Humidity Sensor: Energy

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2012年7月16日星期一

State-Of-The-Art Design And Technology Can Meet Both Energy And Comfort Demands

The CFC phaseout has forced facility executives to take a hard look at their HVAC systems. At the same time, current technology offers significant opportunities for energy savings from the heating and cooling system, typically the second-largest energy user in commercial facilities. On top of all that, the definition of comfort has evolved rapidly over the past decade.

At one time, HVAC systems satisfied the comfort issue by simply making sure the work area was warm or cool enough for most occupants. Now, comfort is being refined to include indoor air quality and outside air exchange.

All in all, it's a tall order: The HVAC system is expected to achieve comfortable conditions for the individual and the masses in the office without harming the delicate global atmosphere. A good example is the CFC phaseout.

Facility executives have three choices: contain CFCs in existing chillers, convert existing units to alternative refrigerants or replace existing machines. Installing new high-efficiency equipment can result in significant energy savings.

Modern HVAC equipment offers improved efficiencies, which are being achieved with better motor performance and better temperature splits in the refrigerant tubes. Today's HVAC systems also offer better part-load efficiencies than older models. Multi-stack units and horizontal screws run more efficiently at part-load levels than earlier models. The economizer bundles are better than they used to be, so the systems run more efficiently.

The recent improvements in chiller efficiencies are the result of refinements in many small places. Manufacturers have done it by better designed compressors, by improving heat transfers. Every component has been reengineered.

New materials, notably plastics, offer major potential for increased HVAC advances that end up benefiting building owners and managers. New materials make units more efficient, easier to install and more corrosion resistant. HVAC systems are becoming more component oriented so they can be put in after the building is built.

Resolving IAQ via HVAC

One of the biggest challenges facing facility managers today is how to meet ASHRAE's current standard for outside air exchange. Variable air volume systems and normal applications need to be reexamined to meet ASHRAE fresh air standard.

To maintain energy efficiency and meet the new standard, multi-zone air-handling systems may need some overhauls. The normal unit has two decks -- one for warm air and one for cool. Provided air is mostly being recirculated, the two decks work effectively.

With the larger temperature differences involved with increased outside air, a neutral zone also may be needed. In a triple-deck system, the outside air is brought by the heat exchanger to that neutral point, before entering the air stream. The result is returned efficiency to the HVAC system in its heating and cooling modes.

Another promising solution is the use of dessicants to pre-condition air without mechanical cooling.

For buildings undergoing major retrofits, the building's air should be tested before renovations begin. Establish the levels of existing contaminants, if any, so that you have a point of reference. After renovations, the air quality should be retested. Periodically, additional IAQ tests should be conducted.

What should building owners do when indoor air actually is better than outside air, as often is the case in buildings located adjacent to major airports? Filtration for gaseous contaminants can play a major role in cleaning the building's air. The health care industry already is aware of the importance of air filtration in controlling the spread of airborne pathogens. But other building owners are just beginning to recognize the importance of proper filtration systems.

Custom comfort

Many advances have been made in HVAC control technology during the past decade. One of the most recent is the ability to control air flow, temperature and even air quality at individual workstations. Because of metabolism and dress in the office, women often complain that they are too cold, while men are too hot.

Advances in DDCs and control systems give us tools to get better air as well as energy conservation from HVAC systems. Everything now is automatic. We can set certain parameters for temperature and humidity with the outside air economizer.

And we can do so much more with the system to protect the health of the people inside the building. For example, if there is a fire and the smoke-detection system is activated, the HVAC controls can stop the air-handling system and start exhausting smoke from the space while alerting local fire and alarm departments.

Electronics in HVAC systems are becoming more integrated with each other: The air-handling unit knows how much is needed from it, and the chiller knows what each air handler is doing and can adjust itself accordingly.

Further refinements in HVAC system controls are on the near horizon. For example, comfort control that relies on more than the temperature to measure a space's overall comfort currently is being investigated by researchers, consulting engineers, ASHRAE and building controls manufacturers. Sophisticated comfort control sensors are being developed that will take into account not just the dry-bulb temperature of today's thermostats but also the mean radiant temperature, air velocity and humidity level.

Julian Arhire is a Manager with DtiCorp.com - DtiCorp.com carries more than 35,000 HVAC products, including industrial, commercial and residential parts and equipment from Honeywell, Johnson Contols, Robertshaw, Jandy, Grundfos, Armstrong and more.

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2012年7月14日星期六

Energy and HVAC Optimization

Let's talk about 30-40% of your electricity bill. That's how much it costs the average homeowner or commercial building owner to provide proper heating, ventilating, and air-conditioning (HVAC). A good HVAC system is the key to maintaining a comfortable, healthy and interior environment. Through the years, I have been asked by many owners for a strategy to reduce their cost of energy and HVAC. They don't want to sacrifice the interior environmental conditions, but they do want a point-by-point plan to follow. The interesting thing that often happens is that energy bills are lowered substantially and the HVAC system performance is improved. This is a standard function of any mechanical engineer specializing in energy and HVAC.

The information on this page will help homeowners, building owners and building operators make informed decisions about existing HVAC systems or future upgrades.

