Conditioner determining a closed condition of an expansion valve
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Solution Overview
Problem
Existing air conditioning apparatuses face challenges in precisely determining when the expansion valve reaches a fully closed state, leading to potential cessation of refrigerant flow and failure in air-cooling operations, especially when refrigerant temperatures are high, due to unclear temperature changes.
Innovation Solution
The apparatus employs a refrigerant circuit with liquid-side and gas-side temperature sensors, an intake pressure sensor, and an indoor temperature sensor to control the expansion valve based on a predetermined closed-valve condition, including the degree of superheating and evaporation temperature, ensuring precise closed-valve sensing even at high refrigerant temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the expansion valve opening degree is controlled so that the temperature of refrigerant in the outlet of the expansion valve reaches a target temperature, then the refrigerant flow rate can be regulated, but the precision of closed-valve sensing deteriorates when the refrigerant temperature is high
Solution Approach 1:
The patent changes the sensing parameters from relying solely on outlet temperature to using the temperature difference (superheating degree) between liquid-side and gas-side refrigerant temperatures. This parameter transformation allows reliable closed-valve detection even when absolute temperatures are high, as the temperature difference remains detectable regardless of the baseline temperature level.
Solution Approach 2:
The patent replaces the conventional single-temperature sensing method with a differential temperature measurement system using two temperature sensors (liquid-side and gas-side). This substitution enables more reliable detection by measuring the temperature gradient rather than absolute temperature, solving the problem of indiscernible temperature changes at high temperatures.
2Ease of operation
If the expansion valve is determined to be fully closed based on outlet temperature rise, then closed-valve sensing can be performed, but refrigerant flow may cease and air-cooling operation fails when temperature change is unclear
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the temperature difference between liquid-side and gas-side refrigerant and adjusts the expansion valve opening degree accordingly. When the temperature difference indicates the valve is fully closed, the controller increases the opening degree to restore refrigerant flow, ensuring continuous air-cooling operation.
Solution Approach 2:
The patent performs preliminary detection of the closed-valve condition by monitoring the temperature difference before complete refrigerant flow cessation occurs. By detecting the closed-valve state early through the temperature gradient, the system can take preventive action to increase valve opening and maintain continuous refrigerant flow.
3Adaptability or versatility
If the opening degree range of the expansion valve is expanded to low opening degree range, then the refrigerant flow rate regulation range is improved, but the precision of detecting fully closed state deteriorates
Solution Approach 1:
The patent transforms the detection parameter from absolute outlet temperature to temperature difference (superheating degree) between liquid-side and gas-side refrigerant. This parameter change enables precise detection of the fully closed state even when the valve operates in the low opening degree range, as the temperature difference becomes pronounced when flow is restricted or stopped.
Solution Approach 2:
The patent adds a new dimension to the detection system by introducing a second temperature measurement point (liquid-side) in addition to the conventional gas-side measurement. This dimensional expansion from single-point to two-point measurement enables detection of temperature gradients, providing precise closed-valve sensing across the full range of valve opening degrees.
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 solution enables precise closed-valve sensing and prevents refrigerant flow cessation, ensuring consistent air-cooling operations by accurately determining the fully closed state of the expansion valve, even under varying temperature conditions.
Implementation Method 1
a liquid-side temperature sensor to detect the refrigerant temperature in an inlet or an intermediate part of the indoor heat exchanger
Implementation Method 2
a gas-side temperature sensor to detect the refrigerant temperature in an outlet of the indoor heat exchanger
Implementation Method 3
an intake pressure sensor to detect refrigerant pressure in an intake side of the compressor
Implementation Method 4
an expansion valve, and an indoor heat exchanger; the air conditioning apparatus performing an air-cooling operation in which refrigerant is circulated sequentially through the compressor, the outdoor heat exchanger, the expansion valve
Implementation Method 5
an indoor heat exchanger; the air conditioning apparatus performing an air-cooling operation in which refrigerant is circulated sequentially through the compressor, the outdoor heat exchanger, the expansion valve, and the indoor heat exchanger
Data Source
AI summary
In an air conditioning apparatus, an expansion valve is determined to be in a fully closed state when a refrigerant temperature in an outlet of an indoor heat exchanger and a refrigerant temperature in an inlet or an intermediate part of the indoor heat exchanger satisfy a closed-valve condition. The temperature in the outlet is detected by a gas-side temperature sensor. The temperature in the inlet or the intermediate part is detected by a liquid-side temperature sensor. The closed-valve condition is in relation to a refrigerant evaporation temperature obtained by converting a refrigerant pressure in an intake side of a compressor to a refrigerant saturation temperature, and in relation to an air temperature of an air-conditioned space cooled by the indoor heat exchanger. The pressure in the intake side is detected by an intake pressure sensor. The air temperature is detected by an indoor temperature sensor.