Special Issue "Sciences in Heat Pump and Refrigeration"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Energy".

Deadline for manuscript submissions: 30 September 2018

Special Issue Editor

Guest Editor
Prof. Dr. Takahiko Miyazaki

Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga koen, Kasuga-shi, Fukuoka 816-8580, Japan
Website | E-Mail
Interests: heat pump and refrigeration; thermally driven heat pump; air-conditioning; refrigerant; adsorption; desiccant; optimization

Special Issue Information

Dear Colleagues,

Heat pump and refrigeration technologies are matured and have been in practical use for many years. Nevertheless, active research and development in this area is still required because of energy and environmental issues related to heat pumps and refrigeration, such as global warming, the depletion of ozone layer, exhaustion of fossil fuels, etc. The energy efficiency of these technologies has been improving year after year, largely due to the strong efforts made by manufacturers, but the improvements in performance will be marginal if we only rely on the extension of existing technologies. Therefore, it is important to embrace advanced technologies and sciences in the next generation of heat pumps and refrigeration technology in order to achieve breakthroughs in this field. In this context, this Special Issue addresses scientific works in the field of heat pumps and refrigeration. The definition of "science" is left to authors, so it is not exclusive to any particular field of engineering studies. Papers should, however, avoid being technical reports. The subjects include, but are not limited to, new materials, such as functional adsorbents and ionic liquids, for adsorption/absorption heat pumps, new refrigerants with low global warming potential, nanotechnology in heat and mass transfer, computational fluid dynamics analysis, flow visualization in micro-channels, system optimization, and so on.

Dr. Takahiko Miyazaki
Guest Editor

Manuscript Submission Information

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Keywords

  • Next generation heat pump/refrigeration
  • Thermally driven heat pump/refrigeration
  • Desiccant air conditioning
  • Heat and mass transfer enhancement
  • Innovative heat exchangers
  • Low global warming potential refrigerant
  • Visualization
  • Computational fluid dynamics
  • Optimization and dynamic control

Published Papers (10 papers)

