The North Carolina Solar Center, in partnership with the Propane Education & Research Council (PERC) and B.J. Williamson LP Gas, has developed a project to demonstrate the technical and economic feasibility of incorporating photovoltaic (PV), solar thermal, and propane-fired combined heat and power (CHP) systems into an integrated Distributed Generation (DG) system at the North Carolina Solar Center’s testing facility on the campus of NC State University. Propane for the project is provided by the North Carolina Propane Gas Association.

Equipment and Configuration

The DG system consists of a solar thermal system, a PV array, and micro-CHP unit powered by propane. These systems work in parallel to produce electric and thermal energy. By integrating the CHP unit with the two solar powered systems, an efficient, clean, and consistent supply of heat and electric power can be achieved. These core components can provide the energy for many applications such as large residential, small commercial, and industrial sites. The thermal energy produced by this system can be used for space-heating, domestic hot water, process heating, dehumidification, and absorption cooling. In this demonstration setup, the thermal loads are hydronic heating and dehumidification. An experimental outdoor heat dump is also used to control the setup for application specific modeling. This DG system is completely grid-tied making it an efficient means to trade electric energy.

Lessons to Share

The project uses a combination of existing technologies to provide an educational demonstration of a low-carbon footprint high-efficiency hybrid solar and propane system. With the advent of Renewable Energy Portfolio Standards in 27 states providing incentives for the installation of renewable generation resources, appropriately sized propane-fired micro-CHP backup to solar may prove to be a new and growing market opportunity. This project will demonstrate the technical viability of incorporating propane-fueled micro-CHP with renewable energy technologies. It will also provide a firsthand opportunity for the public to learn about the technology and evaluate it as a here-and-now, feasible alternative to business as usual, and for the propane industry to learn valuable “early adopter” lessons.

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