Outdoor Heat Exchanger Defrosting for Continuous Room Heating
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Solution Overview
Problem
Conventional air conditioners face inefficiencies in heat exchange due to frost formation on outdoor heat exchangers, requiring a defrosting mode that stops indoor heating, lowers indoor temperatures, and prolongs the restart of heating cycles.
Innovation Solution
An air conditioner system with a controller that manages a defrosting module, including expansion valves and sensors, to operate the front heat exchange member as a condenser and the rear member as an evaporator during defrosting, allowing continuous warm air supply to the room while removing frost without reversing the refrigerant cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the refrigerant circulation is reversed into the cooling cycle for defrosting, then frost is removed from the outdoor heat exchanger, but indoor heating is stopped and indoor temperature drops
Solution Approach 1:
The outdoor heat exchanger is divided into front and rear heat exchange members, allowing independent control of each section. The front member can be operated as a condenser for defrosting while the rear member continues as an evaporator for heating, enabling simultaneous defrosting and heating operations without converting the entire system to cooling mode.
Solution Approach 2:
Different parts of the outdoor heat exchanger are assigned different functions based on their local conditions. The front heat exchange member that has frost accumulation is converted to a condenser to provide heat for defrosting, while the rear heat exchange member maintains its evaporator function for continuous heating, creating local functional differentiation within the same system.
2Object-affected harmful factors
If the cooling cycle is used for defrosting, then frost removal is achieved, but the heating cycle restart takes a long time
Solution Approach 1:
The system performs defrosting operations on the front heat exchange member while maintaining the heating function through the rear heat exchange member. This preliminary action of selective defrosting prevents complete system shutdown and allows the heating cycle to continue without interruption, eliminating the need for lengthy restart periods.
Solution Approach 2:
The heating action continues continuously through the rear heat exchange member even during defrosting operations on the front member. By maintaining the evaporator function in the rear section, the system ensures uninterrupted heating supply to the indoor space, avoiding the stop-start nature of conventional defrosting methods.
3Use of energy by moving object
If the outdoor heat exchanger absorbs heat for refrigerant evaporation, then cooling function is provided, but surface temperature lowers remarkably causing frost formation
Solution Approach 1:
The front heat exchange member, which normally functions as an evaporator absorbing heat and forming frost, is inverted to function as a condenser during defrosting operations. By reversing its function from heat absorption to heat emission, the system eliminates frost formation in that section while the rear member continues its evaporator function.
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 maintains efficient heat exchange and reduces the time to re-establish heating, preventing temperature drops and ensuring continuous warm air supply during defrosting.
Implementation Method 1
the front heat exchange member of an outdoor heat exchanger as a condenser for condensing refrigerant
Implementation Method 2
maintaining a rear heat exchange member as an evaporator
Implementation Method 3
heat-exchanging the refrigerant drawn into the rear heat exchange member after passing the first defrosting unit for room heating
Data Source
Figure 1
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AI summary
An air conditioner (100) including a compressor (110) to compress refrigerant, an indoor heat exchanger (120) to cool or heat a room, using the refrigerant, an outdoor heat exchanger (140) to heat-exchange the refrigerant with outdoor air, the outdoor heat exchanger (140) comprising a front heat exchange member (142) and a rear heat exchange member (144), and a defrosting module (150) to adjust an opening degree of a passage of the refrigerant drawn into the front heat exchange member (142) and the rear heat exchange member (144), wherein the defrosting module (150) includes a first expansion valve (151) to adjust an opening of a passage of the refrigerant introduced into the front heat exchange member (142) and a defrosting unit (151) to adjust an opening degree of a passage of the refrigerant between the front heat exchange member (142) and the rear heat exchange member (144).