CO2 District Energy Network With Decentralized Phase-State Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional district energy systems face inefficiencies in energy transfer, require extensive underground piping, and pose safety risks due to leakage, while also needing multiple pipes and working fluids, which increase energy losses and complexity.

Innovation Solution

A district energy system utilizing CO2 as the energy transfer medium, with decentralized compressor units, heat pumps, and a dual-pipe network that adjusts thermodynamic states at the customer's location to meet specific building needs, minimizing energy losses and using internal recirculation for direct energy transfer between heating and air-conditioning modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If water pipes are implemented in underground channels for district energy systems, then energy transfer is achieved, but safety issues arise due to possible leakage problems affecting electrical and telecommunication wires

Engineering Contradiction:
ImprovesafetyVSAvoidleakage risks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter of the transfer medium from liquid water to gaseous CO2. This parameter change eliminates leakage risks to electrical wires while maintaining energy transfer capability through phase change heat exchange mechanisms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of CO2 leakage into a benefit by utilizing CO2's phase change properties. The CO2 is deliberately allowed to evaporate and condense in controlled manner to transfer heat, turning what could be a harmful leakage into a useful heat exchange mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If multiple pipes are used in conventional district energy systems to provide heating and cooling services, then all energy service requirements are met, but device complexity and energy losses increase

Engineering Contradiction:
Improveenergy service coverageVSAvoidnumber of pipes
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the CO2 transfer medium universal by enabling it to perform multiple functions: heat transfer for heating, heat absorption for cooling, and thermal energy storage. This multi-functionality is achieved through controlling CO2 phase changes, allowing a single pipe system to replace multiple dedicated pipes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges heating, cooling, and thermal storage functions into a single integrated system using CO2 as the universal transfer medium. This consolidation reduces the number of separate pipes and systems needed, thereby reducing device complexity and associated energy losses.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If conventional district energy systems use separate working fluids for heat pump and pipe network, then specific functions are optimized, but energy losses occur in additional heat-exchangers

Engineering Contradiction:
Improvefunction optimizationVSAvoidheat-exchanger losses
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent employs CO2 as a universal working fluid that performs all functions previously requiring separate fluids: heat pumping, heat transfer in pipes, and thermal storage. This eliminates the need for intermediate heat exchangers between different fluid systems, reducing energy losses.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Loss of energy

If decentralized compressor units and heat pumps are installed at customer locations to adjust thermodynamic state, then energy losses are minimized, but device complexity increases

Engineering Contradiction:
Improveenergy transfer lossesVSAvoiddecentralized units
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent segments the district energy system into decentralized units at customer locations, each capable of independently adjusting CO2 thermodynamic state. This segmentation allows localized optimization of energy transfer, minimizing losses by matching supply and demand conditions at each building rather than using a centralized approach.

Inventive Principle:
Principle #1Segmentation

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

This approach reduces energy losses, minimizes pipe requirements, enhances safety by eliminating leakage risks, and allows for efficient use of latent heat, while enabling CO2 storage and reuse for fire extinction or fuel cell applications.

Implementation Method 1

make use of the latent heat of the transfer medium instead of the specific heat

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 2

the thermodynamic state of the working fluid, CO2, is not defined only at a central heating/cooling plant, but also directly at the customer's place

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2122257B1Co2 based district energy system
Publication Date: 2017.04.26 ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE (EPFL)
  • EP2122257B1 patent drawingFigure 1

AI summary

District energy system comprising a pipe system, end user's locations, and an optional plant for transferring an energy transfer medium between said end user' s locations and/or between said optional plant and said end user's locations, characterized by the fact that said energy transfer medium is CO2.