Load Reduction
HVAC Systems
Control Systems
Operation and Maintenance

Load Reduction

The first step to achieve energy and HVAC system optimization is load reduction. This step normally consists of a long range plan which itemizes the actions to be taken based on best return on investment. Reducing your building load allows the existing HVAC system to operate more efficiently. If a new system or systems are being considered, it will be more cost effective to design for the reduced load as opposed to the existing load. A few common load reduction strategies include:

Tighten the building shell and add additional insulation. Adding insulation in existing buildings may not be achievable in some instances, so more consideration should be aimed at the exterior shell, especially windows and doors.
Installing energy-efficient windows. This is a big item on some buildings that still have single pane windows. The installation of double pane windows with a thermal break is a great return on investment. Make sure they are ENERGY STAR qualified windows. Tinting or Low-E coatings will even be better.
Upgrading lighting systems. The average commercial building has a lighting density of 2-3 watts per square foot which maintains proper lighting levels. This is a significant part of the HVAC load and almost any efforts in this direction will lower the cooling requirement for the building. Accent lighting (sometimes called architectural lighting) are not always energy efficient and should not be considered if you want to reduce energy and HVAC costs. Energy-efficient lighting systems emit less heat into conditioned space than older incandescent technology. If you have a return air plenum instead of return air ductwork, consider light troffers so that some of the heat from the lights is returned to the HVAC system instead of going into the occupied area.
Selecting efficient equipment and electronic devices that have a power saver option will reduce the sensible heat gain in the space. Items to consider include copy machines, kitchen equipment, computers and refrigerators.
Control ventilation by having your outside air balanced. Most building owners have drawings of the original HVAC system installation. Have the drawings reviewed by a mechanical engineer to confirm your outside air flow rates conform to the latest code requirements. If no drawings are available, your mechanical engineer should still be able to make recommendations for improvement.

Addressing these items is your first step to reducing energy and HVAC costs.

HVAC Systems

The second step to achieve energy and HVAC system optimization is knowing your system. Your HVAC system is critical to your interior environment, but it also represents a large component of your utility expenses. While it is beyond the scope of this article to discuss every system, a few recommendations can be addressed. Every HVAC system component has increased in efficiency over the years. If your system is more than 13 years old, it's time to begin planning for an upgrade to new equipment. Well maintained residential systems have a life expectancy of about 15 years or so but seem to fail at the worse times. Have a replacement plan ready for the day your equipment fails.

Commercial systems vary, but if your building is using packaged equipment or split systems, the same lifetime can be expected. For larger commercial systems and industrial applications, the HVAC system may be more complex and require an individual analysis by a mechanical engineer. As I said, HVAC systems vary and no one-size-fits-all analysis works for larger systems. What all these systems have in common is they are normally fueled by electricity. Electricity cost money, so any efforts in the direction of increased efficiency is a plus.

HVAC System Tips:

Find a qualified consultant you trust. If you are a home owner or small commercial building owner, find a good HVAC company or mechanic to evaluate and maintain your system. If you are a large commercial building owner, find a commercial HVAC company for normal maintenance and a good mechanical engineer for specific guidance. I do not recommend using a mechanical engineer employed by the HVAC Company; find a third party engineer for unbiased information.
Verify your HVAC system load. Home owners should use ACCA's Manual J calculation method and all others should have a load conducted by a mechanical engineer. Commercial buildings have more requirements related to code conformance, minimum ventilation rates, etc and are individual to each building.
Load reduction-Read the information above.
Select equipment sized for your load. NEVER OVERSIZE! More-is-better does not apply for HVAC systems. It will cost more to purchase the equipment as well as operate it. Get the load and the equipment selection right the first time.
Purchase high efficiency or Energy Star equipment. Many of the new systems include variable speed drives for fans and compressors. Over the years of ownership this will be paid back many times over. Compare standard efficiency equipment to high efficiency equipment in terms of initial cost and life cycle costs. Any good HVAC company or mechanical engineer can obtain this information.
Consider some form of energy recovery for any air exhausted from the building and use it to condition the incoming fresh air. This is air you have paid to condition, so extracting some of the energy before exhausting it should be a priority.
For large commercial buildings, consider conditioning the outside air with a dedicated outside air unit. This will eliminate any problems related to humidity control in most instances. It will also increase occupant comfort and allow for further downsizing of equipment.
Commercial buildings should consider economizers on their equipment. Most current codes require economizers on equipment over 15 tons in size. Often available at a low incremental cost, these units draw in fresh air from the outside when the temperature (sometimes humidity) outside is lower than the temperature inside.
Home owners and small commercial building owners should install programmable thermostats. Commercial building owners should install a Direct Digital Control (DDC) system. The investment in either of these will pay back more than the cost in a small amount of time. Read more below.

Control Systems

The third step to achieve energy and HVAC system optimization is controlling your system.

Programmable Thermostats-The age of digital controls has made saving energy easy. One of the best investments for the homeowner or small commercial building owner is a programmable thermostat. These are simple to use and incorporate strategies based on time scheduling. Most manufacturers offer 7 day programs and setback/setup programs which will turn the HVAC system on and off to compliment your schedule and desired indoor temperature. This is a great way to ensure HVAC systems are used only when necessary.
DDC Systems-For the large commercial building, I consider this as a must have system. Installation costs have steadily decreased and the performance reliability has steadily increased. They can be integrated into any system and expanded as required. Some of the more popular features of these systems are optimized start/stop of the HVAC system, multiple zone control, multiple temperature sensor locations and ventilation control. The best part of these systems is their ability to be scaled up to the largest of commercial applications. This means you can install a simple system and add more controls later to incorporate your whole HVAC system. Again, the payback is short and well worth the investment.

Operation and Maintenance

The fourth and last step to achieve energy and HVAC system optimization is operation and maintenance. The most efficient HVAC systems are well maintained. Ensure reliability, efficiency and a long life for your HVAC system by following these tips.

Summary

Energy and HVAC optimization will reduce your electricity costs. A little time getting to know your system and familiarizing yourself with improvement strategies will save money and increase the life of your equipment.

Visit my site for more information on Energy and HVAC optimization.

I am a professional engineer with over 30 years of design experience relating to plumbing and mechanical systems. The articles I write are the result of many successful commercial and residential installations.

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2012年7月13日星期五

Saving Energy at Home, Part 2

Welcome back! As I said in the first article, "I'm just getting started!" So, where do we go from here?

