Vehicle Climate Control Strategy to Prevent Heat Exchanger Icing
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Solution Overview
Problem
Heat exchangers in vehicle climate-control systems tend to ice up at low outdoor temperatures, leading to energy-intensive thawing processes that reduce efficiency.
Innovation Solution
A method that determines the heating output demand and selects an operating strategy for the climate-control system, combining the use of a heat pump and an additional heating source to maintain efficiency, avoiding icing by operating the heat pump above the dew point and using the additional source to meet the demand, thereby maximizing overall energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the heat pump operates at low fluid temperature to maximize heat extraction efficiency, then the heat exchange efficiency is improved, but the outside-air heat exchanger ices up
Solution Approach 1:
The control unit proactively determines the dew point temperature and compares it with the required fluid temperature before ice build-up occurs. By predicting the icing condition in advance and taking preventive action (switching to alternative heating strategies when Tfluid < Tdew point), the system avoids the harmful effect of ice accumulation while maintaining energy efficiency.
Solution Approach 2:
The control unit acts as an intermediary that coordinates between the heat pump operation and alternative heating sources. When the heat pump would cause icing (Tfluid < Tdew point), the control unit switches to or combines with auxiliary heating methods, mediating between the need for efficient heat extraction and the need to prevent ice build-up on the heat exchanger.
2Power
If the heat pump operates below dew point temperature to meet heating demand, then the heating output is sufficient, but energy is consumed for thawing the heat exchanger
Solution Approach 1:
The control unit continuously monitors the operating conditions and compares the required fluid temperature with the dew point temperature. This feedback mechanism allows the system to detect when operating below dew point would cause icing and to switch to alternative heating strategies, thereby avoiding the energy waste associated with thawing operations.
Solution Approach 2:
The system changes the operating parameters of the heating system based on temperature conditions. When the required fluid temperature falls below the dew point, the control unit changes from heat pump-only operation to alternative heating strategies (such as resistance heating or combined systems), adjusting the operational parameters to prevent icing and avoid subsequent energy-intensive thawing cycles.
3Object-affected harmful factors
If the additional heating source is used to meet heating demand, then icing is prevented, but the overall energy efficiency decreases
Solution Approach 1:
The system dynamically adjusts the mixing ratio of different heating sources based on real-time conditions. The control unit calculates the dew point and determines the optimal combination of heat pump and auxiliary heating, continuously adapting the operating strategy to maintain energy efficiency while preventing ice build-up when necessary.
Solution Approach 2:
The climate control system is designed with multi-functionality, capable of operating in multiple modes: heat pump-only mode for efficient operation above dew point, auxiliary heating mode for ice prevention below dew point, and combined mode for transitional conditions. This universal design allows the system to optimize energy efficiency across different operating conditions.
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 ensures efficient climate control by balancing the use of heat sources, preventing icing and reducing energy consumption, especially in electric vehicles, thereby extending the driving range.
Implementation Method 1
heat exchangers as part of a heat pump by means of which heat is extracted from the outside air for the climate-control of the vehicle
Implementation Method 2
when the outdoor temperatures are low, for example, −4° C. or less, the heat exchanger tends to ice up since said heat exchanger has to be very cold in order to reach the temperature differential that is needed for the heat exchange
Implementation Method 3
additional heating heat source for an interior of the vehicle
Data Source
AI summary
The invention relates to a method for operating a climate-control system (12) for a vehicle (10). According to the invention, total energy efficiencies are determined for a group of operating strategies for the air-conditioning system (12) and an operating strategy with the greatest total efficiency that fulfills the heating output requirement (44) that has been determined, is selected.