scholarly journals Experimental investigation of a high efficiency electric heater and dehumidifier prototype unit

2020 ◽  
Vol 14 (2) ◽  
pp. 43-49
Author(s):  
Norbert Szaszák ◽  
Ákos Pozsa
Keyword(s):  
Latent Heat ◽  
High Efficiency ◽  
Test Chamber ◽  
Thermoelectric Module ◽  
Ambient Air ◽  
Electric Heater ◽  
Laboratory Measurements ◽  
Heating Efficiency ◽  
Ohmic Resistance ◽  
Condensation Mode

In this paper the principle of operation and preliminary laboratory measurements of a prototype of a high-efficiency electrical air heater unit is presented. Unlike conventional heaters, which apply Joule-heat formed by electrical resistance, the developed device uses thermoelectric modules for heating ambient air. Just like in case of resistance heaters, most of the heat is produced as a result of the internal ohmic resistance of the thermoelectric module (resistance heating), however, in case of appropriate air conditions our device is capable of transforming the latent heat of the air moisture into heat energy. In case of condensation mode, some of the moisture condensates on the cold side of the module while its latent heat is transferred to the hot side of the module where it heats the dried air. In this mode, the heating efficiency of the device (e.g., the ratio of the heat added to air and the consumed electricity) is over unity. Following the idea and basic equations of the operation of this device, the results of the laboratory measurements in a climate test chamber is presented.

scholarly journals Classifying the Biological Status of Honeybee Workers Using Gas Sensors

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 166
Author(s):  
Jakub T. Wilk ◽  
Beata Bąk ◽  
Piotr Artiemjew ◽  
Jerzy Wilde ◽  
Maciej Siuda
Keyword(s):  
Gas Sensors ◽  
Laboratory Tests ◽  
Test Chamber ◽  
Ambient Air ◽  
True Positive Rate ◽  
True Positive ◽  
Positive Rate ◽  
Parameters Of Accuracy ◽  
Selection Of

Honeybee workers have a specific smell depending on the age of workers and the biological status of the colony. Laboratory tests were carried out at the Department of Apiculture at UWM Olsztyn, using gas sensors installed in two twin prototype multi-sensor detectors. The study aimed to compare the responses of sensors to the odor of old worker bees (3–6 weeks old), young ones (0–1 days old), and those from long-term queenless colonies. From the experimental colonies, 10 samples of 100 workers were taken for each group and placed successively in the research chambers for the duration of the study. Old workers came from outer nest combs, young workers from hatching out brood in an incubator, and laying worker bees from long-term queenless colonies from brood combs (with laying worker bee’s eggs, humped brood, and drones). Each probe was measured for 10 min, and then immediately for another 10 min ambient air was given to regenerate sensors. The results were analyzed using 10 different classifiers. Research has shown that the devices can distinguish between the biological status of bees. The effectiveness of distinguishing between classes, determined by the parameters of accuracy balanced and true positive rate, of 0.763 and 0.742 in the case of the best euclidean.1nn classifier, may be satisfactory in the context of practical beekeeping. Depending on the environment accompanying the tested objects (a type of insert in the test chamber), the introduction of other classifiers as well as baseline correction methods may be considered, while the selection of the appropriate classifier for the task may be of great importance for the effectiveness of the classification.

Heat dissipation system based on electromagnetic driven rotational flow of liquid metal coolant

2021 ◽  
pp. 1-14
Author(s):  
Lei Wang ◽  
Xudong Zhang ◽  
Dr. Jing Liu ◽  
Yixin Zhou
Keyword(s):  
Liquid Metal ◽  
Thermal Resistance ◽  
Heat Dissipation ◽  
High Efficiency ◽  
Cooling System ◽  
Electric Heater ◽  
Power Relationship ◽  
Rotational Flow ◽  
Large Power ◽  
Dissipation System

Abstract Liquid metal owns the highest thermal conductivity among all the currently available fluid materials. This property enables it to be a powerful coolant for the thermal management of large power device or high flux chip. In this paper, a high-efficiency heat dissipation system based on the electromagnetic driven rotational flow of liquid metal was demonstrated. The velocity distribution of the liquid metal was theoretically analyzed and numerically simulated. The results showed that the velocity was distributed unevenly along longitudinal section and the maximum velocity appears near the anode. On the temperature distribution profile of the heat dissipation system, the temperature on the electric heater side was much higher than the other regions and the role of the rotated liquid metal was to homogenize the temperature of the system. In addition, the thermal resistance model of the experimental device was established, and several relationships such as thermal resistance-power curve were experimentally measured. The heating power could be determined from the temperature-power relationship graph once the maximum control temperature was given. The heat dissipation method introduced in the paper provides a novel way for fabricating compact chip cooling system.

scholarly journals Measurement of Ozone Production Sensor

2010 ◽  
Vol 3 (3) ◽  
pp. 545-555 ◽  
Author(s):  
M. Cazorla ◽  
W. H. Brune
Keyword(s):  
Production Rate ◽  
High Efficiency ◽  
Ambient Air ◽  
Ozone Production ◽  
State University ◽  
Photostationary State ◽  
Sample Chamber ◽  
Efficiency Conversion ◽  
The Difference ◽  
Teflon Film

