Abstract: The heat pipe is a thermal device which allows efficient transport of thermal energy. The experimental work of this research was split into two phases; phase 1 is the development of the facilities, material and test rig preparation. Phase 2 is the actual experiments and measurements of the thermal control mockup inside the modified vacuum chamber (MVC). Due to limited funds, the development on the thermal control subsystem was delayed and the experimental facilities such as suitable thermal vacuum chamber with space standard specifications were not available from the beginning of the research and had to be procured over a period of time. In all, these delays extended the project by one and a half year. Thermal control subsystem needs a special facility and equipment to be tested. The available vacuum chamber is not suitable for the thermal tests. Consequently, the modification of the chamber was a must. A vacuum chamber has been modified to be used as a Thermal Vaccum Chamber (TVC). A MVC is a vacuum chamber modified by using a stainless mirror box with perfect reflectability and the infrared lamp connected with the voltage regulator to vary the lamp intensity as it will be illustrated through the paper.
Abstract: The thermal control in many systems is widely
accomplished applying mixed convection process due to its low cost,
reliability and easy maintenance. Typical applications include the
aircraft electronic equipment, rotating-disc heat exchangers, turbo
machinery, and nuclear reactors, etc. Natural convection in an inclined
square enclosure heated via wall heater has been studied numerically.
Finite volume method is used for solving momentum and energy
equations in the form of stream function–vorticity. The right and left
walls are kept at a constant temperature, while the other parts are
adiabatic. The range of the inclination angle covers a whole revolution.
The method is validated for a vertical cavity. A general power law
dependence of the Nusselt number with respect to the Rayleigh
number with the coefficient and exponent as functions of the
inclination angle is presented. For a fixed Rayleigh number, the
inclination angle increases or decreases is found.
Abstract: A one-dimensional mathematical model was developed in order to analyze and optimize the latent heat storage wall. The governing equations for energy transport were developed by using the enthalpy method and discretized with volume control scheme. The resulting algebraic equations were next solved iteratively by using TDMA algorithm. A series of numerical investigations were conducted in order to examine the effects of the thickness of the PCM layer on the thermal behavior of the proposed heating system. Results are obtained for thermal gain and temperature fluctuation. The charging discharging process was also presented and analyzed.
Abstract: In all industries which are related to heat, suitable
thermal ranges are defined for each device to operate well.
Consideration of these limits requires a thermal control unit beside
the main system. The Satellite Thermal Control Unit exploits from
different methods and facilities individually or mixed. For enhancing
heat transfer between primary surface and the environment,
utilization of radiating extended surfaces are common. Especially for
large temperature differences; variable thermal conductivity has a
strong effect on performance of such a surface .In most literatures,
thermo-physical properties, such as thermal conductivity, are
assumed as constant. However, in some recent researches the
variation of these parameters is considered. This may be helpful for
the evaluation of fin-s temperature distribution in relatively large
temperature differences. A new method is introduced to evaluate
temperature-dependent thermal conductivity values. The finite
volume method is employed to simulate numerically the temperature
distribution in a space radiating fin. The present modeling is carried
out for Aluminum as fin material and compared with previous
method. The present results are also compared with those of two
other analytical methods and good agreement is shown.
Abstract: In space during functioning, a satellite will be heated
up due to the behavior of its components such as power electronics.
In order to prevent problems in the satellite, this heat has to be
released in space thanks to the cooling system. This system consists
of a loop heat pipe (LHP), in which a fluid streams through an
evaporator and a condenser. In the evaporator, the fluid captures the
heat from the satellite and evaporates. Then it flows to the condenser
where it releases the heat and it condenses. In this project, the two
mains parts of a cooling system are studied: the evaporator and the
condenser. The study of the diphasic loop was done starting from
digital simulations carried out under Matlab and Femlab.
Abstract: A hotel mainly uses its energy on water heating, space
heating, refrigeration, space cooling, cooking, lighting and other
building services. A number of 4-5 stars hotels in Auckland city are
selected for this study. Comparing with the energy used for others,
the energy used for the internal space thermal control (e.g. internal
space heating) is more closely related to the hotel building itself.
This study not only investigates relationship between annual energy
(and winter energy) consumptions and building design data but also
relationships between winter extra energy consumption and building
design data. This study is to identify the major design factors that
significantly impact hotel energy consumption for improving the
future hotel design for energy efficient.
Abstract: TUSAT is a prospective Turkish
Communication Satellite designed for providing mainly data
communication and broadcasting services through Ku-Band
and C-Band channels. Thermal control is a vital issue in
satellite design process. Therefore, all satellite subsystems and
equipments should be maintained in the desired temperature
range from launch to end of maneuvering life. The main
function of the thermal control is to keep the equipments and
the satellite structures in a given temperature range for various
phases and operating modes of spacecraft during its lifetime.
This paper describes the thermal control design which uses
passive and active thermal control concepts. The active
thermal control is based on heaters regulated by software via
thermistors. Alternatively passive thermal control composes of
heat pipes, multilayer insulation (MLI) blankets, radiators,
paints and surface finishes maintaining temperature level of
the overall carrier components within an acceptable value.
Thermal control design is supported by thermal analysis using
thermal mathematical models (TMM).