Day Cycle Thermal Storage for Dry Cooling Efficiency
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Solution Overview
Problem
Current dry cooling systems for power plants face efficiency penalties due to limited condensate temperature, higher backpressures, and increased costs, as they rely on ambient air temperatures, which are often higher than wet bulb temperatures, leading to reduced power production and higher electricity costs.
Innovation Solution
A day cycle-based process utilizing thermal energy storage materials that are cooled at night and used to cool air or a cooling medium during the day, enhancing heat transfer efficiency and reducing system costs by leveraging temperature differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If air cooled steam condenser is used to eliminate water consumption, then water dissipation is eliminated, but condensate temperature is limited by ambient air temperature resulting in higher backpressures and lower power production efficiency
Solution Approach 1:
The system performs preliminary cooling of the thermal energy storage material during nighttime when ambient temperatures are lower. This advance cooling action allows the stored material to provide coolness during daytime operation, effectively decoupling the cooling capability from daytime ambient temperature limitations and maintaining lower condensate temperatures for improved power production efficiency
Solution Approach 2:
The thermal energy storage material acts as an intermediary between the ambient air and the condenser cooling system. It absorbs excess heat from the condenser coolant and stores it, then releases stored coolness during high-demand periods, mediating the temperature difference and enabling more efficient heat transfer without direct dependence on ambient air temperature
2Loss of substance
If air cooled steam condenser is used to eliminate water consumption, then water dissipation is eliminated, but system costs and parasitic load increase significantly
Solution Approach 1:
The system changes the operational parameters by utilizing nighttime ambient temperature conditions to pre-cool the thermal energy storage material. This parameter change in timing and temperature utilization allows the system to achieve better thermal performance without proportionally increasing capital or operating costs, as it leverages free nighttime cooling resources
Solution Approach 2:
The thermal energy storage material serves the system's cooling needs by absorbing and storing coolness during nighttime and releasing it during daytime operation. This self-service capability reduces dependence on continuous high-capacity active cooling systems, thereby lowering parasitic load and operational complexity
3Loss of substance
If air cooled steam condenser is used, then water consumption is eliminated, but larger condenser and air fans are required adding to system costs
Solution Approach 1:
By changing the temperature parameter of the cooling medium through nighttime pre-cooling of the thermal energy storage material, the system achieves more effective heat transfer. This allows for a reduction in the required condenser surface area, as the enhanced temperature differential improves heat transfer efficiency and reduces the physical size needed to achieve the same cooling capacity
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 approach increases power generation efficiency, reduces capital and operating costs, and minimizes the efficiency penalty associated with dry cooling systems by effectively utilizing nighttime cool temperatures for daytime cooling needs, thereby improving overall system performance.
Implementation Method 1
a thermal energy storage material is placed in heat transfer communication with lower temperature, e.g., nighttime, air resulting in a cooled thermal energy storage material
Implementation Method 2
The cooled thermal energy storage material is subsequently utilized to cool an item such as a second supply of higher temperature air, e.g., daytime air, or a selected cooling medium
Data Source
AI summary
Processes and systems applying day cycle temperature changes in conjunction with cool storage are provided. A thermal energy storage material is placed in heat transfer communication with lower temperature nighttime air resulting in a cooled thermal energy storage material. The cooled thermal energy storage material is subsequently utilized to cool an item such as a supply of higher temperature air, such as daytime air, or a cooling medium.