Free cooling outdoor unit
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Solution Overview
Problem
The existing free cooling outdoor units experience reduced heat exchange efficiency and increased energy consumption due to high brine concentration, which leads to higher viscosity and increased pump power requirements, especially in cold regions where brine is used to prevent freezing.
Innovation Solution
A free cooling outdoor unit design that includes a refrigerant circuit, a brine circuit, and a water circuit, along with a controller that adjusts the brine circulation based on outside air and water temperatures to prevent brine from freezing, thereby maintaining a lower brine concentration and optimizing energy efficiency by controlling the flow rate and pump speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brine concentration is increased to prevent freezing in cold regions, then freezing protection is improved, but heat exchange efficiency deteriorates and pump power consumption increases
Solution Approach 1:
The patent applies dynamics by making the brine circulation system adjustable rather than fixed. The circulation pump speed and flow rate are dynamically controlled based on real-time temperature conditions. When outdoor temperature is above the freezing point, the system reduces brine circulation or stops it, avoiding unnecessary energy consumption. When temperature approaches freezing, the system increases circulation to maintain freezing protection, thus adapting the brine concentration and flow dynamically to actual conditions.
Solution Approach 2:
The patent changes the operational parameters of the brine system based on temperature conditions. By monitoring outdoor temperature and water temperature, the controller adjusts brine flow rate, pump speed, and circulation amount. This parameter adjustment allows the system to use lower effective brine concentration when freezing risk is low, improving heat exchange efficiency, while maintaining adequate freezing protection when temperatures drop.
2Reliability
If brine concentration is increased to prevent freezing, then freezing protection is improved, but heat exchange efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts brine circulation based on temperature conditions. When outdoor temperature is well above freezing, minimal or no brine circulation is needed, allowing the heat exchanger to operate with fresh water or low-concentration brine, maximizing heat exchange efficiency. When temperature approaches freezing, the system increases brine circulation and concentration to maintain freezing protection, thus dynamically balancing heat exchange efficiency and freezing protection.
Solution Approach 2:
The controller changes brine flow rate and circulation parameters based on temperature measurements. By adjusting these parameters, the system optimizes the balance between heat exchange efficiency and freezing protection. When temperature conditions allow, the system uses parameters that maximize heat exchange; when freezing risk increases, parameters are adjusted to prioritize freezing protection.
3Reliability
If brine concentration is increased, then freezing protection is improved, but viscosity increases leading to higher pump power requirements
Solution Approach 1:
The patent implements dynamic control of pump operation based on temperature conditions. The circulation pump operates at variable speeds rather than constant high speed. When freezing risk is low, the pump runs at lower speed or is stopped, reducing power consumption and system complexity. When freezing risk increases, the pump speed increases to maintain adequate circulation and freezing protection, thus dynamically matching pump power requirements to actual needs.
Solution Approach 2:
The system uses temperature sensors and controllers to automatically monitor and adjust brine circulation without manual intervention. The controller self-adjusts pump operation and brine flow based on temperature feedback, eliminating the need for complex manual control systems or oversized pumps designed for worst-case scenarios. The system serves itself by adapting to changing conditions.
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 system effectively prevents brine freezing and improves energy efficiency by maintaining a lower brine concentration, enhancing heat exchange efficiency and reducing energy consumption.
Implementation Method 1
a second heat exchanger, and a brine flow passage of a second water heat exchanger are connected by pipes so as to cause brine to circulate therein; a fan configured to send air to the second heat exchanger
Implementation Method 2
a brine pump, a second heat exchanger, and a brine flow passage of a second water heat exchanger are connected by pipes so as to cause brine to circulate therein
Implementation Method 3
a flow control valve configured to control a circulation amount of the brine in the brine circuit
Implementation Method 4
a water temperature detection sensor configured to detect a water temperature in the water circuit; an outside air temperature sensor configured to detect an outside air temperature
Implementation Method 5
a controller configured to control, in a case where the outside air temperature is equal to or lower than a freezing temperature of the brine, the circulation amount of the brine based on the water temperature such that a brine temperature is prevented from reaching a temperature equal to or lower than the freezing temperature of the brine
Data Source
Figure 1
Figure 2
AI summary
A free cooling outdoor unit includes: a refrigerant circuit where a compressor, a first heat exchanger, an expansion device, and a refrigerant flow passage of a first water heat exchanger are connected by pipes so as to cause refrigerant to circulate therein; a brine circuit where a brine pump, a second heat exchanger, and a brine flow passage of a second water heat exchanger are connected by pipes so as to cause brine to circulate therein; a water circuit where a water pump, a water flow passage of the second water heat exchanger, and a water flow passage of the first water heat exchanger are connected by pipes so as to cause water to circulate therein; a fan configured to send air to the second heat exchanger; a flow control valve configured to control a circulation amount of the brine in the brine circuit; a water temperature detection sensor configured to detect a water temperature in the water circuit; an outside air temperature sensor configured to detect an outside air temperature; and a controller configured to control, in a case where the outside air temperature is equal to or lower than a freezing temperature of the brine, the circulation amount of the brine based on the water temperature such that a brine temperature is prevented from reaching a temperature equal to or lower than the freezing temperature of the brine.