Cold Water Supply Control for Parallel Free Cooling Circuits
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Solution Overview
Problem
The existing free cooling systems face challenges in independent load control of refrigerant and free cooling circuits, particularly when both circuits operate simultaneously, due to shared air-sending fans and integral heat exchanger arrangements.
Innovation Solution
A cold water supply system with independent refrigerant circuit units and composite units connected in parallel, featuring separate control of compressor frequencies, pump frequencies, and a controller to manage the number of units operated based on outside air temperature and target water temperature, allowing for independent control of each circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If air heat exchangers for refrigerant circuit and free cooling circuit are integrally arranged side by side with a shared air-sending fan, then device complexity is reduced and space is saved, but independent load control on each circuit becomes difficult when both circuits operate simultaneously
Solution Approach 1:
The patent divides the integrated heat exchanger into separate refrigerant circuit heat exchanger and free cooling circuit heat exchanger sections. Each heat exchanger is equipped with its own dedicated air-sending fan, allowing independent control of air flow and cooling load for each circuit while maintaining a compact integrated structure. This segmentation enables separate load control without significantly increasing overall device complexity.
2Device complexity
If a shared air-sending fan is used for both refrigerant circuit and free cooling circuit, then the number of components is reduced, but appropriate control of respective circuits according to their operation states becomes difficult
Solution Approach 1:
The system segments the air distribution function by providing separate air-sending fans for the refrigerant circuit and free cooling circuit. Each fan can be independently controlled based on the specific cooling demands and operational state of its corresponding circuit, ensuring reliable and accurate control while maintaining a relatively simple component structure.
Solution Approach 2:
The patent implements dynamic control capabilities where each air-sending fan's operation can be adjusted independently according to real-time circuit requirements. The control unit monitors operation states of both circuits and dynamically adjusts fan speeds and air flow distribution to match varying cooling demands, enhancing control accuracy and system reliability.
3Adaptability or versatility
If refrigerant circuit and free cooling circuit are operated simultaneously with shared components, then system versatility is improved, but control difficulty increases
Solution Approach 1:
By segmenting the air delivery function into separate dedicated fans for each circuit, the system enables versatile simultaneous operation of both refrigerant and free cooling circuits. Each circuit can be independently controlled and adjusted according to its specific requirements, reducing control complexity while maintaining the ability to handle diverse cooling scenarios.
Solution Approach 2:
The integrated heat exchanger structure provides universal cooling capability for both refrigerant circuit and free cooling circuit through a single compact unit. The separate air-sending fans enable each circuit to perform its specific function independently, allowing the system to adapt to various operational modes including simultaneous operation, thereby enhancing overall system versatility.
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
Enables effective simultaneous operation of refrigerant and free cooling circuits by optimizing compressor and pump frequencies, ensuring efficient cooling while maintaining high Coefficient of Performance (COP) and uniform operating times.
Implementation Method 1
a compressor (11) that compresses the refrigerant
Implementation Method 2
a water heat exchanger (14) that cools water by heat exchange with the refrigerant
Implementation Method 3
an air heat exchanger for refrigerant circuit
Implementation Method 4
the operating frequency of the pump of the free cooling unit
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
A cold water supply system cools water flowing through a water pipe, and supplies the water cooled to a cooling load, the cold water supply system including: an independent refrigerant circuit unit including a first compressor and a first water heat exchanger configured to exchange heat between refrigerant and the water to cool the water; a composite unit configured to cool the water; and a controller configured to control operation of the independent refrigerant circuit unit and operation of the composite unit, wherein the composite unit includes a free cooling unit including a pump and a second water heat exchanger configured to exchange heat between a heat medium and the water to cool the water, and a coupled refrigerant circuit unit including a second compressor and a third water heat exchanger configured to exchange heat between refrigerant and the water to cool the water, and the controller controls an operating frequency of the first compressor, an operating frequency of the second compressor, and an operating frequency of the pump based on a temperature of the water flowing out from the water pipe.