scholarly journals Control of thermal regime of thermoelectric coolers in uniform temperature field

2021 ◽  
Vol 4 (4) ◽  
pp. 329-340
Author(s):  
Vladimir P. Zaykov ◽  
◽  
Vladimir I. Mescheryakov ◽  
Yurii Ivanovich Zhuravlov
Keyword(s):  
Thermal Regime ◽  
Single Stage ◽  
Stationary Mode ◽  
Thermal Mode ◽  
Thermoelectric Cooler ◽  
Modes Of Operation ◽  
Thermoelectric Coolers ◽  
Mode Of Operation ◽  
Operating Current ◽  
Basic Parameters

The comparative analysis of means of control of a thermal mode at minimization of a complex of the basic parameters in various combinations with indicators of reliability and dynamics of functioning of one-stage thermoelectric cooler is resulted. The study was conducted for the operating range of temperature differences, standard heat load and different geometry of the branches of thermocouples. According to the results of research to minimize the sets of basic parameters in interaction with the indicators of reliability and dynamics of work, a number of current modes of operation have been developed. The developed mathematical models for the optimal operating current from the relative temperature difference and heat transfer of the radiator for the proposed operating modes are analyzed. The results of calculations of the main parameters, reliability indicators, and time of transition to stationary mode of operation for different current modes of operation in the range of temperature differences for different geometry of branches of thermoelements are given. The extremes of dependences of the cooling coefficient, heat dissipation capacity of the radiator, the amount of energy consumed on the relative operating current are determined, which is essential for the implementation of the control function. The possibility of choosing the current mode of operation for optimal control of the thermal regime of single-stage thermoelectric devices manufactured by the same technology, taking into account mass, size, energy, reliability and dynamic characteristics. The developed method of optimal regulation of the thermal regime of a single-stage thermoelectric cooler based on minimizing the set of basic parameters allows finding and choosing compromise solutions taking into account the importance of each of the limiting factors.

scholarly journals Comparative analysis of means to control the thermal regime of a cooling thermoelement while minimizing the set of basic parameters

2021 ◽  
Vol 5 (8 (113)) ◽  
pp. 38-50
Author(s):  
Vladimir Zaykov ◽  
Vladimir Mescheryakov ◽  
Yurii Zhuravlov
Keyword(s):  
Comparative Analysis ◽  
Temperature Difference ◽  
Thermal Regime ◽  
Heat Sink ◽  
Single Stage ◽  
Stationary Mode ◽  
Reliability Indicators ◽  
Sink Capacity ◽  
Operating Current ◽  
Basic Parameters

This paper reports a comparative analysis of the thermal regime control means while minimizing a set of basic parameters in various combinations with the indicators of reliability and dynamics of the functioning of a single-stage thermoelectric cooler. The connection has been established between the optimal relative operating current corresponding to the minimum of the set on the relative temperature difference and heat sink capacity of the radiator. The results of calculating the main parameters, reliability indicators, time of entering the stationary mode of operation for various current modes of operation at a fixed temperature difference, thermal load at different geometry of the branches of thermoelements are given. A comparative analysis of the main parameters, indicators of the reliability and operational dynamics of a single-stage cooler under various characteristic current modes of operation has been carried out. Minimizing the set of basic parameters in conjunction with the reliability indicators and operational dynamics of the cooling thermoelement provides a decrease in the refrigeration coefficient up to 40 % compared to the maximum cooling capacity mode, as well as the optimal heat sink capacity of the radiator, the amount of energy expended, the time of entering the stationary mode, the relative intensity of failures. The analysis of the influence of the temperature difference at a predefined thermal load on the relative operating current, the time it takes for the cooler to enter the stationary thermal regime, the heat sink capacity of the radiator, the relative intensity of failures has been performed. The devised method of optimal control over the thermal regime of a single-stage thermoelectric cooler based on minimizing the set of basic parameters makes it possible to search for and select compromise solutions, taking into consideration the weight of each of the limiting factors

scholarly journals Method for increasing the dynamic characteristics of thermoelectric coolers

2021 ◽  
Vol 4 (4) ◽  
pp. 354-367
Author(s):  
Yurii I. Zhuravlov
Keyword(s):  
Dynamic Characteristics ◽  
Thermoelectric Materials ◽  
Operating Mode ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Limiting Factors ◽  
Maximum Temperature ◽  
Thermoelectric Cooler ◽  
Modes Of Operation ◽  
Thermoelectric Coolers

