Integrated Cooling Tower with Direct Indirect Heat Exchanger
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing heat exchange apparatuses face limitations in efficiency and size due to the constraints of indirect heat exchanger design, which restricts the enhancement of sensible heat transfer rates and overall thermal capacity within a given footprint.
Innovation Solution
The integration of a plate type or coil circuit tube type indirect heat exchanger within a housing, allowing for both sensible and latent heat exchange, with the option to operate in wet or dry modes by adjusting the flow of air and evaporative liquid, increases the heat transfer coefficients and reduces the size of the indirect heat exchanger while expanding the direct heat exchanger surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the size of indirect heat exchanger is reduced, then more room is available for adding direct heat exchanger surface area and larger fan diameter, but the sensible heat transfer rate decreases
Solution Approach 1:
The patent changes the operational parameters of the indirect heat exchanger by forcing evaporative liquid through the plates at higher velocities using a pump, which increases the external forced convection heat transfer coefficients and compensates for the reduced heat exchanger area
Solution Approach 2:
The indirect heat exchanger plates serve dual functions: they provide sensible heat exchange with the internal fluid stream while also serving as a support structure for the evaporative liquid distribution system, enabling both direct and indirect heat exchange modes within the same apparatus
2Speed
If evaporative liquid velocity is increased, then external forced convection heat transfer coefficients increase, but the size of indirect heat exchanger must be reduced
Solution Approach 1:
The patent uses a pump to force evaporative liquid through the indirect heat exchanger plates at controlled high velocities, creating forced convection conditions that enhance heat transfer coefficients while allowing compact heat exchanger design
Solution Approach 2:
The system transitions from static or gravity-driven liquid flow to dynamic pumped flow, allowing variable liquid velocities that can be optimized for heat transfer performance while maintaining compact dimensions
3Area of stationary object
If the cooling tower footprint is maintained, then manufacturing costs are reduced, but the thermal capacity is limited
Solution Approach 1:
The patent merges direct and indirect heat exchange sections into a single integrated cooling tower structure, allowing both heat exchange mechanisms to operate simultaneously within the same footprint, thereby increasing total thermal capacity without expanding the facility size
Solution Approach 2:
The indirect heat exchanger is positioned within the cooling tower structure such that the evaporative liquid flows over and through the heat exchanger plates, nesting the indirect heat exchange function within the existing direct heat exchange framework
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 configuration enhances the thermal capacity and reduces manufacturing costs by increasing the fan size and direct heat exchanger area while maintaining the cooling tower's footprint, achieving improved performance and efficiency through increased evaporative liquid velocities and air agitation.
Implementation Method 1
The indirect heat exchange section is comprised of a plate type heat exchanger... to provide both sensible and latent heat exchange with the evaporative liquid
Implementation Method 2
operating at substantially higher evaporative fluid velocities resulting in higher external forced convection heat transfer coefficients
Implementation Method 3
An evaporative liquid is passed through the indirect heat exchange section housing and distributed through the external passageways of the plate type heat exchanger to indirectly exchange heat with the internal fluid stream
Implementation Method 4
provide both sensible and latent heat exchange with the evaporative liquid
Implementation Method 5
Air is moved over the direct heat exchange section to evaporatively cool the evaporative liquid
Data Source
Figure 1
Figure 1A
Figure 1B
AI summary
An improved heat exchange apparatus is provided with an indirect evaporative heat exchange section enclosed in a housing and a direct evaporative heat exchange section both of which are located within the same apparatus. An internal fluid stream is passed through the internal passageways of the indirect heat exchange section. An evaporative liquid is passed across the outside of the external passageways of the indirect heat exchange section to exchange heat indirectly with the internal fluid stream. The evaporative liquid that exits the indirect evaporative heat exchange section housing then passes onto and through the direct heat exchange section. The evaporative liquid exiting the direct heat exchange section is collected in a sump and then pumped upwardly to be distributed again through the indirect heat exchange section housing. The indirect heat exchange section may be comprised of a plate type heat exchanger or a circuit tube type heat exchanger located within a housing. The indirect heat exchange housing may be in direct contact with the air moving through the direct heat exchange section, be in direct contact with the cool evaporative liquid, or both, to enhance the heat transfer from the indirect heat exchange section. Air may be pumped along with the evaporative liquid through the indirect heat exchange section to agitate and increase the velocity of evaporative fluid flowing through the indirect heat exchanger. Air may also be pumped into and through the indirect eat exchange section housing when the evaporative fluid pump is off during a dry mode of operation.