Cooling Water Flow Switching for Extended Free Cooling in HVAC
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Solution Overview
Problem
Conventional air conditioning systems cannot achieve free cooling during periods of high outside air temperature, limiting the effectiveness of cooling water usage.
Innovation Solution
An air conditioning system that includes a cooling tower, a thermal source device, heat exchangers, and flow path switching means to optimize the circulation and usage of cooling water, allowing it to be effectively utilized across various temperature conditions by routing cooling water through different heat exchangers based on temperature thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cooling water is supplied directly to the air conditioner when outside air temperature is low, then free cooling is achieved and energy is conserved, but the period of enablement of free cooling is limited to low temperature periods only
Solution Approach 1:
The cooling water flow is divided into multiple paths: one path goes through the thermal source device to generate cold water, while another path can be directly supplied to the air conditioner for free cooling. The flow path switching means segments the cooling water circulation into different routes based on temperature conditions, enabling both cold water generation and direct free cooling to occur simultaneously or alternatively.
Solution Approach 2:
The system dynamically switches between different operating modes based on outside air temperature. When outside air temperature is low, the flow path switching means enables direct free cooling mode. When outside air temperature is high, it switches to cold water generation mode. This dynamic adaptation extends the effective temperature range for energy-efficient operation.
2Adaptability or versatility
If a flow path switching means is added to route cooling water through different paths, then free cooling can be achieved during high outside air temperature periods, but the device complexity increases
Solution Approach 1:
The flow path switching means serves multiple functions: it switches between direct free cooling mode and cold water generation mode, manages water flow distribution to different heat exchangers, and enables the system to adapt to various temperature conditions. This multi-functionality justifies the added component by providing significant operational flexibility and extended free cooling capability.
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 use of cooling water for air conditioning across a wider range of temperatures, including high outside air temperatures, by efficiently routing cooling water through heat exchangers, thereby enhancing energy conservation and reducing energy consumption.
Implementation Method 1
a cooling tower configured to cool cooling water
Implementation Method 2
a thermal source device configured to generate cold water by the cooling water cooled by the cooling tower
Implementation Method 3
a first heat exchanger configured to exchange heat between air and the cold water generated by the thermal source device
Implementation Method 4
a second heat exchanger configured to exchange heat between a portion of the cooling water cooled by the cooling tower and the air heat-exchanged with the cold water by the first heat exchanger
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In an air conditioning system (101), a cooling tower (2) cools cooling water. A thermal source device generates cold water by the cooling water cooled by the cooling tower (2). A cooling water circulation passage (A) allows circulation of the cooling water between the cooling tower (2) and the thermal source device. A first heat exchanger (5) exchanges heat between air and the cold water generated by the thermal source device. A cold water circulation passage (B) allows circulation of the cold water between the thermal source device and the first heat exchanger (5). A second heat exchanger (6) exchanges heat between a portion of the cooling water cooled by the cooling tower (2) and the air heat-exchanged with the cold water by the first heat exchanger (5). A cooling water branch passage (A'), branching from the cooling water circulation passage (A), introduces to the second heat exchanger (6) the portion of the cooling water introduced to the thermal source device from the cooling tower (2), and introduces to the cooling water circulation passage (A) the portion of the cooling water heat-exchanged with the air by the second heat exchanger (6).