What is a solar water heater?
A solar water heater uses the sun's energy to pre-heat household water before it enters the conventional gas (or electric) water heater. Because Texas is blessed with such sunny weather, a solar water heater could generate up to 90% of your annual water heating needs.
How hot can solar heated domestic water get?
Water heated by the sun can reach temperatures exceeding 212° F, but the normal temperature for household use is only 120° to 130° F.
Are there different kinds of solar water heaters?
Solar water heaters are divided into two kinds of systems: active or passive. Active solar systems rely upon moving mechanical parts in order to transport heat, while passive units simply use the sun to accomplish this action. The bulk of systems installed in Texas are active because they are considered to be more efficient and attractive.
How does a solar water-heating system work?
Every solar water-heating system features a solar collector that faces the sun to absorb the sun's heat energy. This collector can either heat water directly or heat a "working fluid" that's then used to heat the water. In active solar water-heating systems, a pumping mechanism moves heated water through the building. In passive solar water-heating systems, the water moves by natural convection. In almost all cases, solar water-heating systems work in tandem with conventional gas or electric water-heating systems; the conventional systems operate as needed to ensure a reliable supply of heated water.
There are many types of solar water heaters. Each has strengths to recommend it for specific climates and water conditions. Solar system professionals can help you select the most appropriate system for your area and your needs.
Are there any disadvantages to using solar energy?
The energy in sunlight can be used for many purposes, including heating water for a building or swimming pool. And using solar energy has many environmental and life-cycle economic benefits. However, solar energy heating or solar electric products often have higher "first costs" than other, similar products do. This means it will probably cost more initially to purchase and install a solar system than it will to purchase and install another kind of heating or electric system. Still, in nearly all cases, you will recover your initial costs through substantial fuel savings (as shown in lower utility bills) over the life of the product. Many solar systems last from 15 to 30 years.
Can a solar water heater replace an electric or gas water heater?
Not completely. Conventional electric or gas water heating systems are still necessary as a supplement to the solar water heating system, largely because the sun might not shine in a particular area for several days at a time. However, because solar water heaters are designed provide hot water directly to the tank of a gas or electric water heater, they reduce the need for the water heater to run on conventional fuels. And this in turn reduces your gas or electric bill.
Can solar power be used to heat my home and business?
Yes- pre-engineered residential solar space heating systems are readily available to consumers today. But many solar energy professionals can engineer a system for you, on request. However, solar space-heating systems are considerably more expensive than solar water-heating systems. Depending on the size of the space that needs heating, a solar system could cost anywhere from $3,000 to more than $10,000. A solar energy professional in your area can explain what would be involved to purchase this type of solar system. You may want to consider increasing your insulation and using passive solar technologiesâ€”such as large, energy-efficient, south-facing windowsâ€”as an alternative.
What are the benefits of using solar energy to heat water in my home?
First, the fuel is free! Once you recover the higher initial costs of a solar system through reduced or avoided energy costs (that is, lower utility bills), your solar system will require expenditures only for maintenance. And when you include the cost of a solar water heater in a mortgage on a new home, the system often provides a positive monthly cash flow from the first day of ownership.
Second, solar water heaters and other solar technology applications do not pollute. They do not add to the carbon dioxide, nitrogen oxides, sulfur dioxide, and other air pollutants and wastes produced by most of today's power plants, even those that run on natural gas. And they allow you to burn less natural gas in your home, as well.
Aren't solar water heaters bulky and unattractive?
In the 1970s, solar water heating technology was being developed and installed quite rapidly in response to that decade's energy crises. At that time, efficiency and ease of installation were the priorities, often at the expense of appearance. Many people thought that roof-mounted solar collectors were unsightly, even though they helped to reduce the amount of unsightly smoke billowing from coal-fired power plants! Still, the resulting attention to aesthetics has resulted in the "skylight" look of many of today's solar collectors.
How much does a solar water-heating system cost?
The cost may vary from $4,000 to $8,000. It depends largely upon the following variables: "* Size of the family to be served (and therefore the amount of heat required)
* Size, type and brand of solar system
* Type of roof upon which the panels are mounted
* Building code requirements
* Orientation of panels"
Unfortunately, there is no one answer to this question. The cost of a solar system depends on a number of factors, such as the size of the system and the particular system manufacturer, retailer, and installer.
For solar water heaters, you will also be taking into consideration the price of the fuel used to back up the system. In most cases, you will have to add in the cost of supplemental natural gas or electricity to get a fairly accurate estimate of how much you can expect to pay for a solar system.
