Alternative Systems and Smart Houses

Electricity is a uniquely flexible form of energy, and uses for electric power continue to expand. This expansion creates a demand for power companies to increase production and add facilities. At the same time economic, political, and environ mental pressures are forcing power companies to restrict expansion or explore alternative ways to produce electricity. For example, many companies already have large solar or photovoltaic systems feeding their AC distribution grid.

On the residential level, energy-saving appliances and lighting systems help reduce overall demand. Many homes now have complete low-voltage systems, either as a backup or as the sole electrical system. Another emerging development is Smart House technology, which combines standard AC wiring, low-voltage wiring, electronic components, and computer-based controls into one integrated system. Although not all of these developments may gain widespread use, some of the systems presented in this section may help you conserve energy, solve unique problems, or assess future options in your long-range planning.

This Smart House load center includes much more than the standard circuit breaker panel on the left. The yellow hybrid cables carry both 120v AC current and low—voltage control messages. The orange cables distribute control communications and 12v DC current for switches, smoke detectors, security systems, and other low-voltage applications. The coaxial network links video, audio, and computer equipment and shares communications cables with a telephone gateway to be installed.

CONSERVATION

Lighting

Incandescent lighting is estimated to consume 25 percent of all the electricity generated in the United States. Ordinary fluorescent lamps produce an estimated 20 percent of the heat load in an office building. Compact fluorescent lamps, on the other hand, manipulate the AC power with electronic controls to yield more light while consuming up to 70 percent less power. Compact fluorescents also produce belier light, almost no heat, very little radiation, and can have a life span 10 times longer than incandescent lamps.

Because one 75-waft incandescent lamp will use a barrel of oil at the generator during its lifetime, with that barrel of oil producing a ton of carbon dioxide during combustion, using compact fluorescents can re duce generating costs and pollution. These savings result not just from lighting demands but because of the greatly reduced cooling demands as well.

In 1991, California announced a program for state buildings to replace over three million incandescent light bulbs, costing 75 cents each, with compact fluorescents costing about $18 apiece. The initial expense, including automatic motion-controlled light switches and other amenities, was $90 million, but the calculated savings in reduced energy use is $765 million over the next five years. The reduction in pollution associated with the reduced consumption is “equivalent to removing 200,000 cars from the state’s highways,” according to then-governor Deukmejian.

Other U.S. studies indicate that if all the incandescent bulbs were replaced with com pact fluorescent lamps tomorrow, 18 nuclear plants could be eliminated the day after.

Heating

Electric “baseboard” heaters are very popular for retrofit installations and additions because they are clean, easy to install, and eliminate the duct work necessary to connect with a central furnace. Most of these heaters are very inefficient and slow to respond, however. New types of electric radiant-panel heaters, long used in Europe, are more efficient, just as clean, and even easier to install; avail able for installation in ceilings and floors, the improved performance over baseboard types is dramatic, and the efficiency documented. Only unfamiliarity with these devices limits their use in the United States, and this is changing.

Appliances

Refrigerators consume about 20 percent of estimated electricity use in the United States. New refrigerators carry a sticker that indicates average annual operating costs. The real costs vary, depending on how the appliance is used and the utility rates in the area, but this information does permit a relative comparison of available choices. Utility rebates are often based on this relative efficiency; you can buy a belier refrigerator, get a larger rebate, and also pay lower operating costs over the life span of the appliance.

Electric water heaters also consume a lot of power and bear relative-consumption stickers. Rebates are available in some areas, but common- sense improvements can also reduce consumption. An insulating blanket around the heater and hot-water-pipe insulation can reduce costs dramatically as well as improve the functioning of the system. These blankets and pipe insulations are an inexpensive, one time purchase. Paying for heat loss suffered without these items continues month after month, year after year. All wasted heat consumes money that needn’t be spent.

Although the relative-cost figures on new appliances are helpful, they are based on aver age rates. Not only will these rates change, they aren't com parable in all geographic areas. In the Northwest United States rates are low compared to the Northeast because of the tremendous hydro-generating capacity and relatively small population in the Northwest. Readers in the high-rate areas have an added incentive to buy the most efficient appliances they can afford and to consider renewable source systems.

