Tuesday, September 30, 2014

Thermal Imaging for the Homeowner

I've had an infrared thermometer in my tool bag for many years. These devices, small point and shoot meters often with a laser "sight" to ensure proper aiming, do a great job of measuring temperature of terminals, conductors, circuit breakers, transformer cores, etc. and I can be very useful for troubleshooting or diagnosing electrical problems.

Once a significant investment ($100-$200), prices have dropped considerably. This one, the General Tools IRT207, is under $40 from Lowes or Sears;  you can find low end devices for under $20 from some outlets.

Pricier "thermal imaging cameras" are a more recent innovation, which take still photos or video of infrared emissions. Running $2000 and up, these are out of range of most home-owners and small commercial users; but have become mainstays of home inspectors, electrical contracting, energy engineers, etc. And while prices have dropped (and features and capabilities have risen) these devices are still out of reach for most consumers.

But recently, several devices have become available in a much lower price range. While I am sure there are competitive units out there, I'm going to spotlight two different devices from Flir Systems.

First, the FLIR TG165 Imaging IR Thermometer  is a neat cross-over device; an infrared thermometer with a small (80x60 px) video image. The video is a little gung-ho for my taste, with driving rock music and Monster Truck Rally voice-over such as:
  • "...not your old-school spot radiometer..."
  • "....download images and data, and whip up a report later..."

Nevertheless, it seems like a great little device, and at ~$500 retail, it's dropped into the affordable range for many.

Next, and more exciting (to me) is the Flir One: Thermal imaging device for your iPhone 5/5s. This is a case for the iPhone device that includes a thermal / infrared imaging device. At $350 it's even more affordable than the handheld device, has a bigger image size, although perhaps less "point and shoot" ability (laser sight, etc.)

The applications of these types of devices are pretty broad for the creative home-owner, business owner or hobbyist, but some of the things I've stumbled across over the years include:
  • Electrical inspection
  • Mechanical inspection (fans and motors, automotive belts, pulleys, etc.)
  • Energy conservation (checking insulation, windows, doors, ducts, walls, roofs, etc.)
  • Checking for insects / pests / vermin in walls (apparently they produce a thermal signature)
  • Checking  plumbing fixtures.
  • Checking / calibrating cooktops and overs
  • Seeing in the dark (security)

Saturday, September 27, 2014

How to Save Money and Energy Despite Having Electric Baseboard Heat

When I purchased my most recent home, one of my big concerns was the heating system - specifically, electric baseboard heat. I've been living with gas heat for years - hot water baseboard, forced air in Hartford. I was concerned about comfort, of course, but mostly I'd heard much about the high cost of electric heat.

Now there are many innovative adaptive heat controls out there (the Nest device is particularly interesting, and worth it's own blog post at some point) - but for the most part these low voltage controllers are not designed to work with line level voltage used by electric baseboard heat.

Savings Opportunity #1: Zoned Heat

Balancing the cost of electricity, electric heat brings one big benefit - it's inherently zoned. Which means, instead of one thermostat for the whole residence, or perhaps two (upstairs / downstairs), most electric baseboard heaters have independent heat controls, called thermostats. My space (a small condo) for instance, has seven thermostats: living room, kitchen, master bedroom, spare bedroom, two bathrooms, and the basement. So there is a lot of possibility for fine tuning the heat - to heat just the spaces I commonly use, and perhaps save some money.

Savings opportunities include turning down the heat, and closing off unused or little used spaces, and  turning heat down in the bedrooms during the day, and other living spaces at night.

Savings Opportunity #2: Install Digital Thermostats

When I moved in, all of the thermostats in the place were old-school electro-mechanical devices. There was no visible temperature reading or feedback, the rotary dial was exceptionally coarse (with a resolution of 10ºF) , the calibration was highly suspect, and the heat control was simply ON / OFF. If the temperature dropped below a set point, the device turned on 100%, the space heated, and the device eventually turned off.

Such a system is prone to "heat creep" - with the resident feeling a little cold and turning up the heat without a lot of thought to what the actual temperature is (and then acclimating to the higher temperature), and without a good reference to turn heat up or down consistently.

So the first step in saving money is to install a Digital Thermostat. Such devices are available at home improvement stores for about $25 each. Make sure you purchase thermostats intended for line voltage (120/240 VAC) as opposed to low voltage devices intended for oil / gas furnaces.

An aphorism I picked up in the corporate quality world was "If you measure something, it gets better" and the digital thermostats have a thermometer on them providing immediate feedback to the resident. So instead of simply "feeling cold", the resident can look and see the actual temperature. It's amazing how much things like health / energy / activity, as well as the ambient humidity and outdoor light level, affects a person's perception of temperature. So with a digital thermostat, the resident can now see that the room temp is 65ºF (or whatever the comfort level is) and put on a sweater or sweatshirt rather than nudge it up a bit.

In addition, the digital thermostats have a much finer resolution (1ºF) which means even if the resident decides to warm it up a bit, s/he can restrict that to a few degrees. Finally, the digital thermostats use proportionate triac controls - which means that the heat is not simply ON / OFF, but might have four settings: ON / LOW / MEDIUM / HIGH. As the temperature drops, the heat turns on LOW - and if that's enough to warm the space, it never gets past that. So the heat control is more subtle / even and therefore more comfortable.

