Low-cost control for carbon dioxide condensing unit
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Solution Overview
Problem
Contemporary HVAC systems using carbon dioxide as a refrigerant require high-pressure-rated components and complex control systems, leading to increased costs due to the need for high-performance operation at critical or trans-critical conditions.
Innovation Solution
A cooling system design that operates at non-rating points with lower performance, allowing substitution of high-cost components with lower-cost alternatives, utilizing fixed differential expansion valves and controllable shut-off valves controlled by temperature sensors and a controller for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high-pressure-rated components and complex control systems are used to operate at critical or trans-critical conditions, then cooling efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The system operates at non-rating points with lower performance parameters instead of maintaining high-pressure critical or trans-critical conditions. This allows substitution of high-pressure-rated components with lower-pressure components, reducing manufacturing costs while still meeting industry requirements through temperature-based control strategies
Solution Approach 2:
The patent substitutes expensive high-pressure-rated components and complex control systems with lower-cost alternatives including standard-pressure components, fixed differential expansion valves, and simple temperature-based control logic, achieving cost reduction while maintaining adequate performance
2Loss of energy
If high-performance components are used to operate at high-pressure conditions, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex control systems and high-performance components required for high-pressure operation. Instead, it uses simple temperature sensors, fixed differential expansion valves, and basic control logic to manage the system at lower, non-critical pressure conditions
Solution Approach 2:
The system replaces complex high-performance components with simpler, lower-cost alternatives including standard valves, basic temperature sensors, and straightforward control algorithms, thereby reducing device complexity while maintaining operational capability
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
Achieves efficient cooling at a lower cost while meeting industry standards, reducing initial control costs and maintaining performance levels.
Implementation Method 1
a gas cooler configured to receive the compressed refrigerant and provide a first cooled refrigerant
Implementation Method 2
an expansion valve configured to receive the first cooled refrigerant and provide a second cooled refrigerant
Implementation Method 3
an evaporator configured to receive the second metered refrigerant and provide an evaporated refrigerant... wherein the second metered refrigerant in the evaporator may be configured to cool an adjacent space
Data Source
AI summary
A system may include a condenser unit including a compressor configured to receive a refrigerant from a condenser unit input port and provide a compressed refrigerant; a gas cooler configured to receive the compressed refrigerant and provide a first cooled refrigerant at a gas cooler discharge port; an expansion valve configured to receive the first cooled refrigerant and provide a second cooled refrigerant to a condenser unit discharge port; and a first controllable valve configured to receive the first cooled refrigerant and provide a first metered refrigerant combined with the second cooled refrigerant into a combined refrigerant provided to the condenser unit discharge port, the first controllable valve configured to selectively open when a first temperature at the gas cooler discharge port is below a first temperature threshold.