Friday, January 12, 2018

Line Level Thermostats: Smart, Connected

Back in September 2014 I put together a blog post about how to save money when using electric baseboard heat, commonly found in condos and smaller residences, or locations not easily served by natural gas, propane or heating oil.

At that time, there were three primary options:
  • Analog, mechanical thermostats
  • Digital, electronic thermostats
  • Timer based smart thermostats (~$50 these days)
Over time, I've upgraded my residence to include four smart thermostats - bedroom, living room, yoga room, and basement office. And I could probably use one in the kitchen. They have been pretty reliable and useful; when I occasionally turn the heat up for comfort, they come back down to more economical settings at the next time change. The heat goes down to 58F at night, warms up to 65F in the morning before my wake time, and drops down to 62F during the day (when I am typically in the basement working or out of the house). A spare room I use for yoga practice is closed off and kept at 55F unless I'm practicing (~85F) and the thermostat resets if I forget to lower the temp when I'm finished. A little bit of hassle changing the time in the spring and fall, but not a big deal.

With the Consumer Electronic Show going on in Las Vegas this week, I thought it might be a good opportunity to poke around and see what's out there in terms of smart thermostats for line level applications. Here's what I've found:
I'm not at the point of purchasing yet - looking at ~$500 to swap out all the thermostats I'd like to be programmable. But if I were buying right now, I'd go with the Stelpro device - seems to be the most mature technology, works with a lot of smart / programmable house systems. 

Thursday, October 26, 2017

The Short (and Personal) History of Light Bulbs

Once upon a time, light bulbs were pretty simple. You picked a wattage: 40 / 60 / 75 / 100. You picked a brand: GE or Philips or Westinghouse or something generic. There would be some tweaking around the edges (light color, minor increases in efficiency, bulb shape) but pretty much a light bulb was a light bulb. If you got fancy, there were three way bulbs 30 / 70 / 100 or 50 / 100 / 150. And there were some odd shapes and sizes for ceiling fans, chandeliers, wall sconces, etc.

I recently gathered up all the loose bulbs kicking around. I've got a small box of incandescent bulbs - dregs from a much earlier time; replacement units that never quite found their way into a socket. Many of these were installed and replaced (by CFLs or LEDs) others were spares never installed. I confess that, long after CFLs were dominant, I would opt for an incandescent bulb in a few places where I valued the "instant on" ability, dimmability, or the warmer lamp color. And I've got some clear globular lamps that were bathroom vanity lighting for many years.

I've also got a much bigger stash of CFL bulbs. These were much more finicky - I'd buy bulbs that took too long to warm up, bulbs that were slightly different colors, bulbs that were slightly smaller or larger or enclosed. Over time, I replaced most of the bulbs in my home with CFLs, and over time, most of those got swapped out for more efficient and friendlier LED bulbs - I've really enjoyed watching LED technology come into the marketplace, prices to drop, features to improve. Since the CFLs did indeed last longer than incandescent bulbs, there were a lot fewer opportunities to swap them out organically.

So now I've got a bin full of bulbs. I'm too much of a yankee to throw them out  - perhaps envisioning an end-times scenario when older technology bulbs might come in handy. Been interesting to watch this particular bit of technology shift and change over my lifetime.

Saturday, April 29, 2017

Draining a Dehumidifier

Documenting my little "never want to empty that dehumudifier bucket again" project.

(A) Bought a small drain hose ($7, Loew's) which screws onto the dehumidifier drain, directing extracted water into

(B) The reservoir of the sump pump (Little Giant model VCMA-20ULT, $45 online including shipping and handling). When reservoir is sufficiently full, the pump turns on, sending water through a check-valve into

(C) 3/8" plastic tube, which I've run up the wall, into the ceiling, and down to the

(D) washing machine drain, where it empties. The pump turns off when its reservoir is empty, and the check valve keeps the water from flowing back into the pump reservoir.

The only improvements I might make are:

(1) Place a shallow plastic tray or container under the dehumidifier and sump pump in case of some sort of failure or loose fitting. Just an extra level of safety....

(2) Run the drain into a large container with a tap or faucet (like a water cooler) which I could then recycle for houseplants / grey water. Although I'd have to be sure that did not overflow.....

The pump is very quiet, I almost never catch it working, especially compared to the relatively loud dehumidifier. I also have purchased a high current receptacle timer, designed especially for motor drive appliances, to cycle the dehumidifier (on at night, off during the day) if the cycling starts to bug me.

The Model VCMA-20ULT is perhaps a bit overkill (20' Head, 1.3 Gals/min) for my application, but there was not much difference in price between this and the next size down, so I thought it best to be conservative.

Thursday, January 26, 2017

High Temperature Thermostat

One of my side jobs is doing facility support for my local yoga studio. They have some unique HVAC requirements - specifically thermostats that have higher than normal set-points.

Most commercial thermostats go up to 90°F or 94°F maximum. I was able to find one thermostat - the Jackson Systems Model T-32-P which can be programmed up to 122°F heating set-point.

