Companies that generate solvent waste understand that the most cost effective and environmentally acceptable method of managing spent solvent is by not generating it in the first place. Source reduction techniques or minimizing the generation of spent solvent at the source as well as pollution prevention (P2) where toxic solvents are replaced with new non toxic solvents recovery should be investigated before examining the feasibility of recycling the commonly used toxic Solvent Recovery System in many businesses today. This fact sheet will only address issues concerning  the commercial recycling of toxic solvents due to their potential threat to human health and the environment.

Companies must consider many issues before pursuing solvent recycling as a waste management option. While some companies have chosen to install in-house solvent distillation units to recycle their own spent solvent, others have enlisted the services of a commercial solvent recycling company.

In house solvent distillation units minimize transportation, disposal and potential liability costs associated with off-site disposal. Sometimes, however, in-house recycling is not cost effective or consistent with existing facilities and labor skills, or it fails to produce solvent that can be reused by the facility. In these instances, a commercial Waste Recovery System may be preferred

Forty years ago, Harold Hay, 98, invented a simple, inexpensive way to heat and cool a home using the sun’s rays, but without the panels and wiring that come with conventional solar energy systems.

He’s been pushing for its adoption ever since, trying to find footing in each of the solar industry’s last three boom-and-bust cycles.

Yet, despite the merits of his pioneering technology, the energy establishment has shown only fleeting interest.

As Gore said, quoting Upton Sinclair “it is hard to get someone to understand something — if their salary depends upon not understanding it.”

When it comes to climate change, those who refuse to act are mostly those without imagination, or those whose financial interests support the status quo. Passive solar systems cost little or nothing to operate, and so represent a serious threat to the fossil fuel industry.

Hay’s system keeps a house between 65-75 degrees year-round with virtually no electricity. What’s the catch? It requires the house to be built from scratch, and built strong enough to hold a roof-sized pond of water. Still, to have no heating or cooling bills for the life of the home? Wow. [Click the story link at the top of the article for a video of this house and how the system works.]

Even if people didn’t want to have flat roofs, I see no reason why they couldn’t heavily insulate their home and locate the solar pond elsewhere on their property. Then they could use pumps and heat-exchangers to take advantage of the water’s thermal mass. Certainly this could be a great way to cool apartments and commercial buildings as well.

Cheap electricity, fuel oil, and natural gas have kept people using energy-hogging central furnaces and forced-air systems, generating countless gigatons of CO2 for decades. Solutions such as the Skytherm house are as simple and elegant as it gets and produce no CO2. Only two things stand between our current situation and a clean planet and better life: greed and inertia.

Carbon taxes will make the status quo prohibitive, and force many of these types of solutions. There are many details to be worked out, of course, but a better national energy policy can turn this sad situation of needless energy waste around. There’s no excuse anymore, it’s just common sense. It’s high time for solar energy to stop being a science project and get mainstreamed

Have you been thinking about changing your power source over to renewable energy? I have also listed some of the Solar Energy Cons. A person can’t sincerely arrive at an honest conclusion without acknowledging the advantages and minuses. You should check into every aspect of changing over before approaching to your ultimate conclusion.There are more Pros that are not listed here that may or will not be essential to you depending upon your stance regarding the environment.

* Solar energy is a renewable resource. It doesn’t induce pollution while you generate it.
* Sunlight, unlike fossil fuels is all over, all though it is not evenly dispensed throughout the world. Solar energy can be made anywhere, even when there are no local utility supplier, therefore you are able to have power in inaccessible areas.
* With the correct resources, the components necessary to construct a solar system can be bought or produced rather inexpensively
* The nicest matter about solar power is that it’s costless to all.
* The engineering in use to implement solar radiation as energy to get electricity, heat, and mechanical power currently exists
* Solar systems possess no moving elements and can last numerous years.
* You don’t require fuel to be delivered to your home, and you will never run out.
* Granted the correct data, it’s almost always possible to forecast the amount of power a solar energy system will give.
* The systems are silent and becoming more and more unnoticeable.
* You will be able to qualify for financial incentives from the government to assist with paying for your system and also get tax breaks while it is in use.
* Using solar energy means one less home burning fossil fuels, and reduces the creation of greenhouse gas.

