Cold Exchnage System
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Solution Overview
Problem
Existing cooling systems face challenges in accurately controlling medium flow rates due to pressure variations, especially in commercial and industrial buildings, leading to unintended increases in thermal energy delivery to other thermal energy exchangers.
Innovation Solution
A control system comprising a two-way or three-way valve with an adjustable orifice, an actuator, a position sensor with a static measurement principle, and a controller that adjusts the orifice based on the sensed position and compares it to a set position, allowing for software-wise changes in the characteristic curve of the orifice adjusting system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a control valve with adjustable orifice is used to control medium flow rate, then the flow rate can be adjusted according to cooling demand, but pressure variations in the pipe system cause unintended changes in flow rates to other thermal energy exchangers
Solution Approach 1:
The control system continuously monitors the actual position of the adjustable orifice using a position sensor and compares it with the desired position. Based on this feedback, the controller adjusts the orifice position to compensate for pressure variations, ensuring stable flow rate control despite changes in system pressure conditions.
Solution Approach 2:
The system changes the characteristic curve of the orifice adjusting system through software configuration in the controller. This allows adaptation of the control characteristics to match specific system requirements, enabling the valve to maintain accurate flow control under varying pressure conditions by modifying the relationship between control signal and orifice position.
2Ease of operation
If the position of the adjustable orifice is manually adjusted to control cooling delivery, then the amount of cooling can be controlled, but pressure variations cause flow rates to change independently of orifice position
Solution Approach 1:
The position sensor provides continuous feedback on the actual orifice position, which the controller uses to detect deviations from the desired position caused by pressure variations. This feedback loop enables real-time compensation to maintain accurate flow rate control despite pressure changes affecting the medium.
Solution Approach 2:
The system replaces manual mechanical adjustment with an automated electronic control system that includes a position sensor and controller. This substitution enables precise measurement and control of orifice position, eliminating the imprecision of manual adjustment and providing accurate compensation for pressure-induced flow variations.
3Reliability
If pressure increases occur in the pipe system, then flow rates to thermal energy exchangers increase unintentionally, but adding complex pressure compensation mechanisms increases system complexity
Solution Approach 1:
The control system uses position feedback from a sensor to detect changes in orifice position caused by pressure variations. By monitoring the actual position and comparing it with the commanded position, the system can compensate for pressure effects without requiring direct pressure measurement or complex pressure compensation hardware.
Solution Approach 2:
The position sensor acts as an intermediary element that indirectly measures the effect of pressure changes on flow control. Instead of directly measuring or compensating for pressure, the system uses position feedback as an intermediate parameter to achieve flow rate stabilization, simplifying the overall control architecture.
Data Source
AI summary
Various embodiments of the teachings herein include a cold exchange system. An example includes: thermal energy exchangers connected to a refrigerant pipe system; and a control system comprising: an orifice adjusting system including a valve and an actuator, the valve comprising a flow chamber with an adjustable orifice in the pipe; a position sensor to sense a position of the adjustable orifice and/or the actuator and generate a signal indicative of the sensed position; and a controller. The orifice adjusting system adjusts the adjustable orifice in response to a control signal. The control system uses a software-wise change of a characteristic curve of the orifice adjusting system. The position sensor operates using a static measurement principle. The controller compares the signal to a set position of the adjustable orifice and generates the control signal based on the comparison.