Home automation overview

Some of the best practices for automation are designed right at home. I’ve built several automation and monitoring systems for my home that have proved to lower our expenditures at about 2000₪ annually

I’ve explored and built my home automation system using these key products and methods:

  • Google spreadsheets for simple database objects, such as temperature readings and status
  • Google Apps scripts to control and verify the data collected, optimize it and raise alerts if the data is not as expected
  • Raspberry PI and Arduino to gather the data from analog and digital devices, acting also as a DDC to open and close the electric relays of the water heating system
  • Owl micro and Network Owl to gather information about current electricity consumbtion

Saving on electricity

This graph is an actual live daily electric consumption in kWh of our home from the day we installed the system. 
As of July 2016 You can see a steady reduction in energy usage. first I focused on the 2 major “energy drinking” appliances at home:

  • Central Air conditioning system
  • Water heating

When we focused on the central heating system, we noticed that because it’s built to serve the whole home, it is very inefficient at night when only the bedrooms require cooling at summer.
I’ve done a simple calculation. the central air conditioner uses about 25kWh at night which is about 12.5₪ / hour. We have installed an additional small air conditioner that consumes about 0.5kWh (for a whole night it’s about 5kWh) and it cost us about 1800₪, meaning in half a year of only the reduction cost of electricity bills means we have already refunded the 1800₪ we paid and got a better solution for our bedroom than the central air conditioning system.

Saving energy on water heating

Live feed and history from my water heater unit:

For water heating there is the solar thermal water system, but we quickly discovered that there are problems with a system designed for multiple residents that share the solar panels (we live in an appartment building that has such a system). one of the major flaws of this system is that when the solar panels are cold, heat from each home is released from the water tank into the pipes.
Live data using a google spreadsheet for graphics:

I used an arduino, an electric water pump and 2 selenoid taps with some thermal measurements to build a simple system that when the water in the water tank are hotter than the water in the solar panels, the pipes are closed. since an electronic pump was introduced to the system, when the solar panels are hot, the water tank heats about 8°C an hour, for a 120 liter water tank that’s quite fast. also, I’ve added a Raspberry PI to log the data, for future studies. We calculate that this system reduces our water heating electricity bill by about 1200₪ a year at least.

I’ll keep updating this project with images and electrical drawings of the system as soon as possible.

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