Vehicle Cabin Heat Pump Control for Stable Ventilation Heating
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Solution Overview
Problem
Conventional heat pump systems for vehicle cabins face challenges in maintaining consistent heating performance due to variations in heating capacity and responsiveness to environmental changes, such as traveling speed, leading to delayed heating capacity achievement and insufficient responsiveness.
Innovation Solution
A heat pump system incorporating a heat pump cycle with a compressor, condenser, pressure reducing unit, and evaporator, along with a low-temperature side heat medium circuit and control unit, which adjusts the low-temperature side heat medium temperature to ensure a predetermined heating capacity by controlling the compressor rotation speed and operation of heat source devices, effectively utilizing the heat capacity of the low-temperature side heat medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat pump systems are used for vehicle cabin heating, then heating function is provided, but heating capacity varies and responsiveness to environmental changes is insufficient
Solution Approach 1:
The system dynamically adjusts the low-temperature side heat medium temperature based on real-time environmental conditions (traveling speed, heating demand) to optimize heating performance. The control unit continuously modifies operating parameters including compressor rotation speed and heat source device operation to adapt to changing external conditions, ensuring consistent heating capacity while maintaining high responsiveness.
Solution Approach 2:
The invention changes the temperature parameter of the low-temperature side heat medium as a control variable to optimize heat pump performance. By adjusting this temperature parameter based on environmental conditions, the system achieves both consistent heating capacity and rapid responsiveness to external changes, resolving the contradiction between reliability and adaptability.
2Productivity
If heating capacity is increased to meet varying demands, then heating performance improves, but system complexity increases
Solution Approach 1:
The low-temperature side heat medium circuit serves multiple functions: it acts as both a heat source for the heat pump cycle and a temperature regulation medium. By utilizing the same circuit for both heating and temperature control, the system achieves high heating capacity without proportionally increasing device complexity, as existing components perform multiple roles.
Solution Approach 2:
The system uses its own low-temperature side heat medium to provide heating capacity adjustments. The heat medium circuit self-regulates temperature and provides heating feedback to the control unit, enabling the system to achieve variable heating capacity without requiring entirely separate control systems, thus limiting the increase in overall complexity.
3Adaptability or versatility
If compressor rotation speed is controlled to adjust heating capacity, then responsiveness improves, but energy consumption increases
Solution Approach 1:
The control unit receives feedback from temperature sensors monitoring the low-temperature side heat medium and adjusts compressor rotation speed accordingly. This closed-loop feedback control ensures the compressor operates at optimal speeds to meet heating demands without excessive energy consumption, as the system only increases compressor speed when actually needed to maintain target heating capacity.
Solution Approach 2:
The system employs periodic adjustment of compressor rotation speed based on changing environmental conditions and heating demands. Rather than maintaining high speed continuously, the compressor operates at variable speeds in response to periodic changes in external conditions, reducing overall energy consumption while maintaining adequate responsiveness to 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
The system ensures efficient heating performance by adjusting the heat transfer amount in the heating unit, maintaining consistent heating capacity and responsiveness to changes in heating demands, thereby effectively addressing variations in heating requirements.
Implementation Method 1
a compressor (11), the condenser (12) releases heat of a high-pressure refrigerant compressed by the compressor (11)
Implementation Method 2
the condenser (12) releases heat of a high-pressure refrigerant compressed by the compressor (11) and condenses the high-pressure refrigerant
Implementation Method 3
a pressure reducing unit (14b) configured to reduce a pressure of the refrigerant that has flowed out of the condenser (12)
Implementation Method 4
an evaporator (16) configured to cause the refrigerant whose pressure is reduced by the pressure reducing unit (14b) to absorb heat and evaporate
Implementation Method 5
The heating unit is configured to heat ventilation air to be blown into a space to be air conditioned by using a heat source that is the heat released from the high-pressure refrigerant in the condenser
Implementation Method 6
The low-temperature side heat medium circuit is configured to circulate a low-temperature side heat medium and cause the refrigerant in the evaporator to absorb heat of the low-temperature side heat medium
Data Source
AI summary
A heat pump system includes a heat pump cycle, a heating unit, a low-temperature side heat medium circuit, and a control unit. The heat pump cycle includes a compressor, a condenser, and an evaporator. The heating unit heats ventilation air with heat released form refrigerant in the condenser. The low-temperature side heat medium circuit circulates a low-temperature side heat medium such that the refrigerant in the evaporator absorbs heat of the low-temperature side heat medium, and includes a heat source device and a heat amount adjustment unit. The control unit causes an amount of heat transfer in the heating unit for heating the ventilation air to approach a predetermined target value via adjustment in temperature of the low-temperature side heat medium by controlling a rotation speed of the compressor and an operation of at least one of the heat source device and the heat amount adjustment unit.