Some home builders are beginning to list solar water heaters as an option for their homes. Others include them as a standard feature in every home. In some cases, the builder or mortgage company may offer a lower interest rate when solar water heaters or other energy-efficient features are built into a new home, because the buyer can expect to save a significant amount of money on future energy bills. Although a solar water-heating system still costs more than a conventional electric or gas water heater, some states and utilities offer rebates that can reduce the total cost appreciably.
Solar water heating (SWH) is a technology that every homeowner can use to save on utility bills. In a year the average household of four will consume enough energy to heat water to fuel an intermediate sized car for 20,000 miles. Many Solar Domestic Hot Water (sdhw) systems were installed at the turn of the century (early 1900's) in Texas before natural gas became predominant. Over the last twenty-five years of trial and error, modern systems are not only efficient and cost effective, but also extremely reliable.
How do active solar collectors work?
The collector is usually an all copper tube and fin absorber enclosed with an insulated aluminum frame or "box", covered with a low-iron tempered glass glazing. The water contained within the gas or electric water heater is circulated through the solar panels in a single-tank system, or a separate tank is used to pre-heat the water before it enters the conventional water heater in a two-tank system. A two tank system is usually considered to be the best option but if properly managed, a single tank system can provide between 50 and 80% of the household needs for hot water. The water being circulated is gradually heated and the system should be sized to provide between fifteen to twenty-five gallons of hot water per person per day. A reliable automatic control to operate the pump is essential. Fortunately, pumps and electronic controls have evolved and can be expected to provide over twenty years (and counting!) of service.
How do "Drain Back" solar systems work?
The "DB" System Provides a reliable method for ensuring that the collectors and their pipelines never freeze. This is done by removing all the water from the collector(s) and piping when the system is not producing heat. Freeze protection is provided when the system is in the drain mode. Each time the pump shuts off the water in the collector(s) and piping drains into the insulated reservoir tank. To allow for complete drainage the collector(s) and piping are mounted at a slight angle. A sight glass attached to the reservoir tank shows when the reservoir tank is full, indicating that the collector(s) has been completely drained.
The differential control of the "DB" System activates the pump using the same strategy as the "D" System. The solution, distilled water or antifreeze, circulates in a closed loop never coming in direct contact with the potable water in the storage tank. The closed loop includes the collector, connecting piping, pump, reservoir tank and heat exchanger. The heat exchanger wraps around the perimeter of the storage tank heating the potable water in the tank.
Will solar heating affect how much water I will have?
Yes and No. You will actually have much more hot water than ever before. If the system is sized well for your family, you will no longer need to wait for the water heater to "recharge" between showers.
Solar water heaters are always installed in addition to your regular water heater. That means that even during bad weather you will still have hot water. To maximize your savings, you should attempt to use the most hot water in the late morning and early afternoon when the solar system is operating at its peak. Also, it helps to spread your cleaning load over the week. For example, instead of washing seven laundry loads all at once it would pay to do one a day. This will reduce the amount your regular water heater must operate.
Will the solar system affect my existing water heater?
Yes. Since the water heater will operate far less frequently, solar will extend its life significantly. Some water heaters that were retrofitted with solar in 1974 are still in service today, over a quarter of a century later. The life of an ordinary gas heater without solar is between five and ten years.
How much do I save?
It depends upon the size of the system and the needs of your family and the way you currently heat your water. The average annual cost for water heating is usually over half the annual gas bill. Typically a person uses between fifteen and twenty-five gallons of hot water a day, which can cost $5.00 to $25.00 per person every month. A family of four could be spending between $384 to $1200 a year just for heating water. A gas bill is charged at varying rates or tiers, and the most costly level or tier is levied in winter, when you are using the most gas. A solar system can reduce your daily gas consumption and thus you will be purchasing the less expensive Tier 1 or "Lifeline" rates.
Are there any public incentives available?
Yes. There is a federal tax credit available to help lower the final cost. It is 30% of the cost with a maximum limit of $2,000 and is scheduled to expire at the end of 2008. If the water heating system is used in a business then there is no limit or cap and accelerated depreciation (MACRS) can also be used to reduce the financial impact.
How long does it take for a solar heater to pay for itself?
Solar heating does have a payback, and it can vary from four to ten years. But it may be more useful to think of solar as an investment that yields an annual return, much as a bank savings account provides interest. A solar water heater will generate savings that can equal a bank account generating a twenty percent (20%) annual return, and the savings are not taxed as income, as is the interest you earn at the bank. The truth is, if you want hot water... you will be paying for that heat. You may prefer to pay the utility bill forever, or you may wish instead to go solar, and become your own utility. It is quite similar to the reason you once decided to buy your home and stop renting. Solar is simply the best investment available today because it guarantees a return on money that you will otherwise "burn" and helps you develop equity as you bank your savings.