The Micro-controlled Green Home (warning: A bit "preachy")

[crashsite]

The construction trade tends to be "brick and morter" thinkers. Making a home "greener" means adding more insulation, hanging thermal, double-paned windows and plugging up air leaks. Those are important steps but, hardly the only ones that are practical in this day and age.

Enter the computer. The computer is certainly one way to monitor and control household processes (heating, cooling, hot water, water usage, venting, lighting, etc.) and it's very disappointing to me that they are not in much greater usage in this capacity.

The computer has a stigma. Even at its most benign a computer is a fairly imposing entity in a house (welcome by some but, shunned by most). The problem is that the computer represents "technology" and most people hate dealing with technology (as technology). Give them a complex personal problem on a soap opera and they'll follow the story line to their grave but, mention a "kilowatt-hour" and their minds instantly go off to la-la land. I understand completely because I have no desire to embroil myself in the lives of fictional characters on TV but, love the technology (the yin and yang of the medium?)

GPS, in cars, is another example. People hate maps. for the most part people don't grasp the notion that a map is just a scaled down version of the real world (the fact that it's "scaled" and thus represents mathematics is enough to stymie them). Until car GPS gave spoken, "Turn left here" directions, it was only for the few. People here probably have a tough time grasping that but, I'm sure some (prhaps most) of you likely have moms that love having their children into technology but shun it themselves.

However, people don't mind using technology so long as it's "disguised" so it doesn't seem like technology. You and I know that when the "popcorn" button is pressed on a microwave oven, a whole series of very technical things happen. They include, quite likely, a microprocessor and its support, display electronics, interlocks, a power supply and a high-power magnatron RF oscillator beaming into a cavity with "stirring vanes" evening out the RF propagation.

If the average microwave oven user had to do just one more step to pop the corn, a LOT less corn would get popped in this world.

So, what does this all lead up to? Simply that the "green" home needs to also cater to the techno-phobic or the green features made possible by technology simply wont be utilized. That's where peope like you (who will read posts in the microcontroller threads) come in. You see, the question isn't how to implement the technology in the average family home (that's really pretty basic and easy) but, rather it's how to implement it in such a way as to get used effectively.

There are things that even the most techno-phobic people understand and respond to. One is money. You don't show people the number of kWh used each month in a graphical format, as may electric companies print on their bills. You give people a way to see how much different devices are costing them...in real time...while they can do something about it. Let's stick to electricity here just to keep things compact and simple.

If a person has a display that shows that the furnace is costing them $1.37 per hour and that it's been cycling enough over the past couple of days to run up $11.45 onto their bill (with some real suggestions for savings based on ongoing computer analysis of their exact configuration and prevailing weather conditions), I believe that person will work with it to lower the cost. You just never ever mention the words, kilowatt or hours!!!

Same with the water heater and water flow meter and air conditioner and electric range and lighting and power draw from the electrical recepticles. Show where the costs are and suggestions for how to live well and comfortable while addressing the real energy hogs rather than running around the house turning off light switches (like my dad used to do) while letting the high amperage devices run rampant.

As programmers (both computer and PIC) you guys here are in a position to develop the hardware, firmware and software interfaces to "green up" homes in useful and practical ways that will get those results that are needed.

So, why am I not I doing this? Easy to answer. I'm into "electronics" not having meaningful and thought-provoking dialogs with some damn infernal computing machines! In other words, I aint no programmer.

There's certainly a lot more that can be said on the subject but, you get the gist of it I'm sure. And, yes...I questioned whether this should go in this area or the "alternative energy posts" and decided this one was more apropos. I wont be offended if the prevailing opinion is that it's too generalized and not "microcontroller process" oriented enough and gets removed.

 

[blueroomelectronics]

Nicely put, I feel the green home needs a low power brain. My next kit (Ladybug Ethernet PLC) and upcoming kit (Cricket communicating thermostat) were designed with home HVAC and automation in mind. Other great home tech might be XBee (or MiWi) and mains coupled Ethernet clients.

You don't need a power hungry Pentium running day & night.

 

[crashsite]

The Practice Behind the Theory

I feel the green home needs a low power brain. My next kit (Ladybug Ethernet PLC) and upcoming kit (Cricket communicating thermostat) were designed with home HVAC and automation in mind. Other great home tech might be XBee (or MiWi) and mains coupled Ethernet clients.

Oops, bad news. MUCH too complex already! Great ideas for the techno-nerd but, completely irrelavent to the techno-phob.

