Indirect Heating System Research Articles

The Nutrient Content of Litter and Manure from Different Poultry Systems—Updating and Establishing the Nutrient Profile

Representative samples of litter and/or manure from 12 of the most common poultry systems were collected and analysed to provide an accurate nutrient profile from each system. For many systems (turkeys, broilers under indirect heating systems, and pullets), there were no previous values with which to compare composition, but for other systems (broiler breeders and layers), nitrogen and phosphate content were lower as a result of changes in diet and advancements in genetics and management. Nitrogen and phosphate output per 1000 birds was calculated for each system using analysed values for nitrogen and phosphate and measured litter/manure output. Due to a lack of data, it was not possible to compare the nutrient profile of all systems with published values, but where this was possible, some important differences were apparent. For example, the nitrogen and phosphate contents of BB (0–18 weeks) litter were 31% lower and 73% higher than current standard values. Similar differences were also observed for BB (18–60 weeks) (26% lower in nitrogen and 51% higher in phosphate). Turkey litter was found to contain 14% less nitrogen and 37% less phosphate than standard values. Litter from pullet systems contained higher levels of DM (72%), nitrogen, and phosphate than standard values. Litter from free range laying systems also contained higher DM (46%), nitrogen, and phosphate than standard values. This information will be useful in updating environmental legislation and ensuring that poultry producers are able to calculate accurate nutrient management plans for their enterprises. This study also established relations between litter/manure dry matter (DM) and nutrient profile, meaning that this simple measured parameter can be used to predict nutrient profile. The strongest relations were observed between DM and N (R2 = 0.65), DM and phosphate (R2 = 0.53), and DM and MgO (R2 = 0.69). The weakest relation was observed between DM and WSP content (R2 = 0.21), although still significant (p = 0.046). It was concluded that it is necessary to consider the relation within individual systems when using DM as a predictor of nutrient profile rather than using a combined system approach. The water-soluble phosphorus (WSP) content of litter/manure was determined and a baseline was established for each production system. It was also shown that DM is positively related (p < 0.05) to WSP content. This will be important for future legislative compliance based on the WSP content of litter/manure.

A pilot scale study on the effects of various temperature and time conditions on milk quality using direct and indirect heating systems

Effects of various heating temperatures (124, 129, 134, 140 or 143 °C) and holding times (1 and 4 s) on milk quality using direct and indirect heating systems at pilot scale were investigated. Vitamin degradation was observed for both direct and indirect heating and the degradation increased with increasing temperature and holding time, however, no difference could be seen between heating systems. Slight increase in pH and decrease in ionic calcium for direct heating occurred. An increase in fat globule size and aggregate formation were noted for direct heating with more pronounced effects with increasing temperature. Physical stability of milk was unaffected on day of production; however, after 28 days of storage instability was more apparent for indirect heating. No effect of heating system was observed on colour. This suggests that heating may influence milk quality, however, no clear differences between direct and indirect heating were observed for the quality parameters investigated.

Suppressing pre-hydrolysis in TiO2 manufacturing: Design optimization of an indirect heating hydrolysis system

The particle size of TiO2 is critically influenced by the operation of the hydrolysis process. Failure to achieve uniform particle size during hydrolysis can have significant repercussions on subsequent processes, such as washing, reduction and bleaching procedures, ultimately leading to the production of unusable final products. The primary goal of this study is to suppress pre-hydrolysis, which is a factor that impedes the formation of uniform particles during the hydrolysis procedure. To overcome this issue, the researchers designed an indirect heating system to mitigate the pre-hydrolysis phenomenon. For designing indirect heating system, multiphase Computational Fluid Dynamics (CFD) simulations were performed. The proposed optimized design was then implemented and tested in the actual field. The success of the field test was evaluated through settling value tests conducted on the hydrolyzed solution, and the uniformity of particle size was analyzed using Transmission Electron Microscopy (TEM) images, Scanning Electron Microscope (SEM) and Microtrac. The findings of this study demonstrate the effective application of the developed multiphase CFD simulation in enhancing the hydrolysis process for the production of anatase titanium dioxide particles. This successful integration demonstrates the application of mechanical engineering techniques in the fields of chemical engineering.