In this article I have again put together a list of low or no cost things to do that can save you money. Now, each one on its own probably will not make much of a dent in your electric and/or gas bill but when combined and added to what you have already done based on my previous article:

"Save Up to 50% or More on Your Home Electric Bill Almost for Free!" (Of course, you have done all of that, haven't you?) You should see a substantial reduction in your monthly energy bill the next time around.

Ok, where do we begin?

Let's start in the kitchen with the dishwasher. Your dishwasher uses very hot water to clean your dishes. A common fallacy is that you must set your hot water heater to 145 Deg. F in order for the dishwasher to function. In actuality, most dishwashers built after to late '90's have built-in water heaters to bring that water up to the required temperature so check your water temperature and set it at no more than 125 Deg. F. If it is higher, you are wasting money! Also, remember to run your dishwasher during "off-peak hours".

You will need to go to the store and get a good thermometer, look at the inexpensive digital units. Once you purchase one check to make sure it is accurate. You say, "how do I do that?" Very simply, take a glass and fill it half full of water and the rest with ice. Water and ice can only co-exist at one temperature and that is 32 Deg. F., or freezing, let it sit in the 'frig for about 5 to 10 minutes, put your new thermometer in the glass, it should read 32 Deg. F. Oh, by the way, this is not the only time we will be using the thermometer so keep it handy!

Now, where else can we make use of your new "toy"?

Lets' go back to the refrigerator, again, pulling out your trusty "calibrated" thermometer (You did calibrate it, didn't you?) place it in a glass of water that has been standing on the middle shelf of the 'frig for a good half hour or more. You should be in the range of 35 to 38 Deg. F. Any lower you are wasting energy (Money!). CAUTION, do NOT set it above 38 Deg. F. trying to save more money! Food may spoil and food poisoning could result.

Now, lets' move to the freezer section. Again, using your thermometer, place it in the freezer section of your refrigerator and leave it there for at least 15 to 30 minutes. You should have it set for between 0 Deg. F. and 5 Deg. F., any lower and you are wasting energy and money!

Still in the kitchen, lets' look at the faucet in the kitchen sink, and of course, it doesn't drip, does it? If so, FIX IT! Hot water causes the seals to eventually fail causing a drip. Most newer faucets use a simple cartridge that can be easily replaced, DO IT NOW!

Does your kitchen faucet have an aerator nozzle on it? If not, GET ONE! It retards the flow of water (saving MONEY!) and yet helps do a better job of rinsing items. Again, many little grains of sand make a beach; don't over look the small stuff!

While we are on the subject of good old H2O, lets' talk about usage. Do you have low-flow shower heads in the bathrooms, if not GET THEM. I just bought new ones at Wal-Mart for about $13.00 USD! Also, get a cheap egg timer and time your showers! I have it down to 2 minutes!

Do you have low-volume toilets? If not, don't rush out to replace them! First, as always, make sure that the level control is not allowing the unit to leak through (you will hear dripping in the water closet if it is), if it is, FIX IT RIGHT NOW! And if they are not low-volume units you can simply displace some of the water in the tank by using bricks. Now this one you will have to play with to get the level right for a complete flush but in the end you will save water (MONEY!).

If you live in the country, check to see that your well expansion tank has the proper amount of pressure in it, if not, it could be "short-cycling" your well pump and wasting energy as well as shortening the life of the pump (mark this as VERY EXPENSIVE to RELACE!).

Make sure that none of your faucets are dripping; this includes your outdoor faucets! If they are, FIX THEM RIGHT NOW!

Now lets' go to the laundry room and check out your washer and dryer. Now, you can't usually adjust the actual temperature settings (A qualified service technician can) but you can do a couple of things starting by doing all laundry at night during off-peak hours. Where ever possible wash using cold water detergent and dry on as low a setting as the fabrics will allow, also wash and dry like fabrics and colors together. ALWAYS make full loads your goal to help cut down on electric and/or gas usage! And on the dryer make sure your dryer vents are free and clear of lint, fires have been known to start because of excessive lint buildup!

There are two last items that I want to cover, one is cheap, the other you will have to play with to determine if it will work for you.

The first item is what I call "a no-brainer" but is usually overlooked by most people.

Your outside lighting is our next stop. You cannot use efficient fluorescent light bulbs in areas of the country because they do not function below certain temperatures. However, a simple little thing like simply reducing the wattage of the bulbs can make a big difference! Example:

I have 5 standard outdoor fixtures designed to use 60 watt bulbs. By reducing these to 40 watt bulbs I have lowered my usage by 100 watts and you can not see much of a difference at all! If you are located in a low crime area, put a timer on your outdoor lighting circuit. Get one that uses a sensor to turn them on at dusk and off at say 9 or 10PM (what ever works for you!), this way you will not forget to turn them off (which I almost always did!). Or, if not needed, LEAVE THEM OFF entirely when ever possible!

The last item on this free or at least "cheap" list concerns your furnace. If you have a forced hot air system and central air conditioning this could save you a LOT OF MONEY during the cooling season! Now, please understand, this may not work for everyone and it will not work under certain outdoor air conditions such as high humidity especially if your furnace draws fresh circulating air from outside (Please note: this usually pertains to older furnaces only!). Newer furnaces have a "closed circuit" in which they simply recycle the indoor air while using a separate circuit for combustion air that is drawn into the furnace, heated, moved across a heat exchanger and then exhausted to the outside, this way you retain maximum efficiency in your furnace with out wasting what you have already heated, and always remember to change the filter on a regular basis.

During the evening hours if the outdoor air temperature drops below the temperature inside the house and the humidity is relatively low you can reduce your cooling costs considerably by opening a few windows and turning on just the fan switch on your furnace and let it run constantly at night. This will promote a cooling effect in the house without running the air conditioning and "pre-cool" the house. In the morning simply close your windows, continue to allow the fan to run but activate you air conditioning.