I think this needs three things. The first is "Bill Gatesian" thinking. To see not just the technical possibilities but, the mode and method to propagate it for profit. Some Gates type will do this and the rest (including me) will sit back and complain about how only the rich get to make big money. Gates didn't write DOS but, he did see the business potential and had the vision and stamina to buy it and see it through. Are there any Bill Gateses here?

The second thing needed (here's where you Bill Gateses can leap to the breach) is to write the user interface. The idea is simple enough and the technology is simple enough. The user interface is "tricky" but, really also simple enough.

How's this for simple? In addition to the antenna/cable/satellite connection for the home TV set, there's a special channel allocated for the house. The user can use his/her remote control to select the "house channel" (note to self: Get remotes for major manufacturers' TVs designed to provide this function). The TV display will show two main things. First is the costs of each resource (including, if used, power sources that return power to the electric grid) in both real-time and over selectable time periods. Second is a red/yellow/green system to show current usage relative to possible usage with suggestions for getting to "green". That's it. If that sounds simple....it really is.

Beyond the TV remote, the system has to be completely transparent to the homeowner.

The third, and most involved, component is the integrated control and monitor system. Tracking weather (ambient temperature, roof and siding temperature, sunlight, wind, rain, clouds, etc.), household device usage, door/window status, heat flow throughout the house, foundation vent status, and so on. In other words, measure everything that is associated with energy in or out. Then, create an ongoing database to calculate the optimums so they can be charted (simple red/yellow/green indicator with NO numbers) with the suggestions (also simple and direct).

More Gatesian thinking: How do you retrofit existing houses? How do you prompt government to provide incentives for these retrofits? How do you break into the archaic thinking of the construction industry and get the codes updated to require a green system (your system if possible...much as computers use Gates' Windows system for the most part) in all new home construction.

Hey, I didn't say it would be easy to actually implement. I just said that, conceptually, it's really simple.

I reiterate: Somebody's gonna do it. Further, I believe it will be someone like yourself rather than some big conglomerate. But even if you are NOT the next Gates, if you develop the software and package it attractively, perhaps the next Gates will buy up your software and hardware license for $50,000 and go on to make his (or her) billions.

Let's say you and perhaps others on here work out the chipset and code to implement this and nothing comes of it? What have you lost? Nothing. What have you gained? Pretty much what you expect to gain by being here reading these posts right now, anyway. I would be interested to see what people might come up with and, as you can see, would be a harsh and heartless critic (with the added benefit that I'm much too lazy to try to steal your ideas and make a billion with them).

Finally, I must plead, "guilty" as my pentium (including a ton of peripherals) runs pretty much 24/7/365 (except leap years where it's 366).....

 

[August Treubig]

Gates - New is always Best

Bill wouldn't want a retrofit. He would always want to sell you a new "Vista" house. The 7 year old "XP" house would be no good. You would also probably need a new car because the old one wouldn't fit in the "Vista" garage.

Tongue in Cheek!

 

[mrmonteith]

I would suggest individual controllers on each item. Many today do that now but too crude. Like a hot water heater. Ours has a crude controller on it. But if you had one that watched when and how you consumed and told you that if you geared most of your daily usage at the same general time of day it could turn off for the rest to save energy. This way you're not trying to program a central unit to control everything. Just use it to report suggestions, etc.

There's lots of room in everything in the home to make them more efficient. Even the blower fan on furnances use too much current during startup. But I haven't seen any moves in the direction of fixing that. The technology is there. Just not implemented.

Michael

 

[blueroomelectronics]

A ENC28J60 web server is a small low power device like the one pictured below. With decent firmware it can dish out a webpage or two that allow you to control devices connected to it and it would be very similar to setting up a typical router.
**broken link removed**

 

[crashsite]

Like a hot water heater. Ours has a crude controller on it. But if you had one that watched when and how you consumed and told you that if you geared most of your daily usage at the same general time of day it could turn off for the rest to save energy. This way you're not trying to program a central unit to control everything. Just use it to report suggestions, etc.

Wow, don't get me started on water heaters. That's one of my pet peeves and for exactly the reasons you cite. To me it's unconcionable that, in the 21st century water heaters still use a "deaf and dumb" thermal/mechanical switch. At minimum it should be tied to the phone line so it can be off while noone is home and then be able to call and cycle it an hour or so before you arrive...whatever time that may be.

