How does outdoor temperature affect indoor temperature.

Theoretically outdoor temperature dictates indoor temperature. But there is probably a delay. A building should be able to keep its indoor temperature for some time, if insulated at all. Can we see what delay it is?

The delay is probably not constant, as it is also influenced by wind (windchill effect), changes in athmospheric pressure (air tries to move either in or out) and intensity of sunlight (sun shining through window influences room temperature).… Read the rest

Permafrost. Or is it?

How cold it gets under the ground, when ground source heatpump sucks out all the heat? Will the ground freeze?

Probably the answer is ‘depends’. I have heard anectotal evidence from ground source heatpump installers, that they had to dig out too short pipes from underground, during summer, where it was just a big frozen lump.… Read the rest

Heatpump Adventure

Actually not really an adventure, but I did get a ground source heatpump this spring.

While looking for it, I came up with many questions I could not really answer, or did get different answers from different sources. As time goes on, I start to forget about them, so it is about time to write them down and see, if I can get answers for those from experience.… Read the rest

Resize iSCSI partition

Lets have a practical scenario. A disk box, with iSCSI LUN, which is used by a linux box.
LUN fills up, and is resized on that disk box.

On linux side, lets rescan session, to get updated target size visible:
iscsiadm -m session -R

Lets assume, the partition is plain ext4 and available as /dev/sde1

parted /dev/sde

Parted should detect disk size update and notify about it
Warning: Not all of the space available to /dev/sde appears to be used, you can fix the GPT to use all of the space
(an extra 2147483648 blocks) or continue with the current setting?
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Synology DSM 4 & 5 Openvpn client 7

I was pleasantly surprised when I did find out, that had added a VPN client in their DSM 4 release. This VPN client supports either PPTP or openvpn. Openvpn support is what I am interested in. Unfortunately openvpn wizard in DSM assumes that username authentication is used.… Read the rest

Code display in WordPress

I have accustomed in using <code></code> tags in my posts so that many posts have those tags.
Unfortunately , my WordPress theme in its default settings does not really distinguish code in <code></code> tags enough to be easily distinguishable from the rest of the text.… Read the rest

Upgrading old Gentoo installations 1

Sometimes for whatever reason You need to upgrade an old or really old Gentoo installation. Reinstall just is not an option. Upgrading old Gentoo installations is not really a plain sailing. All sorts of circular dependencies come up. For example portage is, bash is 3.2_p39 and python is 2.5.4.… Read the rest

Website statistics. Awstats and Adsense.

After years of relaying on Awstats for my web site statistics I also added Google Analytics. The final push came from adding Adsense. If I already have many external javascripts running on every page of my site, then one more makes no real difference. … Read the rest

Accurate LM35 readings

Sometimes LM35 analog temperature sensors give inconsistent readings. Reading fluctuations are simply too high. Specially if LM35 sensor is connected using a cable that is a meter long or longer.  There are some techniques tu compensate for those fluctuations and get more consistent readings.… Read the rest