EXPERIMENTAL RESEARCH INSIDE A GAS HEATER WITH DIFFERENT INTERMEDIATE HEAT CARRIER MEDIUM
The gas heater is one of the key equipments in gas industry, which plays the role of heating natural gas to the required processing temperature, and the application of gas heater shows a promising prospect. The cylindertype heating device with an intermediate heat carrier medium is most widely employed. Apparently, the selection of intermediate heat carrier medium and the form of heat transfer process of the intermediate heat carrier medium, i.e. the flow field organization in the large capacity cylinder, is the key elements that greatly affect the thermal efficiency of gas heater. A real gas heater experimental system, which is the only one in China, is built. The present paper characterizes water and ethylene glycol as the intermediate heat carrier medium. Experimental measurements and analysis on the flow condition and temperature distribution between the water and ethylene glycol in the cylinder were carried out. The results shown that using ethylene glycol as the heat carrier media can widen the application range of gas heater. The efficiency of the heater with ethylene glycol as the heat carrier medium is at least 3.8% higher than that with water as the heat carrier medium under the same working conditions. The thermal efficiency of gas heater is usually less than 87%.
Flow and heat transfer inside a new diversion-type gas heating device
ABSTRACT The present paper characterizes ethylene glycol flow and heat transfer inside a new diversion-type gas heating device. A two-dimensional (2-D) natural convection heat transfer model was built and solved by the finite volume method with unstructured body-fitted grids. The numerical model was first validated through temperature comparison with the experimental measurements in a conventional device structure. Then analyses and comparisons of the flow fields and temperature distributions with use of different guide plate structures were carried out. The numerical results show that using the guide plate structures can form better organized flow patterns that augment heat transfer. The heat required for heating up the gas passing through the heating device can be reduced by 3% via installing two guide plates.
Application design of a sun-tracking system
As a very good renewable energy, solar energy gets a lot of countries' concerns. How to improve the efficiency of solar panel is now a hot topic and sun tracking is one of the solutions. In this paper, a servo tracking system using dSPACE DS1104 R&D controller board is designed to improve solar collection efficiency. It combines electro-optical tracking and sun trajectory tracking, and can keep solar panels perpendicular to the sun during daylight hours. In order to reduce the amount of computation, a T-S fuzzy system based sun trajectory tracking is proposed. Because of the seamless connection between dSPACE and MATLAB/Simulink, the development cycle time is short. Experimental results show that the system can track the sun precisely and has higher efficiency.