Modeling and Simulation of Indirect Collector Solar Hot Water Heating System Based on TRNSYS

The use of solar energy is one of the important ways of clean energy heating in rural areas in the north, and the collector solar water heating system is an effective way to use solar energy. This paper takes a typical single residential house in a rural area of Shenyang as a research case to design an indirect collector solar hot water heating system. Based on the meteorological data of the winter heating period (November 1 - March 31 of the following year) in Shenyang, TRNSYS software was used to research the heat collection efficiency and scheme design of the heating system. The research results showed that: 1) The best material of the heat exchange coil of the hot water storage tank in the solar water heating system of the indirect collector is stainless steel with a thickness of 0.8mm; 2) The optimal installation angle of solar collectors in Shenyang is 55°; 3) The optimal area of the heat exchanger coil in the hot water storage tank is 4.40m2.

ЕНЕРГОЗБЕРЕЖЕННЯ У ТЕХНОЛОГІЯХ СУШІННЯ ЗЕРНА: ПЕРСПЕКТИВНІ ТЕХНІЧНІ ТА ТЕХНОЛОГІЧНІ РІШЕННЯ

Summary The purpose of the work is to research promising technical and technological solutions for energy saving and the use of alternative energy sources in grain drying technologies. Methods and materials. The obtained results are based on the operational and analytical evaluation of mine-type dryers with hybrid heat supply systems, the technological principle of their operation, grain drying processes and energy saving indicators. Results. Studies of energy saving processes in grain drying technologies have established that today the use of grain dryers with hybrid heat supply systems is relevant, subject to the introduction of advanced technical and technological solutions into their design – cross-flow air and heat recovery systems, built-in heat generator, high-performance production and heating agent consumption systems, etc. In the design of such dryers, it is possible to use all common heat sources: gas, oil, biofuel and hot water radiators, as well as direct and indirect grain heating systems. To obtain heat from biofuel, appropriate technological equipment is required, the function of which is performed by bio-heat generators and complexes based on them. Heat generator complexes of the hybrid type, which burn bio-raw materials and natural gas, to increase the productivity of heat agent formation, additionally have heat exchangers for obtaining hot air in their composition, which can work both autonomously and in tandem with gas burners, which makes it possible to significantly save on energy resources. Conclusions. Technological solutions for the use of mine-type grain dryers with hybrid heat supply systems, which are able to work on solid biofuel, which is a secondary product of agricultural and forestry production, and ensure its burning with specialized technological equipment - bioheat generators, make it possible to partially abandon the traditional energy carrier (natural gas), reduce specific fuel consumption and thus achieve energy savings in the production of heating agent. Key words: grain dryer, heat generator, solid biofuel, combustion and drying processes, heating agent, energy efficiency, grain drying.

Trombe walls with porous medium insertion and their influence on thermal comfort in flats in Cusco, Peru

The Trombe wall is a passive indirect heating system which should be used in Cusco, Peru to improve thermal conditions against the typical frosts and low temperatures during winter in the high Andean regions. Due to this problem, the use of a modified Trombe wall with insertion of porous medium is proposed to improve thermal comfort in flat buildings in Cusco. This research aims to analyse and compare the performance of dwellings without Trombe wall, with traditional Trombe wall, and with Trombe wall with glass and plastic pellets insertion in thermal comfort improvement. Autodesk® CFD was used to simulate and analyse the system. The simulation was performed with three prototype flats (55 m2, 75 m2 and 95 m2) for six months of the year. From the results obtained, the level of thermal comfort in the traditional scenarios is low with an average PMV of -1.86, in the scenarios with Trombe wall is good and in the scenarios with Trombe wall with insertion of porous medium is slightly better than the previous one, reaching an average PMV of +0.10 and a temperature of 21.90°C. The study carried out is important because it represents an efficient eco-sustainable heating alternative that improves the thermal comfort sensation in houses during the coldest months of the year.

Performance Investigation of Ethiopian Local Drinking Alcohol Distillation System Using Solar Dish Concentrator

In Ethiopia, in addition to the large quantity of biomass consumption per year for daily cooking, production of the traditional local “Areke” consumes large amounts of fire wood which further accelerates deforestation. This study introduces solar-based technology for distillation of the local “Areke” using an indirect heating system. A solar parabolic dish collector with an aperture diameter of 0.9 m and an improved truncated cone cavity absorber were installed. The heat transfer process is governed by the principle of natural circulation, boiling, and condensation between a receiver and a distillation column. The experiment was conducted in Debre Birhan city at 20°C ambient temperature and atmospheric pressure of 0.722 atm. The surface temperature of the truncated cone cavity absorber attained a maximum temperature of 300.3°C, and the thermal efficiency attained by the collector was 54.6%. The production efficiency of the solar thermal local alcohol “Areke” distillation system was found to increase by 1.67% compared to the traditional firewood distillation system.