Abstract. A new ambient air monitor, the Measurement of Ozone Production Sensor (MOPS), measures directly the rate of ozone production in the atmosphere. The sensor consists of two 11.3 L environmental chambers made of UV-transmitting Teflon film, a unit to convert NO2 to O3, and a modified ozone monitor. In the sample chamber, flowing ambient air is exposed to the sunlight so that ozone is produced just as it is in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film over the Teflon film prevents ozone formation but allows other processes to occur as they do in the sample chamber. The air flows that exit the two chambers are sampled by an ozone monitor operating in differential mode so that the difference between the two ozone signals, divided by the exposure time in the chambers, gives the ozone production rate. High-efficiency conversion of NO2 to O3 prior to detection in the ozone monitor accounts for differences in the NOx photostationary state that can occur in the two chambers. The MOPS measures the ozone production rate, but with the addition of NO to the sampled air flow, the MOPS can be used to study the sensitivity of ozone production to NO. Preliminary studies with the MOPS on the campus of the Pennsylvania State University show the potential of this new technique.

Realizing high-efficiency power generation in low-cost PbS-based thermoelectric materials

2020 ◽  
Vol 13 (2) ◽  
pp. 579-591 ◽  
Author(s):  
Binbin Jiang ◽  
Xixi Liu ◽  
Qi Wang ◽  
Juan Cui ◽  
Baohai Jia ◽  
...  
Keyword(s):  
Power Generation ◽  
Conversion Efficiency ◽  
Thermoelectric Materials ◽  
High Efficiency ◽  
Low Cost ◽  
Thermoelectric Module ◽  
High Conversion ◽  
High Conversion Efficiency

A high conversion efficiency of 11.2% was realized in a low-cost PbS-based segmented thermoelectric module.

Triethyl phosphate in an antisolvent: a novel approach to fabricate high-efficiency and stable perovskite solar cells under ambient air conditions

2021 ◽  
Vol 5 (20) ◽  
pp. 7628-7637
Author(s):  
Pengyun Zhang ◽  
Ningxia Gu ◽  
Xiang Chen ◽  
Lixin Song ◽  
Pingfan Du ◽  
...  
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Perovskite Solar Cells ◽  
Ambient Air ◽  
Good Stability ◽  
Triethyl Phosphate ◽  
Ambient Conditions ◽  
Novel Approach

In this contribution, PSCs with a high efficiency and good stability are fabricated under ambient conditions without a glove box via introducing triethyl phosphate (TEP) into a perovskite through an antisolvent.

Ambient air-processed mixed-ion perovskites for high-efficiency solar cells

2016 ◽  
Vol 4 (42) ◽  
pp. 16536-16545 ◽  
Author(s):  
Kári Sveinbjörnsson ◽  
Kerttu Aitola ◽  
Jinbao Zhang ◽  
Malin B. Johansson ◽  
Xiaoliang Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Ambient Air ◽  
Perovskite Solar Cell ◽  
Ambient Conditions ◽  
Average Efficiency ◽  
High Efficiency Solar Cells

A mixed-ion (FAPbI3)1−x(MAPbBr3)x perovskite solar cell was prepared under ambient conditions with an average efficiency of 17.6%.

Custom 1-D CFD Numeric Model of Single-Cell Scale Sample Holder for Scanning Thermal Analysis

2012 ◽  
Author(s):  
Logan M. Compton ◽  
James L. Armes ◽  
Gary L. Solbrekken
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Latent Heat ◽  
Thermoelectric Module ◽  
Experimental Results ◽  
Sample Holder ◽  
Current Profile ◽  
Scanning Calorimetry ◽  
Numeric Model

Successful cryopreservation protocols have been developed for a limited number of cell types through an extensive amount of experimentation. To optimize current protocols and to develop effective protocols for a larger range of cells and tissues it is imperative that accurate transport models be developed for the cooling process. Such models are dependent on the thermodynamic properties of intracellular and extracellular solutions, including heat capacity, latent heat, and the physical phase change temperatures. Scanning techniques, such as differential-scanning calorimetry (DSC) and differential thermal analysis are effective tools for measuring those thermodynamic properties. It is essential to understand the behavior of the in house fabricated differential-scanning calorimeter given different cooling and warming rates to reassure and validate the obtained experimental results. A 1-D transient CFD code was created in Matlab using Patankar’s theory to not only validate obtained experimental results but aid in optimizing the control system to produce linear cooling and warming rates. A freezing model was also implemented as a subroutine to numerically observe the effect of heat release and absorption of the sample during a run. The numeric model is composed of a multilayer scheme that incorporates a thermoelectric module which provides the primary temperature control along with the micron sized bridge with sample holder and thermocouple. An electric current profile is imported in from either an experimental run to validate results or from an optimization program to determine the optimum electrical current profile for a desired temperature profile. Numeric detection of heat capacity, latent heat, and thermal resistance has also been demonstrated.