The influence of the efficiency of the initial thermoelectric materials on the dynamics of the functioning of the thermoelectric cooling device for various characteristic current modes of operation in the range of operating temperature drops and heat load at a given geometry of thermoelement legs is considered. The parameters of thermoelectric materials of thermoelements are conventionally divided into three groups: used for batch production, laboratory research and maximum values. The criterion for choosing the operating mode of the thermoelectric cooler takes into account the mutual influence and weight of each of the limiting factors. Since the design conditions can be very diverse, simultaneously varying several limiting factors (constructive, energy and reliability), you can choose the most rational mode of operation. The analysis was carried out for typical current modes of operation of thermoelectric coolers: maximum cooling capacity, maximum cooling capacity at a given current, maximum coefficient of performance, minimum failure rate. It is shown that with an increase in the efficiency of the initial thermoelectric materials, the time for reaching the stationary operating mode of the thermoelectric cooler, the required number of thermoelements, and the maximum temperature difference increase. A method is proposed for reducing the time constant of thermoelectric coolers due to the revealed relationship between the efficiency of thermoelectric materials and the dynamic characteristics of thermoelements. It is shown that an increase in the dynamic characteristics of thermoelectric coolers is achieved without changing the design documentation, manufacturing technology and additional climatic and mechanical testing of products.

scholarly journals DETERMINATION OF THE MAIN PARAMETERS OF THE ROTARY MOWER CUTTING APPARATUS

2020 ◽  
pp. 77-85
Author(s):  
Dmitry Kondratyuk ◽  
Vitaliy Komaha
Keyword(s):  
Cutting Speed ◽  
Soil Surface ◽  
Angular Speed ◽  
Working Length ◽  
Mode Of Operation ◽  
Basic Parameters ◽  
Rotary Cutting ◽  
The Difference ◽  
Translational Speed

For mowing grass during harvesting of hay or haylage, support-free mowers with rotary movement of knives are used mainly, the productivity of which is much greater than segment-finger mowers. Free-cutting cutting apparatuses with rotational movement of knives happen with their rotation around the vertical (rotary) and horizontal (rotary) axes. Mowers that are equipped with rotary cutting devices significantly grind grass, so they are used in mower-grinders and lawn mowers. The purpose of the work is to substantiate the methodology for calculating the structural and kinematic parameters of rotary cutting devices, corresponding to the conditions of their use. The main parameters characterizing the operation of rotary cutting devices are: area, mows than in one revolution of the disk; knife working length; overlapping knives of adjacent rotors; cutting speed. In determining the basic parameters of the rotary cutting apparatus of the mower, the following assumptions were made. It was believed that the angular speed of the rotor and the translational speed of the mower are unchanged, and the movement of the unit is straightforward. In addition, the cutting apparatus performs mowing in a plane parallel to the soil surface, that is, in a plane perpendicular to most plant stems. It is shown that the absolute speed of any point of the knife varies from the maximum value equal to the sum of the peripheral speed of this point and the aggregation speed of the mower, to the minimum - the difference of the above speeds. It was found that the working length of the cutting edge of the knife is directly proportional to the speed of aggregation of the mower and inversely proportional to the angular velocity of the rotor and the number of knives mounted on it. The overlap of the path of the knives of adjacent rotors depends on the radius of the rotor; the number of knives mounted on it and the kinematic mode of operation of the cutting apparatus. Moreover, an increase in the radius of the rotor requires an increase in overlap, and an increase in the kinematic mode and the number of knives leads to a decrease in the overlap between the paths of the knives. The resulting dependence, which allows you to determine the area, mows than in one revolution of the rotor.

scholarly journals hydrocyclone Performance Comparison between Recycled Single Stage and Double Stage Hydrocyclones

2020 ◽  
Vol 21 (3) ◽  
pp. 51-55
Author(s):  
Mohannad A. Raheem ◽  
Raghad F. Qassim
Keyword(s):  
Flow Rate ◽  
Separation Efficiency ◽  
Performance Comparison ◽  
Single Stage ◽  
Feed Concentration ◽  
Modes Of Operation ◽  
Split Ratio ◽  
Inlet Flow Rate ◽  
Water Feed ◽  
The Cost

   This research presents a comparison of performance between recycled single stage and double stage hydrocyclones in separating water from water/kerosene emulsion. The comparison included several factors such as: inlet flow rate (3,5,7,9, and 11 L/min), water feed concentration (5% and 15% by volume), and split ratio (0.1 and 0.9). The comparison extended to include the recycle operation; once and twice recycles. The results showed that increasing flow rate as well as the split ratio enhancing the separation efficiency for the two modes of operation. On the contrary, reducing the feed concentration gave high efficiencies for the modes. The operation with two cycles was more efficient than one cycle. The maximum obtained efficiencies were 97% and 97.5% at 5% concentration, 11 L/min, and 0.9 split ratio for twice recycled single stage and double stage hydrocyclones, respectively. The pressure drop was the same for the two modes of operation. It was concluded that using recycled single stage hydrocyclone was more economical since it reduced the cost of additional hydrocyclone.

