laser exhaust air off into the ceiling and
that duct. The cold air-in ceiling vent was in a different location [didn’t
blow on the microscope] and the Bio-Rad worked very well here, with the room
temp sticking to around 22oC. Most problems after that were caused by users
switching off the air-con [as it got ‘too cold’ for them] and the
room temp raising to apparently 37+oC on one occasion overnight [according to
the min-max thermometer anyway] – even with the laser exhaust vent to the
ceiling, the room warmed up with the confocal on 24hr live-cell time-lapses. As Stephen points out the [argon] lasers
generate about 3kW of heat when running and it’s venting that elsewhere
that is the key to maintaining room temperature. Confocal engineers always say
the confocal doesn’t mind running in a room at any constant temp from 20
to 30oC, just as long as the room temperature doesn’t fluctuate about.
That said our large Zeiss 510 MetaHead laser control box doesn’t have a laser
exhaust ducting vent system like the Leica and Bio-Rad [it all vents out into the
small room shared with two other microscopes]. We have an additional wall
mounted air-con cooler fitted though which maintains the room temp to 22oC
[although again users switch off the air-con as it gets ‘too cold and
noisy’] – I tell the confocal users to switch it back on [or their
image quality will suffer]. This air-con unit points to the centre of the room
and away from the microscopes. It’s a shame they don’t make
microscopes with a mixture of alloys/metals so that they expand/contract uniformly
with temperature fluctuations. I have measured a 40um drift in focus as a large
stage incubator goes from 22oC to 37oC [Axiovert 100]. Keith --------------------------------------------------------------------------- From:
Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Stephen Cody G'day Simon, By ducting the cooling fan from an Argon ion laser through the false
ceiling we were able to avoid such problems. Other sources such as Hg lamp, and
HeNe lasers were insignificant compared to the 100W Argon ion. You need to make
a small "chimney" that rises a little above the false ceiling, so
that building rubble etc does not fall back into your laser housing. Cheers Stephen Cody 2009/3/11 Simon Walker <[hidden email]> Dear List,
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We have an air vent right above the microscope, and every now and then cold gusts would start blowing from there. I talked to our engineer, he said that the entire building had to be reprogrammed, and it's all would be quite difficult to fix. So I got up on a ladder, found a valve on the air duct and shut it off. Everything has been fine since then.
Mike |
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In reply to this post by simon walker (BI)
Dear Simon,
...artic gale across the room causing microscope stages to vibrate and users to freeze...;these are two very different pairs of shoes, your microscopes require a temp stability of +/-0.1degC and a suitable response time to achieve stable focus. This is typically possible using an enclosure of the mic (but difficult for a room with several mics switching on and off and people walking in and out), there are several commercial and self-made solutions for mic enclosures, one of which is available at http://www.embl-em.de (I was involved in developing it, we achieved rock stable focus for 72hours which was the longest period we tested).The issue has been discussed extensively in this list. Make sure the device you choose is capable to cool as well as heat. For your customers and the remainder of the room, the temp control only needs to achieve +/-2degC, which usually is no problem for a standard air conditioning system with enough capacity. We had a very similar problem to the one your describe, because there was only one sensor measuring temp in a large room, but we had subdivided the room into cabinets using curtains, so sometimes the sensor 'saw' temps that were only locally and temporally high and the system over-reacted. In this case your aircon should be clever enough to integrate data from several sensors. Finally we have enclosed some of our our heat generators into independently ventilated cabinets, like the ones used for computer equipment in server rooms. Best, jens
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Hi all,
Of course, despite a budget of tens of thousands of pounds, many microscope Core facilities have a day to day spending power that is next to nothing, after all the essential bills have been paid. Cost recovery slowly brings the budget back temporarily from the red, but then another confocal maintenance contract gets paid. Hence the reliance on bubble wrap, thick card and sticky back plastic [for a temp fix at least] once the new £250,000 confocal has been installed in its typically unsuitable room - and not only does the temp fix work, you get change from £20]. You never quite know how unsuitable a room is for a microscope until it's installed though, and it can take years of badgering and thousands of pounds to get everything acceptable. That said, generally the users complain about personal comfort rather than image quality. In terms of microscope focus and stage drift stability it's fortunate that most of the microscopes I have managed require large incubator enclosures for live cell imaging, and these buffer the stage and objectives from room temperature fluctuations. Plus the mainstay confocals generally come with an anti-vibrational air table of some