Low-heat-loss operation method of line-focusing heat collection system and line-focusing heat collection system
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Solution Overview
Problem
Current solar-thermal power generation systems with line-focusing heat collection modes experience significant heat loss and energy consumption due to low-speed circulation during non-heat collection periods, leading to freezing blockages and inefficient energy utilization.
Innovation Solution
A low-heat-loss operation method for line-focusing heat collection systems, which involves preheating collector tubes using solar energy, adjusting heating modes for injection and drainage processes, and utilizing compressed gas for temperature homogenization and drainage assistance, thereby reducing energy consumption and preventing freezing blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-speed circulation is adopted to prevent freezing blockage during non-heat collection periods, then freezing blockage is prevented, but heat loss and energy consumption increase significantly
Solution Approach 1:
The system performs preliminary heating of the heat transfer working medium before non-heat collection periods begin, storing thermal energy in advance. This allows the medium to maintain adequate temperature without continuous circulation during periods when solar energy is unavailable, thereby preventing freezing blockage while reducing energy consumption.
Solution Approach 2:
The system utilizes the thermal inertia and heat capacity of the heat transfer working medium itself to maintain temperature during non-heat collection periods. By designing the system to leverage the medium's inherent thermal properties rather than relying on active heating or circulation, the system reduces energy consumption while maintaining reliability.
2Reliability
If continuous circulation is maintained to prevent freezing, then freezing blockage is avoided, but circulation pump energy consumption increases
Solution Approach 1:
Instead of continuous circulation, the system implements periodic circulation only when necessary to maintain temperature during non-heat collection periods. This intermittent operation significantly reduces pump energy consumption while still preventing freezing blockage by circulating the medium only during critical temperature periods.
Solution Approach 2:
The system pre-heats the heat transfer working medium before non-heat collection periods, reducing the need for continuous circulation. By establishing adequate temperature margins in advance, the system can minimize or eliminate pump operation during periods when solar energy is unavailable, thereby reducing energy consumption.
3Temperature
If electrical impedance heating is used to heat the heat transfer working medium before injection, then the medium reaches required temperature, but additional energy consumption occurs
Solution Approach 1:
The system utilizes solar energy collected during heat collection periods to heat the heat transfer working medium, making the medium self-sufficient for temperature maintenance. By leveraging the system's own solar collection capability rather than external electrical heating, the system reduces additional energy consumption while achieving the required temperature.
Solution Approach 2:
The system maintains continuous heating of the heat transfer working medium through solar energy during heat collection periods, ensuring the medium is always at the required temperature without needing separate electrical heating cycles. This continuous solar heating eliminates the need for intermittent electrical impedance heating, reducing overall energy consumption.
4Temperature
If natural gas or electric heating furnace is used to supplement energy during small-flow circulation, then temperature requirements are met, but heat loss consumption increases
Solution Approach 1:
The system uses its own solar collection capability to heat the heat transfer working medium during small-flow circulation periods, making the heating self-sufficient. By utilizing internally generated solar thermal energy rather than external natural gas or electric heating, the system eliminates additional heat loss consumption while maintaining temperature requirements.
Solution Approach 2:
The system recovers and utilizes thermal energy that would otherwise be lost during small-flow circulation periods. By capturing and reusing solar thermal energy during these periods, the system eliminates the need for supplemental natural gas or electric heating, thereby reducing heat loss consumption.
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 method effectively reduces heat loss and energy consumption by utilizing solar energy for preheating and drainage, preventing freezing blockages, and improving drainage efficiency, while ensuring safe and thorough heat transfer medium operation.
Implementation Method 1
solar radiation energy is converged into a heat collection system with large-scale mirrors. Heat transfer working mediums such as water, heat transfer oil or fused salt in the heat collection device are heated, so that solar radiation energy with low energy flow density is converged into heat energy with high energy flow density.
Implementation Method 2
The heat transfer working medium is pumped out from the low-temperature storage tank, and heated by a natural gas/electric heating furnace to supplement energy to raise the temperature of the heat transfer working medium.
Implementation Method 3
the heat transfer working medium is injected into the heat collection pipeline at one time after the heat collection pipeline is heated by means of electrical impedance heating.
Data Source
AI summary
A low-heat-loss operation method of a line-focusing heat collection system and the line-focusing heat collection system are provided. The method includes the following steps. Solar energy is utilized to preheat a collector tube in an empty tube state, so that the collector tube is in a preheating mode. After a set preheating temperature is reached, a heat transfer working medium is injected into the collector tube. In the injection process of the heat transfer working medium, an injection section of the collector tube is converted into a focusing mode from a preheating mode. After heat collection is finished, the circulation of the heat transfer working medium is stopped, and the focusing mode of the collector tube is kept. In the drainage process of the heat transfer working medium, an emptying section of the collector tube is converted into a light heat-tracing mode from a focusing mode.