The electrical installation is fairly simple - comparable to changing a light switch. The only complexity is that the older thermostats are DPST (Double Pole, Single Throw) - which is to say they break both lines (in many cases, the baseboard uses 240 VAC with two hot lines). The digital device is SPST (Single Pole, Single Throw) - so one of the baseboard lines needs to be connected directly.

Savings Opportunity #3: Install Programmable Thermostats

Now, simply adding digital thermostats still leaves a lot of room for energy waste - if the resident neglects or forgets to turn the thermostats down at night or during unoccupied periods. In addition, turning the thermostats down at night means waking to a cold home. the next step is to add programmable thermostats to key areas: the living room, the master bedroom, the basement. This device is a bit more expensive: $50 at home improvement stores.

It has the same general functions as the digital thermostat, but adds a programmable function. The device shown in the photo permits four different timed settings per day (typically WAKE / LEAVE / RETURN / SLEEP) and can be programmed differently for weekdays (Mon-Fri) and weekends (Sat-Sun).

An example of heat programming: 
  • Drop the house down to 58ºF at night; some folks like a cool house to sleep
  • Prior to normal wake-up time, heat the house up to 65ºF or a comfortable temperature. 
  • During the day, drop things down to 62ºF (if at work or out of the house). 
  • Increase heat to 65ºF in the late afternoon for the remainder of the evening. 
One of the benefits of a programmable thermostat is that if the resident wants it a little warmer, or happen to be hanging in the living spaces during the day, they can bump the thermostat up confident that it will reset at the next timed change, and not leave the house warm indefinitely.

One downside of programmable thermostats is the need to program the thermostats and maintain the clocks (daylight savings time). The Wikipedia article cited above in fact notes: 
Difficulty with usability in residential environments appears to lead to lack of persistence of energy savings in homes...In addition to potential increased energy consumption, digital programmable thermostats have been criticised for their poor usability. 
But if one is committed to energy (and cost) savings and thoughtful about programming these devices, they can provide real savings. Hopefully, in the future, "smart devices" (such as the Nest device designed for low voltage systems)  that communicate and self adapt to resident patterns and habits will eliminate the need to manually program devices in the future.

Additional Savings: Cleaning Electric Baseboards, Positioning Furniture

In addition to thermostat upgrades, cleaning baseboards periodically will help to improve airflow - even a thin layer of dust will impede the convection flow such devices rely on. In addition, keeping space in front of such devices will prevent hot spots and permit even heating - consider using bricks or pieces of wood to space furniture away from heating units and permit greater air flow.

Wrapping an Electrical Power Cable

This one is a little obscure - but a great place to start. Anyone working with electrical power should learn the best way to wrap a power cord or cable - called the Over / Under Wrapping Method. Whether you use your electrical cords for outdoor equipment, holiday lighting, or home improvement, wrapping a cable properly can save time when it comes to use the cable, and add years to the cable or cord life.

If you want to get away from the coiled cable look (even after you've unwrapped your cable!), and you want to be able to unwrap your cables fast, and want your cables to store without added tension (just say NO to the carpenter's elbow wrap!), then try the following method. It's a little difficult to explain, and may take some practice, but once you have it down you can wrap cables faster AND better than ever before - by the way, this is the method most professional roadies use. 

Proper Cable Wrapping /  Sweetwater.com

A few comments about this video:

First, "...they'll just wrap it up like it's an electrical cord...". In reality, electrical cords get just as tangled, twisted, and damaged as video and audio cables without proper wrapping and stowing.

Second, the demonstration here is fine for smaller cables (audio or video), and shorter lengths. But for longer and/or larger cables, you will probably need to make a larger diameter loop, and rather than pulling back an arm's length (as shown) take a full two wingspan across the body and two arms. The over / under technique still works.

I learned this skill working in the video production field. I always assumed it had naval origins (seems to be the best way to wrap a line for quick and twist-free deployment, and sure enough, it's known as faking a line in those circles) But you can learn it as well.

New Beginnings

My name is Jude. I'm a long time blogger (since 2001) and a longer time electrical engineer (since 1983). I've been working in the field of electrical power quality for my entire career. And while I mostly work with higher power systems (480 VAC / 3 Phase / 200 KVA and up), I've done my share of work with lower power systems for offices, smaller facilities, and residences.

I've decided to start a blog focusing on electrical power and energy for residential and small commercial users - relying on half a lifetime of work in this field, and consolidating, integrating and updating documents, posts, and other material I've written and/or published over the past 30 years.

While the focus and scope of this site will, by its nature, evolve and change over time, I'm hoping to cast a wide net to bring in a variety of subjects of interest:
  • Electrical basics
  • Measuring equipment
  • Energy savings
  • Electrical power quality
  • Lighting
  • Green power
  • Back-up power systems
  • Vehicle power interface
  • Renewable power
I'll be spotlighting companies, products, residences, and industry trends.

Your participation and comments are welcomed - I'm happy to entertain suggestions for topics, products, or issues!