Integral Receiver-Subcooler Heat Exchanger for EV Heat Pump Heating
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Solution Overview
Problem
Existing heating and air-conditioning systems in vehicles, especially hybrid and electric vehicles, face challenges in providing adequate supplemental heat without reversing the refrigerant cycle, leading to increased system complexity and reduced efficiency in cold climates, which affects the electric driving range.
Innovation Solution
A Unitary Heat Pump Air Conditioner (HPAC) system with a compact hot-side heat exchanger assembly that includes a condenser/chiller portion, a refrigerant receiver, and a sub-cooler portion, utilizing a dedicated refrigerant loop and coolant loops to transfer heat energy from waste sources within the vehicle, minimizing the need for electric heaters and optimizing heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the air-conditioning system operates in heat pump mode to provide supplemental heat, then heating capability is improved, but system complexity increases due to reinforced refrigerant plumbing and additional components
Solution Approach 1:
The patent combines the receiver and sub-cooler into a single integrated component that serves both functions simultaneously. The receiver acts as both a moisture separator and a sub-cooling heat exchanger, eliminating the need for separate receiver and sub-cooler components and their associated plumbing
Solution Approach 2:
The integrated receiver-sub-cooler performs multiple functions: moisture separation, refrigerant storage, and sub-cooling of the refrigerant before it enters the expansion device. This multi-functional design reduces the number of components needed in the heat pump system
2Temperature
If the air-conditioning system operates in heat pump mode in cooler climates, then supplemental heating is provided, but system efficiency decreases and condenser damage may occur due to freezing moisture
Solution Approach 1:
The sub-cooler portion of the integrated component pre-cools the refrigerant below its condensing temperature before it enters the expansion device. This preliminary cooling action ensures that the refrigerant is sufficiently cold to prevent moisture condensation and freezing on the condenser surface during heat pump operation in cold climates
Solution Approach 2:
The system changes the temperature parameter of the refrigerant by sub-cooling it to a lower temperature than standard condensation. This parameter change (lower refrigerant temperature) prevents the harmful effect of moisture freezing on the condenser by ensuring the refrigerant is cold enough to maintain proper heat transfer without causing external condensation issues
3Temperature
If electric heaters are used to provide supplemental heat in cold climates, then heating capability is improved, but electric drive range is reduced due to increased current draw
Solution Approach 1:
The patent converts the waste heat from the refrigeration cycle into useful heating for the passenger compartment by operating in heat pump mode. Instead of discarding the heat rejected by the condenser, it redirects this thermal energy to provide supplemental heating, thereby avoiding the need for energy-consuming electric heaters
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 Unitary HPAC system effectively scavenges waste heat to provide supplemental heating, improving driving range in cold climates by reducing electric current usage and maintaining optimal battery temperatures, while maintaining system simplicity and efficiency.
Implementation Method 1
a hot-side coolant loop in thermal communication with the condenser and sub-cooler
Implementation Method 2
a cold-side coolant loop in thermal communication with the evaporator and internal heat exchanger
Implementation Method 3
the evaporator releases the heat to the passenger compartment by condensing the vapor phase refrigerant
Implementation Method 4
the vapor phase refrigerant is transferred to the condenser where the high pressure vapor is condensed into a high pressure liquid refrigerant
Data Source
AI summary
The disclosure relates to a unitary heat pump air conditioner (Unitary HPAC) having a plate type hot-side heat exchanger assembly, a cold-side heat exchanger assembly, and electrically driven compressors and coolant pumps. The plate type hot-side heat exchanger assembly includes a plurality of plates stacked and hermetically sealed between an upstream end plate and a downstream end plate, defining a condenser/chiller portion having a first coolant passageway, a sub-cooler portion having a second coolant passageway, and a refrigerant receiver portion sandwiched between the condenser/chiller portion and the sub-cooler portion. The first coolant passageway and the second coolant passageway are in non-contact thermal communication with the refrigerant passageway.