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Research

Open AccessArticle A Study on the Improvement Effect and Field Applicability of the Deep Soft Ground by Ground Heating Method
Appl. Sci. 2018, 8(6), 852; https://doi.org/10.3390/app8060852
Received: 25 April 2018 / Revised: 19 May 2018 / Accepted: 21 May 2018 / Published: 23 May 2018
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Abstract
The soft ground in coastal areas should be treated when it needs to be used for the sustainably developed of urban or industrial complex constructions. The ground heating method for soft ground improvement was applied in Eastern Europe in the 1960s, but it
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The soft ground in coastal areas should be treated when it needs to be used for the sustainably developed of urban or industrial complex constructions. The ground heating method for soft ground improvement was applied in Eastern Europe in the 1960s, but it was not widely used due to economic and environmental problems. The author developed a device for improving soft ground using an electric heating pipe. This paper investigates the improvement effect and field application of deep soft ground by the ground heating method using the electric heating pipe. Ground heating increases the temperature of the deep soft ground and increases the tip resistance of the static electronic piezo-cone penetration test. Additionally, the pressure of the pore water decreases because the pore water is evaporated due to the ground heating. As a result of the experiment, it was verified that there was an improvement in the effect of deep soft ground by the ground heating method. With ground heating for 96 h, the tip resistance was increased by 61% at a point 0.35 m horizontally away from the electric heat pipe, 22% at 0.97 m, and 2% at 1.31 m. As a result of the field test, it was found that there were no problems in the power supply of the diesel generator and the control panel. It was easy to install the electric heating pipes in the deep soft ground. However, due to boring, the ground was disturbed and water vapor was discharged through this gap. To minimize the discharge of water vapor, it is necessary to drive the electric heating pipe. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessArticle Exergy Analysis of Serpentine Thermosyphon Solar Water Heater
Appl. Sci. 2018, 8(3), 391; https://doi.org/10.3390/app8030391
Received: 31 January 2018 / Revised: 22 February 2018 / Accepted: 1 March 2018 / Published: 7 March 2018
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Abstract
The performance of a solar hot water system is assessed for heat pump and domestic heating applications. Thermodynamic analysis on a serpentine-type thermosyphon flat-plate solar heater is conducted using the Second Law of thermodynamics. Exergetic optimization is first performed to determine the parameters
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The performance of a solar hot water system is assessed for heat pump and domestic heating applications. Thermodynamic analysis on a serpentine-type thermosyphon flat-plate solar heater is conducted using the Second Law of thermodynamics. Exergetic optimization is first performed to determine the parameters for the maximum exergy efficiency using MATLAB optimization toolbox. Geometric parameters (collector surface area, dimensions, and pipe diameter), optical parameters (transmittance absorptance product), ambient temperature, solar irradiation and operating parameters (mass flow rate, fluid temperature, and overall heat transfer (loss) coefficient) are accounted for in the optimization scheme. The exergy efficiency at optimum condition is found to be 3.72%. The results are validated using experimental data and found to be in good agreement. The analysis is further extended to the influence of various operating parameters on the exergetic efficiency. It is observed that optical and thermal exergy losses contribute almost 20%, whereas approximately 77% exergy destruction is contributed by the thermal energy conversion. Exergy destruction due to pressure drop is found negligible. The result of this analysis can be used for designing and optimization of domestic heat pump system and hot water application. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessArticle Conversion of a Direct to an Indirect Refrigeration System at Medium Temperature Using R-134a and R-507A: An Energy Impact Analysis
Appl. Sci. 2018, 8(2), 247; https://doi.org/10.3390/app8020247
Received: 2 January 2018 / Revised: 30 January 2018 / Accepted: 1 February 2018 / Published: 6 February 2018
Cited by 1 | PDF Full-text (6884 KB) | HTML Full-text | XML Full-text
Abstract
This work presents the experimental evaluation of energy consumption and refrigerant charge reduction when a commercial direct expansion refrigeration system is converted into an indirect system. The evaluation (with R-134a and R-507A) used a commercial cabinet with doors for medium temperature and a
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This work presents the experimental evaluation of energy consumption and refrigerant charge reduction when a commercial direct expansion refrigeration system is converted into an indirect system. The evaluation (with R-134a and R-507A) used a commercial cabinet with doors for medium temperature and a single-stage refrigeration cycle using a semi-hermetic compressor and electronic expansion valve; 24-h energy consumption tests were performed at laboratory conditions for each refrigerant and configuration at three heat rejection levels (23.3, 32.8 and 43.6 °C), maintaining an average product temperature inside the cabinet of 2 °C. The work analyses the impact of the conversion on temperature and pressure indicators, as well as, in the energy performance of each element. For R-134a the refrigerant charge was reduced in a 42.9%, but the energy consumption rose by 22.0%–22.8%; for R-507A the charge reduction was of 32.8% with an increase in energy consumption of between 27.7% and 38.7%. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessFeature PaperArticle Impact of Blockage Ratio on Thermal Performance of Delta-Winglet Vortex Generators
