Variable Capacity Compressor Startup for Residual Heat Air Conditioning
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Solution Overview
Problem
Existing air conditioning systems face inefficiencies due to frequent compressor start-stop cycles at part load, leading to reduced refrigeration efficiency and energy consumption, and the inability to effectively utilize residual cold or heat due to incomplete shut-off of throttling components.
Innovation Solution
An air conditioning system incorporating a leak-free thermal expansion valve and a variable capacity compressor with a first and second cylinder, allowing for on-off connections between high and low-pressure pipes to isolate refrigerant temperatures and pressures, enabling the use of residual heat and ensuring smooth compressor startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed-speed compressor is used, then the system structure is simple and cost is low, but the compressor must frequently start and stop at part load, reducing refrigeration efficiency and energy efficiency
Solution Approach 1:
The compressor is divided into multiple independent compression chambers (first compression chamber and second compression chamber) that can operate independently. This segmentation allows the compressor to adjust its effective capacity by deactivating certain chambers, thereby avoiding frequent start-stop cycles at part load while maintaining a relatively simple overall structure.
2Productivity
If a variable capacity compressor with multiple cylinders is used, then the SEER is much higher and frequent start-stop is avoided, but the device complexity and cost increase
Solution Approach 1:
Multiple compression chambers are merged into a single integrated compressor body with shared components such as the crankcase, refrigerant passages, and control mechanisms. This combining approach achieves variable capacity functionality while reducing overall structural complexity compared to having completely separate compressor units.
Solution Approach 2:
The compressor is designed with multi-functionality where the same physical structure serves multiple operating modes. The first and second compression chambers share common infrastructure and can be selectively activated, allowing the single device to function as both a full-capacity and part-capacity compressor without requiring separate systems.
3Device complexity
If conventional throttling parts (capillary tubes, electronic expansion valves) are used, then the system structure is simple, but they cannot completely shut off when the compressor is stopped, causing high-pressure refrigerant to quickly flow to low-pressure side, reducing residual cold/heat utilization
Solution Approach 1:
The throttling device is designed to completely shut off refrigerant flow in advance before the compression chambers are deactivated. This preliminary closing action prevents high-pressure refrigerant from flowing to the low-pressure side, thereby preserving the temperature difference and maximizing residual cold/heat utilization when the compressor stops.
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 configuration improves annual energy efficiency by utilizing residual heat, reduces compressor start-up shocks, and adjusts operating capacity based on load, achieving higher SEER while maintaining lower costs compared to variable-frequency systems.
Implementation Method 1
the leak-free thermal expansion valve is connected between the indoor heat exchanger and the outdoor heat exchanger... before the variable capacity compressor is started, the high-pressure pipe and the low-pressure pipe are connected, and disconnected after the first preset duration
Implementation Method 2
the variable capacity compressor comprises a shell, a first cylinder and a second cylinder... the first cylinder is provided with a first suction hole connected with the suction port, a first exhaust hole connected with the exhaust port
Implementation Method 3
the indoor heat exchanger is connected with one of the high-pressure pipe and the low-pressure pipe; the outdoor heat exchanger is connected with another one of the high-pressure pipe and the low-pressure pipe
Data Source
AI summary
An air conditioning system is provided. The system has a high-pressure pipe, a low-pressure pipe, an indoor heat exchanger, an outdoor heat exchanger, a leak-free thermal expansion valve and a variable capacity compressor. The variable capacity compressor has a shell, a first cylinder and a second cylinder. The shell has a suction port and an exhaust port. The first cylinder has a first suction hole connected to the suction port and a first exhaust hole connected to the exhaust port. The second cylinder has a second suction hole connected to the suction port, a second exhaust hole connected to the exhaust port, and a pressure relief hole connected to the high-pressure pipe and the low-pressure pipe in an on-off manner. Before the variable capacity compressor is started, the high-pressure pipe and the low-pressure pipe are connected and also disconnected after the first preset duration.