515 The Heat Exchange Characteristics of the New Type Heat Exchanger Fabricated with Folding

2005 ◽  
Vol 2005.54 (0) ◽  
pp. 185-186
Author(s):  
Takabumi NAKAHARA ◽  
Ryousuke TANAKA
Author(s):  
Л. А. Кущев ◽  
В. Н. Мелькумов ◽  
Н. Ю. Саввин

Постановка задачи. Рассматривается теплообменный процесс, протекающий в модифицированном гофрированном межпластинном канале интенсифицированного пластинчатого теплообменного аппарата с повышенной турбулизацией теплоносителя. Необходимо разработать компьютерную модель движения теплоносителя в диапазоне скоростей 0,1-1,5 м/с и определить коэффициент турбулизации пластинчатого теплообменника. Результаты. Приведены результаты компьютерного моделирования движения теплоносителя в межпластинном гофрированном канале оригинального пластинчатого теплообменного аппарата с помощью программного комплекса Аnsys . Определены критерии устойчивости системы. Выполнено 3 D -моделирование канала, образуемого гофрированными пластинами. При исследовании процесса турбулизации были рассмотрены несколько скоростных режимов движения теплоносителя. Определен коэффициент турбулизации Tu, %. Выводы. В результате компьютерного моделирования установлено увеличение коэффициента теплопередачи К, Вт/(м ℃ ) за счет повышенной турбулизации потока, что приводит к снижению металлоемкости и уменьшению стоимости теплообменного оборудования. Statement of the problem. The heat exchange process occurring in a modified corrugated interplate channel of an intensified plate heat exchanger with an increased turbulence of the heat carrier is discussed. A computer model of the coolant movement in the speed range of 0.1-1.5 m/s is developed and the turbulence coefficient of the plate heat exchanger is determined. Results. The article presents the results of computer modeling of the coolant movement in the interplate corrugated channel of the original plate heat exchanger using the Ansys software package. The criteria of system stability are defined. 3D modeling of the channel formed by corrugated plates is performed. In the study of the process of turbulence several high-speed modes of movement of the coolant were considered. The turbulence coefficient Tu, % is determined. Conclusions. As a result of computer simulation, an increase in the heat transfer coefficient K, W/(m ℃) was found due to an increased turbulization of the flow, which leads to a decrease in metal consumption and a decrease in the cost of heat exchange equipment.


Author(s):  
D O Onishchenko ◽  
A Yu Krotchenko ◽  
Yu O Fokin ◽  
M V Tverskoy
Keyword(s):  

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1893
Author(s):  
Kwonye Kim ◽  
Jaemin Kim ◽  
Yujin Nam ◽  
Euyjoon Lee ◽  
Eunchul Kang ◽  
...  

A ground source heat pump system is a high-performance technology used for maintaining a stable underground temperature all year-round. However, the high costs for installation, such as for boring and drilling, is a drawback that prevents the system to be rapidly introduced into the market. This study proposes a modular ground heat exchanger (GHX) that can compensate for the disadvantages (such as high-boring/drilling costs) of the conventional vertical GHX. Through a real-scale experiment, a modular GHX was manufactured and buried at a depth of 4 m below ground level; the heat exchange rate and the change in underground temperatures during the GHX operation were tracked and calculated. The average heat exchanges rate was 78.98 W/m and 88.83 W/m during heating and cooling periods, respectively; the underground temperature decreased by 1.2 °C during heat extraction and increased by 4.4 °C during heat emission, with the heat pump (HP) working. The study showed that the modular GHX is a cost-effective alternative to the vertical GHX; further research is needed for application to actual small buildings.


Author(s):  
Andrei A. Akhremenkov ◽  
Anatoliy M. Tsirlin ◽  
Vladimir Kazakov

In this paper we consider heat exchange system from point of view of Finite-time thermodynamics. At first time the novel estimate of the minimal entropy production in a general-type heat exchange system with given heat load and fixed heat exchange surface is derived. The corresponding optimal distribution of heat exchange surface and optimal contact temperatures are also obtained. It is proven that if a heat flow is proportional to the difference of contacting flows’ temperatures then dissipation in a multi-flow heat exchanger is minimal only if the ratio of contact temperatures of any two flows at any point inside heat exchanger is the same and the temperatures of all heating flows leaving exchanger are also the same. Our result based on those assumptions: 1. heat transfer law is linear (17); 2. summary exchange surface is given; 3. heat load is given; 4. input tempretures for all flows are given; 5. water equivalents for all flows are given.


2011 ◽  
Vol 47 (7) ◽  
pp. 833-839 ◽  
Author(s):  
Yingshuang Wang ◽  
Zhichun Liu ◽  
Suyi Huang ◽  
Wei Liu ◽  
Weiwei Li

Author(s):  
Xiao Wang ◽  
Lin Fu ◽  
Xiling Zhao ◽  
Hua Liu

In recent years, with the continuous urban expansion, the central heating sources are commonly insufficient in the areas of Northern China. Besides, the increasing heat transfer temperature difference results in more and more exergy loss between the primary heat network and the secondary heat network. This paper introduces a new central heating system which combines the urban heat network with geothermal energy (CHSCHNGE). In this system, the absorption heat exchange unit, which is composed of an absorption heat pump and a water to water heat exchanger, is as alternative to the conventional water to water heat exchanger at the heat exchange station, and the doing work ability of the primary heat network is utilized to drive the absorption heat pump to extract the shallow geothermal energy. In this way, the heat supply ability of the system will be increased with fewer additional energy consumptions. Since the water after driving the absorption heat pump has high temperature, it can continue to heat the supply water coming from the absorption heat pump. As a result, the water of the primary heat network will be stepped cooled and the exergy loss will be reduced. In this study, the performance of the system is simulated based on the mathematical models of the heat source, the absorption heat exchange unit, the ground heat exchanger and the room. The thermodynamic analyses are performed for three systems and the energy efficiency and exergy efficiency are compared. The results show that (a) the COP of the absorption heat exchange unit is 1.25 and the heating capacity of the system increases by 25%, which can effectively reduce the requirements of central heating sources; (b) the PER of the system increases 14.4% more than that of the conventional co-generation central heating system and 54.1% more than that of the ground source heat pump system; (c) the exergy efficiency of the CHSCHNGE is 17.6% higher than that of the conventional co-generation central heating system and 45.6% higher than that of the ground source heat pump system.


2021 ◽  
Vol 11 (1) ◽  
pp. 46-55
Author(s):  
Arman B. KOSTUGANOV ◽  
Vitaly V. DEMIDOCHKIN

This article discusses the issue of determining the value the average wall temperature of the plate of a recuperative heat exchanger type “air-to-air” with a corrugated mesh insert based on the results processing the data of a physical experiment to determine the thermohydraulic characteristics such heat exchange surfaces. It has been established that the temperature fi eld of heat exchange surfaces of this type is nonuniform, depends on the conditions of heat exchange and hydraulic regimes of air fl ow. Therefore, the adoption of the arithmetic means value of the measured surface temperatures as the calculated average temperature of the heat exchanger wall entails signifi cant errors in the subsequent processing of experimental data and fi nal the values of the heat transfer coeffi cients, the values the Nusselt criterion and the criterion equations of heat transfer. It is proposed to determine the average value the wall temperature of the heat exchanger based on the results of measurements the wall’s temperatures, the estimate of the coordinates the center of distribution the results of measurements the wall temperatures, the equations of heat balance and heat transfer.


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