Many utilities have rebate programs for home insulation, water-heater blankets, hot-water- pipe insulation, energy efficient appliances, and replacement of incandescent lamps with compact fluorescents. Utility companies are adopting these techniques to reduce costs, loads, pollution, and even the building of new

Energy-Saving Light Bulbs

Compact fluorescent: fluorescent diffuser lamp; fluorescent spot lamp

Panasonic twin-tube capsule

Electric light capsule

BACKUP SYSTEMS

Residential Systems

An emergency backup system for a home is relatively inexpensive insurance in case of disaster, and can be extremely reassuring when the power grid goes out. The system, consisting of a transformer, charge controller, and deep-cycle battery, can be located in the garage, basement, or some other vented location. The only maintenance this setup requires is filling the batteries three or four times a year. It stands ready to supply a 12-volt radio, TV, auxiliary lighting, and a citizens band radio. The whole system currently represents an investment of less than $500, including the radios and a small black-and-white television.

These systems are recommended for homes located in hurricane country, class 4 seismic zones, or other areas prone to natural disasters. There are numerous examples of such backup systems performing flawlessly during the aftermath of the 1989 Loma Prieta earth quake in California. They can be very reassuring to home owners until the grid power and communications are resumed.

Computer Backup Power Supplies

Hospitals, police, and fire stations have long relied on ex pensive automatic generator backup systems in case of grid failure. Generator-fed systems are very noisy and costly to operate and maintain, but were necessary to protect the extremely valuable computer data of these organizations. Now another option has emerged.

A UPS, or uninterruptable power supply, is a battery- based system that automatically produces AC backup power for a computer upon AC grid failure. Many large manufacturers are installing massive UPS systems for protection of computer controls of assembly-line robots, and smaller systems for delicate control components.

Small, packaged UPS systems are also available, consisting of a 12-volt (gel) battery, an inverter to change the 12-volt DC into 120-volt AC, and an off-grid warning light or beeper. The current $500 models will provide approximately a half hour of backup power, enough time to organize and save the work in progress. Readers considering home backup systems can also protect their computers by adding an inverter and warning device to their emergency systems at little additional cost.

Twelve-volt electrical systems are gaining in popularity. Improvements in storage technologies developed for 12-volt renewable systems where there is no AC grid, and systems designed to protect computer data, have made this technology useful for backup systems even in developed areas.

Backup Systems Residential Backup Power

A hard-wired deep-cycle battery backup system in a garage or ventilated basement area.

Computer Backup Power

A gasoline-powered generator and a 50- or 100-foot extension cord provide reliable emergency power.

UPS unit supplies power to computer automatically when house power is interrupted (includes battery, inverter, and warning device)

RENEWABLE SOURCE SYSTEMS

General Considerations

Stand-alone itself is a misnomer. Renewable and AC grid systems may be combined, and some states even have laws that require the local grid utility to pay for any electricity fed from the renewable system to the utility grid. In these states, money spent on more generating capacity and suitable storage is returned after the break- even point, when the utility will send regular payments to the system owner for the excess generated power.

Managing these systems is very simple and takes on aver age less than one hour every couple of months. The only difficult part, changing defective batteries, should occur only once every five to seven years.

System configuration will vary depending on needed capacity, whether 12-volt or 120- volt appliances will be used, and if surplus power can be sold to the utility. Readers interested in renewable systems are referred to the growing number of books on the subject, but a brief description here of components and how they are used reveals a lot of possibilities.

Photovoltaic Panels

Thousands of small cruising vessels as well as the Coast Guard use photovoltaic supplied navigational aids, and the U.S. Geological Survey uses photovoltaic-supplied instruments for earthquake-monitoring devices. The reliability of these photovoltaic systems is impressive.

Photovoltaic technology uses modular panels made of silicon-based materials that turn both direct and indirect sunlight into DC electrical flow. Although photovoltaic panels suffer from both transfer and leak losses, direct sunlight de livers a staggering 100 watts per square foot when it strikes the earth. The group of panels, known as an array, may be mounted on the roof of a house or located away from the dwelling. Panel costs have de creased greatly during the last 10 years, and new materials are likely to continue this trend.

