Solar Collector Heat Pipe Valve 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 means to malfunction, allowing condensate to drain back into the evaporator and impeding temperature control.
Innovation Solution
A thermally responsive valve means with a valve head and seat mechanism, where the valve head is positioned downstream of the condenser and upstream of the evaporator, is used to selectively close communication between the condenser and evaporator sections when the condenser temperature exceeds a predetermined value, utilizing a thermally responsive member like a bimetallic device or memory metal to ensure effective temperature regulation, and a biasing spring to maintain the valve in the closed position against increased pressure.
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 is limited and overheating is prevented, but increases in pressure within the evaporator due to vaporization and thermal expansion can act against the valve head to lift it off the valve seat, allowing condensate to drain back into the evaporator and impeding temperature control
Solution Approach 1:
A biasing spring is introduced as an intermediary mechanical element between the valve head and the valve seat. This spring applies a continuous closing force on the valve head, ensuring that when the condenser temperature exceeds the predetermined value, the valve head remains firmly engaged with the valve seat despite pressure increases in the evaporator section. The biasing spring mediates between the thermal control mechanism and the pressure forces, maintaining reliable valve closure for effective temperature control.
Solution Approach 2:
The biasing spring provides a counteracting force that opposes the harmful effect of evaporator pressure increases. Just as counterweight compensates for gravitational force, the biasing spring compensates for the pressure-induced lifting force on the valve head, ensuring the valve remains closed when temperature control is needed. This counterforce mechanism reliably prevents condensate from draining back into the evaporator during high-temperature conditions.
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, but this requires precise positioning and sealing arrangement to ensure effective closure
Solution Approach 1:
Instead of positioning the valve head upstream of the condenser section, the invention inverts the arrangement by positioning the valve head downstream of the condenser section and upstream of the evaporator section. This inverted positioning allows evaporator pressure increases to naturally act against the valve head in the closing direction, urging it against the valve seat. The inversion transforms the pressure force from a potential opening force into a beneficial closing force, improving reliability while simplifying the sealing 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
This solution effectively limits the maximum temperature of the condenser, preventing overheating and ensuring continuous heat transfer by trapping the working fluid in the condenser section, thus maintaining efficient energy transport and preventing system damage.
Implementation Method 1
thermally responsive control means being provided for moving the valve head between an open position and a closed position
Implementation Method 2
A thermally responsive valve means with a valve head and seat mechanism, where the valve head is positioned downstream of the condenser and upstream of the evaporator, is used to selectively close communication between the condenser and evaporator sections when the condenser temperature exceeds a predetermined value, utilizing a thermally responsive member like a bimetallic device or memory metal
Implementation Method 3
an increase in pressure within the evaporator section acts against the valve head to urge the valve head against the valve seat
Implementation Method 4
a radiation absorbing plate for absorbing solar radiation
Implementation Method 5
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 6
transfer the latter with the maximum possible efficiency to a fluid heat transferring means
Implementation Method 7
the essential function of which is to transfer and to distribute heat by vaporization and condensation of a working fluid
Implementation Method 8
heat pipe for a solar collector for converting solar radiation into heat and to transfer the latter
Implementation Method 9
said plate and said evaporator section of said elongate tube being enclosed within an evacuated radiation transparent enclosure to prevent heat loss
Implementation Method 10
evacuated radiation transparent enclosure
Data Source
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.