The Downside To Energy Monitoring and Management

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I've been tracking my utility usage with Venturii for quite a few years now. At first it was merely an amusement to me, but as my budget grew tighter it became an invaluable tool for making effective changes to the way I consume energy. One of the greatest challenges we as consumers face when it comes to our energy consumption is that there are not a lot of convenient ways to monitor this information in a timely manner - most of us have no idea how much energy or water we've used until we get our bill in the mail a month later, and by that time several weeks have already past since that data was collected. This cumulative total every 30 days gives only the broadest glimpse of our utility consumption patterns, and provides almost no information about influences like "How cold was it outside? How many hours of sunshine did I have to compensate with artificial light? How many times and/or how long did I run the stove, dryer, furnace, etc. this month?" Venturii's real-time feedback on your consumption at any given point allows you to walk around your house and turn on or off appliances, lights, or devices and see right then and there how much of a difference it makes to your power consumption.

This kind of feedback can be invaluable for determining where your biggest consumers of electricity, gas and water are around your property, but there is a downside. As we enter the Christmas season, we've set up our Christmas tree. Last year we decided to move away from buying a real tree every year for a number of reasons, not the least of which was the fire hazard the tree posed by the time we actually got to Christmas. Not wanting to decrease the appeal, we splurged a bit and got a very nice fake tree that came pre-lit with 1,300 miniature lights. It looks amazing. However, due to Venturii I know that it draws 470 watts of power, and makes a considerable blip on my power consumption graphs. Therefore, illuminating the Christmas tree is a bittersweet event - it looks beautiful, but I know exactly how much it costs to run.

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There is definitely something to be said for the bliss of ignorance when it comes to energy usage. The more I peruse my graphs and produce increasingly granular reports on energy usage and commodity consumption, the more I feel a deep-seated urge to try to increase the efficiency of things.

Efficiency can be gained by numerous means, the simplest of which is to simply not use a resource.

Turning things off is probably the easiest goal to achieve with any automation platform, and Venturii is no exception. By using Passive Infrared and other forms of occupancy sensors, it is a trivial matter to have Venturii turn off the lights in a space when that space is unoccupied. I've even taken it a step further, utilizing a recent feature addition called Torx Pegs which allows me to do things at regular intervals. I've implemented a new set of instructions that cause Venturii to turn off every light in the house during the day on an hourly basis, providing it is very bright outside. This becomes a bit of a catch-all, especially for areas of the house that do not have occupancy sensors like the kitchen and dining rooms, areas that are often used and often left lit, unattended. Because the Torx peg restricts this sweep to once per hour, it's generally been received by the family as acceptable; if the lights get turned off when my wife is in the kitchen during the day, she simply turns back on the ones she needs to.

One of the more interesting means of improving efficiency involves more intelligence on the system calling the shots. Many of the appliances in my house have their own control systems built in that are designed to be reliable and robust given an unpredictable deployment environment and unforeseeable usage pattern. Many manufacturers have to build to the lowest common denominator, and while this accommodates the widest demographic of appliance users, it is usually sub-optimal.

For example, I have three refrigeration appliances in my house of six occupants. Two are the "normal" kinds an s with a fridge on the bottom and a freezer on top. Our third is an upright freezer. Two of these have been Venturii'd - with at least a couple of DS18B20 temperature sensors installed within key locations. The third, our main fridge in the kitchen, remains a virgin.

Through my analysis of the temperature data collected from the basement's fridge and freezer, I've discovered a number of interesting things about their usage patterns:

• The basement fridge compressor runs about 50% of the time, quite possibly making it the least efficient of the three refrigerators.
• None of the refrigerators have any means to detect ice buildup in the condenser coils and run a defrost cycle every 24 hours whether it needs to or not.
• Occasionally the doors of said appliances get left open. This has forced me to install door position sensors on the fridge and freezer doors in the basement, with an alarm that sounds if either is left open for more than 60 seconds.

I am fairly confident that if I took over control of the compressor and defrost coil, I could make all three refrigerators operate much more efficiently, taking into account time of day, the number of times the door is opened, the cooling load of its' contents, and the ambient air temperature outside of each appliance. More on that later.
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