sort [or you can make one yourself with a heavy slab and anti-vibration rubber pads]. In know the Cancer Research UK facilities in London had great success totally enclosing their imaging microscopes with an in-house designed laminar flow 'live cell' Perspex cabinet - but these are too expensive for many facilities and you really need an in-house workshop to produce them [we don't have one here, and I really miss those guys]. Keith --------------------------------------------------------------------------- Dr Keith J. Morris, Molecular Cytogenetics and Microscopy Core, Laboratory 00/069 and 00/070, The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, United Kingdom. Telephone: +44 (0)1865 287568 Email: [hidden email] Web-pages: http://www.well.ox.ac.uk/cytogenetics/ -----Original Message----- From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of jens rietdorf Sent: 11 March 2009 13:59 To: [hidden email] Subject: Re: Room cooling Dear Simon, ...artic gale across the room causing microscope stages to vibrate and users to freeze...;these are two very different pairs of shoes, your microscopes require a temp stability of +/-0.1degC and a suitable response time to achieve stable focus. This is typically possible using an enclosure of the mic (but difficult for a room with several mics switching on and off and people walking in and out), there are several commercial and self-made solutions for mic enclosures, one of which is available at http://www.embl-em.de (I was involved in developing it, we achieved rock stable focus for 72hours which was the longest period we tested).The issue has been discussed extensively in this list. Make sure the device you choose is capable to cool as well as heat. For your customers and the remainder of the room, the temp control only needs to achieve +/-2degC, which usually is no problem for a standard air conditioning system with enough capacity. We had a very similar problem to the one your describe, because there was only one sensor measuring temp in a large room, but we had subdivided the room into cabinets using curtains, so sometimes the sensor 'saw' temps that were only locally and temporally high and the system over-reacted. In this case your aircon should be clever enough to integrate data from several sensors. Finally we have enclosed some of our our heat generators into independently ventilated cabinets, like the ones used for computer equipment in server rooms. Best, jens simon walker (BI) wrote: > > Dear List, > > Advice please. We have an imaging room containing several imaging > systems, > each of which has the potential to generate a significant amount of heat. > ...Cooling in the room is regulated by chilled air ... Unfortunately > this has the effect of blowing an artic gale across the room causing > microscope stages to vibrate and users to freeze. > > Simon > > -- View this message in context: http://n2.nabble.com/Room-cooling-tp2455239p2461420.html Sent from the Confocal Microscopy List mailing list archive at Nabble.com. |
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In reply to this post by Keith Morris
G'day,
I would just like to add a couple more points. Environmental chambers can only do so much, and most seem to use PID controllers; this technology works very well provided the ambient temperature remains stable. Some of these system pump room air into the incubation chamber and these are naturally more susceptible to temperature fluctuations, while the recycling types are a bit more tolerant. In addition to the heat source from the laser, universities and hospitals are notorious for switching central air conditioning units off, or to low power mode in the evenings and weekends. Most frustrating when you would nurse a timelapse experiment all day only to find that the focus would drift at exactly the same time each night!
While PID controlled microscope incubators are great (I've had several), fuzzy logic controllers are much flexible when it comes to fluctuating room temperature. they are capable of altering the heat load according to requirements. One such microscope incubator system is built by "Clear State Solutions" http://www.clearstatesolutions.com/ . There may be others too, but if your are in the market for an incubator, I would be insisting on fuzzy logic control.
Similar to Keith we installed a Split System, Reverse Cycle air conditioning system in the Bio-Rad room at my previous place of work. The idea being that this would come into play when the hospital supplied air conditioning could not cope, or was switched off. I was hoping for an inverter type system, but when I came back from holidays a standard on/off system had been installed. We too found that users would turn it off, up or down depending if they had just been outside and were feeling hot or cold. In addition this came on with too much force when the room temperature increased, and would fight the hospital air conditioner. The temperature of the air conditioner we installed had to be set very carefully to avoid this. Hence an inverter air conditioning system with fuzzy logic should be much better. That said the solution seemed to come when we plumbed the heat extraction duct from the100mW Ar ion laser through the ceiling.
Of course now we can purchase, "Perfect Focus System", "Zero Focus Drift" and "Definite Focus" systems, which should be considered in any system being purchased for time lapse imaging.
Regards
Steve Cody
2009/3/11 Keith Morris <[hidden email]>
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