Heat exchange performance of ground source heat pump by water cooling method

Ground source heat pump (GSHP) is one of saving energy systems for air conditioning. However, the GSHP is not popular in Japan because an initial cost of the GSHP is higher than an air source heat pump. This paper describes the thermal performance of the GSHP using water cooled method. This system consists of commercialized water cooling heat pump which removed a cooling tower and then attached a heat exchanger. Ground water penetrates under 6 m in depth and there is natural flow of ground water. This system exchanges the heat between ground water and the circulating water in the heat exchanger. This system uses existing two wells. One is 40 m in depth and it is used as borehole. That is expected to save the digging cost of bore hole. A casing pipe whose surface was punched like slit was inserted in the borehole. Heat exchanger is in the casing pipe. The space between the casing pipe and the borehole was filled with silica sand which was performed as filler. The other well is 30 m in depth. Well pump is in the well. The pumping head is in the wall at 24 m. The pump feeds water into 38 m point of the borehole. This pump is used to recover the temperature of underground by feeding water. The proposed system is evaluated by coefficient of performance (COP) of this system. COP is used commonly as index of the performance of GSHP.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Tribological Analysis of Copper-Coated Graphite Particle-Reinforced A359 Al/5 wt.% SiC Composites

[[abstract]]Copper-coated graphite particles can be mass-produced by the cementation process using simple equipment. Graphite particulates that were coated with electroless copper and 5 wt.% SiC particulates were introduced into an aluminum alloy by compocasting to make A359 Al/5 wt.% SiC(p) composite that contained 2, 4, 6, and 8 wt.% graphite particulate composite. The effects of SiC particles, quantity of graphite particles, normal loading, sliding speed and wear debris on the coefficient of friction, and the wear rate were investigated. The results thus obtained indicate that the wear properties were improved by adding small amounts of SiC and graphite particles into the A359 Al alloy. The coefficient of friction of the A359 Al/5 wt.% SiC(p) composite that contained 6.0 wt.% graphite particulates was reduced to 0.246 and the amount of graphite film that was released on the worn surface increased with the graphite particulate content. The coefficient of friction and the wear rate were insensitive to the variation in the sliding speed and normal loading.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

GRADE CLASSIFICATION OF CORROSION DAMAGE ON THE SURFACE OF WEATHERING STEEL MEMBERS BY DIGITAL IMAGE PROCESSING

The Thirteenth East Asia-Pacific Conference on Structural Engineering and Construction (EASEC-13), September 11-13, 2013, Sapporo, Japan

Calorimetry of heat pump system using ultra-fine fluorescent wires and PIV

To understand transport phenomena of heat and fluid flow in various fields of engineering, it is essential to develop experimental methods for measuring the temperature field in a fluid flow. The two-color laser-induced fluorescence (LIF) technique is suitable for performing temperature measurements of water flow. This technique eliminates the influence of laser intensity fluctuations observed in the single-color LIF technique, which is a significant source of error in temperature measurement. However, the two-color LIF technique has not been applied to air flow. Although this problem was solved by developing a technique for spraying fluorescent dye mists, steadily maintaining the non-uniform diameter of the tracer particles of a fluorescent mist, which is thought to influence the evaluated temperature, has been difficult because the mist consistently descends and mixes with the surrounding flows. In this study, we propose a temperature measurement method that uses ultra-fine fluorescent wires to reduce the wire diameter to much less than that of a thermocouple. This is possible because its structure is simple, and any material can be used for the wire. Hence, ultra-fine wires whose Reynolds number is less than 1.0 can be selected. This means that turbulent flow is not generated downstream of the wire and that its wake is negligibly small. Furthermore, the number of wires decreases because a line profile of temperature can be measured using only one wire.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Calorimetry of ground source heat pump using direct expansion method : measurement of flow rate using PIV method

The GSHP that use a direct expansion method is expected to have higher performance of energy-saving than the conventional type of the GSHP. We evaluated the quantity of heat by measuring temperature, humidity and flow rate at the indoor unit of the GSHP system. The purpose of this study was to improve the accuracy of the flow rate measured by hot wire anemometers using PIV method. The average of difference between the flow rate obtained by the hot wire anemometers and PIV method was 23.6% in the heating operation and was 24.0% in the cooling operation. We obtained the compensation formula which corrects the results of the hot wire anemometers using the results of PIV method. The average of difference between the compensated flow rate by the PIV method was reduced to 5.2% in the heating operation and 1.9% in the cooling operation. The compensation formula is used performance evaluation of the GSHP system. The COP obtained by conventional method was 3.4 in the heating operation. The compensated COP was 2.8.papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

3D-3C PIV method by using W-shaped light sheet and color PIV

This paper describes the principle of the 3D-3C PIV system which is based on expanded visualized area by deforming the shape of a laser light sheet into a \u93W\u94 shape. When the shape of the light sheet is W-shape, it becomes possible to visualize parts of a field at various x, y and z positions simultaneously. Since velocity distribution with depth information can be obtained by using the W-shaped light sheet, 3D velocity distribution can be evaluated by interpolating the velocity distributions on each W-plane. The proposed 3D PIV technique is applied to the measurement of the velocity distribution in a vertical buoyant jet. This technique is well suited for measuring the velocity field of an airflow. The color PIV method using the digital SLR camera is also discussed for to maintain the good spatial resolution of the 3D PIV method