Cool Drying Control Using Dew Point Feedback Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cool drying methods for gases, such as compressed air, face inefficiencies due to heat exchanger heating up when the cooling circuit is switched off, leading to temperature and dew point peaks, and energy wastage, as they rely on fixed on/off switching based on evaporator pressure or temperature measurements.
Innovation Solution
A method that measures the lowest gas temperature or dew point and switches the cooling circuit on/off to maintain it within predetermined thresholds, and includes a step to eliminate pressure differences before restarting, ensuring efficient energy use and preventing premature switching off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cooling circuit is switched off based on fixed evaporator pressure or temperature measurements, then energy consumption is reduced, but temperature and dew point peaks occur in the supplied compressed air
Solution Approach 1:
The patent implements feedback control by measuring the lowest gas temperature or dew point in the heat exchanger environment and using this information to control the cooling circuit operation. The system switches off the cooling circuit when the decrease of the lowest measured gas temperature or dew point over a predetermined time interval amounts to less than a preset value, and switches on when it reaches a maximum threshold value, creating a closed-loop control system that responds to actual conditions rather than fixed parameters.
Solution Approach 2:
The patent transitions from static, fixed threshold switching to dynamic control by continuously monitoring the rate of change of the lowest gas temperature or dew point. The switching decisions are based on dynamic conditions - specifically whether the decrease over a time interval is less than a preset value - allowing the system to adapt to varying operating conditions and prevent temperature and dew point peaks.
2Loss of energy
If the cooling circuit is switched off to save energy, then energy efficiency improves, but the heat exchanger heats up causing temperature peaks in the output gas
Solution Approach 1:
The patent applies preliminary action by monitoring the rate of temperature or dew point change before actually switching off the cooling circuit. By detecting when the decrease of the lowest measured gas temperature or dew point over a predetermined time interval amounts to less than a preset value, the system predicts when switching off will occur and prepares accordingly, ensuring that the heat exchanger does not overheat and cause temperature peaks in the output gas.
3Temperature
If the cooling circuit is switched on frequently to maintain low temperature, then temperature control is improved, but energy consumption increases
Solution Approach 1:
The system uses feedback control to determine when switching on the cooling circuit is necessary. The cooling circuit is switched on when the lowest measured gas temperature or dew point reaches a maximum threshold value, and the duration of operation is determined by monitoring when the decrease over a predetermined time interval amounts to less than a preset value. This feedback mechanism ensures the cooling circuit operates only when necessary, avoiding excessive energy consumption while maintaining temperature control.
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 approach optimizes energy savings by switching off the cooling circuit when the lowest gas temperature or dew point decrease is minimal and ensures quick compressor startup by equalizing pressures, preventing overheating and maintaining effective dew point control.
Implementation Method 1
by lowering the air or gas temperature in the evaporator, moisture in the air or gas will condense
Implementation Method 2
this gas is led through the secondary part of a heat exchanger, whose primary part is the evaporator of a cooling circuit
Implementation Method 3
an expansion means between the outlet of the condenser and the inlet of the above-mentioned evaporator
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Method for cool drying gas containing water vapour, whereby this gas is led through the secondary part of a heat exchanger (2), whose primary part is the evaporator (3) of a cooling circuit (4), whereby the temperature or the dew point is measured in the environment of the place where, when cool drying, the temperature of the gas to be dried is the lowest, and whereby the above-mentioned method comprises the step of switching off the cooling circuit (4) when the decrease of the lowest measured gas temperature (LAT) or the dew point during a predetermined period of time amounts to less than a preset value (y).