Buy doing this and setting the air temp to above 75 Deg. F., even 78, you should be able to save on your air conditioning bill during the cooling season, once set point is reached set back to "auto" mode, but this is one you will have to play with to determine your optimal settings and, again, it may not be for you depending where you live.

So there you have it, the second installment of how to cut your energy bill "On The Cheap" as they say. Again, I highly recommend getting "The Energy Savings Manual", see the attached link and stay tuned for "The Rest Of The Story", my final chapter before getting really serious about getting you "OFF THE GRID".

To get your copy of the "Energy Savings Maual" please go to; [http://www.villagemediaproductions.com]

P.S. I'm now down $85 to $100 a month and my utility thought something was wrong with my meter!

Jay is an "EX" utility company employee where he taught power plant maintenance for WE Energies and was head of Customer Service Training for Alliant Energies. Jay also taught building automation and environmental controls installation and operations for companies such as: Johnson Cotrols, Landis & Gyr, Invensys and was head of training in North America for Cleaver-Brooks, Division of Aqua-Chem for several years.

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2012年7月12日星期四

6 Ways to Save on Your Energy Bill and Increase Home Value

People are going green globally! Upgrading home energy efficiency is a major green effort, which is worthy of consideration. Eco-friendly updates conserve energy, save money on utility bills and add to the resale value of our homes.

Even the strictest budget-conscious individual can incrementally heighten home energy efficiency. Let's explore six ways to green-up your home.

1. Programmable Thermostat:

Energy StarR products are highly recommended by the U.S. Environmental Protection Agency. A relatively inexpensive way to increase home energy efficiency is by the installation of an Energy StarR programmable thermostat for your heating/cooling system.

Pre-programming the thermostat settings to fit your family's lifestyle will achieve substantial energy savings, without forgoing a comfortable temperature. These thermostats are designed to reduce amounts of energy required to heat or cool when no one is home, during nighttime hours or when the family is away for extended periods, such as vacations.

2. Appliances:

Due to modern materials and technology, you'll conserve electricity and water, if applicable, with Energy StarR appliances. Consider replacing existing appliances one-by-one for greater home energy efficiency and resale value.

The initial investment will be larger than buying regular appliances, but you will soon realize a return through savings on utility bills. For example, the washing machines contain sensors that determine the precise amount of hot water necessary for each load of clothing. Statistics suggest a savings of about 40% energy and 50% hot water, per load.

Are you aware that refrigerators use more power than most other appliances? Energy StarR refrigerators have cost-effective compressors, improved insulation and produce less heat while running.

Dishwashers are constructed using updated technology, such as sensors to regulate the different cycles and correct temperature of water. The need to consume less hot water contributes significantly to home energy efficiency.

3. Windows and Doors:

Home energy efficiency and comfort substantially increase with the installation of new windows and/or doors. Reportedly, Energy StarR window or door products will save as much as 15% on utility bills.

Unlike their older counterparts, where heat escaped and cold entered, window glass remains warm during winter and cool during summer, without disturbing the light from the sun. The same modern coating that preserves temperature serves as a screen against the sun to protect your cherished possessions from fading.

4. Energy Efficient Insulation:

Adding energy efficient insulation to your home is a gift you give yourself. You can't see insulation, but you will feel the difference in overall comfort and see the difference in utility bills. Similar to older windows and doors, an improperly insulated home lets outside heat/cold in and inside warm/cool air out.

5. Heating and Cooling System:

The rule of ten applies to potential replacement of home heating and cooling systems. After HVAC equipment ages about 10 years, it experiences failure to perform. Energy StarR qualified HVAC systems can save you upwards of $200 annually on home energy bills.

It may be also be time to call a professional if your unit requires excessive repairs; utility bills consistently creep-up or in event of home humidity problems.

6. Roof:

A new roof is a considerable, but necessary expenditure. When your roof needs replacing, the perfect opportunity is presented to explore benefits of reflective roofing by Energy StarR. Experts report that these cool zone roofs use 40% less energy.

Cool zone roofing reflects more rays from the sun, resulting in lowering roof temperature as much as 100F. It also takes appreciably less energy to heat or cool the interior of your home with a cooler roof.

If your budget doesn't have enough wiggle-room to start renovations, you may take one eco-friendly baby step. Start switching incandescent to compact fluorescents - one bulb at a time! Compact fluorescents outlast incandescent bulbs 15 times and use about 20% less energy.

Most home energy efficiency upgrades enhance the eventual resale value of your home and is a selling point worth mentioning to prospective buyers. In the meantime, your home really is your sanctuary; make green efforts that contribute to your comfort.

Bill McCormick is an experienced real estate agent and owner of a Re/Max Executive Realty office covering the market in the metro-west Boston area and is an advocate of ongoing home maintenance to maintain value of property. Bill specializes in Homes for Sale in Upton and also in the towns of Milford, Mendon and Grafton. His website has more tips for house sellers and buyers and also moving tips and you can find them at: http://www.billmccormick.com.

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2012年6月25日星期一

Energy Efficient Ventilation in Your Home

Fresh air and adequate ventilation serve more than just the physical comfort of occupants. While a healthy supply of fresh air is important proper airflow also provides condensation control, removal of airborne pollutants and ensures the safe use of potentially combustible appliances.

Insulation, heating systems and overall ventilation installations need to be considered in a group context for the most energy efficient results. Generally speaking the aim of a good ventilation installation is to maximise energy efficiency without reducing indoor air quality.

Visually the most significant disadvantage of bad ventilation is mould damage associated with high relative humidity. Kitchen and bathroom activities utilise a lot of water in particular and the supply industry has responded by producing wide ranges of domestic fans for bathroom and kitchen installations.