 

[crashsite]

Component Parts

A ENC28J60 web server is a small low power device like the one pictured below. With decent firmware it can dish out a webpage or two that allow you to control devices connected to it and it would be very similar to setting up a typical router.

Of course, such a component part would likely be a part of a "green" house. More so if there is a requirement to remotely control and monitor it. Something simpler could probably be used if all the C&M is done locally within the house. There are boundless ways a system could be implemented so there's no sense in muddling the waters at this phase with possibilities.

Since the easiest thing to control and monitor with electronic controllers is electricity and electrical devices, it makes sense that one would start with that. Have you considered current measuring loops tied to a multiplexer as a kit? Like the clamp-on ammeters. Since there's no "copper" connection to the wires, I think you could get around a lot of the electrical code issues.

 

[blueroomelectronics]

Simple is not necessarily smart, you want something to dial into so you have to have some form of hardware brain. A modern microcontroller does not cost that much and is far more flexible than a simple multiplexer. A smart system would tie all those sensors together and actually be able to report on any anomalies. Such as your furnace is running but the house is taking a long time to heat up, if your alarm system was hooked in it could see if any windows or doors were open and send a message to your cell phone or TV. Also if your alarm system is on it could automatically drop the temperature in your home to save money.
Additionally a zoned HVAC system (normally expensive) could be afforded by the average homeowner all controlled by a central brain. It's done now but is very expensive see Crestron.
I'm actively working on making this sort of thing into a series of kits, I thing the bright minds out there can build a better thermostat. Your thermostat is the heart of your HVAC but typical thermostats are really limited to what they know about their environment. Imagine a thermostat that could see the local weather, geography, etc...

 

[bryan1]

Hi Guy's,
Just to put some light on our idea of a green home. So far the only automation we have if the batteries drop to 24 volts an alarm goes off, ignore it when the batteries drop to 23 volts the power cuts off. Now I found our ammonuim absorbant fridge was using too much lpg and running the resistive heating element wasn't an option I simply put in a 75 watt globe and now my fridge only uses the RE bank @ 75 watts to keep our fridge/freezer dead cold ( infact it's just turned on or the fridge becomes a freezer). As far a water goes we are on rainwater (no mains) and in the near 5 years on the farm we've never had to buyin water. Last week my wife offered our daughter a glass of town water where she spat it out and said I'm not drinking that ( @ 3yrs old not bad). As far as heating/cooling goes we have an abundance of firewood around the farm and on hot days we put on the modiefied water cooler I made that uses 24 volt DC fans directly off a seperate batterybank. So in the height of summer when the townies are sweltering due to the power going off we're sitting back watching the cricket in a cool house.

Why in the world do you need a web based gizmo to tell you your living way over what the earth can handle ( on the mass scale) when by simply embrassing R.E. power on a full time basis a green home your well over 1/2 way there.

 

[mneary]

Water heater? Maybe you just have the wrong one. There are tankless heaters that are completely off until there is water flow. They cost about 3X the tank type, but you get your money back in a few years. Still, a lot cheaper than a solar setup.

 

[futz]

Water heater? Maybe you just have the wrong one. There are tankless heaters that are completely off until there is water flow. They cost about 3X the tank type, but you get your money back in a few years. Still, a lot cheaper than a solar setup.

Like these **broken link removed** that I sometimes install. Nice units.

 

[crashsite]

Distribution of Power and Authority

Simple is not necessarily smart, you want something to dial into so you have to have some form of hardware brain.

There's certainly nothing wrong with a centralized processor to do the high-falutin' book larnin' stuff but, I think it's a better solution to use peripheral devices for doing the grunt work of sensing and then sending the data, in a standardized format, to the smart one.

The modern car is a good example. New cars are a pain to work on and often require special equipment and plug-ins just for basic troubleshooting. Even older cars have always been s.o.b.s to add electrical stuff to or to troubleshoot within wiring harnesses. The manufacturers just don't think about after-market. I actually saw a TV ad just a couple of years ago where they were bragging that they now have a jack on the radio for an MP3 player! It's pissed me off for the past 40+ years that car radios don't have an external input jack.

In other words, don't integrate to the point that you can't break into the system later. The brains should have clearly defined functions that can be expanded (only if desired) without requiring system re-design (note the problems that had to be addressed to add color to B&W TV and stereo to mono broadcasts (both AM and FM) to keep them compatable with the old version. Initial thinking on a green house MUST address the issues of advancements in technology and how homeowners interface with it.

