Method for controlling an integrated cooling and heating facility

Abstract

The invention describes energy cost saving potentials in a food retail system in context with a smart grid system utilising thermal storage and heat recovery technology. The invention is based on case examples and theoretical studies to describe the technology advantages. To obtain the cost optimisation in complex refrigeration systems, a method for minimisation of cost is described.

What is claimed is: 
     
         1 . A method for controlling an integrated cooling and heating facility comprising a vapour compression system with two or more heat exchangers, each arranged for providing cooling or heating, the vapour compression system being connected to an electrical energy grid being external to the vapour compression system and also being connected to a thermal energy grid being external to the vapour compression system, the method comprising the steps of:
 providing a monetary cost function for operating the integrated cooling and heating facility, said monetary cost function establishing monetary energy costs and monetary energy revenues of operating the vapour compression system,
 said monetary energy costs including monetary expenses for electrical energy received from the external electrical grid and consumed by the vapour compression system, and 
 said monetary energy costs also including monetary expenses for thermal energy not provided by the vapour compression system and consumed at a location of the integrated cooling and heating facility and 
 said monetary energy revenue including monetary revenues for thermal energy produced by the vapour compression system and provided to an external thermal grid at, or outside, the location of the integrated cooling and heating facility, and 
   operating the vapour compression system in such a manner that the monetary energy costs established by the monetary cost function are minimised.   
     
     
         2 . The method according to  claim 1 , wherein the monetary energy costs further includes monetary revenue for demand response services supplied by the vapour compression system to the external electrical grid. 
     
     
         3 . The method according to  claim 1 , wherein the vapour compression system is further connected to a thermal grid being external to the vapour compression system, and wherein the monetary energy costs includes monetary revenue for thermal energy supplied by the vapour compression system to the external thermal grid. 
     
     
         4 . The method according to  claim 3 , wherein the step of establishing monetary energy costs comprises establishing revenue for thermal energy supplied by the vapour compression system to the external thermal grid as a function of time. 
     
     
         5 . The method according to  claim 3 , wherein the external thermal grid is or comprises a district cooling grid and/or a local cooling micro-grid for cooling facilities external to the vapour compression system. 
     
     
         6 . The method according to  claim 3 , wherein the external thermal grid is or comprises a district heating grid and/or a local heating micro-grid for heating facilities external to the vapour compression system. 
     
     
         7 . The method according to  claim 3 , wherein the external thermal grid comprises a local thermal power generating facility. 
     
     
         8 . The method according to  claim 1 , wherein the step of establishing monetary energy costs comprises establishing expenses for electrical energy received by the vapour compression system from the external electrical grid as a function of time. 
     
     
         9 . The method according to  claim 1 , wherein the step of establishing monetary energy costs comprises taking ambient conditions into account. 
     
     
         10 . The method according to  claim 1 , further comprising the step of storing work made by a compressor of the vapour compression system in a thermal storage facility of the integrated cooling and heating facility, said thermal storage facility being capable of supplying work stored therein to the vapour compression system in order to reduce energy consumption of the vapour compression system at a time subsequent to the a time when the work is stored. 
     
     
         11 . The method according to  claim 1 , further comprising the step of shifting energy consumption of the vapour compression cycle in time by using a thermal storage facility of the integrated cooling and heating facility, said method comprising the steps of discharging said thermal storage facility in order to reduce the energy consumption from the external electrical grid of the vapour compression cycle, and charging said thermal storage facility in order to increase the energy consumption from the external electrical grid of the vapour compression cycle. 
     
     
         12 . The method according to  claim 10 , wherein the thermal storage facility is or comprises an ice storage connected to the vapour compression system. 
     
     
         13 . The method according to  claim 10 , wherein the thermal storage facility is or comprises a heat reservoir connected to the vapour compression system. 
     
     
         14 . The method according to  claim 1 , wherein the external electrical grid comprises an external electrical power facility. 
     
     
         15 . The method according to  claim 1 , wherein the external electrical grid comprises a local electrical power generating facility. 
     
     
         16 . The method according to  claim 1 , wherein the step of establishing a monetary cost function comprises establishing a function of the form: 
       
         
           
             
               Cost 
               = 
               
                 
                   SUM 
                    
                   
                     ( 
                     
                       
                         X 
                         COP 
                       
                       * 
                       Pe 
                     
                     ) 
                   
                 
                 + 
                 
                   Y 
                   * 
                   Ph 
                 
                 - 
                 
                   
                     SUM 
                      
                     
                       ( 
                       
                         X 
                         * 
                         
                           ( 
                           
                             1 
                             + 
                             
                               1 
                               COP 
                             
                           
                           ) 
                         
                         * 
                         Ph 
                       
                       ) 
                     
                   
                   . 
                 
               
             
           
         
       
     
     
         17 . A controller for controlling an integrated cooling and heating facility, the controller being capable of controlling the integrated cooling and heating facility based on a method according to  claim 1 . 
     
     
         18 . An integrated cooling and heating facility comprising at least one controller according to  claim 17 , wherein the integrated cooling and heating facility is a refrigeration facility comprising a heat recovery system. 
     
     
         19 . An integrated cooling and heating facility comprising at least one controller according to  claim 17 , wherein the integrated cooling and heating facility is a heat pump comprising a cooling recovery system.