Environmentally-conscious home owners will be aware of the new best practise building standards available for energy efficient dwellings. Insulation or 'airtight' architecture is often used - with success - to reduce the heating energy expenditure. This 'airtightness' also contributes to more rapid build-up of internal pollutant sources such as gases, cleaning agent fumes, Allergens such as house dust mites and chemical by-products from home ware and furniture. Unless great insulation is coupled with effective ventilation negative health effects will be felt over time.

Natural airflow can easily be augmented and controlled by installation simple ventilation mechanism in the home. There is a three-point action plan to reach great home air quality goals:

One: Extractor fans installed in key areas such as kitchens, laundries and bathrooms allow for controlled air expulsion in heavy activity rooms.

Two: Whole building ventilation and air condition allows automated regulation air quality throughout the building usually via roof or floor ducting installations. Apart from timers whole building systems can also be installed to utilise sensors to determine appropriate operation times. For example an occupancy or motion sensor will allow a sensor to tailor its usage to times when the house is actually occupied and reduce the overall energy costs of ventilating.

Three: Lastly any area which is temporarily used for activities that increase pollutants (e.g.: painting or fumigating) should be physically aired by opening a window.

Ducting in existing homes will need to be installed with the minimum bends and kinks for more efficient energy flow. Another recent development to consider would be heat recovery units. These units recover heat from air being released outside to warm up incoming fresh air.

Choosing a contractor to install your energy efficient home ventilation system:

Apart from choosing an individual with a background in BER (Building Energy Rated) construction it is also a good idea to find out what their relationship with the supplier is. You want to ensure that future ventilation upgrades and repairs will not be negatively impacted by a relationship with a poor supplier. Home-owners also need to be aware that most legal requirements allow contractors to "trade off" the characteristics of units with different functions. Installing a system using only the minimum performance statistics for all units will not usually add up to a fully compliant home build.

Ventac manufactures and supplies industrial and home ventilation solutions in Ireland and abroad. http://www.ventac.com

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2012年3月4日星期日

Bathroom Exhaust Fan And Energy Efficiency

What a Bathroom Exhaust Fan has to do With Energy Efficiency

Most people don't pay much attention to bathroom exhaust fans until the boogers and cobwebs are hanging half way down to the commode. When the fan gets plugged up, energy efficiency is lost and the exhausting power of the fan is reduced to almost nothing. The normally efficient fan motor heats up, wastes electricity, and applies unneeded expense to the power bill. If your bathroom exhaust fan cover looks like a Kansas dust bowl and the fan motor will no longer hold up a piece of toilet tissue, it's time for a little preventive maintenance.

What is a bathroom exhaust fan?

Mounted in your bathroom ceiling or exterior wall, the bathroom exhaust is given the job of removing moist or awkwardly perfumed air from the room. If moist warm air remains in the room - the possible occurrence of mold and mildew is greatly increased. By removing the moist warm air produced by a shower or bath, the relative humidity is reduced as is the possibility of mold. And, of course, removing the awkwardly perfumed air from the bathroom simply allows the bathroom to be used by the next person sooner.

Does a bathroom fan have a rating system?

Yes, a bathroom fan is rated according to cubic feet per minute ( cfm ) and according to how noisy they are. A less expensive apartment model will be rated at 50 cfm and about 4.0 sones. 4 Sones is the sound of a normal T.v., 3 Sones like office noise, 1 Sone is the sound of a refrigerator, and 0.5 sones like rustling leaves.

Some bathroom exhaust fans have humidity sensors that turn the fan on when moist air is present and then turn the fan off when the air is refreshed and no longer holds noticeable moisture.

Which bathroom exhaust fan would be best for my bathroom?

I would recommend a bathroom exhaust fan rated at 100 cfm or more and a sone level of something around the level of rustling toilet paper. I would also recommend you install a timer switch so you can leave the fan running after you leave the bathroom and have the fan turn itself off about 20 minutes later.

A ceiling fan has a duct attached that is designed to take the warm moist air and discharge it into the great outdoors. Be sure the duct is firmly attached to the fan and that the duct terminates outside and not just into the attic space.

How does a fan waste energy and increase my power bill?

Ceiling fans are dust collectors. Combine the flow of exhausting air with the moisture content of the air and you have a dust collecting system. One, the fan is good at collecting and holding dust, grit and grime and two, the ceiling fan is mounted in the ceiling and hard to see and hard to reach and clean. The ceiling fan becomes the forgotten appliance.

With accumulating dust, the motor and fan will struggle to maintain speed and effectiveness. The motor works harder, runs longer, gets hotter and uses more electricity than it needs to. The exhaust fan turns slower and the electric meter spins faster.

Recently, I was in a home where the homeowner insisted the bathroom fan was working well. I stood under the fan, a test square of toilet paper at the ready, as he turned the fan on. You know how an electric motor can make a humming sound and not do anything. He thought the fan was working since it made a nice humming sound, but the fan was not turning and not exhausting anything. I held the TP square up to the fan and then watched it gentle float to the floor.

Can a ceiling fan earn the Energy Star Efficiency Rating?

Yes, ceiling exhaust fans are rated by the Energy Star program and can earn an Energy Star rating. As with any appliance, look for the Energy Star rating and then look further to see how efficient the appliance is within that rating. One Energy Star ceiling fan maybe noticeably more efficient than another Energy Star rated fan.

Do remember, to maintain that efficiency, the fan needs to be installed and ducted correctly.

Don Ames is the host at http://www.detectenergy.com, for more home energy saving tips, methods and news, visit my website and sign up for the Energy Spy Insider, a great email newsletter.