Thermal evaluation of an indirect air heating system using solar collectors

One of the current problems is the use of energy obtained from fossil fuels, especially due to the emission of greenhouse gases. An option to replace fossil fuels is the use of alternative energies such as solar or wind energy. The objective of this work is to carry out a thermal and energy analysis of an indirect air heating system that receives energy through solar collectors that operate with water as the thermal fluid used in a food dehydration system, in order to know the efficiency of the system and therefore, make improvements to the circuit, in addition to the characterization of the water storage tank of the system, obtain the amount of energy that can be provided and the behavior of temperatures at different operating flows. According to the methodology, the temperature profile was obtained inside the hot water tank in two modes of operation (heating and energy extraction) reaching temperatures of 50 to 70 ° C, where the optimum temperature for drying is found and in turn reaching an efficiency 84%, compared to a conventional drying system that uses LP gas.

Developing the new industrial flatbread baking system using numerical technique to increase the product quality

AbstractBread is one of the most important food sources for consumers, especially in developing and underdeveloped countries. Large quantities of bread are wasted every year because different factors affect the quantity of waste products include flour quality, bread production technology, and the storage condition of the bread. The objective of this study was to improve existing systems and developed the new flatbread industrial baking machine to increase product quality and product storability. Therefore, a rotary bread baking machine with an indirect heating system was designed, and the heat exchangers of the machine were simulated. The results of the simulation were utilized to investigate the uniformity of airflow velocity inside the exchanger and the distribution of heat on the dough on the baking bed. After achieving the most effective design, the exchangers were constructed and installed inside the baking machine. Bread baking experiments with the developed machine and the existing conventional machines were conducted to evaluate the instrumental, sensory, and staling characteristics of the produced flatbreads from different baking machines. The results indicated that the sensory qualities of the bread produced with the indirect heating system in the present study as well as uniformity of baking and sensory acceptability were superior compared to the bread produced from the conventional industrial machines with direct heating systems (with a total sensory score of 5.09 vs. 4.54).Practical ApplicationsIn this research, a superior flatbread baking machine with indirect heat was designed, constructed, and evaluated. The flatbread baked with the indirect heating system had better quality scores and a longer shelf life compared to the flatbread baked with the direct heating system. This type of the flatbread lasted more than 168 hr without mold and it was the best choice for longer‐term storage purposes and for the reduction of food waste. Also, bread prepared using the new machine was free of any contaminants such as polycyclic aromatic hydrocarbons.

CFD investigation of a vertical annealing furnace for stainless steel and non-ferrous alloys strips – A comparative study on air-staged & MILD combustion

A 3D CFD modelling approach of a vertical high temperature furnace in a bright annealing line for stainless steel is presented in this study. The observed line has a maximum production rate of 4.5 tonnes per hour and an overall thermal input of 1.5 MW which is provided by gas burners. The muffle furnace is an indirect heating system equipped with flameless burners, which can operate at nominal power and in off-design. The burners are arranged in four heating zones, which can be controlled separately. Pure hydrogen is used inside the muffle as protection gas around the metal. The metal strip is modelled as a highly viscous fluid with temperature-dependent properties including the specific heat, thermal conductivity and emissivity. Good accordance with measurements from an industrial line was achieved with several values from furnace thermocouples and the transient heating characteristic of a selected strip dimension, thus, demonstrating the applicability of the CFD model for the present investigations. Further simulations were performed with air-staged combustion for an evaluation of combustion and furnace efficiency as well as the thermal load on the furnace’s components. It was found that the efficiency decreased by about 0.5% using flameless combustion. The results also showed a decreased peak temperature of about 1155 °C and a reduced heat flux of about 23.3 kW/m2 (−5%) on the muffle when Moderate or Intense Low oxygen Dilution (MILD) combustion is applied. The present methodology presents an efficient approach for investigation and optimization of indirect heated muffle type furnaces.

OPTIMASI KONSENTRASI ETHYLENE GLYCOL FLUIDA KERJA PADA PERANCANGAN PARABOLIC TROUGH CONCENTRATOR DENGAN REPLEKTOR

An excellence innovation for reducing greenhouse gases are done by developing a new water heater model for household applications. The application of the new model water heater by utilizing Parabolic Trough Concentrator with an indirect heating system uses heat transfer fluid able to improve the reliability of water heater compared to the thermosyphon model. Optimization for the new model is done by enhancing the reflector material and also heat transfer fluid. The experiment is done by applying the same standard measurement in order to set an adequate data for each model. The optimal reflector for the system to concentrating the solar power is polymer substrate as the fluid heated faster. The water-based solution with ethylene glycol 50:50 (v/v) for heat transfer fluid shows the best performance by achieving 98,2 oC for the 10th minute, and after one hour, the final temperature is 100,5 oC. By using a polymer substrate as a reflector for the Parabolic Trough Concentrator and using heat transfer fluid based on ethylene glycol water-based solution by concentrator 50:50 (v/v) shows the best performance among all sample with the fastest heating rate and the highest final temperature after the one-hour experiment. It shows this model has advantages to improve the system reliability by increasing the heating rate of the heat transfer fluid, which able to heat the water on the system faster.

