Clean Energy Solution: SOLVING THE ENERGY CRISIS AND CREATING THE CALIFORNIA SOLAR CENTURY… California Dream System SOLAR-ELECTRIC COOLING AND HEATING SUNSTATION BY GREGORY WRIGHT SPECIAL TO THE WESTERN HVACR NEWS Solar energy is now not only a feasible source of energy for our homes - but a godsend, especially in the energy-stressed western United States. A new solar-electric heat pump system has been developed for residential and light-commercial space heating and cooling and water heating. This solar photovoltaic-powered system, SunStation, can cool and heat residential space and heat water, and provide emergency back-up power during blackouts and after earthquakes. The system will reduce electric power costs for homeowners and, widely installed, reduce the frequency and duration of blackouts by reducing peak demand (and fill the breach for its owners when blackouts, or earthquakes, do occur). According to Les Hamasaki, "SunStation could be called the "California Dream System" where millions of homeowners become "green power" producers (micro- utilities) by generating their own power and reducing their energy consumption from the grid during critical peak-load demand." Solar-photovoltaics, once thought to be an inefficient solar application, is now more feasible than ever - and more needed, as shortages of "traditional" electrical and fossil-fuel energy spread and the world heats up in the new age of climate change and global warming. Solar-energy pioneer Khanh Dinh, founder and president of Heatpipe Technology Company, Inc. in Gainesville, Florida, is the inventor of a potentially revolutionary solar-photovoltaic heat pump air conditioner that incorporates "three design tricks" (as he puts it) that enable his technology to deliver robust cooling in residential and light commercial applications. The three keys to his "Solar Electric Heat Pump" are a high-efficiency DC motor, "load sharing" between the photovoltaic (PV) and utility-supplied electrical power, and the use of two operating speeds. Solar energy and air conditioning are a natural match. "The time of day when air conditioning is most needed of course corresponds closely to the sunniest time; thus, it would be nice to use the sun to power air conditioners," observes Les Hamasaki, president of SUN Utility Network, Inc. of Los Angeles, Heatpipe Technology Co.'s marketing partner. "And of the various ways devised to use the sun to cool air, PV-made electricity has one big advantage: it can substitute directly as the input power for existing air conditioners, so the AC industry does not have to make any major change to adopt a solar-powered electric unit," Dinh points out. The compressor in Dinh's Solar Electric Heat Pump air conditioner is driven by a high-efficiency DC motor - the first of Dinh's "solar design tricks." Small permanent-magnet DC motors, the type run directly off of solar-PV cells, typically have efficiencies reaching 90 percent, while AC motors, using grid power, are only about 60- to 80-percent efficient, allowing Dinh's machines to be built with an Energy Efficiency Ratio (EER) as high as 16.   Dinh's second solar design trick is the division of power input between the sun and the grid. "We do not try to get all the energy needs of an AC system from photovoltaics - it's not yet economical, despite the steady improvement in PV-cell efficiency. Instead, we use solar energy by 'load sharing, meaning that two energy sources - PV and conventional grid-supplied electricity - share the work. When the sun is strong, the solar contribution is high and the conventional-energy contribution is low. The opposite is true on cloudy days and at night. The advantage of this concept is that the total output of the PV can be used immediately, ending the need either for battery storage or for power conditioning equipment to sell your PV energy directly to the utility grid." The third "solar trick" in the Dinh solar-electric AC technology is the use of two speeds. Conventional AC does not run all the time, but turns on and off according to the thermostat setting. However, with a solar-powered system, "free" energy is thrown away if the system is shut off. "Rather than stopping, our system keeps running, at low speed. On the normal, low-speed setting, about 80 percent of the energy needed for air conditioning can come from the PVs. On unusually hot days, the high speed is needed." Because peak cooling loads coincide with available sunlight, demand for utility-generated electricity for cooling is reduced by 50 to 80 percent by the use of photovoltaics, Dinh says. This reduction in peak electricity demand is exactly the kind of non-polluting additional energy "generation" demanded in the current "energy crisis." Additional advantages to the continuously operating two-speed system, Dinh points out, include consistent dehumidification of the conditioned environment, prolongation of the equipment's life, and more consistent hot water in the case of waste heat recovery. The load sharing and the two-speed operation is accomplished by Dinh's proprietary "Power Mixer" circuitry, which mixes DC power from the PV array, adjusts voltage levels, and then mixes it with DC pulses from rectified utility electricity. The rate of mixing depends on the intensity of the solar insolation; it is adjusted every 1/20th of a second, so that the PVs always operate near peak efficiency and the compressor gets enough power with little fluctuation. The Solar Electric Heat Pumps are manufactured in 1- and 1.5-ton capacities and are matched with eight 60-W and 80-W PV modules, respectively, and operate in a vapor-compression cycle powered by the DC motor. A switch activates a reversing valve to pump the refrigerant in the opposite direction and turn the solar cooler into a solar heater in cold weather, or back again when the weather warms. The 4.5-COP-rated heat pumps also can be connected to passive solar storage cylinders or drum walls to maximize their heating efficiencies. Domestic hot water preheating is another application well suited for use with the cooling cycle of the Solar Electric Heat Pump. During the compression cycle, hot refrigerant vapor is captured with a "Yin Yang" heat exchanger, manufactured by Heatpipe Technology Company, and transferred to domestic water. A one-ton unit can generate about 4,000 Btu/h of waste heat, enough to heat water to 110 degrees F. "The comprehensive energy solution is towards conservation, efficiency, and cogeneration. We must create the new Solar Century where millions of roofs, parking lots, and backyards of residential, commercial, and industrial buildings are generating electricity from solar cells or hydrogen fuel cell generators to feed the utility grid and contribute to the solution rather than be the cause of the problem to California's energy crisis.