Outdoor unit and air conditioning device
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Solution Overview
Problem
Existing air-conditioning apparatuses for office buildings do not adequately address refrigerant leakage into outdoor unit housings, particularly with flammable refrigerants, which can lead to safety issues and energy inefficiencies due to lack of detailed leakage prevention and airflow control measures.
Innovation Solution
Incorporating an outdoor unit with a compressor, heat source side heat exchanger, and an air-sending device that maintains refrigerant concentration below a predetermined level by providing a controlled airflow to prevent ignition and ensure safety, even during refrigerant leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerant circulation between outdoor unit and relay unit is implemented, then refrigerant leakage into indoor side is prevented, but refrigerant leakage into outdoor unit housing is not addressed
Solution Approach 1:
The system divides refrigerant leakage protection into two independent segments: one for indoor side protection (existing relay unit system) and one for outdoor housing protection (new air-sending device). This segmentation allows each segment to address its specific leakage risk independently without interfering with the other.
Solution Approach 2:
An air-sending device is introduced as an intermediary element between the outdoor housing interior and exterior environment. This intermediary actively manages air flow to prevent refrigerant accumulation, bridging the gap between the sealed housing and the external atmosphere.
2Loss of energy
If flammable refrigerant is used, then energy efficiency is improved, but safety risk due to ignition increases
Solution Approach 1:
The air-sending device performs preliminary anti-action by continuously or periodically introducing fresh air into the outdoor housing before refrigerant concentration can reach ignitable levels. This preemptive measure counteracts the potential harmful effect of refrigerant accumulation before it can lead to ignition.
Solution Approach 2:
The system converts the potential harm of refrigerant leakage into a benefit by using the leakage detection mechanism to trigger air-sending device operation. The harmful refrigerant leakage event becomes the signal that activates the protective air flow, transforming the hazard into a controlled situation.
3Reliability
If air-sending device is added to control refrigerant concentration, then safety is improved, but device complexity increases
Solution Approach 1:
The air-sending device is designed with multi-functionality, serving both as a refrigerant concentration control mechanism and as part of the overall air circulation system. This universality reduces the need for completely separate safety systems, thereby limiting the increase in overall device complexity.
4Reliability
If refrigerant leakage is detected and damper is activated, then refrigerant discharge is improved, but air flow control precision is insufficient
Solution Approach 1:
The system implements feedback control by continuously monitoring refrigerant concentration levels and adjusting air-sending device operation accordingly. The detected refrigerant concentration provides feedback that modulates the air flow rate, enabling precise control of the refrigerant-to-air ratio and maintaining concentration below safety thresholds.
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 solution effectively maintains refrigerant concentration at safe levels, preventing ignition and enhancing energy efficiency by ensuring safe operation and reducing the risk of refrigerant accumulation in the outdoor unit housing.
Implementation Method 1
a heat source side heat exchanger that exchanges heat between the refrigerant and air
Implementation Method 2
exchanges heat between the refrigerant and air
Implementation Method 3
exchanges heat between the refrigerant and air
Implementation Method 4
an outdoor unit air-sending device disposed at a position where the air is enabled to flow out of a housing to outside thereof
Data Source
Figure 1~2
Figure 3
Figure 3A
AI summary
To provide an outdoor unit and the like capable of preventing a refrigerant in a housing from increasing in concentration due to the leakage of the refrigerant in the housing and thus improving safety. The outdoor unit includes a compressor 10 that compresses a flammable refrigerant, a heat source side heat exchanger 12 that exchanges heat between the refrigerant and air in an unconditioned space, an outdoor unit air-sending device 60 disposed at a position where the air is enabled to flow out of a housing to the outside, the outdoor unit air-sending device being driven to maintain the concentration of the refrigerant in the housing at or below a predetermined concentration, and an outdoor unit controller 70 that controls an operation of the compressor 10 and an operation of the outdoor air-sending device 60. The outdoor unit controller 70 allows the outdoor unit air-sending device 60 to operate in order to maintain the concentration of the refrigerant at or below the predetermined concentration even when the compressor 10 is stopped.