Method of distributing energy for a building, energy management system, system for satisfying the energy requirements of a building, and micro-cogeneration system

Abstract

An energy management system is provided for managing the generation and distribution of energy from an energy source to a building. The building has a desired building environment and a total energy profile including a thermal energy requirement and an electrical energy requirement. The energy management system comprises an energy generator arranged to convert energy from the energy source to thermal energy and electrical energy, a heat recovery unit arranged to recover byproduct heat from the energy generator, a cooling unit arranged to use a first portion of the thermal energy to drive a refrigeration unit, a heating unit arranged to use a second portion of the thermal energy to drive a heating unit, a heat storage unit arranged to store excess heat, and an energy optimizing controller. The energy optimizing controller includes a thermal flow controller and an electrical flow controller, with the thermal flow controller being arranged to distribute the thermal energy and the recovered byproduct heat to at least one of the cooling unit, the heating unit, and the heat storage unit. The electrical flow controller is arranged to distribute electrical energy to at least one of a plurality of electrical components, with the energy optimizing controller being arranged to establish a target total energy cost, calculate an index of performance indicative of an actual energy cost based on an actual electrical load and an actual thermal load, compare the actual energy cost to the target total energy cost, and adjust the distribution of the thermal and electrical energy to thereby obtain a minimum total cost.

What is claimed:  
     
         1 . A method of distributing energy for a building, the method comprising the steps of: 
 A. generating energy including electrical energy, generated heat, and byproduct heat from energy sources selected from the group consisting of natural gas, solar energy assemblies, and an electric grid;    B. recovering at least a portion of the byproduct heat;    C. modeling a total energy profile for the building, the total energy profile including a thermal energy requirement and an electrical energy requirement;    D. assessing a total available heat stream, the total available heat stream including a stream of the generated heat and a stream of the byproduct heat;    E. routing the electrical energy and the streams of generated heat and byproduct heat to the building for use;    F. establishing a target total energy cost for a discrete time interval;    G. calculating an index of performance indicative of an actual total energy cost for the discrete time interval; and    H. optimizing the usage of the electrical energy and the streams of generated heat and byproduct heat over the discrete time interval through an optimizing scheme to thereby maintain a desired building environment at a minimum total energy cost, wherein the optimizing scheme comprises the steps of: 
 a. calculating a minimum electrical energy requirement;  
 b. setting an electrical energy output to meet the calculated minimum electrical energy requirement;  
 c. comparing the total available heat stream to the thermal requirement for the building;  
 d. if the total available heat stream exceeds the thermal requirement for the building, then one of: i) storing an excess portion of the total available heat stream in a storage device; ii) dumping the excess portion to the atmosphere; or iii) decreasing the total available heat stream;  
   e. if the total available heat stream is less than the thermal requirement for the building, then at least one of: i) extracting the stored excess portion from the storage device; and ii) increasing the generated heat stream; and    f. optimizing the system by comparing the actual total energy cost to the target total energy cost and adjusting the usage of the electrical energy and the total available heat stream to thereby provide the minimum actual total energy cost.    
     
     
         2 . The method of  claim 1 , wherein the index of performance is defined as a function of N independent variables within a given region of N space or dimension as follows: 
 IP=IP (x1, x2, . . . , xn), with the region being defined by ψ (x1, x2, . . . , xn)≦0, and wherein the index of performance is calculated by the following equation:     IP =( x 1 +x 2+ x 3+ x 4+ x 5)/ξ,   wherein ξ=kilowatts of energy (electric and heat), and further wherein:    x1=an actual cost of natural gas over the discrete time interval;    x2=an actual cost of grid supplied electrical energy over the discrete time interval;    x3=an actual cost of solar energy assembly supplied electrical energy over the discrete time interval;    x4=an actual cost of solar energy supplied heat energy over the discrete time interval;    x5=an actual cost of grid supplied electrical backup energy; and wherein x1+x2+x3+x4+x5≦non-combined heat, power, gas and electrical energy cost.    
     