Control Features: Because direct sunlight generates more electricity in a panel than sunlight striking at an angle, passive tracking devices are available. These devices consist of a support post, a rack to mount the panels, and two small pressurized gas bottles.

These bottles are installed on the support post so that as the sun moves, one bottle will be exposed to the light. This bottle will heat up, driving the gas to the other bottle. The pressure change moves a pneumatic cylinder that adjusts the position of the tracker. The whole operation is automatic and reliable.

The DC electricity from the panels is fed to storage batteries until the power is needed. Lin ear modifiers adjust panel out put current to suit the storage portion of the system.

Charge controllers are simple devices that limit the in coming DC supply from the array. More elaborate controllers also provide a central point to gauge the capacity and condition of the system. The fancy controllers are expensive and currently used mainly in situations where photovoltaics are the only power source.

Inverters are special trans formers that electronically convert 12-volt DC electricity into standard 120-volt 60-hertz AC current with minimal power loss. This allows a bank of 12- volt batteries to power standard 120-volt appliances and normal house wiring. Inverters are ex pensive but very reliable, and should be considered a one time purchase. Inverters with out fans are recommended because of the decreased noise. Some inverters do have a slight but constant power loss, and they are turned off automatically, using a time switch, or by hand at the end of the day.

Storage

To provide electricity suitable for home use, more durable and long-term storage banks are required. Units known as deep-cycle batteries are used, the storage capacity of which has more to do with system performance than other factors. Typically, storage requirements are calculated to provide electricity after three full days without direct sunlight. Where a 180-amp-hour marine deep-cycle battery (about $80) is perfect for a backup system, stand alone systems will usually benefit from using more exotic and expensive batteries, such as the so-called chloride types which currently cost more than $1,000 for a 400-amp-hour bundle of six cells. Other kinds of batteries fall in between these extremes in both price and performance, and new and better methods loom on the horizon.

12 DC Systems

The primary advantage to using inverted AC power from the storage bank is that existing AC wiring may be used to sup ply the existing appliances. But in situations without an established AC wiring system, direct use of DC output should be considered. The drawback to a 12-volt-only system is that de livery of sufficient wattage re quires much more amperage and therefore much larger wires than an AC system. DC wiring is also more expensive than AC materials and harder to install, but no inverter is required. Electric razors, soldering irons, blankets, hair dryers, washing machines, and even refrigerators and heaters that use 12-volt DC power are currently available. Twelve-volt lamps, fans, radios, tape decks, and so forth, can be purchased from auto-supply stores, and water pumps are available from marine suppliers.

Stand-alone systems are becoming economically attractive alternatives wherever there is enough sunlight, water or wind to supply such a system. With current costs, a stand alone photovoltaic system will begin payback within 8 to 10 years, even sooner if existing AC wiring can be used or you do the rewiring

DC Distribution Panels

Due to the increased amperage found in a straight 12-volt system, different panels and breakers are used. Marine versions are suitable for small-load applications only, such as a backup system. Larger systems require using a panel and breakers designed for the purpose. The breakers are inexpensive but DC panels are rare and sell for about 10 times the cost of a similar AC panel. These DC panels need bigger lugs to tie larger wires to the buses and are manufactured in 12- and 24-volt configurations.

Small Hydro Systems

This technology is less expensive than photovoltaic power generation, but a constant source of water of suitable quality must be available to develop such a system. A small stream is seldom sufficient as a source, and tapping one will not benefit the stream or the fish in it. The critical source qualities necessary are volume and head. Head refers to the vertical drop between the source and the turbine that generates the power. The greater the head, the less water needed to produce pressure at the turbine. With 400 feet of head, small nozzles will consume 4 gallons a minute to produce 100 watts of 12-volt power; with the minimum 12- foot head, larger nozzles must be used to generate 100 watts, and 400 gallons per minute will be consumed. A hydro turbine will operate 24 hours a day. The turbines currently retail for under $1,000.

These represent the least-reliable alternative power source. The most efficient wind generators require an average wind speed of 5 miles per hour just to start generating power. Un less the usual wind is such that you can barely walk from the house to the car without get ting blown over, wind systems will generally prove to be an unwise investment. They may be advantageous for intermit tent use, such as for pumping water into a storage tank.

