Vehicle Coolant Loop with Phase-Change Thermal Storage
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Solution Overview
Problem
In electric and hybrid vehicles, the refrigerant circulation loop for heating, ventilation, and air conditioning consumes excessive energy in winter conditions, leading to reduced battery autonomy and the risk of frost formation on the frontal heat exchanger due to the compressor's increased load and refrigerant condensation at low temperatures.
Innovation Solution
A refrigerant circulation loop with a thermal energy storage module and a controlled distribution element that allows the refrigerant fluid to bypass the evaporator in cold conditions, using a phase change material to preheat the refrigerant before it passes through the heat exchanger, thereby reducing energy consumption and preventing frost formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the compressor speed is increased to maintain cabin comfort in winter conditions, then the heating performance is improved, but the electrical energy consumption increases significantly
Solution Approach 1:
The patent applies preliminary action by preheating the refrigerant fluid using waste heat from the engine coolant before it enters the compressor. This preheating action is performed in advance during vehicle operation, storing thermal energy that will be utilized during heating operations to reduce the compressor's energy consumption while maintaining effective heating performance.
2Productivity
If the frontal heat exchanger is exposed to outside air in very low temperature conditions, then the heat exchange efficiency is improved, but frost formation occurs on the heat exchanger
Solution Approach 1:
The patent introduces an intermediary substance - a glycol-based anti-freeze solution - that circulates through the frontal heat exchanger instead of using refrigerant fluid directly. This intermediary medium has a lower freezing point and does not condense at low temperatures, preventing frost formation while still enabling effective heat exchange between the outside air and the vehicle's thermal system.
Solution Approach 2:
The patent changes the physical parameter of the heat exchange medium by using a glycol-based solution with different thermal properties compared to conventional refrigerant fluid. This parameter change - specifically the lower freezing point and different condensation characteristics - allows the heat exchanger to operate efficiently in sub-zero temperatures without frost accumulation.
3Temperature
If the refrigerant fluid temperature is increased to improve heating performance, then the thermal comfort is improved, but the compressor work and energy consumption increase
Solution Approach 1:
The patent merges two thermal systems - the engine coolant circulation system and the refrigerant circulation system - by introducing a heat exchanger that transfers waste heat from the engine coolant to the refrigerant fluid. This combination allows the refrigerant to enter the compressor at a higher temperature without requiring additional compressor power, as the preheating is achieved through thermal coupling with the engine's waste heat.
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 solution significantly reduces the power consumption of the heating, ventilation, and air conditioning system, increases vehicle autonomy, and prevents frost on the frontal heat exchanger by using stored thermal energy to preheat the refrigerant, ensuring efficient operation even at low temperatures.
Implementation Method 1
a thermal energy storage module (160) having a material capable of changing the phase
Implementation Method 2
the storage module makes it possible to exchange thermal energy with the refrigerant fluid, which advantageously allows to elevate the temperature of the fluid flowing into the circulation loop since the phase change material disposed in the storage module is in a state specific to transmit energy to the refrigerant fluid
Implementation Method 3
a circulation loop can thus be included in the vehicle to bring thermal exchange means to the one and the other of the refrigerant fluid in an appropriate state
Implementation Method 4
The heat exchanger located on the front of the vehicle, usually under the motor cover, said front heat exchanger, operates in particular by means of the outside air through
Implementation Method 5
A compressor can be used to compress the refrigerant fluid in the heating loop and thus change the temperature of the refrigerant led to pass through different thermal exchange means
Implementation Method 6
The refrigerant absorbs or yields heat at the heat exchangers as a function of operating phases of the heat pump
Implementation Method 7
The refrigerant fluid, colder than the ambient air, causes condensation on the walls of the heat exchanger and frost is possible in low temperature and high hygrometry conditions
Data Source
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AI summary
The invention concerns a coolant circulation loop (100) for a motor vehicle comprising a heat-exchange device (120) comprising at least one evaporator (121) and a distribution element (155) controlled to configure the loop in at least a first mode in which the coolant does not pass through the evaporator and a second mode in which the coolant passes through the evaporator. According to the invention, the loop further comprises at least one thermal energy storage module (160) comprising a phase-change material (163), the storage module being arranged on the coolant passage whether the loop is configured in the first or the second mode.