Three-pipe thermal network

Abstract

Thermal network comprising at least one plant, at least one end-user location ( 14,15 ), a pipe system ( 11 - 13 ) and a medium contained within said pipe system ( 11 - 13 ) said plant and said end-user location; said end-user location(s) ( 14,15 ) being connected to the plant through the pipe system ( 11 - 13 ). The thermal network according to the invention is characterized in that it comprises three main pipes ( 11 - 13 ) that are each connected to said plant(s) and wherein the medium is in a liquid state in the first and the third main pipe ( 11,13 ), and in a gaseous state in the second main pipe ( 12 ).

1 . Thermal network comprising at least one plant, at least one end-user location, a pipe system and a medium contained within said pipe system said plant and said end-user location; said end-user location(s) being connected to the plant through the pipe system wherein it comprises three main pipes that are each connected to said plant(s) and wherein the medium, when it is operated, is in a liquid state in the first and the third main pipe, and in a gaseous state in the second main pipe. 
     
     
         2 . Thermal network according to  claim 1  configured in a way that the first main pipe is a supply pipe that has a monodirectional flow from the plant towards the end-user locations, and that the third main pipe is a return pipe that has a monodirectional flow from the end-user locations towards the plant. 
     
     
         3 . Thermal network according to  claim 1 , wherein the pressure in the first main pipe is higher than the pressure in the second main pipe, and wherein the pressure in the second main pipe is higher than the pressure in the third main pipe. 
     
     
         4 . Thermal network according to  claim 1  comprising a liquid pipe bypass connecting the first main pipe to the third main pipe, that guarantees a minimum flow of the medium in said pipes. 
     
     
         5 . Thermal network according to  claim 1  comprising a medium receiver with a part, such as a lower part, connected to the first main pipe and another part, such as an upper part, connected to the second main pipe. 
     
     
         6 . Thermal network according to  claim 1  comprising a condenser configured to generate said liquid state. 
     
     
         7 . Thermal network according to  claim 1  comprising an evaporator configured to generate said gaseous state. 
     
     
         8 . Thermal network according to  claim 1  comprising one end-user location connected via an inlet and an outlet to at least two of the said main pipes and configured in a way that the thermodynamic state of medium at the outlet corresponds to the one desired in the main pipe it is connected to. 
     
     
         9 . Thermal network according to  claim 1 , wherein the medium is CO 2  and is used as an energy transfer medium and wherein at least one end-user location comprises one or several outlets which are adapted for releasing the said CO 2  to connected devices in a continuous or intermittent processes, such as fire extinguishing, Carbon capture and sequestration (CCS) applications, dry ice production, chemical processes, food and beverage processes. 
     
     
         10 . Thermal network according to  claim 1 , wherein the medium is CO 2  and is used as an energy transfer medium and wherein at least one end user location comprises one or several inlets which are adapted for injecting into the network CO 2  from connected devices in a continuous or intermittent processes, such as fire extinguishing, Carbon capture and sequestration (CCS) applications, dry ice production, chemical processes, food and beverage processes. 
     
     
         11 . Thermal network according to  claim 1  comprising a liquid trap on the second main pipe configured for extracting any medium in liquid phase from said second main pipe. 
     
     
         12 . Thermal network according to  claim 1  comprising a gas trap on the third main pipe configured for extracting any medium in gaseous phase from said third main pipe. 
     
     
         13 . Thermal network according to  claim 1  comprising a gas trap on the first main pipe configured for extracting any medium in gaseous phase from said first main pipe. 
     
     
         14 . Thermal network according to  claim 1  comprising a cooling system configured for extracting heat from the flow entering the plant via the third main pipe. 
     
     
         15 . Thermal network according to  claim 1  comprising a subcooling apparatus configured for extracting heat from a liquid entering the plant via the third main pipe and/or leaving a receiver. 
     
     
         16 . Thermal network according to  claim 14 , wherein the cooling system comprises a heat pump used, if present, with the said subcooling apparatus. 
     
     
         17 . Thermal network according to  claim 1  comprising a compressor capable of extracting gas build-up before a condensate extraction pump and compress it at the corresponding pressure within the second main pipe at the plant side. 
     
     
         18 . Thermal network according to  claim 1  comprising a set of receiver isolation valves and a set of receiver flash purge valves operated in such a way as to extract gas build-up before a condensate extraction pump. 
     
     
         19 . Use of a thermal network as defined in  claim 1 , wherein when the heating requirements are higher than the cooling requirements (e.g. in winter), the gas flows from the receiver to the second main pipe at the plant. 
     
     
         20 . Use of a thermal network as defined in  claim 1 , wherein when the cooling requirements are higher than the heating requirements (e.g. in summer), the gas flows from the second main pipe into the receiver at the plant. 
     
     
         21 . Use of a thermal network as defined in  claim 1 , wherein when the cooling requirements are equal to the heating requirements (e.g. in summer), there is no flow in the second main pipe that goes into or comes from the receiver. 
     
     
         22 . Use of a thermal network as defined in  claim 1  comprising the generation of a liquid sate medium and gaseous state medium, wherein the liquid state medium is transferred to the first and third main pipes and wherein the gaseous state medium is transferred to the second main pipe.