The 1990 NEC requires separate overcurrent devices between the DC source and the charge controller, the battery bank, filters (linear modifiers), the inverter, and between the inverter and main AC panel. Although two-wire DC circuits aren't required to use grounding circuit wires, roof-mounted photovoltaic arrays must have GFCI protection tied to the metal frame of the array. These rules apply to both hybrid and stand-alone systems; the protection afforded to the ex pensive components is worth the costs even in stand-alone applications. As long as the renewable-system voltage does not exceed 50 volts, this is the limit of the NEC’S impact on these systems. As this technology gains in usage, however, it's likely to become more regulated.

One last caution: T1 ally, AC systems use the black wire to carry power to outlets and the white wire to return potential to zero. With low voltage DC current, however, it's the red wires that carry the power to the outlet and the black wires that return the potential to zero.

Wind Generators; The NEC

SMART HOUSES

Efficiency

The electronic miniaturization that makes personal computers relatively inexpensive today can be used to manage and control an electrical system as well as the heating, cooling, and other systems in a home. This control can reduce energy use and costs by running the large loads when demand (and cost per kilowatt-hour) is at its lowest. Overall costs are further reduced because the wiring for so-called optional systems, such as telecommunication, inter com, cable TV, and security systems, is included in the Smart House cables, eliminating sub contractors and the need to pull the optional wiring separately. These cables are altogether different from what is commonly used today and can perform many other functions as well. The boxes and panels and most devices are also different. Only the large dedicated-circuit loads will retain the Type NM cables and receptacles familiar to home electricians. The higher initial costs of this approach are offset by the reduced energy consumption and the dramatically improved convenience.

By using the control features to run large-load appliances in the middle of the night, the homeowner pays the lowest possible rate for the energy consumed. By using low-voltage feedback controls, a dishwasher can turn up the water heater just before the cycle begins and turn it down after the cycle is over. Together these controls can turn up the water heater a half hour before shower time on weekdays and back down at other times, saving even more energy.

Modern programmable thermostats are simply reactive devices. Smart House heating and cooling systems, on the other hand, provide not only their basic functions, but can measure inside and outside temperatures and check the date and time of day to anticipate changes in these conditions. Smart House controls will also close the drapes on hot summer days on windows with southern exposure and open them on sunny, cool winter days. Heating and cooling efficiency is improved further by heating only the most frequently used areas of the home. Miniature thermostats and low- voltage fans or baffles in the ducts can direct forced-air heat only where it's needed, by passing other areas. This is called zonal heating and can reduce consumption by 30 percent.

Safety

A Smart system will link the 120-volt appliances in a home to special breakers in the panel so that until the appliance is turned on, no AC power will flow through the circuit. This reduces electromagnetic radiation (EMR) while protecting children from shocks from un protected receptacles. Should a problem develop in an appliance, the Smart technology can notify the homeowner on site or with a phone call, and turn off the power to that specific appliance.

All the control features use low-voltage DC electricity, further reducing EMR fields. One cable also contains two larger DC conductors, and these are intended not only to supply power to electronic memories and so-called phantom loads (clocks, timers, security systems), but to serve DC appliances directly as well. Common home electronics, such as TV, radios, and tape decks, already transform the grid AC into DC power, so that the peaks and valleys of AC current don’t show up as snow or noise in the picture or sound.

Navigating through your house at night is made remark ably safe and easy. A touch of the control panel will light a path through the house to your destination.

If you are home alone and the doorbell rings, there is no need to go to the door. You can view the visitor from any where in the house and issue instructions to him or her. The system can even be set up to call you at your office if no one home and the door bell rings.

Entertainment and Communications

Smart system design provides for TV signals with a pair of special coax cables dedicated to audio and video signal trans mission. This cable can also be used to direct a VCR signal to any TV in the home, and with a video camera, monitor a sleeping baby during commercials or on a split screen. Other wires in the same cable allow the speakers of an audio system to be placed in any room, and the sound to be controlled from anywhere in the home.

Smart cabling has provisions for intercoms and security built in. The telephone system includes a new control box, called a gateway, that has multiline capability and a built- in digital answering machine. Messages can be reviewed through the TV during commercials. In addition, a fiber optic cable-ready link is provided in the box, anticipating future use of this technology. In a Smart House, the smoke detectors may be connected through the gateway to contact the fire department automatically via phone, in forming it of the problem and the address.

