NET ZERO HOMES

NIST test house exceeds goal; ends year with energy to spare The net-zero energy test house at the National Institute of Standards and Technology (NIST) in suburban Washington, D.C., not only absorbed winter's best shot, it came out on top, reaching its one-year anniversary on July 1 with enough surplus energy to power an electric car for about 1,440 miles. Despite five months of below-average temperatures and twice the normal amount of snowfall, NIST's Net-Zero Energy Residential Test Facility (NZERTF) ended its one-year test run with 491 kilowatt hours of extra energy. Instead of paying almost $4,400 for electricity-the estimated average annual bill for a comparable modern home in Maryland-the virtual family of four residing in the all-electric test house actually earned a credit by exporting the surplus energy to the local utility. A net-zero energy house produces at least as much energy as it consumes over the course of a year. A number of states are taking steps toward encouraging or even requiring construction of net-zero energy homes in the future. For example, California will require that, as of 2020, all newly constructed homes must be net-zero energy ready. Both a laboratory and a house, the two-story, four-bedroom, three-bath NZERTF would blend in nicely in a new suburban subdivision. But it was designed and built to be about 60 percent more energy efficient than houses built to meet the requirements of the 2012 version of the International Energy Conservation Code, which Maryland has adopted. The 2,700 square-foot  test house is built to U.S. Green Building Council LEED Platinum standards-the highest standard for sustainable structures. Its features include energy-efficient construction and appliances, as well as energy-generating technologies, such as solar water heating and a solar photovoltaic system. Despite 38 days when the test house's solar panels were covered with snow or ice, the NZERTF's sun-powered generation system produced 13,577 kilowatt hours of energy. That's 491 kilowatt hours more than used by the house and its occupants, a computer-simulated family of two working parents and two children, ages 8 and 14. First year energy use totaled 13,086 kilowatt hours, which was about 3,000 kilowatt hours more than projected usage in a year with typical weather. In a normal year, a comparable home built to meet Maryland's residential energy standard would consume almost 27,000 kilowatt hours of energy. In terms of energy consumed per unit of living space-a measure of energy-use intensity-the NIST test house is calculated to be almost 70 percent more efficient than the average house in Washington, D.C., and nearby states. From July through October, the facility registered monthly surpluses. In November, when space-heating demands increased and the declining angle of the sun reduced the energy output of its 32 solar panels, the NZERTF began running monthly deficits. Through March 31, when the house's net energy deficit plummeted to 1,800 kilowatt hours-roughly equivalent to the combined amount of energy a refrigerator and clothes dryer would use in a year-temperatures consistently averaged below normal. Starting in April, the energy tide began to turn as the house began to export electric power to the grid on most days. In terms of cost, the NZERTF's virtual residents saved $4,373 in electricity payments, or $364 a month. However, front-end costs for solar panels, added insulation, triple-paned windows, and other technologies and upgrades aimed at achieving net-zero energy performance are sizable. In all, estimates that incorporating all of the NZERTF's energy-related technologies and efficiency-enhancing construction improvements would add about $162,700 to the price of a similar house built to comply with Maryland's state building code. Planned measurement-related research at the NZERTF will yield knowledge and tools to help trim this cost difference. Results also will be helpful in identifying affordable measures that will be most effective in reducing energy consumption. And research will further the development of tests and standards that are reliable benchmarks of energy efficiency and environmental performance overall, providing information useful to builders, home buyers, regulators and others.

RENEWABLE ENERGIES CONTINUE TO GROW

Renewable energy use gaining worldwide

Renewables like solar and wind represent the fastest-growing source of energy power generation and will make up a quarter of the global power mix by 2018.

In 2016 renewable energy will overtake natural gas as a power source and will be twice that of nuclear, and second only to coal as a source of power.

The growth of renewables -- non-fossil fuels like hydropower, wind, solar, geothermal and bioenergy -- has been bolstered by increased competitiveness compared with conventional energy.

Non-hydro renewable power, mainly wind and solar photovoltaics, is projected to grow from 4 percent of all power generation in 2011 to 8 percent in 2018.

Still there is some uncertainty about long-term government policies that discourages investment; reduced subsidies in some countries due to economic problems; and tough competition from other energy sources, such as the United States, where a boom in shale gas has made that fuel more competitive.

US President Barack Obama's energy and climate proposals were unveiled Tuesday. Obama's polices constitute a clear example of a target that goes beyond the four years of a presidential mandate.

A report released earlier this month warned the world is on track to surpass by more than double the two-degree Celsius warming goal set by the United Nations, unless urgent measures are taken. The recommendations include curtailing coal-fired power stations and phasing out fossil fuel subsidies.

Let's continue the growth in all areas of renewables right here in the USA.

JUST TO REMIND YOU

Here are the five most practical and popular ways that solar energy is used:

IN NO SPECIAL ORDER.

1.       Small portable solar photovoltaic systems.

      We see these used everywhere, from calculators to solar garden products; portable units can be used for everything from RV appliances while single panel systems are used for traffic signs and remote monitoring stations.

2.       Solar pool heating. 

      Running water in direct circulation systems through a solar collector is a very practical way to heat water for your pool or hot tub.

