Thermal-Fluids Analysis of a Hybrid Solar/Compost Waste Heat Updraft Tower

This paper presents the results for a feasibility study of a solar chimney which uses low-grade waste heat from compost in conjunction with solar energy transmitted via a transparent roof top.The feasibility study shows that the solar chimney's turbine power increases with pressure ratio, the height of the chimney as well as the differential temperature in the chamber.This paper also outlines the thermodynamic modeling related to using waste heat from composting to increase the air temperature in the inlet chamber of a solar chimney.It is found that from this analysis that the average temperature in the chamber increases as a function of the chimney inlet chamber axial length.The combined raw in input total heat gain for this hybrid solar composting chimney is found to be 6.24 MW of which 66% (4.12 MW) is comprised of solar, and 34% (2.12 MW) is comprised of composting energy Index Terms-Composting, waste heat recovery, solar updraft tower . I. INTRODUCTIONResearch suggests that only 8% of our nation's supply of electricity comes from renewable energy.The remaining amount of produced power typically comes from the burning of fossil fuels and other nonrenewable sources.This opens the door for various types of renewable energy to be introduced into the power grid, coming in numerous forms such as of solar, wind, and hydroelectric.The stakeholders for the development of this renewable energy technology include the community, nation and global inhabitants.A solar updraft tower is a renewable energy structure that harvests energy from the sun and creates high velocity wind speed in its collector to run turbines.A compost pile contains microbes that digest organic material and break it down into smaller parts.When they do this, they produce heat as a byproduct.The heat production depends on the size of the compost pile, its moisture content, aeration, and C/N ratio.A well composted mass often reaches temperatures of 66C to 82C, which falls within the range of low-grade waste heat.Compost managers strive to keep the compost below about 65°C since hotter temperatures cause the beneficial microbes to die off.Aeration is typically used to manage the compost temperature.The energy liberated by aeration can be fed into the