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2012年1月29日星期日

How to Monitor Your Home Energy Use

Monitor Makes for a Smart Home

This is something that is fairly new on the market for monitoring home energy usage. The purpose of an energy monitor is to facilitate energy conservation. Studies show that households that have real time energy data available save 5 to 15 % on their energy bills.

In this article, I would like to introduce you to the Agilewave Energy Monitor. This is just one power monitor that has the ability to monitor each electrical circuit, each gas appliance, the water meter, and the climate.

But, before we get to the Agilewave, I would like to make a few comments about cell phones. My son was putting his cell phone through it's paces the other evening for my enjoyment. First of all, he turned it into a guitar. Guitar strings appeared on the screen and when you ran a finger over the screen, the cell phone sounded like you were strumming a guitar. Wow, I was amazed and thought that was cool. Then he took me outside into the night, held the cell phone up to the sky, and the cell phone pointed the way to the big dipper and displayed and named the stars and the constellations as the cell phone swung across the sky. Now, that was really cool.

Now, I get to thinking, we have it backwards. Why have a smart phone and a dumb house? We expect our cell phones to take care of us when all we really need to do is make a phone call. When we go home, we take our homes just the way they are and then whine and complain when the power bill arrives. It's backwards.

Ok, now back to the Agilewaves Building Optimization System.

1. The Agilewave comes with 19 electrical sensors. More can be added as needed. A 30 amp sensor costs $60 and a 600 amp sensor costs $133.

2. The basic complete unit costs $2,400.

3. The sensor unit, ASIP ( Agilewaves Sensor Integration Panel ) is attached to each circuit in the electrical panel and monitors just that circuit. This allows you to monitor the kids stereo, the washing machine, the microwave, etc.

4. Agilewave comes with software that allows your home computer to analyze and display the information that is sent by the ASIP.

5. For a water flow sensor, the size of the water pipe is needed. Water flow sensor costs $500 to $900.

6. For a gas flow sensor, again the size of the pipe is needed as well as the pipe pressure. Gas flow sensor about $1,100.

7. Climate sensors cover more than you probably initially thought. These sensors include water temperature, room temperature, heating duct temperature, outdoor temperature, and room humidity. These sensors cost about $150 each.

8. The display on the computer screen is divided into sections, the sections include: a pie chart showing where the electricity is being used, the current month, day, and time. A peak demand indicator comparing today with yesterday, last month and the month before. Graphs showing water use in gallons, electricity in kWh, gas in therms, carbon in pounds, and cost in dollars and cents. Buttons switch the screen between reports and charts. Details by floor, room, appliance, circuit, or utility.

9. Includes a notification system that can report unusual power usage to your cell phone via text message or email.

Wow, the poor teenager doesn't have a chance.

The smart word is getting used a lot these days. Seems like everybody wants to get a piece of smart. Everything from smart meter to smart alec. We would be better off if we had a smart home instead of a smart phone. And remember, the day is just around the corner when every new home will have solar power and smart home technology built right in. For us old home people, we will just have to play catch up.

Hey folks, thanks for stopping by, I hope your a little smarter, come back soon, but I won't be leaving the light on for you... Don Ames

Don Ames is the host and author of http://www.detectenergy.com. Web site dedicated to conserving power at home. Ask me a question or sign up for my free weekly email newsletter.

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2012年1月28日星期六

Energy Efficiency And HVAC Technology

The following overview offers a quick reference to key considerations with some of the most effective technologies. As with lighting, trial installations are a good idea; so is working with manufacturers and distributors.

Getting the most from HVAC controls

Because a building's performance can be dramatically improved by installing and fully using HVAC controls, it is essential to understand and correctly use those controls. The place to start is with a close look at what is really transpiring in your building, 24 hours a day, seven days a week.

What is happening with each piece of equipment? On holidays? Weekends? As the seasons change, do your operations change? It is important to understand where and how energy is being consumed in order to identify where waste is occurring and where improvements can be implemented. Then it is imperative to ask, "What exactly do I want these controls to do?"

Energy management systems (EMS) are designed to run individual pieces of equipment more efficiently and to permit integration of equipment, enhancing performance of the system. In a typical EMS, sensors monitor parameters such as air and water temperatures, pressures, humidity levels, flow rates, and power consumption. From those performance points, electrical and mechanical equipment run times and setpoints are controlled.

Seven-day scheduling provides hour-to-hour and day-to-day control of HVAC and lighting systems and can account for holidays and seasonal changes. As the name implies, night temperature setback allows for less cooling in summer and less heating in winter during unoccupied hours.

Optimal start/stop enables the entire system to look ahead several hours and, relative to current conditions, make decisions about how to proceed; this allows the system to ramp up slowly, avoiding morning demand spikes or unnecessary run times.

Peak electrical demand can be controlled by sequencing fans and pumps to start up one by one rather than all at once and by shutting off pieces of HVAC equipment for short periods (up to 30 minutes), which should only minimally affect space temperature. Economizers reduce cooling costs by taking advantage of cool outdoor air. Supply-air temperature-reset can prevent excessive reheat and help reduce chiller load.

An EMS can provide an abundance of information about building performance, but someone has to figure out what they want the EMS to do and then give it directions. Calibrating controls, testing and balancing are key to any well-maintained HVAC system, but are especially critical to optimize control efforts.

Variable speed drives and energy-efficient motors

Variable speed drives (VSDs) are nearly always recommended as a reliable and cost-effective upgrade.

VSDs are profitable where equipment is oversized or frequently operates at part-load conditions. Savings of up to 70 percent can be achieved by installing VSDs on fan motors operating at part-load conditions. They may be applied to compressor or pump motors and are generally used in variable air volume (VAV) systems. They are also cost effective in water-side applications. Backward-inclined and airfoiled fans are the best VSD candidates.