Innovative home-wiring technology that incorporates improved safety, greater efficiency, and control features and options that have not been possible before is emerging. This system is referred to as Smart House and is the product of a collaboration of more than 40 different groups, including utilities, software designers, and others.

Smart House: Light sensor; Window/door security sensor; Vehicle sensor; Video camera

Smoke/heat detector

Motion/occupancy detector

Intercom/alarm unit

Audio/video entertainment outlet and controls

Clock/radio timer

Wireless transceiver

Furnace/air conditioner monitor and controller

Window covering control

Maxi-control computer with touch-screen video display

Light controls

Electronic door locks

Garden sprinkler valves

Remote garage door control

Lights

Smart outlets

Appliance outlets

Ceiling fan module

Temperature sensor

Brownout Protection

A home automation system can also use the normal assortment of motion detectors, infrared-beam detectors, and sonic detectors already on the market to graphically pinpoint the location of an intruder on any video screen. With a mini- cam concealed in each room, the intruder can even be seen on screen.

Control Systems

All this flexibility and the new features would be impossible without the computer control that interconnects these different circuits in a logical way. The Smart House system is so refined that the user needs no computer knowledge at all. It’s simply a matter of viewing a list of options on a TV screen and picking the desired function by touching the screen. Voice-activated controls are being developed for the sight impaired and for the physically challenged.

Another control feature allows the user to key any telephone on site and tell the system what to do. TV and VCR remote controls may also be used to operate the whole system; and small touch-tone keypads can be placed where needed for system control. Un like the touch-screen control, users need to remember the relationship between commands and various functions, but if the telephone control is used, it will function from a telephone anywhere in the world.

These control functions are just a few of the possibilities. Others include sprinkler controls, skylights that open and close automatically, and virtually every household function that can be automated. The significant difference with Smart control features is that they may be easily programmed to perform these and other complex functions automatically, with different cycles for week day and weekend schedules, and the programmed functions can be added to or modified using quick, simple methods.

Backup Power

Smart control features are pro vided with an electric backup so that once the basic functions of the system are established, these functional commands are held in the system memory even in the event of loss of grid power. This is identical to the small UPS system described earlier, except the power is used to protect the memory of the whole system and not just a single computer.

In areas where brownouts occur at times of peak demand, some states have laws that allow the power company to disengage large appliances such as dryers and air conditioners from the grid for short periods. These voluntary programs re quire special devices to accomplish this, a job that Smart controls will do better. Besides the reduced costs incurred, power companies usually pro vide an annual rebate to users as well. After a peak overload, there are lots of appliances set to start again simultaneously, further straining the generating and transmission systems of the grid. With the link between the utility and the user provided by the Smart House interface, utilities can phase in the restored power gradually and eliminate this shock to their systems.

Convenience

Although home automation will cost more initially, the benefits of improved safety and efficiency, and the tremendous flexibility built into the system, aren't just another step for ward, but an entirely different approach to home wiring. The homeowner will be able to use and control the formerly independent operations as a single system, accomplishing complex tasks easily.

By integrating the home systems (and renewable on-site system) with the utility grid, a daily check on household power consumption can be displayed on the TV each evening, and the Smart system can be instructed to continue, increase, or decrease consumption the next day.

Hybrid Systems

Although the Smart House is a packaged product, these options can be installed piece meal, according to site-specific opportunities and use requirements. In other words, al though most homeowners must depend on utility- supplied AC current, elements from photovoltaic, small hydro, and wind-driven systems can be grafted into an AC residential system fairly easily. As the cost of utility-generated power increases, reliability decreases, and pollution gets worse, hybrid and independent systems look better and better.

Proposed uses of new systems appear wide-ranging and thorough, and other uses and options will undoubtedly be incorporated as smart technology continues to evolve. During its short life, the ways we use electricity have changed dramatically and some mistakes have been made in the process. This pattern isn't likely to change; remember this is an evolving technology. Even with the advent of Smart systems, there is plenty of room in the technology for creative thought and innovative solutions.