Solar Water Heaters Washington DC
Solar Water Heating
Back in the mid-1970s, my father had a solar water-heating system installed on our house in Memphis, Tenn. The neighbors thought we were "with it," but like so many solar water systems back then, the equipment was unreliable. We ended up with little more than a flashy piece of junk on our roof. Solar has come a long way since then. These days, solar water heating is a well-established, highly effective technology that can be used virtually anywhere in the country. Sure, solar water systems can be expensive to buy and install, but they have a number of benefits: They don't pollute.
They provide a cushion against fuel shortages and the wild price fluctuations of oil and gas. They lessen our reliance on foreign oil. And, perhaps most important, they can save money in the long run. The sun, after all, is free fuel. Water heating accounts for nearly one-fifth of all energy consumption in the residential sector nationally, according to the Department of Energy. Given that, it shouldn't be a surprise that more than a million American homes and businesses, and half a million swimming pools, are equipped to use water heated by the sun. And the number is growing. Brad Collins, executive director of the nonprofit American Solar Energy Society in Boulder, Colo., said solar water systems in the 1970s and '80s usually had good design, but were not always reliable in their technology and installation. "Today, things are substantially improved, and what you have is a win-win-win," Collins said. "You have good technology, good maintenance, good installation and vendors who will stand behind their product.
Domestic solar hot water is a no-brainer." Harnessing the Sun A solar water heater is simply a mechanism to harness the sun's energy to heat water. All you need for such a system is an unshaded roof area that faces south and, of course, the sun. Solar water systems vary widely, but they are alike in one regard: They usually have solar collectors and storage tanks. The typical flat-plate collector is a thin, flat, rectangular box with a transparent cover that is mounted on a roof, facing the sun. It looks like a skylight. The sun heats an absorber plate in the collector, which in turn heats fluid running through tubes within the collector. In an active system, the heated fluid is pumped to a storage tank inside the house.
In a passive system, the fluid moves by gravity into a storage tank on the roof. In the simplest systems, household water is heated directly as it passes through the collectors; this is known as an open-loop or direct system. In closed-loop systems, some other type of fluid, such as diluted antifreeze, is heated as it passes through the collector's tubes. The fluid then passes through a heat exchanger, which is usually in the water-storage tank, where it transfers the heat to the water. In most cases, but not all, solar water-heating systems work alongside conventional gas or electric hot-water heaters, which activate when necessary. First Things First The first thing to ask yourself when considering whether to install a solar water system is how much you spend each year to heat your water. The DOE estimates the nationwide energy use for water heating at about 18 percent of residential consumption, but that number can vary considerably depending on where you live. In many areas, heating water can account for 30 percent or more of residential energy consumption. If you live by yourself or don't use a large amount of hot water, then you probably won't save much money with a solar water system.
But if you have a large family, a swimming pool that you want to heat, or you wash a lot of dishes and clothes, then a solar water system could be for you. The time it takes to recoup your investment depends on many variables: size of family, tax incentives, cost of the system and where you live. Solar water systems can cost anywhere from $1,000 to $5,000 or more, and vary from region to region. A swimming pool system typically costs $2,000 to $4,000. (See story on page 26.) It takes a little math to figure your savings. According to an analysis by the Florida Solar Energy Center in Cocoa, Fla., if your total monthly utility bill is $160 a month, and 25 percent of that comes from heating water, then your monthly expense for heating water is $40. If you buy a $2,000 solar water heater that provides an average of 60 percent of your hot water needs, you will save $24 a month - or $288 a year.
If it provides all of your hot water, your savings will be $480 a year. Every situation is different, but if you save $24 a month, the payback will be 6.9 years, which does not include the operational and maintenance costs of $25 to $30 a year that your solar water system will require. For the remainder of the life of the solar water heater - which can be more than 20 years - 60 percent of your hot water will be free. "There's a saying in the industry that the price of the fuel is in the initial purchase price of the equipment," said Griffin Carrison, president of Thermal Conversion Technology Inc. of Sarasota, Fla. "Once you have the equipment, you don't have any fuel costs." Kicking the Tires Once you decide that a solar water system makes sense, you need to determine the type and size that are right for you. Solar-equipment experts use worksheets or computer programs to help determine how large a system you need.
