Air-conditioning apparatus, air-conditioning method, and control program
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Solution Overview
Problem
Conventional air-conditioning systems for vehicles require high power consumption to remove moisture or frost from evaporators, leading to inefficiencies in heat exchange and potential mildew and odor issues.
Innovation Solution
The system employs a waste heat recovery unit that utilizes waste heat from components like variable voltage variable frequency inverters or dynamic braking resistors to dry or defrost evaporators, reducing the need for additional power and maintaining efficient heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the circulation direction of the refrigerant is reversed to make the evaporator function as a condenser for heat generation, then moisture or frost removal is achieved, but power consumption increases significantly
Solution Approach 1:
The invention converts waste heat from the inverter, which would otherwise be discarded, into a useful resource for removing moisture and frost from the evaporator. By directing this previously wasted thermal energy to the evaporator surface, the system achieves effective drying and defrosting without requiring additional power input or reversing the refrigerant circulation.
Solution Approach 2:
The system uses its own internally generated waste heat to service the evaporator drying and defrosting needs. Rather than requiring an external power source or additional heating components, the air-conditioning apparatus utilizes heat already produced during normal inverter operation to maintain the evaporator in a moisture-free state.
2Temperature
If the evaporator is used as an indoor heat exchanger for cooling, then interior cooling is achieved, but dew condensation occurs causing mildew and abnormal odor
Solution Approach 1:
The invention converts the inverter's waste heat, which would otherwise be useless, into a beneficial drying mechanism that prevents mildew and odor. The waste heat is directed to the evaporator to evaporate condensed moisture, transforming a thermal byproduct into a protective function that eliminates the harmful effects of dew condensation.
Solution Approach 2:
The invention introduces waste heat from the inverter as an intermediary thermal source to address the moisture problem. This intermediary heat source acts as a mediator between the cooling function and the drying requirement, allowing the evaporator to perform both cooling and self-drying functions simultaneously.
3Temperature
If the evaporator is used as an outdoor heat exchanger for heating, then interior heating is achieved, but frost forms on the evaporator lowering heat exchange efficiency
Solution Approach 1:
The invention converts waste heat from the inverter into a useful defrosting mechanism. By directing this waste thermal energy to the evaporator surface, the system removes frost accumulation that would otherwise insulate the heat exchanger and reduce its efficiency, thereby maintaining optimal heat exchange performance during heating operation.
Solution Approach 2:
The evaporator uses the system's own waste heat to remove frost from its surface, enabling self-maintenance of its heat exchange efficiency. This self-service mechanism ensures that the evaporator remains free of frost insulation without requiring external power input or interrupting the heating operation.
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 effectively reduces power consumption for moisture or frost removal, prevents mildew and odor, and maintains efficient heat exchange by using waste heat to dry or defrost evaporators, thereby enhancing the overall performance of the air-conditioning system.
Implementation Method 1
a waste heat recovery unit 80 having a heat-release part 82 that releases waste heat from a waste heat source WS
Implementation Method 2
an indoor heat exchanger 10 that performs heat exchange with air inside a passenger compartment
Implementation Method 3
an outdoor heat exchanger 210 that performs heat exchange with air from the exterior
Data Source
Figure 1
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Figure 3
AI summary
A railway vehicle air-conditioning apparatus (100) is equipped with: an indoor heat exchanger (10) that evaporates a refrigerant; a cooperative device group (20) that forms, together with the indoor heat exchanger, a refrigeration cycle using the refrigerant by exchange of the refrigerant with the indoor heat exchanger; a waste heat recovery unit (80) that has a waste heat recovery part (81) that recovers waste heat from a waste heat source (WS) and a heat-release part (82) that releases, to an indoor heat exchanger, heat transmitted to the heat-release part, and that is switchable between (a) a heat-releasing state in which the waste heat recovered by the waste heat recovery part is transmitted to the heat-release part and released by the heat-release part, and (b) a heat-release-stopped state in which the waste heat recovered by the waste heat recovery part is less transmittable than when in the heat-releasing state; and a controller (90) to (i) control the waste heat recovery unit to be in a heat-release-stopped state when the refrigerant is being exchanged between the indoor heat exchanger and the cooperative device group, and (ii) control the waste heat recovery unit to be in a heat-releasing state when the exchange of the refrigerant is stopped.