Air conditioner and its operating method
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Solution Overview
Problem
Conventional air conditioners for cleanrooms face challenges in achieving precise temperature control and power efficiency, with constant-speed compressors leading to inefficient power consumption and limited cooling capacity variability, while variable-frequency compressors compromise accuracy for domestic use.
Innovation Solution
An air conditioner with a compressor operating at adjustable frequency, a heating unit that diverges and recirculates the heating medium through a thermal dose adjusting valve on the downstream side, and a control unit using PID calculations and moving averages to manage valve openings and compressor speed, ensuring accurate temperature control and power savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a compressor driven at a constant revolving speed is used, then temperature control accuracy is improved, but power consumption efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from a constant-speed compressor to a variable-frequency compressor that can adjust its operating speed. The control unit varies the compressor's operating frequency based on cooling load requirements, enabling the system to maintain temperature control accuracy while improving power consumption efficiency by matching compressor output to actual demand.
Solution Approach 2:
The patent changes the operating parameter of the compressor from fixed speed to variable frequency. By controlling the compressor at different operating frequencies (e.g., high frequency when cooling capacity is needed, low frequency or standby when not needed), the system achieves both accurate temperature control and energy efficiency.
2Use of energy by moving object
If a compressor operated at variable operating frequency is used, then power saving is improved, but temperature control accuracy deteriorates
Solution Approach 1:
The patent implements feedback control where the control unit continuously monitors the temperature in the controlled space and adjusts the compressor's operating frequency accordingly. When the temperature approaches the target value, the compressor frequency is reduced or stopped; when temperature deviates, frequency is increased. This closed-loop feedback ensures both power saving and temperature control accuracy are achieved simultaneously.
Solution Approach 2:
The system dynamically adjusts the compressor operating frequency based on real-time temperature conditions, enabling the variable-frequency compressor to achieve both power efficiency and temperature precision through adaptive control.
3Use of energy by moving object
If the cooling capacity is varied by adjusting the expansion valve opening, then power saving is improved, but the variable range is limited and service conditions are restricted
Solution Approach 1:
The patent changes the primary control parameter from expansion valve opening to compressor operating frequency. By varying the compressor frequency over a wide range (from low frequency to high frequency and standby), the system achieves both power saving and broad adaptability to different service conditions, overcoming the limited variable range of expansion valve control.
4Device complexity
If a variable-frequency compressor is used, then the air conditioner can be reduced in size and simplified, but temperature control accuracy deteriorates
Solution Approach 1:
The patent uses feedback control to compensate for the inherent variability of variable-frequency compressors. The control unit continuously monitors temperature and adjusts compressor frequency in real-time, ensuring that despite the simplified structure, temperature control accuracy is maintained within the required range.
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 enables precise temperature control within a narrow error range (+/-0.03°C) while reducing energy consumption and simplifying the air conditioner's design, preventing compressor instability and liquid back phenomena, and stabilizing cooling capacity.
Implementation Method 1
a cooling unit in which a compressor 11, a condenser 12, an expansion valve 13 and a cooling coil 14 are connected in this order by pipes 15 in order to circulate a heating medium
Implementation Method 2
a heating unit which causes a part of the heating medium flowing out from the compressor 11 toward the condenser 12 to diverge, and causes it to return to flow into the condenser 12 on a downstream side of the compressor 11, through a heating coil 21 and a thermal dose adjusting valve 22
Implementation Method 3
a blower which causes air to flow from the inlet to the outlet
Data Source
AI summary
An air conditioner includes: a cooling unit having a compressor operated at a variable operating frequency to adjust a revolving speed thereof, a condenser, an expansion valve and a cooling coil; and a heating unit for causing the heating medium flowing from the compressor toward the condenser to diverge, and to return to flow into the condenser, through a heating coil and a thermal dose adjusting valve disposed on the downstream side thereof; so as to control a temperature of air by the cooling and heating coils. When an opening manipulated variable of the thermal dose adjusting valve exceeds a first threshold value over a period of time, an operating frequency of the compressor is decreased, and when the opening manipulated variable of the thermal dose adjusting valve falls below a smaller, second threshold value, over the said period of time, the operating frequency of the compressor is increased.