Home Automation

Saving power on the home network

As part of our ongoing quest to reduce our energy usage and carbon footprint we have installed a compressive home energy logging system which uses various sensors to monitor our energy consumption, generation and environment data which are collated in Home Assistant and also on our home data logger

As part of our ongoing quest to reduce our energy usage and carbon footprint we have installed a compressive home energy logging system which uses various sensors to monitor our energy consumption, generation and environment data which are collated in Home Assistant and also on our home data logger website.

In August 2017 we performed a major upgrade to our home network with the addition of a TP-Link T1600G-52TS JetStream 48-Port Gigabit Smart Switch with 4 SFP Slots and then in October we upgraded to 10Gb fibre using a MikroTik CRS309-1G-8S+IN for our Synology network attached storage devices and our main workstation computers.

The TP Link gigabit switch was linked to the 10Gb MikroTik switch via a SFP fibre adapter and short link fibre cable.

Our network cupboard is monitored using a modified Kasa Smart Plug by TP-Link model HS10 which logs energy usage and mains voltage.

Old Network setup
Old Network setup

Connected to the network monitoring smart plug are the following devices:

  • APC Back-UPS 210 Watts /350 VA
  • Gigabit Internet Gateway Network PC running our home logging software, Home Assistant, MySQL databases, backup processing scripts and various docker images.
  • SG-3100 Netgate Security Gateway Appliance with pfSense Plus Software
  • TP-Link T1600G-52TS JetStream 48-Port Gigabit Smart Switch with 4 SFP Slots
  • MikroTik CRS309-1G-8S+IN – 10 Gb network switch

All the above are running 24 hours a day, 7 days a week, 52 weeks a year and the average power consumption varies between 50 and 55 watts depending on load of the Gigabit PC.

We only run the docker images between 7am and 11pm and this adds approximately 1-2 watts to the baseline power consumption.

The annual energy usage is approx. 464kWh/year which at our current electricity costs of £0.18832 per kWh is £87.43 per year.

The chart below shows the daily power consumption of the network devices.

Old Network Power Consumption
Old Network Power Consumption

Increasing Electricity costs

We are currently using a fixed term 12-month electric contract at £0.18832 per kWh which is average based on our location in the UK. In the past 10 years energy prices have risen over 50%. There have been warnings that the energy prices may increase by an additional 30% in 2022, so with this in mind we decided to try to reduce our annual consumption further and investigate additional generation options.

Solar Upgrade Plans

We are considering upgrading our existing 10-year-old 500w PV solar panels and removing the solar thermal hot water panel and replacing with 3.2kW solar PV panels and a hybrid inverter and battery system.

We would also add a solar bypass system which would feed additional energy into the hot water cylinder when the batteries are full and home energy usage is low.

Due to the extra weight this would add to the roof structure we will need to have the 120-year-old roof wooden beams reinforced.

As this will need to be done from the outside the existing slates and insulation removed and additional timber fitted to each.

We have spoken to a local builder who specialises in roofs we may have to put all the planned solar upgrades on hold until the price of wood and other materials decreases, and availability improves as there are currently shortages across the building industry and prices are over 100% higher than previous years.

New 28 port network switch with 10Gb

With our current TP-Link 48 port 1Gb switch we are only using half the ports and 4 x 10Gb ports on the MikroTik switch.

As the Synology Diskstation and the workstation computers are not running at night the switch was unused for around 9 hours each day but still consuming standby power and with half of the 48 1Gb ports not being used the switches internal circuits still used power for these as well.

We created a spreadsheet of all our current network devices and allowing for expansion we found that we could use a smaller single rack mounted network switch with 24 x 1Gb ports and 4 x 10Gb SFP+ slots for the two NAS drives and our 2 main workstation computers.

All other devices could continue to use 1Gb network ports as before.

As we have had good experiences with TP-Link switches and hardware in the past we decided to purchase a single replacement switch which would meet all our requirements and have a lower power consumption.

We found the TP-Link TL-SG3428X JetStream which is a 24-Port Gigabit L2+ Managed Switch with 4 10GE SFP+ Slots which we could use with our existing fibre converters and would be a direct replacement for our existing two network switches and costs £174.32 ex VAT (£209.19 including VAT).

New TP Link Network Switch
New TP Link Network Switch

The new switch was ordered from Broadband Buyer and it arrived the following day.

The switch has a USB serial console port which allowed us to connect to console and set the switches IP address with the remaining configuration completed via the web-based UI.

TP Link web user interface
TP Link web user interface

The 10Gb switch and 48 port switches were removed from the network rack and all existing cables removed from the patch panel to allow the installation of the new switch.

Removing patch cables
Removing patch cables

The new switch was installed, and the patch cables reconnected to the patch panel as required.

New Network setup
New Network setup

We have 12 network cables running from the patch panel to the loft workshop, but we only need two network cables for the computers and 4 for the test equipment. As all the loft computers and devices are using a 1Gb connection we decided to use just three of the ports on the new switch for the loft and install a basic 16 port network switch in the loft which is powered on when the main bench power is enabled.

New Network Power Consumption

With the new network switch installed alongside our other network cupboard equipment we found that the power consumption had dropped to 29.9W during the daytime and 27.6W at night.

New Network Power Consumption
New Network Power Consumption

This is a saving of around 24 watts of mains energy which costs £39.60 saving us £47.83 per year.

With the switch costing £209.18 it should take around four years at current energy prices to recoup the costs but with energy prices increasing at current rates the payback time should be faster.

Permalink


comments

Leave a reply

Your email address will not be published. Required fields are marked *

Share this post

Support the blog

AB Electronics Raspberry Pi shop