Container Refrigeration Heating Control via Hot Gas Bypass
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Solution Overview
Problem
The existing container refrigeration apparatuses face challenges in accurately adjusting heating capability, leading to either insufficient heating or excessive energy consumption due to the complexity and inefficiency of the two open/close valves in the hot gas bypass circuit.
Innovation Solution
A container refrigeration apparatus with a compressor control section to adjust the operating speed of the compressor, a refrigerant amount control section to manage refrigerant flow, and fan control sections to optimize fan operation, allowing for precise temperature control and refrigerant management during heating operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two open/close valves are used in the hot gas bypass circuit to adjust heating capability, then heating capability can be adjusted in two stages, but the refrigerant circuit becomes more complex and costs increase
Solution Approach 1:
The patent removes the complex two-valve system from the hot gas bypass circuit and replaces it with a single valve connected to a refrigerant tank. This extraction of unnecessary components simplifies the refrigerant circuit while maintaining the ability to adjust heating capability through the single valve's flow rate control and the tank's refrigerant supply function.
Solution Approach 2:
The single valve in the patent performs multiple functions: it controls hot gas flow in the bypass circuit and works in conjunction with the refrigerant tank to provide both heating and cooling capabilities. The refrigerant tank serves as both a storage container and an active component for adjusting refrigerant flow, eliminating the need for separate two-stage valve mechanisms.
2Adaptability or versatility
If two open/close valves are used in the hot gas bypass circuit, then heating operation can be performed, but fine adjustment of heating capability cannot be made
Solution Approach 1:
The patent replaces the static two-stage valve system with a dynamic single valve that can be adjusted to various degrees of opening. This allows continuous modulation of the hot gas flow rate through the bypass circuit, enabling fine adjustment of heating capability rather than being limited to two fixed stages. The valve's position can be dynamically controlled to match precise heating requirements.
Solution Approach 2:
The invention changes the control parameter from discrete valve states (open/closed) to continuous valve opening degree. By adjusting the valve's opening parameter across a range rather than limiting it to two positions, the system achieves precise control over heating capability. The refrigerant tank's pressure and flow characteristics further contribute to this parameter-based fine adjustment.
3Manufacturing precision
If compressor operating speed is controlled during heating operation, then heating capability can be precisely adjusted, but control system complexity increases
Solution Approach 1:
The patent replaces complex mechanical control systems with electronic control of the compressor's operating speed. Instead of using multiple mechanical valves and linkages to adjust heating capability, the system uses electronic control signals to vary the compressor's rotation speed, which directly affects the refrigerant circulation rate and heating output. This substitution reduces mechanical complexity while improving control precision.
Solution Approach 2:
The control system dynamically adjusts the compressor's operating speed based on temperature feedback and heating requirements. This dynamic control allows precise temperature management by continuously adapting the refrigerant circulation rate to match the container's thermal needs, achieving accurate temperature control without requiring complex static mechanical adjustment mechanisms.
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 solution enables quick and appropriate adjustment of heating capability, ensuring the container reaches the target temperature efficiently while preventing refrigerant-related issues, thereby improving the reliability and energy efficiency of the refrigeration process.
Implementation Method 1
a compressor (30) which compresses a refrigerant
Implementation Method 2
In the evaporator, a refrigerant absorbs heat from the air inside the container to evaporate, thereby cooling the inside air
Implementation Method 3
a condenser (31) which condenses the refrigerant compressed by the compressor (30)
Data Source
AI summary
A container refrigeration apparatus includes: a refrigerant circuit which performs a refrigeration cycle, and includes a main circuit sequentially connecting a compressor, a condenser, a main expansion valve and an evaporator, and a hot gas bypass circuit through which a refrigerant compressed in the compressor bypasses the condenser and the main expansion valve to flow into the evaporator; and a compressor control section which controls operating speed of rotation of the compressor during heating operation for heating inside of a container by the evaporator while returning the compressed refrigerant from the compressor to the compressor through the hot gas bypass circuit and the evaporator so that a temperature inside the container reaches a target temperature.