🎐 Kanthaus has a [https://en.wikipedia.org/wiki/Heat_recovery_ventilation central heat-recovery ventilation system], consisting of a [https://shop.systemair.com/de-DE/save--vtc--700--l--wrg--geraet/p609989 Systemair SAVE VTC 700] ventilation unit in the K22 attic and an extended system of pipes in valves to the majority of the rooms.

The ventilation unit supplies fresh air to the house, slightly warmed by the stale air it extracts from the house. Both air flows do not mix, they just transfer the heat inside the heat exchanger.

The system automatically adjusts the fan speed to maintain a consistent relative indoor humidity, thereby saving electric power.

== Air flow schema ==
[[File:Ventilation-plan.png|thumb]]
There are exceptions between floors:

* [[Silent office|Silent Office]] has supply instead of intake
* K22-0 just has one intake in the [[Freeshop storage|Free Shop Storage]], but no supply - it pulls fresh air from the hallway and through the [[Freeshop lounge|Free Shop Lounge]]

Also, ventilation piping is work-in-progress and will be extended as the house evolves.

== Statistics ==

You can get some statistics about the ventilation system in [[Grafana]]. Those statistics are pulled from the ventilation unit via [https://git.kanthaus.online/kanthaus/ventilation-watcher an ESP32 device communicating with it via Modbus].

== Maintenance ==

* Intake filters in the rooms: change and wash every 1-3 months when heating is running
* Central filters in the attic: replace and buy new filter every 12 months, ideally before winter
* Heat exchanger in the attic: wash every 1-2 years, maybe?

=== Change and wash intake filters ===

They are located in all rooms where air is sucked into the pipe, to prevent the pipe from getting dirty. Especially when radiators are running, a lot of dust is kicked up in the air and ends in the filters.

To check if a change is necessary, measure the air flow into the intake with an air flow meter (currently in K22-1-1). It doesn’t hurt to replace the filters more often.

You can take the filters out by simply pulling out the valve.

Fresh filters are in a box, currently in the Ex-food-storage (K22-1-1) as of 2023-02-23. Put the new filter on the outside of the pipe and insert the valve again. It’s a bit tricky to prevent the filter from getting pushed too far into the pipe.

You can wash the filters with a lot of water and dry them. Then they can be reused a few times, until holes appear.

=== Central filters in the attic ===

The SAVE VTC 700 ventilation devices has two filters, one for fresh air and one for used air. It’s important to replace the fresh air filter every 12 months, because it gets filled with dust and dirt from outside air. Especially spring and summer add a lot of pollution. When the filter gets full, the air supply can get smelly and the ventilation system doesn’t provide as much air. Hence, it’s good to replace the fresh air filter in autumn.

The used air filter doesn’t need to replaced regularly, as we have to filters on the intakes in the room (see section above).

First, buy a new fitting F7 filter, like those: - https://www.as-luftfilter.de/Ersatzflter-Lueftungsgeraete/Systemair/VTC-700/Ersatzfilter-passend-fuer-Systemair-VTC-700—Gueteklasse-F7.html - https://rt-handel.de/Ersatzfilter-Lueftung/Systemair/VTC-700/Ersatzfilter-passend-fuer-Systemair-VTC-700-Filterklasse-F7

Then turn off the ventilation device, open the main cover and unscrew the left panel. Slide out the old filter and take a picture to show it to interested people ;) Insert the new filter, carefully screw the panel on, close the main cover and turn on ventilation again.

=== Wash heat exchanger ===

We didn’t do this so far, but the heat-exchanger can be rinsed with water to get rid of fine dust. This should increase its efficiency.
[[Category:Technical]]
[[Category:Repro]]

Server

2024-11-06T17:28:15Z

Tilmann:

⭐️ We have a server running locally that provides a few services to residents as well as guests.