Solar Energy Cons

I’ve listed the Cons for using Solar Energy as well. Although there aren’t many disadvantages, they should still be weighed in.

* If you don’t know where to get the components at a discount, the original costs can be kind of high.
* Solar panels can require a lot of space. That’s why the roof is the optimal location for them to be set up.
* You can’t generate solar energy at nighttime, so you need a way to store it. Batteries are a good energy storage choice. With the right information, you can purchase batteries for as low a $10 apiece or even free!
* Bad weather conditions can impact the amount of energy generated.

As you can see the Solar Energy Pros overbalance the Solar Energy Cons. If you are worried about the environment and you also acknowledge the income saving potential of using solar power, then this can be a good path for you to choose. I think that someday in our lifetime, solar power will become a more popular choice. By harnessing the power of sunshine, the Earth could change for the better one home at a time. Besides, our grandchildren will appreciate it.

Solar water heaters can be used to heat swimming pools and spas.

In a solar pool-heating system, the existing pool filtration system pumps pool water through the solar collector, and the collected heat is transferred directly to the pool water. Solar pool-heating collectors operate just slightly warmer than the surrounding air temperature and typically use inexpensive, unglazed, low-temperature collectors made from specially formulated plastic materials. Glazed (glass-covered) solar collectors are not typically used in pool-heating applications, except for indoor pools, hot tubs, or spas in colder climates. In some cases, unglazed copper or copper-aluminum solar collectors are used.

In residential applications where the goal is usually to extend the swimming season into spring and fall, heating a swimming pool with solar energy requires a solar collector that is 50% to 100% of the surface area of the pool. In general, adding more square footage lengthens the swimming season and allows owners to use the pool in colder weather. A pool cover or blanket significantly reduces heat loss in a cost-effective manner and helps maintain warm temperatures for long periods.

A solar pool-heating system costs between $2,000 and $10,000 to buy and install, depending on size. Costs run between $7 – $12 per square foot depending on system design and collection type. This provides a return on investment between 1.5 and 7 years, depending on the cost of the auxiliary energy being displaced.

Maintenance of solar pool-heating systems is minimal. The systems are pre-engineered and can be sized for any pool by simply adding additional solar panels to obtain an adequate solar collector area.

The only moving part on a solar pool-heating system is the diverting valve. This valve controls when the water circulates through the collector loop. If the collector temperature is sufficiently higher than the temperature of the water in the pool, water is diverted from the filter systems through the collector loop. The water bypasses the solar collectors during the night or cloudy periods. Some smaller systems are operated manually or with timers. Larger systems are operated by electronic sensors and controls.

Here’s a look at some things we can expect in the future from solar technologies.

All our buildings will feature energy-efficient design, construction, and materials as well as renewable energy technologies. In effect, each building will both conserve energy and produce its own supply, to be one of a new generation of cost-effective “zero-energy buildings” that have no net annual need for nonrenewable energy.

In photovoltaic research and development, there will be more breakthroughs in new materials, cell designs, and novel approaches to product development. In a solar future, your mode of transportation—and even the clothes you wear—could produce clean, safe electric power.

With today’s technology roadmaps to lead the way, concentrating solar power will be fully competitive with conventional power-generating technologies within a decade. Concentrating solar power, or solar thermal electricity, could harness enough of the sun’s energy to provide large-scale, domestically secure, and environmentally friendly electricity, especially in the southwestern United States.

The enormous solar power potential of the Southwest—comparable in scale to the huge hydropower resource of the Northwest—will be realized. A desert area 10 miles by 15 miles could provide 20,000 megawatts of power, and the electricity needs of the entire United States could theoretically be met by a photovoltaic array within an area 100 miles on a side.

Within 10 years, photovoltaic power will be competitive in price with traditional sources of electricity.

Solar electricity will be used in an electrolysis process that separates the hydrogen and oxygen in water so the hydrogen can be used in fuel cells for transportation and in buildings.

Just as solar energy can heat the water for a building, it can also heat and cool the air.

