SOLAR ENERGY PROGRAM: CHAPTER FROM THE ENERGY AND ENVIRONMENT ANNUAL REPORT 1979

Solar energy has become a major alternative for supplying a substantial fraction of the nation's future energy needs. The Department of Energy (DOE) supports activities ranging from the demonstration of existing technology to research on future possibilities; and at LBL projects are in progress which span that range of activities. To assess various solar applications it is important to quantify the solar resource. In one project, LBL is cooperating with the Pacific Gas and Electric Company in the implementation and operation of a solar radiation data collection network in northern California. Special instruments have been developed and are now in use to measure the solar and circumsolar (around the sun) radiation. These measurements serve to predict the performance of solar designs which use focusing collectors (mirrors or lenses) to concentrate the sunlight. Efforts are being made to assist DOE in demonstrating existing solar technology. DOE's San Francisco Operations Office (SAN) has been given technical support for its management of commercial-building solar demonstration projects. The installation of a solar hot water and space heating system on an LBL building established model techniques and procedures as part of the DOE Facilities Solar Demonstration Program. Technical support is also provided for SAN in a DOE small scale technology pilot program in which grants are awarded to individuals and organizations to develop and demonstrate solar technologies appropriate to small scale use. In the near future it is expected that research will exert a substantial impact in the areas of solar heating and cooling. An absorption air conditioner is being developed that is air cooled yet suitable for use with temperatures available from flat plate collectors. With inexpensive but sophisticated micro-electronics to control their operation, the performance of many-component solar heating and cooling systems may be improved, and work is under way to develop such a controller and to evaluate commercially available units. Research is continuing on 'passive' approaches to solar heating and cooling where careful considerations of architectural design, construction materials, and the environment are used to moderate a building's interior climate. Computer models of passive concepts are being developed in a collaborative project with Los Alamos Scientific Laboratory. These models will be incorporated into public domain building energy analysis computer programs to be used in systems studies and in the design of commercial buildings on a case study basis. The investigation of specific passive cooling methods is an ongoing project; for example, a process is being studied in which heat storage material would be cooled by radiation to the night sky, then provide 'coolness' to the building. The laboratory personnel involved in the solar cooling, controls, and passive projects are also providing technical support to the Solar Heating and Cooling Research and Development Branch of DOE in developing program plans, evaluating proposals, and making technical reviews of projects at other institutions and in industry. Low grade heat is a widespread energy resource that could make a significant contribution to energy needs if economical methods can be developed for converting it to useful work. Investigations continued this year on the feasibility of using the 'shape-memory' alloy, Nitinol, as a basis for constructing heat engines that could operate from energy sources such as solar heated water, industrial waste heat, geothermal brines, and ocean thermal gradients. Several projects are investigating longer-term possibilities for utilizing solar energy. One project involves the development of a new type of solar thermal receiver that would be placed at the focus of a central receiver system or a parabolic dish. The conversion of the concentrated sunlight to thermal energy would be accomplished by the absorption of the light by a dispersion of very small particles suspended in a gas. Work continued this year on chemical storage processes (such as 2SO{sub 3} = 2SO{sub 2} + O{sub 2}) that could play an important role in providing long-term storage for high temperature power generation cycles. Another project is exploring biological systems. The possibility is being explored of developing a photovoltaic cell, based on a catalyst (bacteriorhodopsin) which converts light to electrical ion flow across the cell membrane of a particular bacteria