Performance Testing of a Thermoelectric Cooler for Medical Application

2011 ◽  
Vol 255-260 ◽  
pp. 1537-1540
Author(s):  
Fu Jen Wang ◽  
Jung Chieh Chang ◽  
Kuo Chien Lin ◽  
Yat Huang Yau
Keyword(s):  
Heat Transfer ◽  
Performance Testing ◽  
Experimental Tests ◽  
Medical Application ◽  
Cooling Capacity ◽  
Cold Chain ◽  
Heat Transfer Analysis ◽  
Thermoelectric Cooler ◽  
Open Market ◽  
Thermoelectric Coolers

Thermoelectric cooler has the advantage of being portable, simple, compact, noiseless, reliable, and environmentally benign. It is quite suitable for transporting and storage for bio-medical products (such as vaccine and blood) which are very sensitive to temperature variation. However, the coefficient of performances (COP) and the cooling capacity of the thermoelectric coolers available in the open market are relatively low. In this study, the effort will be focused on the design of the heat transfer aspect for a thermoelectric blood cooler specific for bio-medical application. Optimized thickness at 0.0025m of a plate fin with length at 0.598m could be obtained through heat transfer analysis. Performance tests have been conducted to investigate the influence of cabinet temperature in the thermoelectric blood cooler. Experimental tests revealed the optimized plate fin can provide satisfactory cooling performance, and to cool down the cabinet until 2°C within 40 minutes. Some tests including different voltage input, loading condition and ambient temperature tests for blood storage have been conducted as well to validate the quality of blood cold chain storage. It is expected that the developed thermoelectric cooler for blood cold chain system will perform stable cold storage and precise temperature control specific for medical application.

scholarly journals Basic Parameters of the Thermal Regime of Rivers in the Vistula River Catchment

2010 ◽  
Vol 14 (1) ◽  
pp. 185-192 ◽  
Author(s):  
Monika Oksiuta
Keyword(s):  
Water Temperature ◽  
River Water ◽  
Thermal Regime ◽  
Measurement Data ◽  
Natural Variability ◽  
Stream Network ◽  
River Catchment ◽  
Vistula River ◽  
Basic Parameters ◽  
River Water Temperature

Abstract Seasonal and multi-annual variability of river water temperature has been analysed based on data from 24 gauge stations of the IMGW network. It has been characterised by means of several values of the thermal regime parameters: mean annual, semi-annual (November-April, May-October) and amplitude. The variability of water temperature in the catchment and in the stream network has been estimated. Measurement data included seven stations at the Vistula river. On the background of natural variability, rivers or their segments have been distinguished where water temperature is impacted by anthropopressure.

scholarly journals Estimation of coefficient of performance of thermoelectric cooler using a 30 W single-stage type

2021 ◽  
Author(s):  
Rotimi Adedayo Ibikunle ◽  
Mutalubi Aremu Akintunde ◽  
Isaac Femi Titiladunayo ◽  
Adekunle Akanni Adeleke
Keyword(s):  
Heat Exchange ◽  
Electrical Power ◽  
Thermoelectric Module ◽  
Single Stage ◽  
Coefficient Of Performance ◽  
Thermoelectric Cooler ◽  
Cooling Period ◽  
Vegetable Samples ◽  
Cooling Chamber ◽  
Before And After

Abstract In this study, a single stage thermoelectric cooler (TER, of size: 21 × 14.2 × 13.5 cm) with thermoelectric module (TEM, of type inbc1-127. 05 with size 40 × 40 × 4.0 mm) and applied electrical power of 30 W and current of 2.5 A, was adopted to estimate the coefficient of performance (COP) of thermoelectric refrigerator (TER). The TER uses a fan to cool the heat exchange region of the TEM. The temperature of the fruit/vegetable samples used in this study was taken before and after cooling for a specific period. The temperatures at both the hot and cold sides of the TEM were also taken at every specific cooling period. The experimented TER can cool vegetable/fruit from about 27 to 5°C within 3 h. The aim of this study is to determine the COP of TER to ascertain the possible applications. The temperature gradient at the heat exchange section of TEM was used to estimate the average theoretical COP to be 0.99, the heat extracted from the cooling chamber and the power supplied was used to estimate the average practical cooling COP to be 0.52; which is within 0.4–0.7 standard COP for a single stage type of TER.

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