Auxiliary Heating Research Articles

Nutritional Analysis of Elote Tamales Cooked in a Hybrid-Solar Cooker

Cooking traditional meals using a solar cooker is often challenging because it may require maintaining temperatures of 63 to 180°C for extended periods. A popular Mesoamerican/Mexican dish, “tamale,” is a vapor-cooked corn dough meal/flour wrapped inside corn husk, which may be prepared in a solar cooker. However, its nutritionally rich variety, “elote tamal” prepared from ground fresh corn kernels of tender corncobs with added sugar, fresh milk, and butter, becomes unpalatable under such solar cooking. The initial slow rise in temperature leads to the fermentation of the dough-milk mix and degrades the product. We show that an auxiliary electric heater boosting the temperature at the initial period in an electric-solar hybrid cooker can overcome this limitation. Furthermore, we found significant differences in the total sugar and titratable acidity in the slow-cooked elote tamal. These differences are associated with the incipient fermentation introduced in the milk-containing dough mix during the slow heating stage in traditional solar cooking. We analyzed and compared the protein, fat, moisture content, ash, total sugars, total fibers, titratable acidity, and color of elote tamales prepared under four different cooking conditions. Milk-based tamales under solar cooking require an additional thermal booster at the initial stage to avoid fermentation and eventual loss of quality of the cooked dish. This research is also relevant to the solar cooking of other milk-based meals.

Tritium neutral beam injection on JET: calibration and plasma measurements of stored energy

Neutral beam injection (NBI) is a flexible auxiliary heating method for tokamak plasmas, capable of being efficiently coupled to the various plasma configurations required in the Tritium and mixed deuterium-tritium experimental campaign on the Joint European Torus (JET) device. High NBI power was required for high fusion yield and alpha particle studies and to provide mixed deuterium-tritium (D-T) fuelling in the plasma core, it was necessary to operate the JET NBI systems in both deuterium and tritium. Further, the pure tritium experiments performed required T NBI for high isotopic purity and reduced 14 MeV neutron yield. Accurate power calibrations are also essential to machine safety. Previously on JET there have been a number of questions raised on the NBI power calibration, in particular following the Trace Tritium Experiments (TTEs). Operator activities on the tokamak NBI system, including calibrations, were performed in 2020. Following these activities, a series of plasma experiments were devised to further corroborate the T NBI power by comparing the plasma response to the D NBI power. A series of stationary, L-mode plasmas were performed on JET with different beam combinations used in different phases of the same pulse. By comparing the plasma response for D and T NBI it was possible to corroborate the T NBI power calibration using the D NBI power calibration. The stored energy as measured by magnetic diagnostics, corrected for fast particle stored energy, show that the uncertainty in NBI power calibration in T is comparable to that in D.

Resonance in radio frequency sheath admittance and enhanced impurity emission near the ion cyclotron frequency

Ion cyclotron resonance heating (ICRH) is of considerable interest among all auxiliary heating techniques, because it transfers power directly to ions, targets the high-density core, and involves the cheapest radio-frequency (RF) components. During ICRH operation, RF sheaths form on the ICRH antenna itself, nearby hardware, and far-field surfaces. These sheaths are associated with large hot-spot formation and impurity emissions. This work presents high-resolution numerical modelling of RF sheaths in nuclear fusion scenarios using hPIC2, a Debye-scale particle-in-cell code. The modelling reveals a new RF sheath phenomenon which occurs when the RF is resonant with a species ion cyclotron frequency or harmonic in an oblique magnetic field. This resonance of the RF sheath causes modifications of the energy-angle distributions of the ions impacting on the walls, with consequent increase in wall impurity emission. Due to the 1/R scaling of the magnetic field in a tokamak, such cases are possible on divertor or vacuum chamber surfaces, depending on the geometry of the tokamak and the RF heating scenario. A simple physics interpretation using a driven damped harmonic oscillator is proposed, where the ion sheath transit time plays the role of damping the RF sheath admittance. Critically, the resonance leads to increased ion heat flux at the wall as well as increased physical sputtering, despite a lack of increase in RF rectified sheath potential.