Productivity, exergy, exergoeconomic, and enviroeconomic assessment of hybrid solar distiller using direct salty water heating.

In this work, experimental work is presented on the performance of a hybrid solar distiller comprising solar still (SS) combined with parabolic trough solar collector (PTSC) using direct heating of salty water by the collector. In this technique, the salty water supplied to the SS is heated by passing it directly through the parabolic receiver without using heat transfer mediums that reduce the system efficiency. The study is carried out at different salty water depths inside the SS basin under hot climate conditions of Upper Egypt. The system performance is compared with a previous system using oil as a heat transfer medium between PTSC and still (indirect heating). The advantages of this technique are its ability to reduce initial salty water depth in the basin and avoid using the pumping system and heat exchanger compared to the direct heating. The performance of the proposed system is evaluated based on productivity, energy payback time (EPBT), exergy, enviroeconomic, and exergoeconomic methodologies. Findings illustrate that the present system rises the energy efficiency by about 12%, 27.5%, and 46% and the system exergy efficiency by about 14%, 30%, and 49% at salty water depth 15 mm, 10 mm, and 5 mm in the basin compared with the indirect heating system. Moreover, using this technique of salty water heating reduces the production cost of freshwater by about 71% compared with the direct heating system. The exergoeconomic and enviroeconomic parameters of the direct heating mechanism are more effective compared with those of the indirect heating mechanism.

Solar-LP gas hybrid plant for dehydration of food

This paper presents the thermal and energy analysis of a Solar-LP gas hybrid drying plant built in Zacatecas, Mexico. It is focused on the dehydration of agricultural products. The drying system is a forced convection hot air type with a drying chamber. For the air heating required in the drying process, there are two solar thermal systems: a direct air heating system (48 solar air heaters with an area of 111.1 m2) and an indirect air heating system (40 solar water collectors with an area of 92.4 m2 and 6000 L of thermal storage). Also, there is a backup system of conventional energy (LP gas burner). Two hybrid tests were carried out to dry Nopal (Opuntia ficus-indica) initially operating with the direct system, after that with the indirect system and complementing the energy demand of drying with the conventional system. The effective drying time was 14.3 and 11.7 h, removing a total of 179 and 183 kg of water, respectively. The air temperature at the entrance of the drying chamber was around 59 °C. The solar fraction obtained for this hybrid mode of operation was around 80%. The thermal analysis of the direct and indirect air heating system, together with the conventional system, are presented and discussed. The performance of the solar systems is finally compared with a conventional LP gas drying system via a cost and return on investment analysis.

An indirect heating solution to reduce CO2 emission and improve efficiency of gas distribution networks

The gas industry relies on indirect heating to prevent gas from freezing when it is transferred from high-pressure networks to lower pressure distribution systems. The main challenge in preheating natural gas is designing an indirect heating system capable of consistently maintaining a target temperature, despite large load diversity. The most common form of heating technology has traditionally been water bath heaters and boiler houses. In this paper, a novel technology is introduced, and its performance compared to existing installations. The Immersion Tube Thermosyphon Heater was developed specifically to address high load diversity; it combines a high-efficiency immersion burner with a sub-atmospheric two-phase loop thermosyphon. The use of low-temperature steam provides a flexible and precise solution for temperature control easily adapted to variable gas flows. The Immersion Tube Thermosyphon achieved an average thermal efficiency of 90%, considerably higher than the 46% efficient water bath, allowing an estimated annual saving of 7,660 tonnes CO2 for 1-megawatt gross heat capacity operating with a 50% load factor.

Consideration on Isothermal furnace using Indirect Heating System

Consideration on Isothermal furnace using Indirect Heating System

Structural and compositional changes in eucalyptus wood chips subjected to dry torrefaction

The aim of this study was to evaluate the structural and compositional changes in eucalyptus wood chips subjected to dry torrefaction. The experiment was conducted in a semi-continuous screw reactor with indirect heating system. Wood chips samples of three initial moisture contents (0, 15 and 30% dry basis) were torrefied up to three final temperatures (220, 260 and 300°C) and at three heating times (10, 15 and 20min). The effect of these variables was evaluated through the analysis of chemical composition, thermogravimetry and mechanical durability of the torrefied wood chips. The increase at temperature and time of torrefaction, as well as the drop in the initial moisture content, promoted significant structural and compositional changes in the wood chips. The torrefied samples present a higher resistance to thermal degradation, more friable structure, higher lignin and lower polysaccharides contents than the untreated samples. These changes made it possible to increase the quality of the eucalyptus wood chips to be use as a solid fuel.