Toward All Slot‐Die Fabricated High Efficiency Large Area Perovskite Solar Cell Using Rapid Near Infrared Heating in Ambient Air

2020 ◽  
Vol 10 (37) ◽  
pp. 2001567 ◽  
Author(s):  
Shih‐Han Huang ◽  
Cheng‐Kang Guan ◽  
Pei‐Huan Lee ◽  
Hung‐Che Huang ◽  
Chia‐Feng Li ◽  
...  
Keyword(s):  
Solar Cell ◽  
Near Infrared ◽  
High Efficiency ◽  
Ambient Air ◽  
Perovskite Solar Cell ◽  
Infrared Heating ◽  
Large Area ◽  
Slot Die

scholarly journals Evaluation of cation exchange membrane performance under exposure to high Hg<sup>0</sup> and HgBr<sub>2</sub> concentrations

2019 ◽  
Vol 12 (2) ◽  
pp. 1207-1217 ◽  
Author(s):  
Matthieu B. Miller ◽  
Sarrah M. Dunham-Cheatham ◽  
Mae Sexauer Gustin ◽  
Grant C. Edwards
Keyword(s):  
Cation Exchange ◽  
High Efficiency ◽  
Absolute Humidity ◽  
Elemental Mercury ◽  
Mercury Vapor ◽  
Ambient Air ◽  
Atmospheric Mercury ◽  
Promising Alternative ◽  
Gaseous Elemental Mercury ◽  
High Concentrations

Abstract. Reactive mercury (RM), the sum of both gaseous oxidized Hg and particulate bound Hg, is an important component of the global atmospheric mercury cycle, but measurement currently depends on uncalibrated operationally defined methods with large uncertainty and demonstrated interferences and artifacts. Cation exchange membranes (CEMs) provide a promising alternative methodology for quantification of RM, but method validation and improvements are ongoing. For the CEM material to be reliable, uptake of gaseous elemental mercury (GEM) must be negligible under all conditions and RM compounds must be captured and retained with high efficiency. In this study, the performance of CEM material under exposure to high concentrations of GEM (1.43×106 to 1.85×106 pg m−3) and reactive gaseous mercury bromide (HgBr2 ∼5000 pg m−3) was explored using a custom-built mercury vapor permeation system. Quantification of total permeated Hg was measured via pyrolysis at 600 ∘C and detection using a Tekran® 2537A. Permeation tests were conducted over 24 to 72 h in clean laboratory air, with absolute humidity levels ranging from 0.1 to 10 g m−3 water vapor. GEM uptake by the CEM material averaged no more than 0.004 % of total exposure for all test conditions, which equates to a non-detectable GEM artifact for typical ambient air sample concentrations. Recovery of HgBr2 on CEM filters was on average 127 % compared to calculated total permeated HgBr2 based on the downstream Tekran® 2537A data. The low HgBr2 breakthrough on the downstream CEMs (< 1 %) suggests that the elevated recoveries are more likely related to suboptimal pyrolyzer conditions or inefficient collection on the Tekran® 2537A gold traps.

Analysis of a Latent Heat Storage Device With Radial Fins

2013 ◽  
Author(s):  
Y. Kozak ◽  
T. Rozenfeld ◽  
G. Ziskind
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Latent Heat ◽  
Close Contact ◽  
Thermal Storage ◽  
Ambient Air ◽  
Contact Melting ◽  
Storage Device ◽  
Melting Time ◽  
Cfd Model

Phase-change materials (PCMs) can store large amounts of heat without significant change of their temperature during the phase-change process. This effect may be utilized in thermal energy storage, especially for solar-thermal power plants. In order to enhance the rate of heat transfer into PCMs, one of the most common methods is the use of fins which increase the heat transfer area that is in contact with the PCM. The present work deals with a latent heat thermal storage device that uses a finned tube with an array of radial fins. A heat transfer fluid (HTF) flows through the tube and heat is conducted from the tube to the radial fins that are in contact with the bulk of the PCM inside a cylindrical shell. The thermal storage charging/discharging process is driven by a hot/cold HTF inside the tube that causes the PCM to melt/solidify. The main objective of the present work is to demonstrate that close-contact melting (CCM) can affect the storage unit performance. Accordingly, two different types of experiments are conducted: with the shell exposed to ambient air and with the shell submerged into a heated water bath. The latter is done to separate the PCM from the shell by a thin molten layer, thus enabling the solid bulk to sink. The effect of the solid sinking and close-contact melting on the fins is explored. It is found that close-contact melting shortens the melting time drastically. Accordingly, two types of models are used to predict the melting rate: numerical CFD model and analytical/numerical close-contact melting model. The CFD model takes into account convection in the melt and the PCM property dependence on temperature and phase. The analytical/numerical CCM model is developed under several simplifying assumptions. Good agreement is found between the predictions and corresponding experimental results.

Sign in / Sign up

Export Citation Format

Share Document