Improving solar dryer performance with automatic control of auxiliary heated air

This research aims to design and test automatic auxiliary heating unit for solar dryer cabinets to improve drying performance. The auxiliary heating unit utilizes an infrared furnace with cooking gas, a fin heat exchanger, and a blower. It is equipped with an automatic control system to regulate the temperature of the dryer. An agricultural product used in the experiment was fresh pineapple slides. The experimental test was divided into three cases; using (i) solar dryer, (ii) hot air dryer from the automatic auxiliary heating unit and, (iii) combined solar dryer with auxiliary heating unit. Temperature of the automatic auxiliary heating unit was controlled at 55.0 ± 3.0 °C and the air flow speed in the dryer cabinet was 1.5 ± 0.2 m/s. The thermal output from the automatic auxiliary heating unit was more than 2700 W. From the tests, it was shown that the drying time could be reduced to 12.5 h from 32 h, when the solar dryer was combined with the automatic auxiliary heating unit, compared to using only solar dryer. Dried pineapple products showed good quality. Comparative analysis of CIELAB color properties indicated low pigmentation. From a simple economic analysis, return on investment was less than 3.0 months. The use of automatic auxiliary heating units to the solar dryer enabled reduction in drying time and improved product quality.

Investigation of the thermal performance and environmental impact of a forced circulation solar water heating system during the heating season

A thermal analysis of a forced circulation solar water heating system (SWHS) was carried out. Three different models were analyzed: SWHS without an auxiliary heater, SWHS with an auxiliary heater, and electric heater only. The study was carried out for the province of Mersin-Turkiye. Flat plate collectors with different structural properties were used in simulations, the best results were obtained with the collector with black chrome absorber coating. This system met 55% of the hot water requirement on the design day without requiring any auxiliary heater. During the season, 18.7% of hot water needs were met in January, 20.42% in February, 37.6% in March, 31.2% in November, and 20.5% in December. SWHS with an auxiliary heater, consumed 1130.3 kWh of electrical energy during the heating season, resulting in 540.3 kg of CO2 emissions. 33 % reduction in greenhouse gas (GHG) emissions is achieved with this system compared to a base system powered by electricity only. The hot water use profile is an essential factor in the design of the SWHS. Since the systems using fossil fuels can meet the needs of the users, energy storage techniques must be adapted to the SWHS to be an alternative.

Design of power and phase feedback control system for ion cyclotron resonance heating in the Experimental Advanced Superconducting Tokamak

Ion cyclotron range of frequency (ICRF) heating system is an important auxiliary heating method in the experimental Advanced Superconducting Tokamak (EAST). In EAST, several megawatts of power are transmitted with coaxial transmission lines and coupled to the plasma. For the long pulse and high power operation of the ICRF waves heating system, it is very important to effectively control the power and initial phase of the ICRF signals. In this paper, a power and phase feedback control system is described based on field programmable gate array (FPGA) devices, which can realize complicated algorithms with the advantages of fast running and high reliability. The transmitted power and antenna phase are measured by a power and phase detector and digitized. The power and phase feedback control algorithms is designed to achieve the target power and antenna phase. The power feedback control system was tested on a dummy load and during plasma experiments. Test results confirm that the feedback control system can precisely control ICRF power and antenna phase and is robust during plasma variations.

