Vehicle Heat Pump De-Icing Using Waste Heat for Cabin Heating
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Solution Overview
Problem
Heat pumps face efficiency issues due to ice fouling on the outside heat exchanger, which degrades performance and can lead to increased energy consumption, mechanical wear, and passenger discomfort, as existing methods rely on increasing compressor output or using electric resistive heaters.
Innovation Solution
A method utilizing waste heat from vehicle components to de-ice the outside heat exchanger by selecting a waste-heat heat exchanger based on temperature thresholds and flowing coolant through it to both the outside and cabin heat exchangers, independently controlling heat delivery to maintain cabin heating and de-ice the outside exchanger without relying on compressor-generated heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressor output speed is increased to generate heat for melting accumulated ice on the outside heat exchanger, then de-icing effectiveness is improved, but energy consumption increases and compressor mechanical wear accelerates
Solution Approach 1:
The system uses waste heat from the vehicle's own operation (engine coolant or refrigerant from the heat pump system) to de-ice the outside heat exchanger, making the system self-sufficient without requiring additional energy input from the compressor or external power sources
Solution Approach 2:
The system changes the temperature parameter of the coolant by routing it through the outside heat exchanger, utilizing the temperature difference between the warm coolant and the iced heat exchanger surfaces to melt the ice without mechanical compression
2Reliability
If compressor output speed is increased to generate heat for de-icing, then ice fouling is mitigated, but compressor lifespan is reduced due to increased mechanical wear
Solution Approach 1:
The system uses waste heat from the vehicle's own operation (engine coolant or refrigerant from the heat pump system) to de-ice the outside heat exchanger, making the system self-sufficient without requiring additional energy input from the compressor or external power sources
Solution Approach 2:
The system replaces the mechanical compression method with a thermal conduction method, using the temperature difference between warm coolant and iced surfaces to melt ice, thereby eliminating mechanical wear on the compressor
3Reliability
If heat delivery to the outside heat exchanger is increased during de-icing, then ice accumulation is reduced, but excessive heating of the passenger cabin may occur
Solution Approach 1:
The system segments the coolant flow into separate loops: a first coolant loop for de-icing the outside heat exchanger and a second coolant loop for cabin heating, allowing independent control of each function without interfering with the other
Solution Approach 2:
The system applies different temperature qualities of coolant to different locations: warmer coolant is routed to the outside heat exchanger for de-icing while cooler coolant is routed to the cabin heat exchanger for comfortable heating, optimizing each location's thermal requirements
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 approach reduces energy consumption, minimizes mechanical wear on the compressor, and maintains passenger comfort by efficiently using waste heat to de-ice the outside heat exchanger while satisfying cabin heating demands.
Implementation Method 1
selecting a first waste-heat heat exchanger based on a temperature of the first waste-heat heat exchanger exceeding a first temperature threshold, flowing coolant in a first coolant loop through the first waste-heat heat exchanger
Implementation Method 2
flowing the coolant in the first coolant loop through an evaporator heat exchanger, wherein the evaporator heat exchanger is thermally coupled to a gas cooler heat exchanger by a refrigerant loop
Implementation Method 3
flowing the coolant in the first coolant loop through an evaporator heat exchanger, wherein the evaporator heat exchanger is thermally coupled to a gas cooler heat exchanger by a refrigerant loop
Implementation Method 4
flowing a first portion of coolant in a second coolant loop exiting the gas cooler heat exchanger through a cabin heat exchanger
Implementation Method 5
flowing a second portion of coolant in the second coolant loop exiting the gas cooler heat exchanger through an outside heat exchanger
Data Source
AI summary
Methods and systems are provided for operating a dual loop heat pump system in a de-icing mode which enables the heat pump system to maintain a target rate of heat delivery to a cabin while de-icing an outside heat exchanger by leveraging waste-heat available at one or more waste-heat sources. In one example, responsive to an outside heat exchanger de-icing request and a cabin heating request, selecting a first waste-heat heat exchanger based on a temperature of the first waste-heat heat exchanger exceeding a first temperature threshold, flowing coolant to the first waste-heat heat exchanger, flowing a first portion of the coolant exiting the first waste-heat heat exchanger to a cabin heat exchanger, and flowing a second portion of the coolant exiting the first waste-heat heat exchanger to an outside heat exchanger.