Photovoltaic cogeneration in the built environment

Building integrated photovoltaic (BiPV) systems can form a cohesive design, construction, and energy solution for the built environment. The benefits of building integration are well documented and are gaining significant public recognition and government support, PV cells, howe,er, convert only a small portion of the incoming insolation into electricity. The rest is either reflected or lost in the form of sensible heat and light. Various research projects have been conducted on the forms these by-products can take as cogeneration. The term cogeneration is usually associated with utility-scale fossil-fuel electrical generation using combined heat and power production. It is used here in the same spirit in the evaluation of waste heat and by-products in the production of PV electricity. It is important to have a proper synthesis between BiPV cogeneration products, building design, and other HVAC systems in order to avoid overheating or redundancy. Thus, this paper looks at the state-or-thr-art in PV cogen from a whole building perspective. Both built tramples and research will be reviewed. By taking a holistic approach to the research and products already available, the tools for a more effective building integrated system can be devised. This should increase net system efficiency and lower installed cost per unit area. An evaluation method is also presented that examines the energy and economic performances of PV/T systems. The performed evaluation shows that applications that most efficiently use the low quality thermal energy produced will be the most suitable niche markets in the short- and mid-term. (C) 2001 Elsevier Science Ltd. All rights reserved.