Hi all,
Thanks again for your replies regarding heat and dust. I think I have a solution that meets my requirements.
I decided to build a simple encasing for the laptop myself, using an aluminium flightcase as available from any hardware store. For cooling, I made two 78 mm holes in it at both sides and put an 80mm 12V case fan in front of each of the holes on the outside (one as inlet, one as outlet). (I chose the outside to have enough space left on the inside for the laptop
.
Furthermore, I did some minor modifications for running cables through the side of the flightcase and raising the laptop inside of the flightcase, so the airflow mainly cools the bottom of the laptop. I paid attention to the ventilation inlets and outlets of the laptop itself and positioned the flightcase fans accordingly to get an optimal airflow. I also used a sealant to prevent air leakages.
To prevent dust, I put a filter in front of the fan that serves as an inlet. The filter is currently just a regular vaccuum cleaner motor filter. Although the filter does work, I noticed that it lowers the airflow considerably, so I just ordered some "official" case fan filters, as supplied by Azerty (
http://www.azerty.nl/8-283/fanfilter.html), which seem to be less obstructive. I will try several (AC Ryan, Akasa, Nexus) to see which one gives best results.
I might also put a filter in front of the fan that serves an an outlet. Although this is not required for dust prevention, it does make both fans have the same airflow (m^3/hour) and thus prevents a vaccuum build-up inside of the flightcase that may suck in dusty air through any remaining splits/small holes.
Here are some pictures of the result:
Flightcase, opened:
Flightcase, closed, inlet fan:
Flightcase, closed, exhaust fan:
The three cables running through the side are the laptop power supply, ethernet and usb to a Xanura PMIX35 (but I'm probably going to virtualize the latter by using an RFXCOM ethernet interface + RS232 serial interface and my good old CTX35; the PMIX will then be used for testing purposes on my development machine).
The laptop is running Vista Business. I know, as you said, it's overkill, but I found a nice affordable laptop with some extra horsepower (Core 2 Duo T8100), and coming from a very slow, underpowered instable VIA mini-itx server, it feels right to have some spare CPU cycles left
.
Beside running Homeseer, it serves as my fileserver, downloadserver and musicserver for our Sonos system, and also has WAMP server installed for some additional (private only) webpages/scripting. For remote access I installed an SSH daemon and use tunneling/client-to-server port forwarding on top of SSH to access all other services (such as SFTP and Remote desktop). Using public/private keys for access and only opening up port 22 inbound in my router/firewall should be sufficientlty secure (hopefully
. The tunneling/client-to-server port forwarding also gives me direct access to my Axis network cameras, if needed.
As far as temperatures are considered: I used 3 Oregeon Scientific sensors to measure temperatures for some time. I put one in the room where the server is located. This is also the room where the washing machine, dryer, central heater and solar panel inverters are located, so ambient temperatures are kind of high (between 25 to 29 degrees, but more or less stable thanks to the mechanical ventilation of this room). I put another sensor inside of the flightcase, next to the laptop and one on the outside, in the fan air exhaust. Here's a graph of the temperatures on a typical day:
Red is ambient room temperature. Green is temperature inside of the flightcase and blue is flighcase fan exhaust temperature. It turns out that the exhaust temperature is 1.5 to 2.0 degrees C higher than ambient temperature, which looks fine to me.
The laptop consumes between 14 and 26 Watt, depending on load, with the screen turned off (as is usually the case). The two fans add another 2 Watt each. I did try running the fans at 5 Volt; these are Zalman ZM-F1 fans that are capable of running (and more importantlty starting up) at 5 Volt as well, which has the additional benefit that the fans could be powered through the USB bus (power consumption of each fan is 0.7 Watt at 5V), preventing adapter loss, but concluded that the resulting airflow was inadequate: exhaust fan temperatures rose to more than 7 degrees C above ambient temperature. I will retry this option with the other fan filters; maybe the airflow will be sufficient with these less obstructive filters.
Now we'll just have to wait and see if it still works in a few years time
.
Lennart