Air-handler configurations controlled by variable inlet vanes or outlet dampers squander energy at part-load conditions. Using throttle valves to reduce flow for smaller pumping loads is also inefficient. The efficiency of motors begins to drop off steeply when they run at less than 75 percent of full load; they can consume over twice as much power as the load requires. VSDs operate electronically and continually adjust motor speed to match load.

The power to run the VSD is proportional to the cube of the speed (or flow), which is why this technology is so efficient. If the speed is reduced by just 10 percent, a 27 percent drop in power consumption should result. A VSD pilot study performed by EPA found that VSD retrofits realized an annual average energy savings of 52 percent, an average demand savings of 27 percent and a 2.5-year simple payback.

Perform harmonic, power factor, electric load, and torsional analyses before selecting a VSD. Though harmonic and power factor problems are not common in VSD applications, VSDs should generally be equipped with integral harmonic filters (or a three-phase AC line reactor) and internal power factor correction capacitors (or a single capacitor on the VSDs' main power line). In general, this equipment is not standard and must be specified.

Improved design and better materials enhance the performance of energy-efficient motors, which use 3 to 8 percent less energy than standard motors; units with efficiencies of 95 percent are available.

To achieve maximum savings, the motor must also be properly matched with its load, increasing run time at peak efficiency. Motors operate best when running at 75 to 100 percent of their fully rated load; motors routinely operating below 60 percent of rated capacity are prime candidates for retrofit. For motors whose loads fluctuate, VSDs should also be considered.

Smaller, more efficient motors are integral to a system downsizing stratagem; downsizing a 75 horsepower standard motor to a 40 horsepower energy-efficient model will result in energy savings of 15 percent.

Some energy-efficient motors have less "slip" than standard-efficiency motors, causing energy-efficient motors to run at slightly higher speeds; consider a larger pulley to compensate for the higher speed and to maximize energy savings. Installing a new pulley or adjusting the existing one can also be an alternative to a VSD when the cost for the VSD is prohibitive or the load has been reduced.

Improving fan system performance

A common way to improve the efficiency of the air distribution system is to convert constant air volume (CAV) systems to VAV. One authority on energy issues, E-Source, reports that "typical (VAV) air flow requirements are only about 60 percent of full CAV flow."

VAVs respond to load requirements by varying the volume of the air through a combination of pressure controls and dampers rather than by varying the air's temperature. According to the air pressure, fan power and volume of conditioned air are reduced, thus increasing energy efficiency. Of course, it is crucial to maintain indoor air quality (IAQ) when altering air handling systems.

To maximize savings, VAV components such as VSDs, variable-pitch fan blades, diffusers, mixers, and VAV boxes must be operating properly; careful zoning is also required to achieve VAV optimization.

E-Source recommends considering the following VAV retrofit procedures:

• complete load reduction measures and calculate the maximum and minimum air flow requirements,

• measure existing fan performance; examine duct system for possible improvements,

• stage fans that are in parallel configurations,

• commission the system thoroughly,

• optimize static pressure setpoint and implement reset control, and

• possibly remove return air fans.

Energy-efficient and properly sized motors are also recommended along with careful control strategies. Installing a self-contained, thermally powered device to each diffuser can add greater control to VAV systems by controlling individual spaces, rather than entire zones, and eliminate the need for VAV boxes. Such a device also offers VAV-style capabilities to CAV systems.

VAV retrofit costs and paybacks can vary widely. Installation problems related to fan control, reduced supply air distribution, location of pressure sensors and their reliability, in addition to deficient design, can diminish a VAV retrofit's performance. Because VAV boxes are relatively expensive and one is required for each zone, it is generally not cost effective to partition the space into many zones. Careful zone designation -- according to occupancy, internal loads and solar gain -- will maximize efficiency, increase comfort and reduce reheat.

When reheat cannot be eliminated, consider these steps to minimize it: ensuring thermostat calibration; increasing supply air temperatures during the cooling season; and monitoring reheat year round and possibly employing reheat only during winter months. Where reheat is used primarily to control humidity, a desiccant wheel or a heat pipe might be considered.

Downsizing existing VAV fan systems is a relatively low-cost way to save energy when loads have been reduced or when the air distribution system was oversized to begin with. The following are means to downsize fans or airflow requirements:

• Reduce static pressure setpoint to meet actual temperature and airflow requirements.

• Rightsize motors and upgrade to energy-efficient models; install larger pulleys.

• Replace the existing fan pulley with a larger one; that will reduce the fan's power requirements by reducing its speed.

• Make sure the fan's speed corresponds to the load. Reducing a fan's speed by 20 percent reduces its energy consumption by approximately 50 percent.

There are several ways to determine if VAV fan systems are oversized. If a motor's measured amperage is 25 percent less than its nameplate rating, it is oversized. If a fan's inlet vanes or outlet dampers are closed more than 20 percent, it is oversized. If the static pressure reading is less than the static pressure setpoint when inlets or dampers are open and VAV boxes open 100 percent, as on a hot summer day, the system is oversized. Again, be sure to consider IAQ requirements when downsizing air handling systems.

Chillers and thermal storage

No one wants to replace a perfectly good chiller just because of the CFC phaseout. But once load-reducing efficiency upgrades have been completed, it may actually be profitable to replace an oversized chiller. That's especially true given rising prices and tightening supplies of CFC refrigerants.

Oversized units 10 years or older are good candidates for replacement. A high-efficiency chiller reduces energy costs throughout its lifetime; initial costs are reduced because the replacement chiller is smaller than the old one. Depending on the old unit's efficiency and load, a high-efficiency chiller's energy consumption can be.15 to.30 kW/ton less, decreasing energy consumption by as much as 85 percent if combined with downsizing.

An alternative to replacement is to retrofit chillers to accommodate a new refrigerant and to match reduced loads. That may involve orifice plate replacement, impeller replacement and possibly compressor replacement, depending on the chiller's specifics.