Heat transfer analysis and structure optimization of unit of flat plate based on a response surface test: An experimental teaching perspective in higher education

The Flat Plate is a common component of solar photothermal experiment and an important teaching tool in the new energy teaching experiment. Aiming at the problem of low heat transfer efficiency and poor teaching effect of traditional roll-bond flat plate, this paper conducts a numerical simulation study on the flow and heat transfer characteristics in the ”Y” -shaped channel unit. The four parameters of width, length, runner parting angle and runner width are used as control variables to optimize the heat transfer structure of the runner. Taking the ”Y” -shaped channel unit as the research object, the finite element model of conjugate heat transfer was established by using Fluent. Through numerical simulation analysis, it is concluded that in the defined length and width interval, the thermal efficiency increases first and then decreases with the increase of the length of the heat transfer unit, and the pressure drop coefficient has a negative correlation with the length and width of the unit. The runner width has a positive correlation with the thermal efficiency and a negative correlation with the pressure drop coefficient. Then, according to the Box-Behnken principle, a response surface test for heat transfer optimization was designed, an optimization model with thermal efficiency and pressure drop coefficient as the response indicators was established, and the optimal element design scheme was determined. The optimization results show that when the subunit length of the heat transfer runner is 40 mm, the width is 35 mm, the parting angle is 60°, and the runner width is 11 mm, the thermal efficiency of the ”Y”-shaped runner is 0.782, and the pressure drop coefficient is 0.121. Finally, a direct-expansion solar auxiliary heating system is built to test the scheme. The experimental results show that the collector using the ”Y”-shaped channel shows better solar energy utilization, which increases the COP of the system by 15.2%. This study provides a reference for the design and optimization of other types of flow channels to improve the heat transfer efficiency of the roll-bond flat plate. Through optimization, the system has innovated in the experimental mode, effectively made up for the shortcomings in the training of new energy professionals, and enriched and developed the experimental theory system and teaching methods of higher education of energy and power majors.

Multi-hole coupling power monitor with tapered sub-waveguide for dual-frequency high-power gyrotron

In magnetically confined fusion plasmas, a gyrotron is an essential auxiliary heating device for generating and sustaining plasma through electron cyclotron resonance heating owing to its ability to generate high-power microwaves. Microwaves emitted from a gyrotron are often transmitted through waveguides, and the transmitted power is monitored by a power monitor with a multi-hole directional coupler at the miter bend of the transmission line. Recently, a high-power dual-frequency gyrotron has been installed and operated in the Large Helical Device. A power monitor with good sensitivity to multiple frequencies is required to monitor the power transmission of the different frequencies at the same transmission line. In order to realize the power monitor, which can couple with the multiple-frequency microwaves, we focused on a sub-waveguide shape in the power monitor and investigated the influence of the tapered sub-waveguide by conducting electromagnetic simulations using a simple model. We also performed the high-power test using a power monitor with a tapered sub-waveguide. The experimental result was different from the simulation, but enough receiving power was obtained at both 116 and 154 GHz.

Engine preheating under real-world subfreezing conditions provides less than expected benefits to vehicle fuel economy and emission reduction for light-duty vehicles

Six light-duty vehicles, both gasoline- and diesel-fueled, were driven a prescribed 13.8 km route in a real-world low-traffic environment under Finnish subfreezing winter conditions (−28 ... −10 °C). Cold starts, hot starts, and starts with different preheating strategies were used. Fuel consumption and emissions of particles and nitrogen oxides (NOx) were examined by a chasing method with a mobile laboratory. Both electric preheaters (0.3–1.2 kW) and fuel-operated auxiliary heaters (5 kW) were used in the experiments where a cold engine was preheated before starting. While most vehicles showed potential for reducing fuel consumption and emissions of particles (PM), black carbon (BC), and NOx during hot starts compared to subfreezing-cold starts, the benefits of preheating were relatively small and limited to only a few vehicles. The fuel consumption for the 13.8 km drive decreased less than 4% with one gasoline vehicle and one diesel vehicle by preheating. These two vehicles are both equipped with a fuel-operated auxiliary heater, and taking the fuel consumption of the heater during preheating into account leads to about 30% higher total fuel consumption, canceling the preheating benefit out. These two vehicles also showed the largest reductions in PM, BC, and NOx emissions achieved with preheating, e.g., the PM emission reductions being 72% (the gasoline vehicle) and 24% (the diesel vehicle). Whereas the NOx emission reduction for this gasoline vehicle was 41% when considering only the drive, it decreases to 15% when the NOx emissions from the auxiliary heater during preheating are also taken into account. High particle number (PN) emissions from all vehicles and NOx emissions from the diesel vehicles were detected. The PN emissions of particles larger than 23 nm were up to 2 orders of magnitude higher and the NOx emissions up to a factor of 21 higher than the corresponding limits in the European regulations for type-approval of new vehicles. The PN emissions did not depend on the start types; thus, no benefits to reduce them with preheating were detected. The limit-exceeding PN emissions are partially explained with the used measurement method for PN taking both nonvolatile and semivolatile particles into account, whereas the regulations take only the nonvolatile particles into account. The PM emissions were also observed to consist mostly of semivolatile material in most of the cases, organics being the main component of the semivolatile material.