One way to do that is to modularize, not integrate further. Keep the sensors and the brains as separate entities. Keep the brains as loosely tied to the software as possible so that software changes and upgrades can be done easily without affecting everything else.

It's virtually certain that whatever interface that someone who has the skills to make such an interface comes up with will have problems. People wont understand the simple elegance of it (as envisioned by the techno-nerd, anyway) and probably many iterations will be needed to come up with the right mix that people can respond to and use. The initial green house thinking has to address this issue and design to provide the flexability.

Your whole "kit concept" should lend itself well to modularization but, to do that requires the right selection of modules and interface specifications. I believe that one module should be a multi-input current transformer multiplexer that then feeds it's data to the brains (along with all the other peripheral sensors).

Even the IDE concept for hard drives (keep the peripherals smart so as to free up the CPU for more pressing tasks) is questionable in this application. If the processor is (as you say, a simple, dedicated device) that monitors only the house functions and act theron, speed and big CPU loads are just not an issue. Simplicity, reliability, expandability and versatility need to take priority.

 

[crashsite]

"I Am a Lumberjack and That's Okay..."

Why in the world do you need a web based gizmo to tell you your living way over what the earth can handle ( on the mass scale) when by simply embrassing R.E. power on a full time basis a green home your well over 1/2 way there.

Well.....there are a number of flies in your ointment.....

Living off the land is hard work, fighting the forces of nature for each resource, mano-a-mano. You obviously just thrive on it. The rest of us are much too lazy to put in that sort of dedication and effort. Fortunately! In a world of farmers the technology needed for large scale farming doesn't need to get developed as there's no city folk that need to be fed...and, all that entails (no industrialization and capitalistic competition driving technology, etc.).

You can't go back 100 years and say, okay...this was just a practice run. Now, let's start over and do it green. We must start from here and now. It's just too bad that even in the absolute opulence of technology we've enjoyed for at least the past 75 years that we are even having the "green" discussion when it comes to homes.

Some probably envy you your "Amish" (okay, techno-amish) life. Not me! I live in rural America (in the middle of Oregon) and do use wood (only occasionally my electric furnace) and that's Paul Bunyan enough for me.

 

[crashsite]

Water heater? Maybe you just have the wrong one. There are tankless heaters that are completely off until there is water flow. They cost about 3X the tank type, but you get your money back in a few years. Still, a lot cheaper than a solar setup.

I've given some thought to water heaters over the years (peope do tend to obsess over their peeves, eh?). The tankless version has been around for quite a long time but, is still not in common use. I'm not sure why. Why isn't it commonly used in new construction? There must be some reason and if substantial energy costs offset the initial cost, it can't be a "selling feature" (especially in a new home where this cost is small compared to the overall house/land)

As new (or even as a retrofit) I've always liked the multitank idea. To put small (one or two gallon) tanks at the tap locations (kitchen, bathrooms, laundry room, etc.) with a thermal switch. That would give pretty much instant hot water and then, as the cold "hot" water comes through the pipes it refills the small tank. As the hot water from the main tank trips the switch, the main tank water comes out the tap.

I also believe there are methods for "purging" the hot water from the pipe and returning it to the master tank so the heat is not lost between hot water uses. But, it's a rather nasty, compex system that might be more trouble than it's worth (involves an extra tank and electric pumps).

The nice thing about the distributed tank option is that it's easy to retrofit into existing homes. If you have room to put a couple of extra one gallon bleach bottles under a sink, there's enough room. A 115 V system is adequate for such small tanks and up to about 10 gallon, under-sink tanks often use this power.

 

[kchriste]

The tankless version has been around for quite a long time but, is still not in common use. I'm not sure why.

You'd need to upgrade your electrical to at least 200A service or have natural gas plumbed in to use those instant water heaters. They require a large amount of energy for a short period of time. Plus they won't handle multiple taps drawing hot water at the same time very well so if two people want to shower at once in the morning and the dishwasher is running you'll probably need more than one unit.

As new (or even as a retrofit) I've always liked the multitank idea.

Not a bad idea as long as you have the extra space. The problem will be the increased maintenance costs; now you're replacing 3 or more tanks every 15yrs or so instead of one. What does that do for the environment?
It's better to build smarter and lay out the house so all the bathrooms, kitchen are close together and the tank is placed near the middle of all of them. The tanks should be better insulated and have a programmable timer built in so the heater only enabled when it is needed.