3.       Thermal glycol energy to heat water. 

      In this method (indirect circulation), glycol is heated by the sun's rays and the heat is then transferred to water in a hot water tank.
This method of collecting the sun's energy is more practical now than ever. In areas as far north as Edmonton, Alberta, solar thermal to heat water is economically sound. It can pay for itself in three years or less.

4.       Integrating solar photovoltaic energy into your home or business power. 

      In many parts of the world, solar photovoltaics is an economically feasible way to supplement the power of your home. In Japan, photovoltaics are competitive with other forms of power. In the US, new incentive programs make this form of solar energy ever more viable in many states. An increasingly popular and practical way of integrating solar energy into the power of your home or business is through the use of building integrated solar photovoltaics.

5.       Large independent photovoltaic systems. 

      If you have enough sun power at your site, you may be able to go off grid. You may also integrate or hybridize your solar energy system with wind power or other forms of renewable energy to stay 'off the grid.'

Want to know the Difference?

Solar Thermal vs. Photovoltaic

It is important to understand that solar thermal technology is not the same as solar panel, or photovoltaic, technology. Solar thermal electric energy generation concentrates the light from the sun to create heat, and that heat is used to run a heat engine, which turns a generator to make electricity. The working fluid that is heated by the concentrated sunlight can be a liquid or a gas. Different working fluids include water, oil, salts, air, nitrogen, helium, etc. Different engine types include steam engines, gas turbines, Stirling engines, etc. All of these engines can be quite efficient, often between 30% and 40%, and are capable of producing 10's to 100's of megawatts of power.

Photovoltaic, or PV energy conversion, on the other hand, directly converts the sun's light into electricity. This means that solar panels are only effective during daylight hours because storing electricity is not a particularly efficient process.

Heat storage is a far easier and efficient method, which is what makes solar thermal so attractive for large-scale energy production. Heat can be stored during the day and then converted into electricity at night. Solar thermal plants that have storage capacities can drastically improve both the economics and the dispatchability of solar electricity.

SOLAR FACTS

Here are the five most practical and popular ways that solar energy is used:


1. Small portable solar photovoltaic systems. We see these used everywhere, from calculators to solar garden products. Portable units can be used for everything from RV appliances while single panel systems are used for traffic signs and remote monitoring stations.

2. Solar pool heating. Running water in direct circulation systems through a solar collector is a very practical way to heat water for your pool or hot tub.

3. Thermal glycol energy to heat water. In this method (indirect circulation), glycol is heated by the sun's rays and the heat is then transferred to water in a hot water tank.

This method of collecting the sun's energy is more practical now than ever. In areas as far north as Edmonton, Alberta, solar thermal to heat water is economically sound. It can pay for itself in three years or less.

 4. Integrating solar photovoltaic energy into your home or business power. In many parts of the world, solar photovoltaics is an economically feasible way to supplement the power of your home. In Japan, photovoltaics are competitive with other forms of power. In the US, new incentive programs make this form of solar energy ever more viable in many states. An increasingly popular and practical way of integrating solar energy into the power of your home or business is through the use of building integrated solar photovoltaics.

5. Large independent photovoltaic systems. If you have enough sun power at your site, you may be able to go off grid. You may also integrate or hybridize your solar energy system with wind power or other forms of renewable energy to stay 'off the grid.'

SAVE MONEY WITH SOLAR WATER HEATERS

Solar Water Heaters


Solar water heaters—also called solar domestic hot water systems—can be a cost-effective way to generate hot water for your home. They can be used in any climate, and the fuel they use—sunshine—is free.

How They Work

Solar water heating systems include storage tanks and solar collectors. There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don't.

Most solar water heaters require a well-insulated storage tank. Solar storage tanks have an additional outlet and inlet connected to and from the collector. In two-tank systems, the solar water heater preheats water before it enters the conventional water heater. In one-tank systems, the back-up heater is combined with the solar storage in one tank.

Pumps circulate a non-freezing, heat-transfer fluid through the collectors and a heat exchanger. This heats the water that then flows into the home. They are popular in climates prone to freezing temperatures.





Passive solar water heating systems are typically less expensive than active systems, but they're usually not as efficient. However, passive systems can be more reliable and may last longer. There are two basic types of passive systems:

• Integral collector-storage passive systems

These work best in areas where temperatures rarely fall below freezing. They also work well in households with significant daytime and evening hot-water needs.

• Thermosyphon systems

Water flows through the system when warm water rises as cooler water sinks. The collector must be installed below the storage tank so that warm water will rise into the tank. These systems are reliable, but contractors must pay careful attention to the roof design because of the heavy storage tank. They are usually more expensive than integral collector-storage passive systems.


Solar water heating systems almost always require a backup system for cloudy days and times of increased demand. Conventional storage water heaters usually provide backup and may already be part of the solar system package. A backup system may also be part of the solar collector, such as rooftop tanks with thermosyphon systems. Since an integral-collector storage system already stores hot water in addition to collecting solar heat, it may be packaged with a demand (tankless or instantaneous) water heater for backup.