Y.H. Diao

Experimental study on the heat transfer characteristics of a new type flat micro heat pipe heat exchanger with latent heat thermal energy storage

An experimental energy storage system has been designed using a new type flat micro heat pipe heat exchanger that incorporates a moderate-temperature phase change material paraffin with a melting point of 58°C. The basic structure, working principles, and design concept are discussed. The heat transfer process during the charging and discharging of the heat exchanger under various operating conditions has been experimentally investigated. Results show that the performance of the new type flat micro heat pipe was steady and efficient during charging and discharging. The average thermal storage power and absorption efficiency have been determined to be approximately 537 W and 92.5%, respectively.

AN EXPERIMENTAL INVESTIGATION ON HEAT TRANSFER CHARACTERISTICS FOR MICRO-CAPILLARY EVAPORATOR

Abstract An experimental investigation on heat transfer characteristics for a kind of micro-capillary groove evaporator has been carried out in this article. The binary liquid mixture used in this experiment was composed of 2-Methylpentane and methanol. The experimental results showed that when the liquid mixture mole fraction X1 (2-Methylpentane):X2 (methanol) equals to 1:9, the enhanced heat transfer effect was the best. This kind of binary liquid mixture was applied for all three evaporators with different dimensions; the optimal ratio of depth on the width of the micro-groove for the evaporator was obtained. Compared with the available results in the previous studies, the experimental results showed that the temperature of the heated surface could be reduced in the range of 10°–20° at the same heat flux. The experimental results showed that this kind of evaporator could be capable of cooling for high-power electronic chips.

Experimental Investigation of a New Flat Plate Solar Heat Collector by Micro Heat Pipe Array

The performance of a new flat plate solar heat collector with perfect combination of high efficiency and low cost is investigated experimentally. The new system described in this study uses a novel micro heat pipe array as a key component for the system. One such flat plate heat collector contains over 300 micro heat pipes per 1m2 and the hydraulic diameter of the micro heat pipes is 0.4–1.0mm. A detailed heat transfer experimental study is conducted during daylight hours over several months, focusing on the collector efficiency and overall efficiency of the system as well as total heat loss factor. The results show that the collector’s maximum instantaneous efficiency is up to 88%. Compared with conventional evacuated glass tube solar water heater, the system offers the additional benefits of high pressure resistance, low weight, good reliability and durability, easy integration into buildings and absence of freezing during winter months. Besides, compared with traditional flat-plate solar water system which is mainly sheet-and-tube concept, the system also shows many advantages: higher efficiency, much cheaper, absence of tube-bonding and freezing etc. Therefore, the system proposes a unique substitute to common solar water heating systems.Copyright