Retrofitting may entail gasket and seal replacement and motor rewinding. Depending on the refrigerant and the way the retrofit is performed, the chiller may lose either efficiency or capacity. To determine whether replacement or retrofit is a better option, consider both initial and life-cycle costs.

Retubing the condenser and evaporator yields sizable energy savings but whether it makes sense, given its high cost, depends on the condition of the chiller. Water-cooled condensers are generally more efficient than air-cooled units. Because condenser water flows through an open loop, it is susceptible to fouling. Scale build-up will inhibit heat transfer efficiency; maintenance is therefore required to keep the surfaces clean.

Absorption chillers are an alternative to centrifugal models. Absorption chillers cost up to $150 per ton more than vapor compression chillers like centrifugal units, but can be profitable in areas of high electrical demand charges or where steam or gas is available, depending on the local utility rate structures. Using a combination of the two chiller types can reduce electrical demand charges.

Thermal energy storage (TES) uses conventional chiller equipment to produce conditioned water or ice (or occasionally another phase-change material) in off-peak periods. Water is withdrawn from storage during the day or at peak hours and circulated through the cooling system.

TES systems can be incorporated into new and existing systems and can provide partial load leveling or full load shifting. TES helps decrease operating and maintenance costs; in some cases, a smaller chiller can be specified. Some systems provide lower supply air and water temperatures, so air and water flow requirements can be cut.

Water-side improvements

Fill material, size and fan configurations affect cooling tower efficiency. Cellular fill (aka film packing) increases efficiency over other fill types. Oversizing the tower to allow for closer approach to ambient wetbulb temperature can improve its efficiency. Generously sizing the tower and increasing its share of the chiller load can make economic sense because a cooling tower's initial cost and energy use per ton are less than a chiller's.

At part-load conditions, applying a VSD to the fan (or pump) will improve the tower's efficiency. Systems with VSDs and several fans are more efficient when all tower cells are operating at reduced speed as opposed to one or two cells at full speed.

Because cooling towers contain large heat exchange surfaces, fouling -- scale or slime build-up -- can be a problem. The efficiency of improperly treated systems can be improved with effective water treatment. High-efficiency towers are available; induced-draft types are more popular and efficient than forced-draft towers. Performance can also be improved by increasing cooling surface area.

In traditional pumping systems, flow is generally constant volume; a throttle valve reduces flow at part-load conditions, inhibiting efficiency.

Installing VSDs on secondary pumps in variable flow systems, rightsizing pumps and motors to meet load requirements, and upgrading single loop systems to primary/secondary loop configurations can increase the performance and reliability of pumping systems. In upgrading chilled water pumps, it is important to meet maximum and minimum flow rates through the chiller.

Other cooling options

Desiccants are dehumidification materials which can be integrated into HVAC systems to reduce cooling loads and increase chiller efficiency while improving indoor air quality and comfort. Formerly found only in niche and industrial applications, desiccant cooling is extending throughout commercial markets.

Desiccants make sense when the cost to regenerate them is low compared to the cost to dehumidify below dewpoint and can reduce HVAC energy and peak demand by more than 50 percent in some cases.

Evaporative coolers provide one of the most economical and efficient means of cooling, using up to 75 percent less energy than vapor-compression systems. Though initial cost is typically higher, paybacks for evaporative coolers range between six months and five years. Though evaporative coolers are particularly prevalent in the arid West and Southwest, they can service most U.S. climates. E-Source states that, in combination with evaporative cooling, desiccant cooling can eliminate refrigerative air conditioning in many climates.

Hybrid systems that integrate evaporative cooling with conventional HVAC technologies offer additional opportunities. To improve performance consider lower air velocity; better fill materials; higher fan, pump and motor efficiencies, including VSDs; better belts or direct drive; improved housing; improved controls; and duct sealing. Proper maintenance is key to energy-efficiency.

Packaged air-conditioning units are typically found in buildings or building zones where the cooling load is less than 75 tons. Running these units at part load can severely reduce efficiency. They are generally not as efficient as chiller systems but can be upgraded and rightsized when replaced. Existing systems can be improved by using higher efficiency compressors, larger condensers and evaporators, and VSDs, though life expectancies of 10 to 12 years for these technologies may mean that retrofits are not cost-effective.

Heat pumps are among the most energy-efficient heating and cooling technologies available today. Low operating costs, increased reliability and long life expectancies improve their viability. They function best in moderate climates and proper sizing is critical.

Multi-unit configurations can service larger loads and provide zoning; large, modernized central units offering capacities of up to 1000 horsepower or 750 kilowatts are gaining popularity. Air-to-air type heat pumps are the most common because of low up-front costs; ground supply heat pumps are the most efficient but tend to have higher initial costs.

Boiler upgrades

Especially in colder climates, improved boiler performance -- with improved fuel and airflow controls over a range of load conditions and increased heat transfer surface areas -- can contribute substantially to energy savings. Smaller units arranged in modular systems increase efficiency up to 85 percent while small units replacing those with open-loop condensing systems shoot combustion efficiency up to 95 percent.

Boiler retrofits, combined with improved maintenance measures, can also increase efficiency -- up to 90 percent. New burners, baffle inserts, combustion controls, warm-weather controls, economizers, blowdown heat recovery and condensate return conversions provide increased efficiency opportunities. A smaller "summer" boiler might be a good option when a boiler is required year round though at reduced capacities in warmer conditions. The much smaller summer boiler is sized for reduced loads; the main boiler is shut down.

HVAC upgrades can provide tremendous economic benefits, improve occupant comfort and system reliability, and reduce operating costs. But to maximize benefits and minimize capital investment, load-reducing measures, such as lighting upgrades, should precede HVAC system upgrades.

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