Liquid-Suction Heat Interchanger for Low-GWP Clothes Dryer Heat Pumps
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Solution Overview
Problem
Heat pumps in clothes treatment appliances face challenges with high Global Warming Potential (GWP) refrigerants and efficiency variations due to ambient temperature changes, which affect the operating conditions and increase energy consumption.
Innovation Solution
Incorporating a liquid-suction heat interchanger with thermally coupled refrigerant lines, where the first line is connected between the evaporator and compressor, and the second line between the condenser and restrictor, to enhance enthalpy exchange and reduce power consumption, while maintaining thermal isolation against the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrocarbon refrigerants (R-290, R-1270) are used to reduce GWP, then environmental performance is improved, but flammability risk increases requiring charge limits of 150g
Solution Approach 1:
The patent changes the refrigerant charge parameter from the conventional 150g limit to a higher charge (e.g., 200-300g) by implementing a liquid-suction heat interchanger that optimizes system performance and safety, allowing increased refrigerant quantity for better cooling capacity while managing flammability risks through improved heat exchange efficiency
Solution Approach 2:
The liquid-suction heat interchanger acts as an intermediary component between the condenser and evaporator, enabling efficient heat transfer that allows higher refrigerant charges to be used safely by optimizing the refrigeration cycle and reducing the need for excessive refrigerant quantities
2Power
If additional heat exchangers are added to exchange heat with ambient air, then cooling capacity is improved, but device complexity and operational difficulty increase
Solution Approach 1:
The patent merges the liquid-suction heat interchanger functionality into the existing refrigerant circuit between the condenser and evaporator, combining heat exchange functions without requiring separate ambient air heat exchangers, thus improving cooling capacity while avoiding additional system complexity
Solution Approach 2:
The liquid-suction heat interchanger performs multiple functions simultaneously: it acts as both a heat exchanger for cooling the liquid refrigerant and a suction line for the compressor, eliminating the need for separate ambient air heat exchangers while achieving improved cooling capacity
3Power
If refrigerant charge is increased beyond 150g limit, then cooling capacity is improved, but safety compliance with IEC 60335-2-11 standard is violated
Solution Approach 1:
The patent changes the safe operating parameters by implementing a liquid-suction heat interchanger that allows higher refrigerant charges (200-300g) to be used safely, improving cooling capacity while maintaining safety compliance through optimized heat exchange that reduces the risks associated with higher refrigerant quantities
4Loss of energy
If conventional refrigerant lines are used without thermal isolation, then manufacturing simplicity is maintained, but energy efficiency decreases due to heat loss to environment
Solution Approach 1:
The patent applies thermal isolation locally to the liquid-suction heat interchanger and its connecting refrigerant lines, providing insulation only where heat loss to the environment would affect system efficiency, rather than insulating the entire refrigeration system, thus reducing energy loss while maintaining manufacturing simplicity
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 configuration increases stability and reliability, reduces refrigerant mass flow, decreases compressor power consumption, and enhances cooling capacity and COP, particularly for hydrocarbon refrigerants, while adhering to flammable refrigerant charge limits and reducing drying time and energy consumption.
Implementation Method 1
a liquid-suction heat interchanger, wherein the liquid-suction heat interchanger comprises a first refrigerant line and a second refrigerant line that are thermally coupled to each other
Implementation Method 2
a first refrigerant line and a second refrigerant line that are thermally coupled to each other
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a heat pump P' for a clothes treatment appliance H. The heat pump P' comprises a compressor 1, a condenser 2, a restrictor 3, and an evaporator 4, and further comprises a liquid-suction heat interchanger 8. The liquid-suction heat interchanger 8 comprises a first refrigerant line 9 and a second refrigerant line 10 that are thermally coupled to each other. An inlet 9i of the first refrigerant line 9 of the heat interchanger 8 is coupled to an outlet 4o of the evaporator 4, and an outlet 9o of the first refrigerant line 9 is coupled to an inlet 1 i of the compressor 1. An inlet 10i of the second refrigerant line 10 is coupled to an outlet 2o of the condenser 2 and an outlet 10omicron of the second refrigerant line 10 is coupled to an inlet 3i of the restrictor 3. The first refrigerant line 9 and the second refrigerant line 10 are thermally isolated against an environment of the liquid-suction heat interchanger 8. A clothes treatment appliance H according to the invention comprises such heat pump P'.