     
         3 . The method of  claim 2 , wherein the energy is generated using at least one of a microturbine or a fuel cell assembly, and wherein the index of performance is further calculated by considering the following variables and constraints: 
 x6=turbine efficiency;    x7=fuel cell efficiency;    x8=turbine/fuel cell heat recovery efficiency;    x9=solar heating or cooling efficiency;    x10=heat storage cost;    x11=heat storage capacity;    x12=heat storage time constant;    x13=solar heat incident on building;    x14=heat needed by building to maintain desired temperature;    x15=desired building temperature for occupied regions;    x16=electrical energy usage, including alternating current usage and direct current usage;    x17=reliability of the grid-supplied electrical energy;    x18=reliability of the total available heat stream;    x19=power quality service cost,    x20=actual building thermal energy usage;    x21=actual building electrical usage;    x22=fraction of the electrical energy requirement supplied by the microturbine and the fuel cell;    x23=fraction of the electrical energy requirement supplied by the electric grid;    x24=fraction of the electrical energy requirement supplied in the form of direct current;    x25=fraction of byproduct heat used to satisfy a portion of the thermal energy requirement for heating the building;    x26=fraction of byproduct heat used for dehumidification of the heat storage device;    x27=fraction of byproduct heat used to satisfy a portion of the thermal energy requirement for cooling the building;    x28=temperature of the heat storage device;    x29=the heat storage capacity for a first set of designated regions of the building; and    x30=maximum Δ temperature of the first set of designated regions of the building;    wherein heat storage minimum temperature≦x28≦heat storage maximum temperature;    wherein minimum temperature≦x31≦maximum temperature, and further wherein:    x24≦1;    x25≦1;    x26≦1;    x27≦1;    x30≦a predetermined level; and wherein a minimum solar input≦x13≦a maximum solar input; and wherein    x10≦direct heat production cost,    x11≦maximum allowable physical size,    x12≧minimum possible value.    
     
     
         4 . The method of  claim 1 , wherein the index of performance is defined as a function of N fuzzy variables within a given region of N space as follows: 
 IP=IP (x1, x2, . . . , xn), with the region being defined by ψ (x1, x2, . . . , xn)≦0, and wherein the index of performance is calculated by the following equation:     IP =( x 1 +x 2+ x 3 +x 4+ x 5)/ξ,   wherein ξ=kilowatts of energy (electric and heat), and further wherein:    x1=an actual cost of natural gas over the discrete time interval;    x2=an actual cost of grid supplied electrical energy over the discrete time interval;    x3=an actual cost of solar energy assembly supplied electrical energy over the discrete time interval;    x4=an actual cost of solar energy supplied heat energy over the discrete time interval;    x5=an actual cost of grid supplied electrical backup energy;    wherein x1+x2+x3+x4+x5≦non-combined heat, power, gas and electrical energy cost; and 
 including the additional steps of:  
 determining a degree of membership in each of at least two of the fuzzy variables;  
 mapping the at least two degrees of membership onto a control surface adapted to optimize the energy usage; and  
 assigning a priority to at least one of the variables in response to the control surface mapping.  
   
     
     
         5 . The method of  claim 1 , wherein the group of energy sources further includes at least one of refuse-generated methane gas and biomass-generated methane gas.  
     
     
         6 . The method of  claim 1 , wherein the storage device is a fast response thermal storage unit.  
     
     
         7 . The method of  claim 1 , wherein the electrical energy requirement includes a direct current requirement and an alternating current requirement, and calculating an optimal fraction of at least one of the direct or alternating current requirements relative to the electrical energy requirement.  
     
     
         8 . The method of  claim 1 , wherein the step of modeling the total energy profile for the building includes the steps of assessing an occupancy pattern of the building and a usage pattern of the building.  
     
     
         9 . The method of  claim 1 , wherein the step of modeling the total energy profile for the building includes the step of calculating the effect of environmental factors on the building.  
     
     
         10 . The method of  claim 1 , including the step of using a dehumidification system to alter the total energy profile.  
     