== File sharing services ==

The server provides the possibility to store and exchange data. Some services are publicly available (e.g. connecting with an anonymous user), for others you need a user account with some privileges. All file services are only available in the <code>full</code> [[Wifi|network]] and served via [[wikipedia:Samba_(software)|Samba]]. Use your computers file manager to browse the available network computers and locate the server as <code>KANTHAUS-SERVER</code>. If this doesn’t show up in your file manager or the link is broken, you can try entering <code>smb://kanthaus-server/</code> directly into your file managers address bar. This should work on most Linux environments.

=== Getting a user account ===
To get a user account, speak to an admin (e.g. Antonin or Tilmann). The admin will add you to the Ansible user configuration and ask you to set a temporary password using your account. You can change the password yourself, e.g. via <code>smbpasswd -r kanthaus-server -U yourusername</code>.

Actually, you have two passwords:

* System user account: Used for local access and SSH access. Change password using <code>passwd</code> when logged in
* Samba account: Used for accessing the samba network shares. Change password using command above remotely or using <code>smbpasswd</code> when logged in.

==== Kanthaus cloud copy ====
* The share <code>kanthaus-public</code> offers an anonymously usable read only copy of the public part of the kanthaus cloud.
* The share <code>cloud.kanthaus.online</code> offers a read only copy of the whole kanthaus cloud. You need to have a user with the permissions class <code>kanthaus</code>.

The cloud copy is synchronized from the Kanthaus cloud once every minute.

==== Internal cloud ====
The share <code>internalcloud</code> stores some data which should only be available from inside Kanthaus (e.g. financial data) and is only available to users with the permissions class <code>internal</code>. Please make sure to only put security sensitive stuff in here and also make sure to not leak your user credentials or the contents of this folder, when you have access to it.

This folder is part of the daily backup.

==== Home folder ====
Every user account also has their personal <code>home</code> folder available as the <code>homes</code> storage. All data you put here is only available to yourself. Inside the home folder, there is a directory called <code>storage</code>. This folder lies on an easily expandable, cheap hard-disk storage. It is slower to access but suitable to store lots of data (e.g. backups of your computer).

Your home folder is part of a daily backup. Please put files called <code>.nobackup</code> into folders that you don’t want to be backed up (e.g. to save storage space). The <code>storage</code> folder is '''not''' part of the backup, but the hard-disks have a raid configuration to tolerate the loss of one hard-disk.

== Shell access ==

When you have a user account, you can also use SSH to connect to the server and use it for computing tasks. To set an initial password, ask an admin. When you already have file sharing access, you can add your SSH public key to the <code>homes/.ssh/authorized_keys</code> and use that for logging in. Same as above: In your home directory there is a symlinked folder called <code>storage</code> which is on spinning disks, whereby the rest of your home folder is on limited SSD space.

== SFTP Access ==

You can use software like FileZilla to access your home folder through <code>sftp://kanthaus-server</code> providing your username. See the Shell Access section above for other details.

=== How to unlock the encrypted <code>kanthaus-server</code> via network ===
* be in <code>kh-admin</code>
* <code>ssh -p 2222 root@192.168.178.249</code>
** your key must be stored on the server in <code>/etc/dropbear-initramfs/authorized_keys</code> -> <code>update-initramfs -u</code>
** ED25519 key fingerprint: <code>SHA256:mvCVYx8D/Fv/qYq+a/H4MoRAcfExAUsAFW3L2NVHnD0</code>
* enter password (stored in keepass -> Server)

== System specs ==

* System is designed to save power but still have some computing resources.
* CPU: Intel Core i5-2500K (4x 3.3 GHz)
* Ram: 16 GB DDR3L
* SSD: 1 TB Samsung 860 Evo as root file system
* HDD: BTRFS pool with 2 disks. Current usable size 3 TB

== Backups ==

Backups are done using Borgmatic. The backup target is the local hard-disk storage, so it does not safe us against fire or theft of the computer. We might think about adding a remote backup as well.

== Other services ==

* Foodsharing Gitlab CI runner (dockerized)
* House bus services
** local Web interface (dockerized)
** Logging daemon to externally hosted influxdb
* Virtual machines (kvm/libvirt)