Session: 12-02: Hydrogen Energy, Alternative Fuels, Bioenergy, and Biofuels

Paper Number: 130609

130609 - Modeling of Small-Scale Hybrid Biogas Renewable Energy Facility 

Abstract: 

The objective of this paper is to demonstrate the feasibility of using small scale biogas renewable energy facilities on urban farmland applications. In this study, a Khadi and Village Industries Commission (KVIC) biogas plant was designed to provide thermal energy input into an internal combustion engine.  Several previous studies have addressed the use of the KVIC system for bio-gas renewable energy production. Our current application focuses on small scale farms, on the order of 2 acres, whereby farmers can leverage the use of renewable energy technology to power their infrastructure. Additionally, a photovoltaic (PV) system was designed to provide energy for electric resistance heating in the biogas digester to maintain optimal temperatures for manure to decompose in. The KVIC hardware is comprised of a deep well and a floating drum. The system collects biogas and holds it at a relatively constant pressure.  As biogas is produced, the drum biogas rises, while as the biogas is consumed, the drum falls. The methane gas weekly output by volume of 0.372 m³ from the KVIC digester was used to fuel an ACME AM-1500BG 1KW Biogas Generator. This resulted in 1.06 kWh energy output per week when storing biogas over the course of seven days and using the generator at the end of the seventh day. The paper provides details of a systems level thermal model developed to simulate the charging and discharging of the biogas plant. Predictions from the thermal model for the temperature transient and heat input from manure to the biogas powerplant as well as time constants (biogas plant and manure) of the thermal system are presented herein. The total annual energy output of the KVIC plant was 55.2 kWh. Modeling the PV system using National Renewable Energy Laboratory (NREL) System Advisor Model (SAM), the system nameplate capacity was calculated to be 6.30 kW with an annual AC energy output of 11,735 kWh, resulting in a Levelized Cost of Energy (LCOE) of 11.7¢/kWh and payback period of 9.6 years. The initial investment of the system is $19K. An area for improvement would be making the hay insulation layer thicker to reduce the thermal energy losses from the biodigester to the soil. Reduced thermal losses results in lower electrical power demand, increasing the efficiency of the system. Future work includes specifying any plumbing and fittings required in the biodigester. An area for improvement would be to take 6-inch soil temperatures over a year and find the minimum and max temperatures recorded.

Presenting Author: Ryan Salcido Calif. State Polytechnic Univ. at Pomona

Presenting Author Biography: Ryan Salcido is an Undergraduate Student in Mechanical Engineering at Calif. State Polytechnic Univ., Pomona.

Authors:

Ryan Salcido Calif. State Polytechnic Univ. at Pomona
George Lockwood Calif. State Polytechnic Univ. at Pomona
Cedric Rebullar Calif. State Polytechnic Univ. at Pomona
Kevin Anderson Calif. State Polytechnic Univ. at Pomona
Maryam Shafahi Calif. State Polytechnic Univ. at Pomona