Analysing the effects of heating and gas puffing in Proto-MPEX helicon and auxiliary heated plasmas *

The Material Plasma Exposure Experiment (MPEX) is being constructed at Oak Ridge National Laboratory to investigate critical fusion reactor issues, such as plasma–material interactions (PMIs) under reactor-relevant conditions and time scales. The linear device Proto-MPEX was used as a test bed to address anticipated research and development issues associated with heating scenarios and establish the physics basis for MPEX. The SOLPS-ITER code suite has been applied to understand plasma and neutral transport in Proto-MPEX and to increase confidence in predictive simulations for MPEX. Coupling between COMSOL and SOLPS is performed to implement a 2D electron heating profile of the helicon source. The simulations show reasonable agreement with the experimental data for plasma with helicon and auxiliary electron cyclotron heating (ECH). Both Bohm and constant diffusion (D: 0.5 m2 s−1 and : 1 m2 s−1) simulations show similar levels of agreement with respect to the sparse experimental data available, assuming a few per cent impurity concentration. ECH significantly increases the target electron temperature, however, the target electron density is reduced compared to helicon-only heated plasmas due to an increase in flow velocity and radial losses. The simulations show that further increasing the ECH power results in an increase in the target electron density due to increased recycling flux and ionization. The results indicate that ECH significantly enhances the target heat flux, with ECH power of 50 kW increasing the target heat flux from 0.4 to 17 MW m−2. It is found that a small amount of gas puffing (GP) near the target plate can further increase the target heat fluxes at the higher ECH power cases, but the target heat flux is reduced at higher GP conditions due to a significant reduction in electron temperature via radiation. ECH and GP scenarios can generate a higher target flux, facilitating improved PMI studies with more reactor-relevant plasma conditions.

Effect of operating parameters on the performance of rotary desiccant wheel energized by PV/T collectors

The main energy input of a desiccant air conditioning system is the low-quality thermal ener-gy required for regeneration, which can be obtained from waste heat, geothermal resources or solar energy. Regeneration thermal energy can be produced as well as energizing components such as fans, pumps, auxiliary air heaters, and control elements of the system by using pho-tovoltaic-thermal solar collectors (PV/T). In this study, parametric analyzes were performed to investigate the effect of regeneration temperature and air frontal velocity on the tempera-ture and dehumidification performance of a solid silica-gel desiccant wheel and on the wa-ter-cooled PV/T collectors used to provide the regeneration thermal energy. The regeneration temperature was varied between 50 and 70°C, and air frontal velocity between 1.3 and 4.1 m/s. The analyzes show that the dehumidification efficiency increases from 13.94% to 33.04% as regeneration temperature increased from 50°C to 70°C at 1.3 m/s air frontal velocity at which dehumidification efficiency is maximum. At 4.1 m/s air frontal velocity, the required regener-ation thermal energy is maximum and increases from 49.64 kW to 132.48 kW at the same re-generation temperature change. The low regeneration temperature resulted in desirable latent performance and undesirable sensible heat transfer performance in DEW. Finally, considering the whole system, it was concluded that the optimum regeneration air temperature for the performance parameters is 60°C.

