Heat Pump Hot Gas Bypass Layout for Rapid Exterior Defrosting
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Solution Overview
Problem
Conventional heat pumps with hot gas bypass defrosting cycles face inefficiencies due to incomplete defrosting, excessive compressor load, and prolonged heating-stop periods, as they can only bypass hot gas to a limited extent, leading to residual frost and compressor issues.
Innovation Solution
A high-speed defrosting heat pump design that bypasses hot gas evenly across all tubes of the exterior heat exchanger, allowing 100% hot gas bypass during defrosting, ensuring complete evaporation of refrigerant and maintaining optimal temperature and pressure, using a three-way valve for control to enhance efficiency and reduce compressor stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional hot gas bypass defrosting is used, then defrosting operation can be performed, but defrosting speed is slow and heating-stop period is prolonged
Solution Approach 1:
The exterior heat exchanger is divided into multiple tube groups (first, second, third tube groups) with separate hot gas supply paths. This segmentation allows hot gas to be distributed simultaneously to multiple sections, enabling parallel defrosting operation and significantly reducing the overall defrosting time compared to sequential defrosting of single tubes.
Solution Approach 2:
Different tube groups are supplied with hot gas through dedicated control valves (first, second, third hot gas control valves) that can independently regulate gas flow to each section. This local control capability allows optimized defrosting for each tube group based on its specific frost accumulation, improving overall defrosting efficiency while reducing total operation time.
2Reliability
If limited hot gas bypass is used in conventional systems, then system stability is maintained, but defrosting completeness is insufficient and residual frost remains
Solution Approach 1:
The system enables 100% hot gas bypass by coordinating multiple hot gas control valves to fully open during defrosting operation, dramatically increasing the volume of hot gas supplied to the exterior heat exchanger. This parameter change from limited to full bypass ensures sufficient heat input to completely remove frost from all tube groups while maintaining system stability through controlled valve coordination.
3Ease of operation
If multiple control valves are used for hot gas bypass, then defrosting control is improved, but device complexity increases
Solution Approach 1:
Multiple hot gas control valves are used to independently control different tube groups, providing精细化 control for each section. This multi-functionality allows the system to handle different defrosting requirements of various tube groups simultaneously, improving operational flexibility and control precision despite the increased number of components.
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 design achieves rapid defrosting, reducing heating-stop time, completely removing frost, and preventing compressor damage by ensuring thorough heat exchange and pressure reduction, with defrosting completed in 30-100 seconds versus 5-10 minutes, and maintaining stable gas pressure between 4-6 kPa and 10-15 kPa.
Implementation Method 1
a compressor adapted to compress a refrigerant to high temperature and high pressure
Implementation Method 2
a condenser adapted to condense the high temperature and high pressure refrigerant discharged from the compressor to a liquid phase by radiation
Implementation Method 3
a condenser adapted to condense the high temperature and high pressure refrigerant discharged from the compressor to a liquid phase by radiation
Implementation Method 4
expansion valves adapted to expand the liquid-phase refrigerant discharged from the condenser to a low pressure by means of a throttling action
Implementation Method 5
an evaporator adapted to evaporate the throttled refrigerant to a gaseous phase by means of the heat absorption
Implementation Method 6
an evaporator adapted to evaporate the throttled refrigerant to a gaseous phase by means of the heat absorption
Implementation Method 7
the high-temperature and high-pressure hot gas is introduced to the exterior heat exchanger to cause the temperature at the exterior heat exchanger to become raised, such that the frost or ice generated on the outside of the exterior heat exchanger becomes removed
Implementation Method 8
the frost or ice generated on the outside of the exterior heat exchanger becomes removed
Data Source
AI summary
Disclosed is a high speed defrosting heat pump having a closed refrigerant circulation loop including a four-way valve so as to conduct cooling and heating operations by switching a refrigerant-circulating direction by means of the four-way valve. A three-way valve is disposed on a refrigerant pipe connected between a compressor and the four-way valve, and a bypass pipe is branched off from the three-way valve in such a manner as to be connected to a refrigerant pipe connected between an expansion valve and a exterior heat exchanger, such that the hot gas discharged from the compressor is introduced to the exterior heat exchanger via the bypass tube by the control of the three-way valve.