Solar storage tanks are usually 50-, 60-, 80- or 120-gallon capacity. A small (50- to 60-gallon) system is enough for one to three people, a medium (80-gallon) system is adequate for a three- or four-person household, and a large (120-gallon) system is appropriate for four to six people, according to the DOE. To size the collectors, allow about 20 square feet of collector area for each of the first two family members. Allow 8 square feet for each additional family member if you live in the Sun Belt and 12 to 14 square feet per additional person if you live in the north. You can also buy solar water systems with smaller collectors that are retrofitted to existing water heaters. They will provide only 50 to 60 percent of the hot water because of their smaller size, but they also cost less up front. You then need to work with contractors to decide which type of system - passive or active, closed-loop or open-loop - is right for you. Active systems are more common in colder climates with sustained freezing temperatures, but passive systems may be okay there too.
"I have customers up here who have had passive systems for 20 years, and they're still clicking away," said Henry Vandermark, president of Solar Wave Energy Inc. in Charlestown, Mass. But no matter what you choose, experts say it is important to make sure the equipment you buy is certified to ensure it meets quality standards. Nationally, the Solar Rating Tue, 01 Jan 2002 00:00:00 Clarke Canfield The Facts About Mold http://www.smart-homeowner.com/node/7971
Exposure can occur if people inhale the spores, accidentally ingest them or directly handle moldy materials. Also, mold can sometimes produce chemicals called mycotoxins. Mycotoxins may cause illness in people who are sensitive to them or if they are exposed to large amounts in the air. Large exposures are typically associated with certain occupations, such as farming. Q. How does mold grow? A. All mold needs water to grow. Mold can grow almost anywhere there is water, high humidity or dampness. Most often, molds are confined to areas near the source of water. Removing the source of moisture - such as through repairs or dehumidification - is critical to preventing mold growth. Q. What is stachybotrys chartarum? A. Stachybotrys chartarum (also known as stachybotrys atra) is a type of mold that has been associated with health problems. It is a greenish-black mold that can grow on materials with a high cellulose content - such as drywall, dropped ceiling tiles and wood - that become chronically moist or water-damaged due to excessive humidity, water leaks, condensation or flooding. Q. How can you tell if stachybotrys is present in your home? A. Many molds are black in appearance but are not stachybotrys.
For example, the black mold commonly found between bathroom tiles is not stachybotrys. Stachybotrys can be positively identified only by specially trained professionals through a microscopic exam. Q. How can stachybotrys affect your health? A. Typically, indoor air levels of stachybotrys are low; however, as with other types of mold, health problems can occur with higher levels of stachybotrys. These include allergic rhinitis (cold-like symptoms), dermatitis (rashes), sinusitis, conjunctivitis and aggravation of asthma. Some related symptoms are more general - such as fatigue and inability to concentrate. Symptoms usually disappear after the contamination is removed. There has been some evidence linking stachybotrys with pulmonary hemosiderosis in infants who are generally less than six months old.
Pulmonary hemosiderosis is an uncommon condition that results from bleeding in the lungs. In case studies of pulmonary hemosiderosis, the exposure to stachybotrys came from highly contaminated dwellings, where the infants were continually exposed over a long period of time. Q. What should you do if mold is present in your home? A. Although any visible mold can be sampled by an environmental consultant and/or analyzed by a laboratory specializing in microbiology, these tests can be expensive - from hundreds to thousands of dollars. There is no simple and cheap way to sample the air in your home to find out what types of mold are present and whether they are airborne. Even if you have your home tested, it is difficult to say at what levels health problems would occur.
The most effective way to treat mold is to correct underlying water damage and clean the affected area. Q. How should mold be cleaned? A. People cleaning mold should be free of symptoms and allergies. Small areas of mold should be cleaned using a detergent/soapy solution or an appropriate household cleaner. Gloves should be worn during cleaning. The cleaned area should then be thoroughly dried. Dispose of any sponges or rags used to clean mold. If the mold returns quickly or spreads, it may indicate an underlying problem, such as a leak. Any underlying water problems must be fixed to successfully eliminate mold problems. If mold contamination is extensive, a professional abatement company may need to be consulted. Source: Interviews, New York City Department of Health