Energy and exergy-based threshold setting for the auxiliary heating source of a hybrid solar/IR drying system

In special case of spirulina drying, the energy and exergy investigations were performed for a pure solar dryer and a hybrid solar/infrared (IR) drying system. For three drying temperatures 40, 50 and 60 °C, the specific energy consumption (SEC) and energy utility ratio (EUR) were evaluated and it was found that the maximum contribution of IR to the drying process was at 40 °C, in which SEC was reduced by 12.18 % and EUR was increases by 14.4 %. But at higher temperatures, negligible contribution of auxiliary heat source was found and less fraction of supplied power was used for removing the water content of the samples. The variation of exergy efficiency was also evaluated at different temperatures, and it was noted that the hybrid dryer had the best performance at 40 °C, while the conventional solar dryer showed better exergy efficiencies at 50 °C and 60 °C. As a result, a convenient criterion was established for optimum use of IR source in a hybrid system. Uncertainty analysis was performed.

Development and evaluation of a hybrid smart solar dryer.

A hybrid smart solar dryer (HSSD) based on indirect forced convection and a controlled auxiliary heating system was developed, fabricated, and tested to be convenient for sunny and cloudy weather conditions. The achievements of the developed dryer focus on controlling the temperature of the dryer, increasing the drying rate, reducing energy consumption, and providing high-quality products. The HSSD was tested and evaluated for drying basil and sage herbs at 30, 40, and 50°C. The results showed that the fresh basil and sage leaves of 1kg with a moisture content of 84.7% and 75.53% (wet basis) were dried within 58, 46, 32 and 38, 28, and 20h at 30, 40, and 50°C, respectively. Correspondingly, the traditional drying methods achieved 96h outdoors and 144h indoors at room temperature. The average of the fabricated flat-plate solar collector efficiency (thermal efficiency, ηfpsc ) was ranged from 49.18%±9.52% to 66.02%±2.8%. The highest drying rates were achieved with the HSSD method. Moreover, the HSSD method led to a remarkable saving in energy with values ranging from 25.54% to 77.1% versus the traditional drying methods. While the best quality in terms of essential oil content and microbial load for the dried basil and sage herbs was achieved by the HSSD at 40°C. Finally, the HSSD is a promising energy-efficient method where it can save 70% of energy consumption, thus reducing the carbon footprint of drying processes, and providing higher quality products compared to the conventional methods.

Dynamic characteristics and energy efficiency evaluation of a novel solar seasonal thermal storage - heating system

This paper proposes solar seasonal thermal energy storage system compounded with long-term and short-term energy storage tanks for a single-family dwelling, which using assisted water source heat pump to further improve the systems stability. With the objective of improving the solar energy utilization efficiency and reducing the primary energy consumption, the dynamic simulation model of the “heat collection-heat storage-heat supply” system under the non-stationary boundary conditions throughout the year is established. The energy transfer and conversion law of each subsystem and the dynamic operation characteristics are analyzed through simulation method. The system cooperative control strategy is proposed and parameter optimization is carried out. Results indicate that the annual heat collection efficiency of the water source heat pump composite system has been improved by 2.2 % compared with the electric auxiliary heating system. Meanwhile, the heat storage efficiency and the solar energy guarantee rate increased by 5.8 % and 8.3 %, respectively. Moreover, the optimal water source heat pump composite system not only improves energy efficiency and achieves the cost savings compared with the electric auxiliary heating system, but also reduces carbon dioxide emission by 10.3 %, which have great advantages for energy saving and emission reduction.