Space Heating

A solar space-heating system can consist of a passive system, an active system, or a combination of both. Passive systems are typically less costly and less complex than active systems. However, when retrofitting a building, active systems might be the only option for obtaining solar energy.

Passive Solar Space Heating

Passive solar space heating takes advantage of warmth from the sun through design features, such as large south-facing windows, and materials in the floors or walls that absorb warmth during the day and release that warmth at night when it is needed most. A sunspace or greenhouse is a good example of a passive system for solar space heating.

Passive solar design systems usually have one of three designs:

• Direct gain (the simplest system) stores and slowly releases heat energy collected from the sun shining directly into the building and warming materials such as tile or concrete. Care must be taken to avoid overheating the space.
• Indirect gain (similar to direct gain) uses materials that hold, store, and release heat; the material is located between the sun and living space (typically the wall).
• Isolated gain collects solar energy remote from the location of the primary living area. For example, a sunroom attached to a house collects warmer air that flows naturally to the rest of the house.

For more information about passive solar space heating, visit the EERE Passive Solar Heating, Cooling, and Daylighting page.

Active Solar Space Heating

Active solar space-heating systems consist of collectors that collect and absorb solar radiation combined with electric fans or pumps to transfer and distribute that solar heat. Active systems also generally have an energy-storage system to provide heat when the sun is not shining. The two basic types of active solar space-heating systems use either liquid or air as the heat-transfer medium in their solar energy collectors.

Liquid-based systems heat water or an antifreeze solution in a hydronic collector. Air-based systems heat air in an air collector. Air-based solar heating systems usually employ an air-to-water heat exchanger to supply heat to the domestic hot water system, making the system useful in the summertime. Both of these systems collect and absorb solar radiation, then transfer the solar heat directly to the interior space or to a storage system, from which the heat is distributed. An auxiliary or backup system provides heat when storage is discharged. Liquid systems are more often used when storage is included.

Here is a summary of the many different types of active solar space-heating systems:

Medium-temperature solar collectors are generally used for solar space heating. Solar space heating systems operate in much the same way as indirect solar water-heating systems, but they have a larger collector area, larger storage units, and more complex control systems. They are also usually configured to provide solar water heating and typically provide 30% to 70% of the residential heating, or combined heating and hot water, requirements. Active solar space-heating systems require more sophisticated design, installation, and maintenance techniques.

• A very economical, but specialized space heating system is based upon use of transpired air collectors, mounted as an exterior cladding on a south-facing wall. These systems are used for ventilation preheating. This system heats only outdoor air. These collectors are unglazed, and a blower or fan is used to draw air through perforations in the wall to deliver ventilation air into the building. Solar ventilation air preheating systems are generally used in commercial and industrial applications that require large quantities of ventilation air, including: a) buildings that require much outdoor ventilation, such as warehouses, large manufacturing plants, and airplane maintenance hangars; b) crop drying; and c) pre-heatingof boiler combustion air.

Space Cooling

Cooling and refrigeration can be accomplished using thermally activated cooling systems (TACS) driven by solar energy. These systems can provide year-round utilization of collected solar heat, thereby significantly increasing the cost effectiveness and energy contribution of solar installations. These systems are sized to provide 30% to 60% of building cooling requirements using solar, with the remainder usually dependent on TACS fueled by natural gas. The TACS available for solar-driven cooling include absorption systems and desiccant systems. Generally, solar cooling is not used because of the high initial costs of TACS and the solar fields needed to drive them.

• Solar absorption systems use the thermal energy from a solar collector to separate a binary mixture of an absorbent and a refrigerant fluid. The refrigerant is condensed, throttled, and evaporated to yield a cooling effect, which is then re-absorbed to continue the cycle. Double-effect absorption systems (which use the heat twice in series) are about twice as efficient as single-effect systems, but require significantly higher input temperatures. Because of the high temperature requirements of absorption cooling systems, evacuated-tube or concentrating collectors are typically used.
• Solar desiccant systems use thermal energy from the solar collector to regenerate dessicants that dry ambient air; they then use that dry air in indirect and/or direct evaporative stages to provide cooled air to the load. The solar heat is used to regenerate the desiccant, driving off the absorbed water. Some systems use flat-plate collectors at intermediate temperatures.