 

[futz]

You'd need to upgrade your electrical to at least 200A service or have natural gas plumbed in to use those instant water heaters. They require a large amount of energy for a short period of time. Plus they won't handle multiple taps drawing hot water at the same time very well so if two people want to shower at once in the morning and the dishwasher is running you'll probably need more than one unit.

The mid size Rinnai that gets sold most commonly will handle two showerheads full blast and then some with no problem. As you say, they do eat lots of energy at peak load. The beauty of them is that they eat zero energy the rest of the time, unlike a storage tank.

I can't imagine an electric on-demand water heater ever becoming popular. The amp draw would have to be pretty huge. NG is so much simpler.

 

[crashsite]

Tanks for the Memories

I can't imagine an electric on-demand water heater ever becoming popular. The amp draw would have to be pretty huge. NG is so much simpler.

Water heaters are sort off the topic but, as long as the thrust is "green" I suppose not too bad.

Speaking of taps, let me tap into your expertise with tankless heaters. I can envision a long calrod running through the center of a water pipe to quickly heat the water (even so, the calrods in your electric oven, even in free air, take some time to heat up). But, even assuming that "instant" hot water means "less delay" and a less abrupt cold-to-hot transition, the direct nature of the heating element to water interface makes sense.

However, can natural gas come on and overcome the thermal inertia of the pipe and its own flame containment system to heat the water all that quickly? On a cold, winter day (when the water is extra cold) how long does it actaully take to have fully hot water from a tap?

As an interesting side note, I was in Thule Greenland for a couple of weeks back in the mid 90s (Northstar Hotel) and the showers (presumably Danish design) actually had a temperature scale on the tap handle. It seemed to be pretty effective (although I didn't have a way to test how accurate). Is there something similar on the "on demand" water heaters to even out the temperature?

 

[futz]

I can envision a long calrod running through the center of a water pipe to quickly heat the water (even so, the calrods in your electric oven, even in free air, take some time to heat up). But, even assuming that "instant" hot water means "less delay" and a less abrupt cold-to-hot transition, the direct nature of the heating element to water interface makes sense.

1. I don't know what a calrod is.
2. I only assume someone, somewhere makes an on-demand electric water heater. I've never seen or heard of such a beast (though I've installed big electric booster heaters for restaurant dishwashers). I've only seen natural gas and propane ones.

However, can natural gas come on and overcome the thermal inertia of the pipe and its own flame containment system to heat the water all that quickly?

YES. And they're surprisingly compact. The water flows through a heat exchanger in the flame. The heater has a water flow sensor that modulates the flame size depending on the amount of flow. Provided you don't exceed the heater's flow capacity you can expect ice cold inlet water to come out the other end at approximately 140F. Once you exceed the heater's flow capacity the outlet temp will be lower.

On a cold, winter day (when the water is extra cold) how long does it actually take to have fully hot water from a tap?

Only as long as it takes the water to get from the outlet of the water heater to the faucet. Well of course there's some small loss to warm up the pipe, but that's the same no matter how you heat the water.

As an interesting side note, I was in Thule Greenland for a couple of weeks back in the mid 90s (Northstar Hotel) and the showers (presumably Danish design) actually had a temperature scale on the tap handle. It seemed to be pretty effective (although I didn't have a way to test how accurate).

Were they Danfoss faucets (Danish company)? I seem to vaguely remember that they used to make tub/shower valves - they don't anymore as far as I know. But their hydronic controls are top notch. Nice stuff.

Pretty much every faucet manufacturer has at least one model that is thermostatically controlled. Most don't bother to give you an actual temp dial. Usually you set it by feel. Set the temp you like and from then on you can just turn the water on and it tries to keep the output at that temperature.

Is there something similar on the "on demand" water heaters to even out the temperature?

Not the same thing at all, but on-demand heaters use modulating burner controls to adjust to load. At low flow the burner will only make a small flame but at higher flows it opens up more and more till it runs full blast at max flow.

 

[crashsite]

Spare the Calrod, Spoil the...uhm...not sure.

1. I don't know what a calrod is.

A calrod is just a resistance rod (such as an oven element). I think it was probably a brand name at one time and got into general usage like the Bandaid or Skilsaw. I've heard (but, don't know) that it's short for "caloric rod".

Thanks for the info. Very detailed, well presented and useful.

No, I don't recall the brand name of the shower faucet at the North Star. I just remember thinking...hey, neat...wonder why we don't have them in the US.