Vehicle HVAC Heating Split Control for Low-Temperature Heat Pumps
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Solution Overview
Problem
Air conditioning systems in hybrid or electric vehicles face inefficiencies in heating capacity due to the decreasing coefficient of performance of heat loops at low external temperatures, necessitating optimization of the complementary electrical heating device's usage to maintain optimal system performance.
Innovation Solution
A control process that determines the optimal heating capacity distribution between the heat loop and the electrical heating device by calculating coefficients 'a' and 'b' for linear approximation of the heat loop's coefficient of performance, allowing for adjustment of the electrical heating device's capacity to complement the heat loop's capacity, thereby optimizing the overall coefficient of performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the heat loop operates in heat pump mode to provide heating capacity, then the coefficient of performance is generally greater than 1, but the coefficient of performance decreases significantly as the external temperature decreases
Solution Approach 1:
The system dynamically adjusts the heating capacity distribution between the heat loop and electrical heating device based on real-time external temperature conditions. The control device continuously monitors external temperature and automatically optimizes the proportion of heating provided by each source, transitioning from heat-loop-dominant at higher temperatures to a more balanced or electrical-dominant approach at lower temperatures.
Solution Approach 2:
The system changes the operational parameters of the heat loop and electrical heating device based on external temperature. Specifically, it adjusts the heating capacity output of each component according to temperature thresholds and performance characteristics, optimizing the overall coefficient of performance across different temperature ranges.
2Reliability
If the electrical heating device is used to support the heat loop at low external temperatures, then the heating capacity is maintained, but the overall coefficient of performance decreases because electrical heating has a coefficient of performance equal to 1
Solution Approach 1:
The system applies partial action by using the electrical heating device only to the extent necessary to maintain required heating capacity at low temperatures. Rather than relying solely on electrical heating when the heat loop becomes inefficient, the system calculates the optimal partial contribution from each source, using electrical heating only when and where needed to supplement the heat loop.
Solution Approach 2:
The control device dynamically determines the optimal heating capacity distribution between the heat loop and electrical heating device based on real-time conditions. It continuously adjusts the proportion of heating provided by each source to maintain overall system efficiency while ensuring sufficient heating capacity is delivered.
3Power
If the heating capacity of the heat loop is increased to meet overall heating capacity requirements, then the heating demand is satisfied, but the coefficient of performance of the heat loop decreases due to excessively low external temperatures
Solution Approach 1:
The system segments the total heating capacity requirement into two separate sources: the heat loop and the electrical heating device. Each source operates at its optimal capacity level rather than forcing one source to meet the entire demand. The control device calculates and distributes the heating load between these two segments based on their respective efficiency characteristics at current operating conditions.
Solution Approach 2:
The system employs multiple heating sources (heat loop and electrical heating device) that can function independently or in combination. This multi-functionality allows the system to select the most efficient heating source for each portion of the heating demand, optimizing overall energy utilization while meeting total heating 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 enhances the overall coefficient of performance of the air conditioning system by effectively distributing heating capacity between the heat loop and electrical device, improving efficiency and reducing energy consumption, especially at low external temperatures.
Implementation Method 1
a heat loop operating according to a so-called 'heat pump' mode... in which the heat loop provides a heating capacity for the heat loop
Implementation Method 2
an electrical heating device providing a complementary heating capacity for the electrical device
Implementation Method 3
at least one external heat exchanger, an internal heat exchanger or a water-air exchanger radiator
Data Source
AI summary
The invention relates to a control process for an air conditioning system. The air conditioning system comprises a thermal loop (1) used as a heat pump and an electrical heating device (2). The process calculates a global heating capacity (HCglo) in function of the temperature chosen by the passenger, the speed of the blower and the temperature of the exterior air. Then, the process calculates a heating capacity (HC1) of the thermal loop (1) and compares this heating capacity (HC1) of the thermal loop to the global heating capacity (HCglo). If the global heating capacity (HCglo) is superior to the heating capacity (HC1) of the thermal loop, the process determines a heating capacity (HC2) of the electrical heating device (2). This heating capacity (HC2) of the electrical heating device (2) added to the heating capacity (HC1) of the thermal loop (1) allows to obtain the global heating capacity (HCglo) required in function of the temperature selected by the passenger.