It actually seems to be a very versatile device, with a ton of flexibility for many different systems:
  • Up to 3H/2C conventional and heat pump systems
  • 7 day programmable
  • Large backlit display
  • Auto or manual changeover
  • Keypad and/or setpoint lockout
  • Smart fan logic for commercial control
  • Adaptive recovery
  • Optional indoor sensor (T-32-S1 or TS-32-S2) or outdoor sensor (T-32-OTS)
  • Outdoor temperature display with optional outdoor sensor (T-32-OTS)
  • Available with integrated Modbus communications (Version 2.20)
We've got three of these installed right now - two in a large studio (forced air and baseboards, both heat only, and programmed for automatic warm up and night settings) and one in a small studio (heat / cool / forced air, no programming) and all are working great. 

Thursday, June 25, 2015

Summer Peak Savings

EnergizeCT, the energy saving arm of Eversource, has an interesting web page devoted to reducing peak demand: CT Power Update: Demand / Air Quality - with a tool that maps forecasted and actual demand.

My suspicion is that, as smart metering rolls out, utilities such as Eversource will begin to pro-rate energy based on time of use (peak / off-peak) and perhaps even ding consumers for peak demand and/or low power factor, as they do commercial and industrial clients.

On the same page, they are also promoting a "Wait Until 8" program to encourage consumers from running major appliances during peak demand hours (12 noon - 8 pm). Things like dishwashers, clothes dryers, swimming pool pumps, etc. that could be run more consciously.  

Friday, May 1, 2015

Tesla Energy: Powerwall Home Battery

The internet (and public radio, for that matter) is abuzz with the launch of the Powerwall Home Battery, by Tesla Energy. 

Link through to read the details, but here are some highlights:
  • Applications include load shifting, decreasing need to sell solar power back to utility, and back-up power. 
  • Two primary capacity ratings, 7 kWh (daily use applications, $3000) and 10 kWh (back-up applications, $3500)
  • Does not include inverter. 
  • Ten year warranty.
Sorry, Elon Musk, but I need to rain on your parade. As the owner of a small condo (1200 square feet, including the basement, which is finished as my office) that has electric everything (heat, hot water, dryer, stove and oven), and as an electrical engineer concerned with energy efficiency, I happen to monitor my home energy use. I'm not a spendthrift - I've converted all the thermostats to digital / timer, all my lights are CF or LED, I keep the heat at 65F when I'm around and 58F overnight or when I'm out.

In February this year (admittedly brutally cold), I used an average of 175 kW-Hr per day.

 April (not quite warmed up, but more typical of a regular month), it fell to 60 kW-Hr per day.

So tell me just how useful your 7 or 10 kW-Hr worth of battery is going to be for me?

Yes, if one is burning fossil fuel for heat, cooking, clothes drying, hot water, has a modern energy efficient home, then I imagine 10kW-Hr could give you close to a days worth of power, if you don't dry your hair, turn on the A/C, or switch on a space heater. And it seems to be that if the bulk of home energy use is still coming from fossil fuels (to run a home for 12 hours on 10 kW-Hr, that seems to be a prerequisite) we're not really that revolutionary.

Edit: And because this has been sticking in my craw for a day or so, I did some additional digging.  According to the US Energy Information Administration:

In 2013, the average annual electricity consumption for a U.S. residential utility customer was 10,908 kilowatthours (kWh), an average of 909 kWh per month. Louisiana had the highest annual consumption at 15,270 kWh, and Hawaii had the lowest at 6,176 kWh.
909 kW / month = 30 kWh / day. And with most of the USA averaging 4-5 hours of peak solar production, (let's call it 8 hours of solar power), our "back-up" is going to need to supply at least 16 hours, or 20 kWh of demand. Twice the Tesla device capacity.

This is not rocket science (oops, bad analogy, I'm a big fan of Space-X). Folks have been using battery back-up in UPS (Uninterruptible Power Supplies) for decades for critical applications (computers, networks, patient care, etc.) - in much higher power ratings. But truth be told, it's really not all that cost-effective, most applications switch to some other form of energy storage for extended outages. Perhaps there's a mechanical solution (magnetic bearing flywheel? compressed fluid?), a thermal one (some form of heat engine), a chemical one (fuel cell), or something else. 

I like what you are trying to do. But it's sad that in all the interviews I've heard and stories I've read today, nobody has really done the math. 10 kW-Hr is not nearly enough capacity to take a typical home off the grid, even on a sunny day.

Tuesday, February 24, 2015

Follow-up: Bait and Switch - Electric Supplier Edition

Lawmakers Seek To Ban Variable Rate Electricity Contracts

Lawmakers signaled Tuesday they would revisit the controversial third-party electricity supplier market and seek to ban variable rates in residential electricity contracts.

It will be the second consecutive year the legislature aims to address consumer complaints about third-party suppliers, who they say attract customers with deceptively low teaser rates that quickly expire and leave consumers open to paying variable rates well above the standard rate available from a utility company.

Hugh McQuaid | Feb 24, 2015 3:44pm

Thanks to CT News Junkie for keeping on top of this!