Three-Pipe Thermal Network to Eliminate End-User Rotating Machines
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Solution Overview
Problem
Existing thermal networks require complex equipment and rotating machines at end-user locations, increasing footprint and maintenance needs, and struggle with varying heating and cooling demands across locations.
Innovation Solution
A thermal network using three pipes, two filled with liquid and one with gas, eliminating the need for rotating machines at end-user locations by leveraging latent heat of vaporization and direct heat exchange, with controlled phase transitions to manage temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotating machines (pumps or compressors) are installed at end-user locations to maintain pressure in thermal networks, then heat and cooling delivery is enabled, but equipment complexity and maintenance needs increase
Solution Approach 1:
The invention extracts the rotating machines (pumps and compressors) from end-user locations and relocates them exclusively to the central plant. This is achieved by using a three-pipe configuration where liquid-phase CO2 is pumped from the plant to end-users, undergoes phase change to gas, delivers thermal energy, then returns as liquid without requiring local compression. The central plant handles all rotating machinery, eliminating local equipment complexity while maintaining system reliability.
Solution Approach 2:
The invention changes the physical state parameter of the working fluid (CO2) along the pipeline. By maintaining CO2 in liquid phase in the first and third pipes and gas phase in the second pipe, the system enables thermal energy transfer without requiring rotating machines at end-user locations. The phase transition from liquid to gas at end-users and back to liquid in the return pipe eliminates the need for local compressors.
2Stress or pressure
If rotating machines are installed at end-user locations, then pressure maintenance is achieved, but footprint and substation size increase
Solution Approach 1:
The invention removes rotating machines from end-user locations, extracting the pressure-maintenance function from distributed locations and consolidating it at the central plant. The three-pipe system with phase-changing CO2 enables pressure maintenance through hydrostatic pressure from liquid column height and phase transition dynamics, eliminating the need for local pumps or compressors and thereby reducing substation footprint.
Solution Approach 2:
The invention uses hydraulic principles with liquid-phase CO2 in the first and third pipes to maintain pressure through the weight and continuous flow of the liquid column. The phase transition from liquid to gas at end-user locations creates pressure differentials that drive flow without requiring local rotating machines, reducing equipment footprint while maintaining adequate pressure for thermal energy delivery.
3Productivity
If rotating machines are used at end-user locations, then thermal energy delivery is enabled, but maintenance requirements increase
Solution Approach 1:
The invention extracts all rotating machines from end-user locations and concentrates them at the central plant. This eliminates maintenance requirements at distributed locations while maintaining thermal energy delivery capability. The three-pipe system with phase-changing CO2 enables thermal transfer through passive heat exchange, removing the need for local pumps or compressors that would require maintenance.
Solution Approach 2:
The system enables self-service thermal energy delivery through the inherent properties of CO2 phase transitions. The liquid-to-gas phase change at end-users and gas-to-liquid in the return pipe creates natural flow dynamics and pressure differentials that drive the system without requiring local rotating machines, thereby eliminating maintenance needs at end-user locations while maintaining productivity.
4Loss of energy
If two-pipe systems are used with CO2 phase changes, then thermal energy transfer is achieved, but circulation control between temperature stages is undefined
Solution Approach 1:
The invention segments the thermal network into three distinct pipes with defined functions: first pipe for liquid CO2 supply, second pipe for gaseous CO2 return, and third pipe for liquid CO2 return. This segmentation provides clear circulation pathways between different temperature stages, eliminating the undefined circulation control problem of two-pipe systems while maintaining energy efficiency through dedicated flow paths for each phase and direction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces equipment complexity and maintenance, improves energy efficiency, and enhances operational reliability by minimizing the need for rotating machines, allowing compact installation and efficient heat and cooling delivery across diverse temperature ranges.
Implementation Method 1
leveraging latent heat of vaporization and direct heat exchange, with controlled phase transitions to manage temperature variations
Implementation Method 2
the energy transfer medium is in a liquid state in the first and the third main pipe, and in a gaseous state in the second main pipe
Data Source
AI summary
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).