Appl. Sci. 2018, 8(2), 181; https://doi.org/10.3390/app8020181
Received: 29 December 2017 / Revised: 22 January 2018 / Accepted: 24 January 2018 / Published: 26 January 2018
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Abstract
The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (di) called blockage ratio (R
[...] Read more.
The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (di) called blockage ratio (Rb) of 0.28, 0.35 and 0.42 were tested and their performance was compared to that of a longitudinal strip and plain tube under similar test flow conditions. Experiments were conducted over a wide range of flow rates, 3.35 × 10−5–8.33 × 10−5 m3/s, which correspond to 5500 ≤ Reynolds number (Re) ≤ 14,500 in the 14.3 mm i.d. tube. The results revealed that using DWTs dramatically increased the Nusselt number (Nu) by as much as 364.3% and the friction factor (f) by 15.5 times compared with those of a plain tube. Thermal performance (η) increased with a corresponding increase in Rb. The highest thermal performance (η) obtained was 1.4. Showing a notable improvement on the thermal performance of the system, DWTs are proposed as a favorable insert device. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessArticle Dynamic Performance Analysis for an Absorption Chiller under Different Working Conditions
Appl. Sci. 2017, 7(8), 797; https://doi.org/10.3390/app7080797
Received: 4 July 2017 / Revised: 31 July 2017 / Accepted: 31 July 2017 / Published: 5 August 2017
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Abstract
Due to the merits of energy saving and environmental protection, the absorption chiller (AC) has attracted a lot of attention, and previous studies only concentrated on the dynamic response of the AC under a single working condition. However, the working conditions are usually
[...] Read more.
Due to the merits of energy saving and environmental protection, the absorption chiller (AC) has attracted a lot of attention, and previous studies only concentrated on the dynamic response of the AC under a single working condition. However, the working conditions are usually variable, and the dynamic performance under different working conditions is beneficial for the adjustment of AC and the control of the whole system, of which the stabilization can be affected by the AC transient process. Therefore, the steady and dynamic models of a single-effect H2O-LiBr absorption chiller are built up, the thermal inertia and fluid storage are also taken into consideration. And the dynamic performance analyses of the AC are completed under different external parameters. Furthermore, a whole system using AC in a process plant is analyzed. As a conclusion, the time required to reach a new steady-state (relaxation time) increases when the step change of the generator inlet temperature becomes large, the cooling water inlet temperature rises, or the evaporator inlet temperature decreases. In addition, the control strategy considering the AC dynamic performance is favorable to the operation of the whole system. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessArticle Numerical Calculation of the Performance of a Thermoacoustic System with Engine and Cooler Stacks in a Looped Tube
Appl. Sci. 2017, 7(7), 672; https://doi.org/10.3390/app7070672
Received: 3 February 2017 / Revised: 16 June 2017 / Accepted: 27 June 2017 / Published: 30 June 2017
Cited by 1 | PDF Full-text (546 KB) | HTML Full-text | XML Full-text
Abstract
The performance of a thermoacoustic system that is composed of a looped tube, an engine stack, a cooler stack, and four heat exchangers, is numerically investigated. Each stack has narrow flow channels, is sandwiched by two heat exchangers, and is located in the
[...] Read more.
The performance of a thermoacoustic system that is composed of a looped tube, an engine stack, a cooler stack, and four heat exchangers, is numerically investigated. Each stack has narrow flow channels, is sandwiched by two heat exchangers, and is located in the looped tube. In order to provide a design guide, the performance of the system is numerically calculated by changing the following three parameters: the radius of the flow channels in the engine stack, the radius of the flow channels in the cooler stack, and the relative position of the cooler stack. It was found that when the three parameters are optimized, the efficiency of the engine stack reaches 75% of Carnot’s efficiency and the coefficient of the performance (COP) of the cooler stack is 53% of Carnot’s COP, whereas 33% of the acoustic power generated by the engine stack is utilized in the cooler stack. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessArticle Optimal Design of an Air-to-Air Heat Exchanger with Cross-Corrugated Triangular Ducts by Using a Particle Swarm Optimization Algorithm
Appl. Sci. 2017, 7(6), 554; https://doi.org/10.3390/app7060554
Received: 22 March 2017 / Revised: 8 May 2017 / Accepted: 17 May 2017 / Published: 26 May 2017
Cited by 6 | PDF Full-text (3364 KB) | HTML Full-text | XML Full-text
Abstract
Air-to-air heat exchangers with cross-corrugated triangular ducts are widely used in various industrial fields to recover waste heat. The geometric parameters of the heat exchangers greatly affect the performance and total annual cost of these systems. In this study, the effectiveness-number of transfer
[...] Read more.