Parallelization of a 3D FDTD code and physics studies of electromagnetic wave propagation in fusion plasmas

Numerical codes for electromagnetic wave propagation in magnetized plasmas are mainly based on frequency-domain asymptotic methods, which provide a fast solution and are thus valuable for experiment design and control applications. However, in several cases of practical interest (e.g. mode conversion), these tools run close to their limits of validity and should be compared to full-wave solutions. The code RFFW solves Maxwell's equations with the finite-difference time-domain method in 3D geometry, for scenarios involving high-frequency waves with arbitrary electric field spectrum in plasmas with axisymmetric equilibrium. In fusion-related problems, the code may conduct investigations of wave propagation and absorption relevant to auxiliary plasma heating and current drive, reflectometry and instability control. The code has been parallelized with a hybrid OpenMP-MPI scheme, which has allowed exploiting the much larger processing power and memory of current-day supercomputers. In this work, we present the main aspects of the physics implemented in the code, and also refer shortly to the parallelization scheme. Furthermore, we show results that exhibit the strong scaling performance of the code, and examine cases of electron-cyclotron heating application in medium-sized tokamaks.

Modeling of a hybrid power system integrating solar radiation and syngas combustion energy

AbstractThis study aims to model a hybrid power system that can continuously generate power by switching between two possible thermal sources: solar radiation and combustion energy from synthesis gases. The system comprised a hybrid energy receiver, solar dish, Stirling generator, fluidized‐bed gasifier, boiler, and water tank. The solar dish was a dual‐reflection solar collector that used two mirrors, namely the main and subordinate concentrators, to concentrate a broad expanse of solar radiation onto a hybrid energy receiver. The fluidized‐bed gasifier was employed for the production of synthesis gases. The synthesis gases were combusted to provide an auxiliary heat source for the Stirling generator when solar radiation was insufficient. Solar radiation or combustion energy was alternatively introduced into the hybrid energy receiver and converted to power by a 1‐kW‐scale beta‐type Stirling engine. In this manner, the Stirling generator could serve as a base‐load power plant regardless of solar conditions. In this study, a complete quantitative model was developed for a demonstration plant by incorporating thermodynamic and dynamic models of the beta‐type Stirling engine, a ray‐tracing model for the dual‐reflection solar dish, an energy model of the hybrid energy receiver, and experimental data for the fluidized‐bed gasifier. The performance response of the system during switching between solar radiation and combustion energy was predicted. The modeling results indicated that switching can result in a continuous power output ranging from 600 to 1200 W. With synthesis gas combustion as the auxiliary heat source, the hybrid Stirling power system can be operated continuously, and the overall power output is increased by 109.82% compared to a conventional concentrated solar power system that only uses solar radiation.

Cooling and Heating a Greenhouse in Baghdad by a Solar Assisted Desiccant System

Modeling the microclimate of a greenhouse located in Baghdad under its weather conditions to calculate the heating and cooling loads by computer simulation. Solar collectors with a V-corrugated absorber plate and an auxiliary heat source were used as a heating system. A rotary silica gel desiccant dehumidifier, a sensible heat exchanger, and an evaporative cooler were added to the collectors to form an open-cycle solar assisted desiccant cooling system. A dynamic model was adopted to predict the inside air and the soil surface temperatures of the greenhouse. These temperatures are used to predict the greenhouse heating and cooling loads through an energy balance method which takes into account the soil heat gain. This is not included in conventional methods. The results showed satisfactory agreement with published papers. Also, the results of heating and cooling loads obtained revealed good agreement with those obtained from conventional methods when the soil heat gain is included. Two identical collectors in series of total area of 5.4m2 were employed as a heating system which provides an outlet air temperature of 30 o C at air mass flux of 0.06 kg/s.m2 at midday in January. While, a 65 oC outlet air temperature was achieved for the same mass flux at midday in August. The desiccant cooling system was operated in five operating modes; the ventilation mode and four recirculation modes with 20%, 50%, 70%,and 90% recirculation. The simulation results showed that a regeneration temperature of 60-70 o C is satisfactory for a cool supply air temperature of about 19.5 o C. Also, it was noted that 20-30 % recirculation of return air would result in suitable indoor greenhouse conditions for most periods of system operation. In addition, the coefficient of performance COP of the system was high compared with the conventional vapor compression systems.

