US 9,811,068 B2
Optimal energy management of a rural microgrid system using multi-objective optimization
Ratnesh Sharma, Fremont, CA (US); and Xianjun Zhang, Tempe, AZ (US)
Assigned to NEC Corporation, Tokyo (JP)
Filed by NEC Laboratories America, Inc., Princeton, NJ (US)
Filed on Aug. 20, 2015, as Appl. No. 14/831,483.
Application 14/831,483 is a division of application No. 13/543,820, filed on Jul. 7, 2012, granted, now 9,146,547.
Claims priority of provisional application 61/509,642, filed on Jul. 20, 2011.
Prior Publication US 2015/0355618 A1, Dec. 10, 2015
Int. Cl. G05D 5/00 (2006.01); G05D 9/00 (2006.01); G05D 11/00 (2006.01); G05B 19/042 (2006.01); G05B 17/02 (2006.01); G05B 13/04 (2006.01)
CPC G05B 19/042 (2013.01) [G05B 13/04 (2013.01); G05B 17/02 (2013.01); G05B 2219/25289 (2013.01)] 13 Claims
OG exemplary drawing
1. A computer implemented method to improve energy efficiency of a farm with livestock waste with a microgrid, comprising: generating a comprehensive cooling, heating, and power (CCHP) microgrid model; performing on a computer a multi-objective optimization to improve system efficiency of energy utilization and reduce environmental problems caused by animal waste; displaying results of the optimization for review; modeling, an objective function of system operating cost (OC), including biogas, fuel cost (FC), internal combustion engine (ICE) start up and shut down cost (SSC), equipment operation and maintenance cost (OMC), and cost of electricity bought from the grid (EBC) as follows:

OG Complex Work Unit Drawing
where ΔT is hourly time step, CBio is the biogas cost in dollars per liter ($/L), Ft,GB,ACC are fuel cost of ICEs, gas boiler, and absorption chiller for cooling in L/h, SU, SD are start up cost and shut down cost in $, OMICE,GB,ACC,AR are operation and maintenance cost of ICEs, GB, ACC, and AR in $/kWh, PGB,ACC,AR,t is output of gas boiler, absorption chiller for cooling and absorption refrigerator in time t in kW, CGriE is electricity cost of the grid in $/kWh, Pgrid,t is the power bought from the grid in kW, M is the number of generators, and N is a time t counter;
and optimizing the microgrid based on dispalyed result, start and shut down cost, operating and maintenance cost, and cost of electricity; wherein the steps are carried out by a computer having a processor and memory.