     
         11 . The method of  claim 10 , wherein the dehumidification system is a dessicant dehumidification system.  
     
     
         12 . The method of  claim 11 , including the step of using a fractional portion of the byproduct heat to recondition the dessicant dehumidification system.  
     
     
         13 . The method of  claim 1 , including routing the total available heat stream to the building using at least one of a heat exchanger or an absorption cooling device.  
     
     
         14 . The method of  claim 1 , wherein the byproduct heat is recovered using a heat exchanger.  
     
     
         15 . The method of  claim 1 , wherein the byproduct heat is dumped using a heat exchanger.  
     
     
         16 . The method of  claim 1 , wherein the byproduct heat is dumped to the atmosphere using a bypass valve.  
     
     
         17 . An energy management system for managing the generation and distribution of energy from an energy source to a building, the building having a desired building environment and a total energy profile including a thermal energy requirement and an electrical energy requirement, the energy management system comprising: 
 an energy generator arranged to convert energy from the energy source to thermal energy and electrical energy;    a heat recovery unit arranged to recover byproduct heat from the energy generator;    a cooling unit arranged to use a first portion of the thermal energy to drive a refrigeration unit;    a heating unit arranged to use a second portion of the thermal energy to drive a heating unit;    a heat storage unit arranged to store excess heat; and    an energy optimizing controller, the energy optimizing controller including a thermal flow controller and an electrical flow controller, the thermal flow controller being arranged to distribute the thermal energy and the recovered byproduct heat to at least one of the cooling unit, the heating unit, and the heat storage unit, the electrical flow controller being arranged to distribute electrical energy to at least one of a plurality of electrical components, the energy optimizing controller being arranged to establish a target total energy cost, calculate an index of performance indicative of an actual energy cost based on an actual electrical load and an actual thermal load, compare the actual energy cost to the target total energy cost, and adjust the distribution of the thermal and electrical energy to thereby obtain a minimum total cost.    
     
     
         18 . The system of  claim 17 , including a dessicant dehumidification system to remove moisture from the building.  
     
     
         19 . The system of  claim 17 , wherein the heating unit includes a heating heat exchanger.  
     
     
         20 . The system of  claim 17 , wherein the cooling unit includes a cooling heat exchanger.  
     
     
         21 . The system of  claim 17 , including a bypass valve to dump an excess portion of the thermal energy to the atmosphere.  
     
     
         22 . The system of  claim 17 , wherein the energy generator can be selected from the group consisting of a micro turbine, a fuel cell, an electric grid, and solar cells.  
     
     
         23 . The system of  claim 17 , including a power converter for converting a portion of the electrical energy to at least one of direct current or alternating current, and further wherein the energy optimizing controller also includes a converter controller for controlling the power converter.  
     
     
         24 . A system for satisfying the energy requirements of a building comprising the steps of: 
 generating electrical energy and byproduct heat from one or more energy sources selected from the group consisting of natural gas, solar heating assemblies, and an electric grid;    determining the available amount of electrical energy;    determining the available amount of byproduct heat;    determining the energy requirements of the building, the energy requirements of the building including building heating requirements and building electrical energy requirements;    using the electrical energy and the byproduct heat to meet the energy requirements of the building; and    optimizing the using of the electrical energy and the byproduct heat through an optimizing scheme to minimize a total energy cost, wherein the optimizing scheme comprises the steps of: 
 establishing a target total energy cost;  
 calculating an index of performance indicative of an actual energy cost;  
 comparing the actual energy cost to the target total energy cost; and  
 adjusting the usage of the electrical energy and the byproduct heat.  
   
     
     
         25 . A micro-cogeneration system comprising: 
 a gas fired micro-turbine for providing electrical and thermal energy;    means for recovering byproduct heat from the micro-turbine;    a heat exchanger system for converting a first portion of the thermal energy into useable heat;    an absorption cooler system for converting a second portion of the thermal energy into useable energy to drive a refrigeration cycle; and    means for distributing the electrical and thermal energy to a building for use.