Feasibility and investigation of residential HVAC system with combined ground source heat pump and solar thermal collectors in different climates of Iran

Geoexchange is one of the most energy-efficient, environmentally clean, and cost-effective space-conditioning systems available on the market. Seasonal storage of solar energy in geothermal boreholes is sharply interesting as a means of heating and cooling in buildings with different applications. In this study, a closed-loop geo-exchange and solar thermal system with two different heat exchangers are examined in an energy-efficient house. TRNSYS, a simulation software tool, was used to model the yearly performance of the hybrid ground-source heat pump (GSHP) system. Two different types of ground heat exchangers, e.g., tube-in-tube and U-tube were employed. The mass flow rate through the heat exchangers and the solar collector was examined to choose the best scenario for each of them. The economic benefits of a gray water heat recovery system and solar collector were studied; the results show that 517 and 536 US Dollars/Year can be saved from each of them, respectively. System performance analysis was carried out in different cities with various climates in Iran. Moreover, a complete economic assessment was evaluated for all cases. The results show that for the same inlet water temperature to GSHP, the tube-in-tube heat exchanger can pass 45% more flow than the U-tube heat exchanger for the same size as the HP. Furthermore, in the absence of the solar collector, a 2.7 × 108 kJ increase was conducted in the auxiliary heater component yearly. Finally, four different climates were evaluated for the launching of the GSHP system with a solar thermal collector. The hot and dry climate with 27 °C fluid inlet to a heat pump, a total borehole depth of 220 m, and an initial cost of $ 25,047 was selected as the most appropriate weather conditions for launching the system in Iran.

Performance of a solar greenhouse-biogas hybrid dryer for dehydration of water hyacinth (Eichhornia crassipes)

The development of a solar greenhouse dryer combined with an anaerobic digester for biogas production can reduce carbon emissions and create zero waste. This paper presents the performance of a solar greenhouse biogas dryer (SGBD) that burns biogas to supplement the drying of water hyacinth. The SGBD has an overall efficiency of 87% for 100 kg of fresh water hyacinth. The auxiliary heating system enabled the SGBD to achieve drying temperatures of 24.5 to 45.0 degrees during cloudy and rainy days and produce high quality dried products. There was a fivefold increase in drying capacity and a reduction in drying time of six hours (38%) using the SGBD. End users of the dried product judged it to have improved consistency in color and shape. The SGBD cost less than US$3800 to build with a payback period of five months. This design demonstrates a low-cost and simple technology for small businesses.

Performance Improvement of a Solar-Assisted Absorption Cooling System Integrated with Latent Heat Thermal Energy Storage

Phase change materials (PCMs) have emerged as promising solutions for latent heat thermal energy storage (LHTES) systems, offering considerable potential for storing energy derived from renewable sources across various engineering applications. The present study focused on optimization of solar cooling system by integrating LHTES with different PCM tank configurations. TRNSYS simulation software was selected for the study, and the collected experimental data from laboratory system prototype were used for system validation. The results indicate that the use of PCM led to a noteworthy decrease of 6.2% in auxiliary energy consumption. Furthermore, the time during which the heat carrier temperature flow exceeded 90 °C from the storage tank to the auxiliary fluid heater was extended by 27.8% when PCM was utilized compared to that of its absence. The use of PCM in LHTES is more effective under variable weather conditions. On the day when changes in weather conditions were observed, around 98% of the cooling load was provided by produced sun energy. The results of the research can be used to optimize the solar cooling system, which will help reduce the environmental impact of cooling systems running on non-renewable fuels.