In the very near future, global economies will face enormous challenges to resolve an ever growing need for ecologically friendly renewable energy resources.

Replacement of conventional fossil fuel or nuclear energy resources by renewable energies will mandate industries, academia and research institution to provide immediate technological solutions to curb the global environmental pollution.

Within coming decades, the green technology industry will undergo unprecedented growth and will represent a significant component of the US gross national product. To facilitate the technological growth, it is incumbent for the United States to keep pace with other industrial nations to educate, inform and facilitate use of the cleanest of all renewable energy resources, namely solar-power co-generation systems. As the richest industrial nation and largest consumer of the global energy resources and environmental polluters, we must assume a national moral imperative to lead by example.

The following are examples of solar-power, co-generation system installations in residential applications. The description for each installation outlines basic system configurations.

Palm Springs, California
Residential power demand for a single-family dwelling involves specific limits of energy use allocations for area lighting, kitchen appliances, laundry, and air conditioning systems. In this example, the allowed maximum lighting power consumption is 3 watts per square foot of habitable area. The laundry load allowed is 1,500 watts for the washer and dryer.

The first 3,000 watts of the total combined lighting and laundry loads are accounted at 100 percent and the remaining balance is applied at 35 percent. The total appliance loads when exceeding quantity of five are also derated by 25 percent. Air conditioning and other loads such as pool, sauna, and Jacuzzi are applied at their 100 percent value. The demand load calculation of a 1,400 square foot residential dwelling indicates a continuous demand load of about 3,000 watts per hour. If it is assumed that the residence is fully occupied and is in use for 12 hours a day, the total, daily-demand load translates into 36,000 watt/hours per day.

Since the average daily irradiance or insolation in Southern California is about 5.5 hours, the approximate solar power system required to satisfy the daily demand load will be about 6,000 watts. Occupancies which are not fully inhabited throughout the day may require somewhat smaller systems.

In general, an average eight hours of habitation time should be used for sizing a solar power system, which in this example would yield a total daily power demand of 24,000 watt hours that in turn, translates into a 4,000-watt solar power system.

The Heavenly Retreat Project
Here is an example of excellence in solar-heating and power-generation design. The designer has taken maximum advantage of applying sustainable-energy systems design and has blended the technology with the natural setting of the environment.

The Heavenly Retreat is a unique, celestially-aligned, passive and active solar home, with two built-in integrated greenhouses, located at 9000 feet elevation in the northern New Mexico Rockies. The heavily forested land is located on the northwest face of an 11,600 foot peak facing Wheeler Peak, the highest point in New Mexico a landmark in the Southern Rockies. The property slopes and is set amidst tall pines and fir trees. The south side of the property opens to a large garden with a solar calendar that marks the sunrises and sunsets through the year within a meditation circle and seating area.

The passive solar design was established by first visiting the natural, forested area many times over a three-year period, from 1985 to 1988, to measure and observe the motions and arc of the Sun and Moon, as well as establish celestial cardinal points to North and South. The design aligns many rooms and exterior walls toward Polaris in the north, and thus establishes solar south. Many rooms have markers and cast shadows along the floors that show when the sun is at the solar south position, thus indicating the daily time of local solar noon, creating a silent rhythm within the living spaces.

Using these studies of the sun, moon and planetary alignments, as well as building with adobe, heavy beam, and recyclable-product construction and insulation, the home is a tribute to its environment being embedded into the forest floor, and rising with three terraced stories to a meditation room with a pyramid skylight and a geodesic dome garage. It produces its own solar electricity (3.6 kW) and solar thermal heating (180,000Btus/hr) for ten zones of hydronic, radiant-floor heating. It includes three, year-round producing greenhouses, and an organically cultivated summer garden.

Stepping outdoors from one of three patios, trails go off into the forest with over 50 acres of alpine forest and meadows, sharing the forest with deer, elk and many other animals. The home was completed in 2002 and continues to be refined and developed, offering seminars in solar design and construction as well as to serve as a spiritual retreat for guests.

The owner and the designer of the project spent many years contemplating the project and undertook special design effort and planning to honor and respect the surrounding environment that surrounded the building. The project was not designed to be just a sustainable-energy design installation project, rather a holistic environmental design that could unite technology and ecology.

The sustainable energy system is configured by deployment of eleven, solar-thermal panels with a control system which augments water heating by use of a supplemental propane boiler. The heated water is the primary heat source which provides space heating as well as a domestic hot water (DHW) system. At present the solar-thermal system accounts for about 60-70 percent of the heat, thus reducing propane use about 40-50 percent.

At present, net-power output of the photovoltaic power system is rated at 3.6kW AC. The solar power generation consists of two systems; one is installed in the garden, and another in the kitchen above the counter which also serves as a solar window. The kitchen solar power panels are custom made building integrated photovoltaic panes referred to as BIPV, custom manufactured by Atlantis Energy which is build with quadruple-pane tempered glass panels which sandwich Shell Solar Power Max cells by a lamination process. DC to AC power conversion is achieved by use of two stacked Trace SW-4048 inverters and Outback MX-60 Charge Controllers.

The roof mount solar BIPV is secured to the building structure at an angle which matches the pitch of the rest of the roof, which is about 32 degrees up from the horizon in close proximity to the optimal angle matching the geographic latitude for an equinox alignment which favors’ the winter angle. The battery backup system has a 1600 Amp/hour back-up capacity. The batteries are kept on “float” much of the time and are equalized twice a year.

Metering is a ­dual-rate “Time of use” and the utility consumption averages 1,400 Kwhs/ month. Even with recent electric rate increases, the ­average monthly bill is $130/month. The owner also pays a $15 monthly fee for an extra green power program offered by the local utility. The owner estimates that monthly saving resulted from use of the solar-power system amounts to at least  $200.00 per month. The owner’s average propane bill now ranges from $80/month in the summer time, to about $250/month in the winter. Without the solar thermal system installation his summer bill would range from $150/month and winter over $600/month, an average of 60 percent energy cost savings.

As of 2006, with federal and newly passed state incentives the owner will be able to claim about 30 percent average tax credits from both federal and state laws. At present the State of New Mexico does not have a cash rebate program.

Final note:
At present, investor-owned, electrical-power-generating entities in the United States offer optional green power to their clients at substantially high rates. In view of rising natural gas prices, solar power is considered to be the best hedge against energy-cost escalation.

In recent years, the  solar-power photovoltaic industries have expanded at an annual rate of 40 percent. Current global demand for solar-power photovoltaic ­panels indicates that solar-power technology will by 2010 exceed $40 Billion dollars.

It should be noted that the U.S., the most prosperous nation in the world, at ­present has 4.5 percent of the global population, it consumes 25 percent of the world’s resources and produces 30 percent of the world’s pollution. SLDT

© 2008, Dr. Peter Gevorkian. Printed with permission.