Indirect Heat Pump Coolant Loop Layout for Low-Refrigerant EV Heating
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Solution Overview
Problem
Direct heat pump systems in new energy electric vehicles are complex, costly, and prone to refrigerant leakage, with high maintenance costs and reduced system longevity due to complex refrigerant circuits and large refrigerant charges, limiting their efficiency and driving range.
Innovation Solution
An indirect heat pump system with a refrigerant unit, cold water handling unit, and hot water handling unit, where the refrigerant exchanges heat with coolants (cold and hot water) rather than loads directly, using a compact refrigerant unit and interlocked two-way valves to manage coolant distribution to various loads, simplifying the coolant circuit and enhancing system stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a direct heat pump system is used with multiple heat exchangers and complex refrigerant circuits, then thermal efficiency is improved, but system complexity and cost increase significantly
Solution Approach 1:
The patent extracts the plate heat exchanger from the traditional direct heat pump system, separating the refrigerant circuit from the coolant circuit. This eliminates the need for complex refrigerant piping to multiple loads while maintaining thermal efficiency through dedicated heat exchangers for each load type.
Solution Approach 2:
The system segments the heat exchange functions into separate dedicated heat exchangers (refrigerant evaporator for battery cooling, refrigerant condenser for cabin heating, plate heat exchanger for HVAC cooling). This modular segmentation simplifies the overall system architecture while preserving thermal performance.
2Adaptability or versatility
If a direct heat pump system with multiple heat exchangers and long pipelines is used, then cooling and heating functions are achieved, but refrigerant leakage risks and maintenance costs increase
Solution Approach 1:
The patent extracts the refrigerant circuit from direct contact with coolant circuits, using separate dedicated heat exchangers for each function. This isolation eliminates refrigerant leakage risks into the coolant system while maintaining all required cooling and heating functions through controlled heat transfer interfaces.
Solution Approach 2:
The patent introduces dedicated heat exchangers as intermediary devices between the refrigerant system and various coolant circuits. These intermediaries enable reliable heat transfer while preventing direct refrigerant-c coolant contact, thereby eliminating leakage risks.
3Adaptability or versatility
If a direct heat pump system with large refrigerant charge is used, then system functionality is ensured, but purchase cost and safety requirements increase
Solution Approach 1:
The patent extracts the refrigerant from direct contact with large coolant volumes, using compact dedicated heat exchangers with minimal refrigerant charge. This maintains full system functionality through efficient heat transfer while dramatically reducing the total refrigerant quantity required.
4Temperature
If a PTC heater is used for heating, then heating function is achieved, but energy consumption from batteries increases, reducing driving range
Solution Approach 1:
The patent converts the waste heat from the refrigerant compression process into useful cabin heating through the refrigerant condenser. This transforms what would be wasted energy into a beneficial heating source, eliminating the need for energy-consuming PTC heaters and extending driving range.
Solution Approach 2:
The patent utilizes the phase transition of refrigerant from gas to liquid in the condenser to release compression heat for cabin heating. This phase change process efficiently transfers thermal energy without requiring additional energy input, replacing the energy-intensive PTC heating method.
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
The indirect heat pump system reduces the complexity and cost of refrigerant circuits, improves system stability, and allows for flexible load configuration, enhancing energy efficiency and extending the driving range of new energy electric vehicles by safely switching between cold and heat sources.
Implementation Method 1
an outlet of the compressor communicates with a first inlet of the condenser; a first outlet of the condenser communicates with a first inlet of the evaporator through the throttle valve
Implementation Method 2
a hot water inlet of the hot water handling unit communicates with a second outlet of the condenser; a hot water outlet of the hot water handling unit communicates with a second inlet of the condenser
Implementation Method 3
a plurality of cold water two-way valves are disposed in pipelines of the cold water handling unit and are configured to control the on and off of the cold water in the loads
Data Source
AI summary
An indirect heat pump system includes a refrigerant unit, a cold water handling unit, and a hot water handling unit. A cold water inlet of the cold water handling unit communicates with an evaporator; a cold water outlet of the cold water handling unit communicates with the evaporator; the cold water handling unit is connected to a plurality of loads in parallel. A hot water inlet of the hot water handling unit communicates with a condenser; a hot water outlet of the hot water handling unit communicates with the condenser; the hot water handling unit is connected to the loads in parallel; and a plurality of hot water two-way valves are disposed in pipelines of the hot water handling unit and are configured to control the on and off of the hot water in the loads.