Performance Evaluation of Hybrid Ground-coupled Heat Pump Indirect Heating Systems

Abstract This paper proposed two kinds of hybrid ground-coupled heat pump (HGCHP) indirect heating systems (system 1and system 2) for a villa building in Beijing. The numerical simulation of two systems is carried out based on the TRNSYS software. The influences of different operating modes on energy performance are analyzed. And the economic feasibility is discussed using the life cycle cost (LCC) method. The results indicate that system 2 shows better energy performance with the designed solar fraction for DHW (f sol,DHW ) below 80%. When the higher f sol,DHW is feasible, system 1 is preferred. Besides, system 1 shows advantage in keeping the soil temperature constant. In terms of LCC, both systems are better options compared with the conventional GCHP system.

Feasibility Analysis of Solar Assisted Ground-coupled Heat Pump Indirect Heating Systems

This paper presents a novel solar assisted ground-coupled heat pump indirect heating system (SA-GCHPIHS) designed for a residential building in Beijing for space heating and supplying domestic hot water. The recharging strategy for ground heat exchanger (GHE) is analyzed and determined based on system energy performance. The impacts of operation strategies and heating load ratio are simulated and compared, and the system with heat pump and water tank installed in series (SA-GCHPIHS(s)) showed better performance than SA-GCHPIHS(r) when domestic hot water (DHW) load dominates the heating load. And more energy would be saved by SA-GCHPIHS(s) as DHW load grows larger.

APPLICATION MACHINE DRYER MECHANICAL FORCED CONVECTION IN THE PROCESS OF DRYING CASSAVA CHIP

Implemented Mocaf flour processing on SMEs still has a weakness in the process of drying cassava chips.The drying process is using natural sun drying. In hot conditions in full sun drying takes 2 to 3 days while in the rainy season between November and April the SMEs unproductive because of the delay time of drying, the chip mocaf grow mushrooms with the consequences of the whole production must be discarded. Thus most of the cluster chose not to produce in the rainy season.Application of forced convectionmechanical dryer is an alternative of drying technology in the fermented cassava chips drying process due have a good quality and a longer storability. Forced convectionmechanical dryer is designed with indirect heating system consisting of a heat exchanger unit, the drying chamber, shelves, blower and frames. Cassava chips drying machine capacity is 40-80 kg/batch is divided into 80 shelves. Fuel is LPG. The results of machine performance test showed an effective drying cassava chips is 3.5 hours by the end of the temperature distribution between 31.9 to 47.6 ° C and a water content of 12.1 to 12.9%, with the desired optimum water content of the cassava chips for further processing into flour mocaf is 12-13%.

Impact of direct and indirect heating systems in broiler units on environmental conditions and flock performance

This study compared the impact of three indirect heating systems to direct gas flame heaters on a selection of flock performance and environmental indicators in commercial broiler units. No statistically significant differences (P≥0.05) were found in flock mortality rates, bird weight, water consumption, stress response, carbon dioxide, ammonia, temperature, relative humidity, litter quality, within-flock Campylobacter levels or mean Campylobacter counts when flock data from any of the three indirect heating systems were compared to flocks reared in houses with direct heating systems. Differences in litter quality were observed between upper and lower litter layers in all houses, regardless of heating type, which may have implications for bird health and welfare. Carbon dioxide concentrations in houses with direct heating systems were significantly higher than those in houses with indirect heating systems during the first 10 days of bird life (P≤0.05). This was due to the increased use of heating systems during this period of the flock cycle. Differences in CO2 concentrations had no effect on flock performance, possibly due to the fact that concentrations did not exceed known safe levels. A statistically significant increase in stress response was observed in birds as a result of partial depopulation (thinning) within houses, irrespective of heating system type used (P≤0.05). Stress associated with thinning may have consequences for bird welfare and food safety. In conclusion, the results of our study suggest that indirect heating systems do not appear to negatively impact on flock performance, stress response, within-flock Campylobacter levels or mean Campylobacter counts and do not appear to significantly alter environmental conditions within broiler houses when compared to houses equipped with direct heating systems. Indirect systems are a viable alternative for heating broiler houses in terms of flock performance, bird welfare and food safety.