Engine-Driven Heat Pump Control for Parallel Evaporator Selection
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Solution Overview
Problem
Existing engine-driven heat pumps face challenges in maintaining heat exchange balance between outdoor and indoor units due to varying outside air temperatures and heating loads, making it difficult to select an optimal main evaporator.
Innovation Solution
An electronic control unit is designed to select the suction superheat degree as the control target, employing expansion valves at the inlets of the outdoor heat exchanger, waste heat collector, and supercooler to optimize the main evaporator selection based on outside air temperature and heating load, ensuring efficient heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the outdoor heat exchanger is used as the main evaporator, then heat exchange with outside air is improved, but heat exchange balance with indoor unit deteriorates under varying outside air temperature and heating load conditions
Solution Approach 1:
The system dynamically switches between different evaporators (outdoor heat exchanger, waste heat collector, or both in parallel) based on operating conditions such as outside air temperature and heating load. This dynamic configuration allows the system to adapt to varying conditions while maintaining optimal heat exchange efficiency.
Solution Approach 2:
The outdoor heat exchanger serves multiple functions: it can operate as the primary evaporator, work in parallel with the waste heat collector, or be bypassed entirely depending on conditions. This multi-functionality resolves the contradiction by allowing the same component to adapt to different operational requirements.
2Productivity
If the outdoor heat exchanger is used as the main evaporator, then outdoor heat exchange is optimized, but heat exchange balance between outdoor and indoor units deteriorates
Solution Approach 1:
The control unit continuously monitors operating conditions including outside air temperature and heating load, and uses this feedback information to determine the optimal evaporator configuration. This feedback mechanism ensures that heat exchange balance is maintained while maximizing outdoor heat exchange efficiency when conditions are favorable.
Solution Approach 2:
The system dynamically adjusts the evaporator configuration based on real-time conditions. When outside air temperature and heating load indicate favorable conditions, the outdoor heat exchanger operates as the main evaporator for optimized efficiency. When conditions change, the system transitions to alternative configurations to maintain heat exchange balance.
3Ease of operation
If a single expansion valve controls superheat degree, then control simplicity is maintained, but optimal evaporator selection according to conditions becomes difficult
Solution Approach 1:
The control system dynamically assigns different control targets (superheat degrees) to different expansion valves based on which evaporator is active. The electronic control unit switches between controlling the first expansion valve (outdoor heat exchanger), second expansion valve (waste heat collector), or both simultaneously, providing adaptability while maintaining straightforward control logic for each configuration.
Solution Approach 2:
The electronic control unit acts as an intermediary that manages the complexity of multi-evaporator selection and expansion valve control. It processes operating conditions, determines optimal evaporator configuration, and automatically adjusts the appropriate expansion valves, thereby providing adaptability without requiring complex manual control.
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 electronic control unit effectively selects the optimal main evaporator according to outside air temperature or heating load, maintaining efficient heat exchange and extending heating operation duration by adjusting expansion valve targets and preventing liquid compression in the compressor.
Implementation Method 1
outdoor heat exchanger which serves as an evaporator when communicated with a suction circuit
Implementation Method 2
outdoor heat exchanger is used as a main evaporator
Implementation Method 3
waste heat collector collecting engine waste heat to a coolant
Implementation Method 4
waste heat collector is connected in parallel with an outdoor heat exchanger
Implementation Method 5
a first expansion valve is provided at an inlet of the outdoor heat exchanger
Implementation Method 6
outdoor heat exchange expansion valve
Implementation Method 7
compressor driven by an engine
Implementation Method 8
compressor suction route
Implementation Method 9
outdoor heat exchanger which serves as an evaporator
Implementation Method 10
heat exchange with an outside air
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provided is an engine-driven heat pump wherein an optimal main evaporator can be selected according to an outside air temperature or a heating load. The engine-driven heat pump (1) connects a waste heat collector (12) in parallel with an outdoor heat exchanger (11) when the outdoor heat exchanger (11) functions as an evaporator, wherein a supercooler (13) is connected in parallel with the outdoor heat exchanger (11) and the waste heat collector (12) in the above-mentioned case so that a degree of suction superheat (SHO) can be selected as a control target in place of the respective degrees of superheat of a first expansion valve (31), a second expansion valve (32), and a third expansion valve (33), and the degree of suction superheat (SHO) is selected as a control target of the first expansion valve (31), and the degrees of superheat (SH2, SH3) at the outlets of the second expansion valve (32) and the third expansion valve (33) are employed as the control targets of the second expansion valve (32) and the third expansion valve (33).