Unitary HPAC Heat Exchanger Integration for Compact Cold-Climate 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 increasing system complexity or reducing electric driving range, particularly in cold climates where traditional heat pump modes are inefficient and may damage components.
Innovation Solution
A compact Unitary Heat Pump Air Conditioner (HPAC) system with a hot-side heat exchanger assembly featuring stacked, hermetically sealed plates for a condenser/chiller, receiver, and sub-cooler portions, along with an electrically driven compressor and coolant pumps, which scavenges waste heat from vehicle electronics to provide supplemental heating without reversing the refrigerant cycle.
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, sub-cooler, and condenser into a single integrated heat exchanger assembly. This merging eliminates the need for separate receivers and sub-coolers, reducing the number of components and refrigerant plumbing connections required when operating in heat pump mode, thereby resolving the technical contradiction between improved heating capability and increased system complexity
Solution Approach 2:
The integrated heat exchanger assembly performs multiple functions simultaneously: it acts as a condenser for heat rejection, a receiver for refrigerant storage, and a sub-cooler for refrigerant sub-cooling. This multi-functionality allows the system to operate efficiently in heat pump mode without requiring additional specialized components, thus improving heating capability while avoiding increased system complexity
2Temperature
If traditional heat pump mode is used in cold climates, then heating is provided, but condenser efficiency decreases and damage risk increases when surface temperature drops below 32°F
Solution Approach 1:
The patent introduces a coolant circulation system as an intermediary between the condenser and the environment. Instead of relying solely on air-to-refrigerant heat transfer in the condenser, coolant circulates through the condenser core to absorb heat, preventing the condenser surface temperature from dropping below freezing point. This intermediary coolant system protects the condenser from freezing damage while maintaining heating capability in cold climates
3Temperature
If electric heaters are used to provide supplemental heat in cold climates, then heating capability is improved, but electric driving range is reduced due to increased current draw
Solution Approach 1:
The patent converts the waste heat generated by vehicle electronics and the refrigeration cycle into useful heating energy. The integrated heat exchanger assembly captures waste heat from the refrigerant during condensation and from vehicle electronics, transferring it to the coolant circulation system for heating the passenger compartment. This approach provides supplemental heating in cold climates while actually recovering and utilizing energy that would otherwise be wasted, thereby improving heating capability without increasing electric current draw and preserving electric driving range
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 supplements passenger compartment heating using waste heat, improving driving range in cold climates by minimizing electric current usage and maintaining optimal battery temperatures, while being compact and easily installable in various vehicle compartments.
Implementation Method 1
a first hot-side coolant passageway in non-contact thermal communication with the refrigerant passageway
Implementation Method 2
The first coolant passageway and the second coolant passageway are in non-contact thermal communication with the refrigerant passageway
Implementation Method 3
a second hot-side coolant passageway in non-contact thermal communication with the refrigerant passageway and configured to transfer thermal energy to or from the liquid phase refrigerant
Implementation Method 4
the vapor phase refrigerant is compressed to a high pressure vapor by the compressor
Implementation Method 5
the low pressure vapor is compressed to a high pressure vapor by the compressor, the vapor phase refrigerant is transferred to the condenser where the high pressure vapor is condensed into a high pressure liquid refrigerant by releasing the heat to the ambient air
Data Source
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AI summary
The disclosure relates to a unitary heat pump air conditioner (100) having a plate type hot-side heat exchanger assembly (102), a cold-side heat exchanger assembly (110), and electrically driven compressor (112) and coolant pumps (114, 116). The plate type hot-side heat exchanger assembly (102) includes a plurality of plates (120) stacked and hermetically sealed between an upstream end plate (126) and a downstream end plate (128), defining a condenser/chiller portion (103) having a first coolant passageway (124a), a sub-cooler portion (106) having a second coolant passageway (124b), and a refrigerant receiver (19) portion sandwiched between the condenser/chiller portion (103) and the sub-cooler portion (106). The first coolant passageway (124a) and the second coolant passageway (124b) are in non-contact thermal communication with the refrigerant passageway (122).