Vehicle HVAC Secondary Coolant Loop for Heat Pump Efficiency
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Solution Overview
Problem
Secondary loop heat pump systems in vehicles are less efficient due to indirect heat transfers and lack adaptive control, which limits their competitiveness with other heating and cooling systems, particularly in hybrid and electric vehicles where energy efficiency and safety are critical.
Innovation Solution
A vehicle HVAC system with a refrigerant loop and a coolant loop, utilizing multiple valves to direct coolant flows through refrigerant-to-coolant heat exchangers and air-to-coolant heat exchangers, with a control module to dynamically adjust coolant flows based on operation modes, enhancing energy efficiency and safety by minimizing refrigerant circulation through cabin heat exchangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If air-to-air heat pump systems are used, then energy efficiency is improved, but device complexity and cost increase due to sophisticated controls and refrigerant valves
Solution Approach 1:
The patent introduces a secondary coolant loop as an intermediary between the refrigerant system and the cabin air handling system. The refrigerant exchanges heat with coolant in heat exchangers, and the coolant then handles the thermal management of cabin air. This intermediary approach simplifies the control system by eliminating the need for complex refrigerant valve arrangements while maintaining high energy efficiency through optimized heat transfer pathways.
2Temperature
If air-to-air heat pump systems with refrigerant circulation are used, then heating and cooling performance is improved, but safety risks increase due to potential evaporator breaches and elevated CO2 concentration
Solution Approach 1:
The patent uses a secondary coolant loop as a safety intermediary that completely isolates the refrigerant from the cabin air handling system. The coolant acts as a barrier medium that transfers thermal energy without any risk of refrigerant leakage into the passenger compartment. This eliminates safety concerns related to evaporator breaches and CO2 concentration while preserving full heating and cooling performance capabilities.
Solution Approach 2:
The patent extracts the refrigerant circulation pathway from the cabin air handling system by implementing a separate secondary coolant loop. The refrigerant is confined to its own closed loop for heat pump operations, while the coolant handles all interactions with the cabin air system. This separation removes the safety hazards associated with refrigerant presence in the cabin while maintaining effective climate control.
3Reliability
If secondary loop heat pump systems are used, then safety and cost are improved by minimizing refrigerant circulation, but energy efficiency decreases due to indirect heat transfers
Solution Approach 1:
The patent optimizes the intermediary coolant loop system by implementing high-efficiency heat exchangers at each transfer point. The refrigerant-to-coolant heat exchangers and the coolant-to-air heat exchangers are designed with enhanced heat transfer surfaces and optimized flow characteristics. This minimizes the thermal resistance introduced by the indirect heat transfer pathway, thereby improving energy efficiency while maintaining the safety advantages of the secondary loop architecture.
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 system improves energy efficiency and safety by enabling adaptive control, potentially eliminating the need for high-voltage PTC heaters, and reduces refrigerant usage and costs, while maintaining effective climate control for both passenger compartments and vehicle components.
Implementation Method 1
a refrigerant loop having first and second refrigerant-to-coolant heat exchangers
Implementation Method 2
a coolant loop having a plurality of valves for directing a first flow of coolant through the first refrigerant-to-coolant heat exchanger
Data Source
AI summary
A vehicle having a heating and cooling system includes a refrigerant loop having first and second heat exchangers, and a coolant loop. The coolant loop includes a plurality of valves directing a first flow of coolant through a first refrigerant-to-coolant heat exchanger, a second flow of coolant through a second refrigerant-to-coolant heat exchanger, and a third flow of coolant including a first portion of the first flow of coolant exiting the first refrigerant-to-coolant heat exchanger and a first portion of the second flow of coolant exiting the second refrigerant-to-coolant heat exchanger through an auxiliary coolant loop, and a control module for controlling the plurality of valves to direct the flows of coolant dependent upon a mode of operation. The auxiliary coolant loop is for heating/cooling one or more components, such as a battery, dependent upon the mode of operation.