Solar Collector Heat Pipe Valve Layout for Condenser Overheat Control
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Solution Overview
Problem
Existing solar collector heat pipes face issues with overheating condensers due to increased pressure from vaporization and thermal expansion, which can cause the valve mechanism to fail in controlling temperature, leading to potential damage and reduced heat transfer efficiency.
Innovation Solution
A thermo-mechanical flow control valve with a lift valve mechanism, utilizing a thermally responsive member like a memory metal or bimetallic device, is positioned downstream of the condenser and upstream of the evaporator, allowing the valve head to move towards the condenser when the temperature exceeds a predetermined value, creating a tighter seal against increased pressure and preventing fluid return to the evaporator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a valve means is provided to close communication between condenser and evaporator when condenser temperature exceeds a predetermined value, then the maximum temperature of the condenser can be limited, but increased pressure within the evaporator can act against the valve head to lift it off the valve seat, causing the valve to fail in controlling temperature
Solution Approach 1:
A biasing means (spring) is introduced as an intermediary element between the valve head and the thermally responsive control means. This spring applies a biasing force to the valve head to maintain engagement with the valve seat, counteracting the harmful effect of evaporator pressure that tends to lift the valve head off the seat. The biasing means acts as a mediator that ensures reliable valve closure despite pressure fluctuations.
Solution Approach 2:
The biasing means provides a counteracting force (biasing force) that opposes the harmful force generated by increased evaporator pressure. This counterweight principle ensures that the valve head remains firmly engaged with the valve seat even when high pressure within the evaporator attempts to lift it, thereby maintaining reliable temperature control.
2Reliability
If the valve head is moveable from open to closed position in a direction towards the condenser section, then when the valve head is in its closed position, an increase in pressure within the evaporator section acts against the valve head to urge the valve head against the valve seat, creating a tighter seal
Solution Approach 1:
Instead of positioning the valve head on the evaporator side of the valve seat (conventional arrangement), the invention inverts the arrangement by positioning the valve head on the condenser side of the valve seat. This inversion causes increased evaporator pressure to act against the valve head in a beneficial manner, urging it tighter against the valve seat to improve sealing, rather than lifting it off as would occur with a conventional arrangement.
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
Effectively limits the maximum temperature of the condenser, preventing overheating and maintaining efficient heat transfer by trapping the working fluid in the condenser, ensuring continuous operation and extending the lifespan of the heat pipe system.
Implementation Method 1
A thermally responsive control means, such as a spring formed from memory metal or a bimetallic device, is provided for moving the valve head between a first position and a second position
Implementation Method 2
A thermally responsive control means, such as a spring formed from memory metal or a bimetallic device, is provided for moving the valve head
Implementation Method 3
a radiation absorbing plate for absorbing solar radiation and an elongate tube containing a heat transfer medium having an evaporator section, in thermal contact with said radiation absorbing plate
Implementation Method 4
the essential function of which is to transfer and to distribute heat by vaporization and condensation of a working fluid (heat-transfer medium)
Implementation Method 5
the essential function of which is to transfer and to distribute heat by vaporization and condensation of a working fluid (heat-transfer medium)
Implementation Method 6
said plate and said evaporator section of said elongate tube being enclosed within an evacuated radiation transparent enclosure to prevent heat loss
Implementation Method 7
said plate and said evaporator section of said elongate tube being enclosed within an evacuated radiation transparent enclosure to prevent heat loss
Data Source
Figure 1~2
Figure 3~6
Figure 7~10
AI summary
A heat pipe comprises an evaporator section 5 having a radiation absorbing plate 6 a portion of an elongate tube 7, and a condenser section 10 at a distal end of the elongate tube 7 remote from the evaporator section 5. A flow control valve 20 is provided between the evaporator section 5 and the condenser section 10 to selectively interrupt communication between said sections when the temperature within the condenser section 10 exceeds a predetermined maximum. A temperature sensitive member, ( coil of memory metal 34', or discs 34") acts between a support plate 26 and a seat 36 located on a valve pintle 30 to urge the valve head 22 towards the valve seat 24 when the temperature of the temperature sensitive member 34 exceeds a predetermined limit. A return spring 38 is provided to bias the valve head 22 away from the valve seat 24.