Let the Sun Shine In
Four major things motivated my topic this month:
- The rising costs of fossil fuels;
- My personal interest in conserving the environment;
- Tax time; and
All of our budgets are being stretched by the rising costs of fossil fuels. There are many reasons for this, including geopolitical events like the nationalization of fossil fuel companies in Russia, Venezuela and Bolivia, and conflicts in the Middle East. Earth has a limited supply of easily (inexpensively) extracted fossil fuels, and increasing worldwide demand. In particular, we are no longer the only big customer on the world market. Even at our current, historically high consumption levels, both India and China are challenging the U.S. as having the biggest demand and market for fuel. Alternative energy sources, like solar power can help reduce our dependence on foreign oil.
As easily extracted fossil fuels become less abundant, we have to find “new” reserves. Those new sources are often in ecologically sensitive areas, like the Alaskan wilderness, and offshore. The risk of environmental accidents like those causes by the Exxon Valdez could have an impact on parts of the world that can never recover. Consumption is just half of the issue: what you don’t burn, you don’t pollute the atmosphere with. More and more experts are agreeing that global warming is caused by human impact on the earth, including emission gasses. Solar energy panels emit no harmful byproducts to the environment.
When we were kids, April was known as the month with showers. As adults, it is known as the month we give a substantial part of the money we have earned back to the government. The good news is that alternative energy sources are supported by Federal and local incentives in the form of tax rebates. Residential projects currently offer 25% of the project cost as a rebate. Commercial projects can offer as high as 30% of the installation, unlimited! These incentives significantly shorten the payback schedule for your solar installations.
Spring, glorious Spring, when we see the sun again in Chicago. Our long winter is coming to an end, and we are reminded of why anyone would want to live here. The sun is a resource that we appreciate because it provides light, lifts our spirits, make us warm, and makes our plants grow. It can also help reduce our energy bills.
Using the energy from the sun is not a new concept, but many things have changed since the 70’s when the first energy crunch hit. Solar collectors have improved, controls have improved, and our manufacturers and installers have had years to refine and perfect their installations.
How much energy is available from the sun? There is something called the solar constant, which refers to the approximately 440 BTU/hr/sq. ft. of energy generated by the sun that could potentially reach the earth. Of that potential energy, 30 to 60% is lost in the journey, and 170 to 315 BTU/hr/sq. ft. eventually reaches the surface. Here in Illinois, we receive 1260 to 1575 BTU/sq. ft./Day of energy from the sun. For optimum output, panels should be installed at a 45 degree angle and face South. Optimum output from a panel is roughly 220 BTU/hr/sq. ft. To absorb or collect this energy, there are several different panel or collector styles available. They range in design from photovoltaic, to tubes painted black with parabolic mirrors focusing on them, to flat panels, to vacuum tube collectors. All of these styles of collectors have different outputs per sq. ft. and different limitations to their installation details. The more efficient the panel, the more energy it absorbs, and the less it reflects. In addition, different panels may operate better for example, on a cloudy day, than others.
In the hydronic heating and plumbing industry, we can easily use panels that are hydronic in nature. We circulate a glycol solution through the panel, and the fluid absorbs the energy from the solar collector in the form of temperature, and the system pump then carries the energy to where it can do some work. Typical applications for hydronic based solar systems include supplement to comfort heating, domestic hot water production and pool heating. Comfort heating may initially seem the most intuitive application, but winter has the highest energy consumption, and the most adverse solar conditions. For Domestic water applications the panels are typically sized for 60% of the total load to insure that there is always a heat sink for the energy. Of all the applications, pool heating may make the most sense of all since we use our pools in the summer when the solar conditions are optimum. A rule of thumb for sizing pool systems is that you use enough solar panels to cover all of the surface of the pool.
This is just the tip of the iceberg, so to speak. Look for upcoming solar seminars from Bornquist, and from our local distributors. Learn about solar energy, how we can reduce our impact on the environment, reduce our energy bills and reduce our dependence on foreign oil. Solar systems, like those from Viessmann, represent practical alternative energy technology that is available today.