Technology
Assessment |
Conventional simple flat-plate solar
collectors were developed for use in sunny and warm climates. Their benefits are greatly
reduced when conditions become unfavorable during cold, cloudy and windy days.
Furthermore, weathering influences such as condensation and moisture will cause early
deterioration of internal materials resulting in reduced performance and system failure. |
Thermomax
Technology |
Thermomax Evacuated Heat Pipe
Solar Collectors (tubes) operate differently than the other collectors available on the
market. These solar collectors consist of a heat pipe inside a vacuum sealed tube, as
shown.
Each tube contains a sealed cooper pipe
(heat pipe). The pipe is then attached to a black copper fin that fills the tube (absorber
plate). Protruding from the top of each tube is a metal tip attached to the sealed pipe
(condenser). These tubes are mounted, the metal tips up, into a heat exchanger (manifold).
As the sun shines on the black surface of the fin, the alcohol is heated and hot vapor
rises to the top of the pipe. Water, or glycol, flows through the manifold and picks up
the heat from the tubes. The heated liquid circulates through another heat exchanger and
gives off its heat to water that is stored in a solar storage tank. A Thermomax system is
simple to install and easy to expand. |
| Memotron |
In the newly developed Memotron tube the
maximum working temperature is controlled by means of a memory metal spring which is
positioned inside the heat-pipe's condenser.
The memory metal is programmed to change its shape at a pre-set temperature. This allows
for the condenser fluid to be retained inside the condenser. When the programmed
temperature has been achieved, the memory metal spring expands and pushes a plug against
the neck of the heat pipe blocking the return of the condensed fluid and stopping heat
transfer.
At temperatures below the maximum programmed limit,
the spring contracts allowing the condensed fluid to return to the lower section of the
heat pipe. It is than evaporated due to the heat from from the absorber plate,
transferring thermal energy to the condenser. Thermomax's patented Memotron tube is the
state of the art technology and provides complete safety through effective temperature
control. |
| Shock
Absorber |
Thermomax system is designed for all weather
conditions. While the ambient temperature is in sub-zero range, the condenser can
experience super high temperatures (300 F).
A patented flexible neck system absorbs both thermal and mechanical shocks. |
Today
|
Thermomax's advanced evacuated
"heat-pipe" solar collector is a breakthrough in solar technology. It is an
efficient and durable solar energy system. It is effective throughout the year and saves
its user a considerable amount in expensive fuels. |
Performance |
Thermomax's collector performs not only at
noon or on clear sunny days, but also when the sun is low or the weather is cloudy. Wind
or low temperatures have less effect on its performance.
|
Quality |
The high quality of Thermomax products is the
result of ongoing refinement and optimization of the product process guided by Dr. Framarz
Mahdjuri. The quality and durability of Thermomax solar products have contributed to an
unequaled history of achievements in the development and implementation of solar
technology. This continues a tradition of innovation begun over four decades ago when NASA
invented the Heat Pipe. Thermomax brings this superb space technology to the market place
as an economically competitive option for Solar Energy. Our ISO 9001 & 9002 Quality
Management Certifications ensure
that Thermomax quality systems meet the highest standard. |
Heat
Transfer |
Transfer of heat from the absorber plate
(collector) is via an efficient and very fast heat conductor, the "heat-pipe."
This has a very low heat capacity but an exceptionally rapid conductivity. The
"heat-pipe" also provides the system with a diode function. Due to the physical
properties of the "heat-pipe,. the maximum working temperature of the system is
controlled. |
Insulation |
The vacuum in the glass tube, being the best
possible insulation for a solar collector, suppresses heat losses and also protects the
absorber plate and the "heat-pipe" from external adverse conditions. This
results in exceptional performance far superior to any other type of solar collector. |
Photo Thermal Conversion Technology |
A solar collector absorbs solar radiation and
converts it into heat (photo-thermal conversion). The high efficiency solar collector
implies maximum absorption of incident solar radiation with a minimum thermal and optical
loss. Selective coating characteristics of the absorber and the vacuum insulation are the
most important parts of an advanced collector. A selective surface has high absorption
(low reflection) for the solar spectrum and low emissivity for the infrared heat
radiation. The selective coating used in the collector consists of a very precise thin
layer of an amorphous semiconductor plated on to a metal substratum having a low emission
for long-wave radiation. |
Vacuum
Technology |
Due to the atmospheric pressure and the
technical problems related to the sealing of the collector casing, the construction of an
evacuated flat-plate collector is extremely difficult. To overcome the enormous
atmospheric pressure, many internal supports for the transparent cover pane must be
introduced. However, the problems of an effective high vacuum system with reasonable
production costs remain so far unsolved.
It is more feasible to apply and adapt the mature technology related to the lamp
industries with proven mass production. Building a tubular evacuated solar collector and
the maintenance of its high vacuum, similar to light bulbs and TV tubes, is practical. The
ideal vacuum insulation of the tubular evacuated solar collector, obtained by means of a
suitable exhausting process, has to be maintained during the life of the device to reduce
the thermal losses through the internal gaseous atmosphere (convection losses). |
Heat
Pipe Technology |
A heat pipe acts like a high conductance
thermal conductor. Due to its thermal-physical properties, its heat transfer rate is
thousand's times greater than that of the best solid heat conductor of the same
dimensions. The basic heat pipe is a closed container consisting of a capillary wick
structure and a small amount of vaporizable fluid. The heat pipe employs an
evaporating-condensing cycle, which accepts heat from an external source, uses this heat
to evaporate the liquid (latent heat) and then releases latent heat by reverse
transformation (condensation) at a heat sink region. This process is repeated continuously
by a return feed mechanism of the condensed fluid back to the heat zone.
In the solar collector, the condensation zone is at a higher level than the evaporation
zone. The transport medium condensed (in the condensation zone) returns to the evaporation
zone under the influence of the gravity. Then, there is no need of capillary wick
structure.
The maximum operating temperature of a heat pipe is the critical temperature of the used
heat transfer medium. Since no evaporation/condensation above the critical temperature is
possible, the thermodynamic cycle interrupts when the temperature of the evaporator
exceeds the critical temperature. |
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