Split Outdoor Heat Exchanger Defrosting With Indoor Fan Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Air-conditioning systems face a decrease in indoor comfort during heating-defrosting operations due to reduced heating capacity and temperature drops, as the defrosting process typically stops the heating operation, leading to decreased indoor space temperatures.
Innovation Solution
An air-conditioning apparatus with a compressor, indoor and outdoor heat exchangers, a bypass pipe, and a flow switch device, where the controller adjusts the rotation speed of the indoor fan based on detected temperature differences to maintain indoor comfort during heating-defrosting operations by ensuring continuous heating and efficient defrosting of both heat exchangers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heating operation is stopped during defrosting to melt frost on the outdoor heat exchanger, then the frost is effectively removed, but the indoor space temperature decreases and comfort deteriorates
Solution Approach 1:
The outdoor heat exchanger is divided into two separate heat exchangers (first and second heat exchangers with independent refrigerant flow paths). During defrosting, one heat exchanger is defrosted while the other continues to provide heating, allowing simultaneous defrosting and heating operations without stopping the heating function.
Solution Approach 2:
The heating operation continues uninterrupted during defrosting by using the second heat exchanger to maintain indoor heating while the first heat exchanger undergoes defrosting. This ensures continuous useful heating action without the need to stop the heating operation.
2Temperature
If the heating operation continues during defrosting of the outdoor heat exchanger, then indoor comfort is maintained, but the heating capacity decreases and room temperature drops
Solution Approach 1:
By segmenting the outdoor heat exchanger into two independent units, the system can allocate one unit for defrosting while the other unit maintains full heating capacity. This segmentation allows the heating function to continue at optimal capacity without compromise during defrosting operations.
3Speed
If the indoor fan continues rotating during defrosting to maintain air circulation, then air flow is maintained, but cold air is supplied from the indoor heat exchanger reducing comfort
Solution Approach 1:
The controller predicts that the indoor heat exchanger temperature will drop below a predetermined threshold during defrosting operation. In advance, before the temperature actually drops, the controller stops the indoor fan to prevent cold air supply. This preliminary action avoids the comfort issue before it occurs.
Solution Approach 2:
The controller monitors the indoor heat exchanger temperature in real-time during defrosting operation and uses this feedback to determine when to stop or restart the indoor fan. When the temperature rises above the threshold after defrosting, the fan is restarted to resume air circulation.
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 effectively prevents room temperature drops and maintains indoor comfort by optimizing fan rotation speed in response to temperature changes, ensuring continuous heating and efficient defrosting of both heat exchangers, thus enhancing the heating-defrosting operation's effectiveness.
Implementation Method 1
a bypass that causes a portion of high-temperature and high-pressure refrigerant discharged from a compressor to flow into the first heat exchanger and the second heat exchanger
Implementation Method 2
The outdoor heat exchanger causes heat exchange to be performed between refrigerant flowing therein and outdoor air
Implementation Method 3
an indoor heat exchanger that is connected to the discharge port of the compressor and functions as a condenser at a time of a heating operation
Implementation Method 4
an indoor fan that sends air to the indoor heat exchanger
Data Source
AI summary
An air-conditioning apparatus includes an outdoor heat exchanger. The outdoor heat exchanger includes a first heat exchanger and a second heat exchanger. A controller performs a heating operation and a heating-defrosting operation, in which one of the first heat exchanger and the second heat exchanger functions as an evaporator, an other one the first heat exchanger and the second heat exchanger functions as a condenser. When a temperature of the indoor heat exchanger by a temperature detection unit is treated as a first temperature, and a temperature of the indoor heat exchanger by the temperature detection unit is treated as a second temperature, the controller reduces a rotation speed of an indoor fan in a case where the second temperature is lower than the first temperature and where a difference between the first temperature and the second temperature is greater than or equal to a first setting value.