Refrigeration device for container

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Solution Overview

Problem

The existing container refrigeration apparatuses face challenges in efficiently adjusting heating capability, leading to either inadequate heating or excessive energy consumption due to the complexity and limitations of the bypass valve system, which complicates fine temperature control.

Innovation Solution

The apparatus controls the compressor's operating speed and adjusts the refrigerant circulation based on the degree of superheat, using a hot gas bypass circuit to manage refrigerant flow and fan operation, ensuring precise temperature control by varying the refrigerant amount and flow rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two open/close valves are used to adjust heating capability in the bypass circuit, then heating capability can be adjusted in two stages, but the refrigerant circuit becomes more complex and costs increase

Engineering Contradiction:
Improveheating capability adjustmentVSAvoidrefrigerant circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent removes the complex two-valve bypass circuit system and extracts only the essential heating function. Instead of using two open/close valves to create two-stage heating adjustment, the invention uses a single bypass circuit with continuous refrigerant flow control, eliminating unnecessary components while preserving the core heating capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than controlling heating capability by opening/closing valves to restrict flow, the invention inverts the approach by using a continuous bypass circuit where refrigerant flows freely and controls heating through compressor operating speed adjustment. This reverses the traditional valve-based discrete control method to a continuous speed-based control system.

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If two open/close valves are used to control refrigerant flow in bypass pipes, then heating capability can be adjusted, but fine adjustment of heating capability cannot be achieved

Engineering Contradiction:
Improveheating capability adjustmentVSAvoidheating capability precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent transitions from static discrete valve positions (open/closed states) to dynamic continuous control. By adjusting the compressor's operating speed continuously, the system achieves fine-grained control over refrigerant circulation量和 heating capability, enabling precise temperature control rather than coarse two-stage adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the control parameter from discrete valve opening states to continuous compressor speed parameter. This allows the heating capability to be adjusted precisely by varying the compressor speed across a continuous range, achieving fine adjustment that was impossible with binary valve states.

Inventive Principle:
Principle #35Parameter changes

3Speed

If compressor operating speed is increased to quickly heat the container, then heating speed improves, but energy consumption increases

Engineering Contradiction:
Improveheating speedVSAvoidcompressor energy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic or variable compressor operation rather than continuous high-speed operation. The compressor speed is dynamically adjusted based on the heating demand and temperature differential, operating at high speed only when rapid heating is needed and reducing speed as the target temperature approaches, thereby optimizing energy consumption while maintaining heating speed when necessary.

Inventive Principle:
Principle #19Periodic action

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 allows for quick and appropriate adjustment of heating capability, ensuring the container reaches the target temperature efficiently while preventing refrigerant phase issues that could damage the compressor, thus enhancing the apparatus's reliability and energy efficiency.

Implementation Method 1

the high temperature refrigerant compressed in the compressor (30)

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

bypasses the condenser (31) and flows into the evaporator (33), thereby heating the inside of the container

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP2505939B1Refrigeration device for container
Publication Date: 2021.05.26 DAIKIN INDUSTRIES LTD
  • EP2505939B1 patent drawingFigure 1
  • EP2505939B1 patent drawingFigure 2
  • EP2505939B1 patent drawingFigure 3

AI summary

A container refrigeration apparatus includes: a refrigerant circuit (20) which performs a refrigeration cycle, and includes a main circuit (21) sequentially connecting a compressor (30), a condenser (31), a main expansion valve (32) and an evaporator (33), and a hot gas bypass circuit (22) through which a refrigerant compressed in the compressor (30) bypasses the condenser (31) and the main expansion valve (32) to flow into the evaporator (33); and a compressor control section (81) which controls operating speed of rotation of the compressor (30) during heating operation for heating inside of a container by the evaporator (33) while returning the compressed refrigerant from the compressor (30) to the compressor (30) through the hot gas bypass circuit (22) and the evaporator (33) so that a temperature inside the container reaches a target temperature.