Transcritical CO2 Refrigeration With Multi-Temperature Ejectors

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Solution Overview

Problem

Current carbon dioxide refrigeration systems using natural refrigerants are less efficient due to high throttling losses between heat rejection and absorption processes, leading to increased power usage and operational costs.

Innovation Solution

A transcritical carbon dioxide refrigeration system employing multiple ejectors at different temperatures, including a mid-temperature and low-temperature cycle with corresponding ejectors and a gas cooler/condenser, to recover pressure and work, reducing the need for pumps and enhancing energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If carbon dioxide refrigeration systems use natural refrigerants, then environmental friendliness is improved, but energy efficiency deteriorates due to high throttling losses

Engineering Contradiction:

Improveenvironmental impactVSAvoidthrottling losses

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The system divides the refrigeration cycle into multiple temperature levels (high, mid, low temperature cycles) with separate ejectors for each level. This segmentation allows optimized heat rejection and absorption at different temperature ranges, reducing overall throttling losses while maintaining environmental benefits of CO2 refrigerant

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes the transcritical properties of carbon dioxide by operating at different pressure and temperature parameters across multiple cycles. By changing operational parameters (temperature levels, pressure ratios) for each ejector cycle, the system optimizes heat transfer efficiency and reduces throttling losses inherent in conventional single-cycle CO2 systems

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If multiple ejectors are added to reduce throttling losses, then energy efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvethrottling lossesVSAvoidsystem configuration

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges multiple ejector cycles (high, mid, low temperature) into a single integrated refrigeration system with a common gas cooler/condenser. This combining approach allows the system to achieve reduced throttling losses through multiple ejectors while sharing common components, thereby limiting the increase in overall device complexity

Inventive Principle:

Principle #5Merging (Combining)

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

The system improves energy efficiency and reduces overall power consumption while maintaining environmental friendliness by utilizing the recovered work to compress refrigerant, thereby lowering operational and maintenance requirements.

Implementation Method 1

Methodology Applied

Scientific EffectEjector effect: Injector

Data Source

PatentUS9897363B2Transcritical carbon dioxide refrigeration system with multiple ejectors

Publication Date: 2018.02.20 HEATCRAFT REFRIGERATION PRODUCTS LLC

AI summary

The present application provides a carbon dioxide based refrigeration system. The carbon dioxide based refrigeration system may include a mid temperature cycle with a mid temperature ejector, a low temperature cycle with a low temperature ejector, and a gas cooler/condenser in communication with the mid temperature cycle and the low temperature cycle.