Air-to-air heat exchangers with cross-corrugated triangular ducts are widely used in various industrial fields to recover waste heat. The geometric parameters of the heat exchangers greatly affect the performance and total annual cost of these systems. In this study, the effectiveness-number of transfer units (ε-NTU) method was utilized to develop the thermal mathematical model, which was verified by comparing it with previous research. The configuration parameters of the heat exchanger were optimized in this study. The particle swarm optimization (PSO) algorithm was applied using both single and multi-objective algorithm. The colburn factor (j factor), friction factor (f factor), and comprehensive thermal hydraulic performance index (JF factor) were considered as objective functions to be optimized using a single objective and multi-objective algorithm. Then, the entropy generation rate and total annual cost were optimized by using a multi-objective PSO algorithm. In addition, to identify the influential geometric parameters, a global sensitivity analysis was performed. The sensitivity analysis showed that the apex angle θ, channel height H, and heat exchanger height Lh influenced the performance and annual total cost of these systems. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessArticle Using Thermal Shock to Inhibit Biofilm Formation in the Treated Sewage Source Heat Pump Systems
Appl. Sci. 2017, 7(4), 343; https://doi.org/10.3390/app7040343
Received: 30 December 2016 / Revised: 16 March 2017 / Accepted: 24 March 2017 / Published: 30 March 2017
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Abstract
Treated sewage source heat pump systems can reuse the waste energy in the treated sewage. However, biofilms in the heat exchangers decrease the system efficiency. This work investigates the feasibility of thermal shock at accessible temperatures in heat exchangers for biofilm inhibition. Bacillus
[...] Read more.
Treated sewage source heat pump systems can reuse the waste energy in the treated sewage. However, biofilms in the heat exchangers decrease the system efficiency. This work investigates the feasibility of thermal shock at accessible temperatures in heat exchangers for biofilm inhibition. Bacillus subtilis biofilms were formed on coupons and in a miniaturized plate heat exchanger. Thermal shocks at different temperatures (50–80 °C) for different exposure times (1–60 min) were used to treat the biofilms. The results showed that thermal shock had a significant bactericidal and biofilm inhibition effect, and the effect was enhanced as the temperature and the exposure time increased. Data fitting of the biomass showed that temperature had a more significant influence on the biofilm inhibition effect than exposure time. The results of the heat exchanging experiments showed that high temperature thermal shock could significantly mitigate the heat transfer deterioration caused by the biofilms, indicating that thermal shock could be used as a viable biofilm inhibition approach for heat exchangers. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessArticle The Effects of Wet Compression by the Electronic Expansion Valve Opening on the Performance of a Heat Pump System
Appl. Sci. 2017, 7(3), 248; https://doi.org/10.3390/app7030248
Received: 9 January 2017 / Accepted: 1 March 2017 / Published: 3 March 2017
Cited by 1 | PDF Full-text (3659 KB) | HTML Full-text | XML Full-text
Abstract
In this study, by controlling the Electronic Expansion Valve opening, the influence of wet compression on a heat pump system was experimentally investigated in different heating conditions. The results demonstrate that the discharge temperature decreased and the mass flow rate increased, due to
[...] Read more.
In this study, by controlling the Electronic Expansion Valve opening, the influence of wet compression on a heat pump system was experimentally investigated in different heating conditions. The results demonstrate that the discharge temperature decreased and the mass flow rate increased, due to quality of the rising liquid droplets. It was also found that the heating capacity and power input of wet compression increased more than that of dry compression, with a superheat of 10 °C. The maximum COP (Coefficient of Performance) exists at a specific quality of ca. 0.94 to 0.90, as the power input in the region of wet compression is proportionally larger than the increase in the heating capacity, according to the decreasing quality. When the Entering Water Temperature of the Outdoor Heat Exchanger was 10 °C, 5 °C, and 0 °C, the COP increased by a maximum of ca. 12.4%, 10.6%, and 10.2%, respectively, in comparison to the superheat of 10 °C. In addition, the superheat at the discharge line is proposed as a proper controlling parameter to adjust the quality at the suction line, by varying the opening of the expansion valve during wet compression. Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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Open AccessArticle Simulation of Hybrid Photovoltaic Solar Assisted Loop Heat Pipe/Heat Pump System
Appl. Sci. 2017, 7(2), 197; https://doi.org/10.3390/app7020197
Received: 10 December 2016 / Accepted: 7 February 2017 / Published: 16 February 2017
Cited by 2 | PDF Full-text (2548 KB) | HTML Full-text | XML Full-text
Abstract
A hybrid photovoltaic solar assisted loop heat pipe/heat pump (PV-SALHP/HP) water heater system has been developed and numerically studied. The system is the combination of loop heat pipe (LHP) mode and heat pump (HP) mode, and the two modes can be run separately
[...] Read more.
A hybrid photovoltaic solar assisted loop heat pipe/heat pump (PV-SALHP/HP) water heater system has been developed and numerically studied. The system is the combination of loop heat pipe (LHP) mode and heat pump (HP) mode, and the two modes can be run separately or compositely according to the weather conditions. The performances of independent heat pump (HP) mode and hybrid loop heat pipe/heat pump (LHP/HP) mode were simulated and compared. Simulation results showed that on typical sunny days in spring or autumn, using LHP/HP mode could save 40.6% power consumption than HP mode. In addition, the optimal switchover from LHP mode to HP mode was analyzed in different weather conditions for energy saving and the all-year round operating performances of the system were also simulated. The simulation results showed that hybrid LHP/HP mode should be utilized to save electricity on sunny days from March to November and the system can rely on LHP mode alone without any power consumption in July and August. When solar radiation and ambient temperature are low in winter, HP mode should be used Full article
(This article belongs to the Special Issue Sciences in Heat Pump and Refrigeration)
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