Linear Model of DHW System Using Response Surface Method Approach

Using alternative and clean energy resources is considered the most effective method to deal with the environment and energy crises nowadays. In this study a comparative analysis of FPC data for DHW are theoretically and experimentally evaluated to optimise the design parameters. A forced circulation solar heating system using flat-plate collector, is modelled using T*SOL as a new approach, for hot water requirements of a laboratory unit at Szent Istvan University, in Gödöllő, Hungary. The modelling shows 69% solar fraction and 510 kWh annual solar gain. Furthermore, the comparison study was based on these two factors, and the two results matched with 93.12% accuracy. After the modelling, practically, the exergy analysis was conducted to determine and highlight the losses of the system. Since Hungary is considered a cold climate country, it was found that the thermal and optical losses from the collector and the piping system were tremendous. Then all the necessary design parameters were studied to achieve the optimal working points using non-linear correlation response surface method (RSM, which has never been used as an analysis tool in the solar field) at two perspectives (solar fraction and annual yield) for seven factors using R script. The factors were collector surface area, inclination angle, glycol-water ratio, tank capacity, boiler capacity, desired hot water temperature, and volume flow-rate. We identified the most influential single factors using ParetoPlot and each two-factorsꞌ interaction using contour plots. The most influential factors on the solar yield are solar collector surface area, tank capacity, desired hot water temperature and volume flow rate by magnitude effects of +129.7, +125.3, +50.9 and +17.2 kWh per annum, respectively

Mathematical modelling and experimentation of soy wax PCM solar tank using response surface method

Worldwide, governments tend to reduce the CO2 emissions, and the storage of the solar energy system is still considered the most challenging problem to solve under the current state. Mainly, in relatively cold countries, as domestic hot water or for heat process services, where the loss in the tank is huge. Any improvement in the design can achieve a higher solar yield. Since water is the usual medium for heat storage, the integration with phase change material (PCM) can store energy when there is abundant energy and release it when it is needed. In this study, we conducted a capsulated PCM soy wax 52⁰C in an insulated water tank filled with 5 litres of water. To estimate the appropriate number of samples and the quantity of the PCM at two temperature levels using the response surface method with non-linear correlation for the charging phase. The results show 3.16, 0.95, 0.38 first degree magnitude effect for temperature, sample numbers, and wax quantity respectively and 0.29, -0.38 second-degree magnitude effect for quantity and temperature. In addition, an illustration of each two-factors interaction contour plots. &nbsp

Examination of heat treatments at preservation of grape must

Heat treatment is a well-known process in food preservation. It is made to avoid and to slow down food deterioration. The process was developed by Louise Pasteur French scientist to avoid late among others wine further fermentation. The different heat treatments influence the shelf life in food production. In our article we present the process of grape must fermentation, as grape must is the base material of wine production. The treatment of harvested fresh grape juice has a big influence on end product quality. It is our experiments we examined the same grape must with four different methods in closed and in open spaces to determine CO2 concentration change. There are four different methods for treatment of grape juice: boiling, microwave treatment, treatment by water bath thermostat and a control without treatment. As a result of the comparison it can be stated that the heat treatment delays the start of fermentation, thereby increasing shelf life of grape must. However, no significant differences were found between two fermentation of heat-treated grape must by the microwave and water-bath thermostat. The different heat treatment of grape must base materials was done at the laboratory in Faculty of Mechanical Engineering of Szent István University. The origin of the table grapes used for the examination was Gödöllő-hillside

Reduction of toxin content of Triticum durum in the milling process

The DON toxin in terms of human and animal health is a serious food safety risk factor. Thanks to the favorable impact of vintage effect occurring in recent years the Fusarium contamination of wheat and consequently a high DON toxin concentration often cause problem. Therefore, it is important that there be methods during of wheat milling process, which reduces the level of toxin. Experience has shown that Triticum durum wheat species is more sensitive to Fusarium infection than Triticum aestivum species. According to professional literature, almost the prevention is considered to be the exclusive method to keep the content of DON-toxin below safe level. It is very difficult, sometimes impossible to correct those food safety risks, which polluted the products in the process of cropping. My objective was to investigate, if it possible to decrease DON-toxin content of durum wheat and to minimize the food safety risk by application of milling technology with good production practice and technological conditions. According to results of measurements, Sortex Z color sorting decreased DON-toxin content of wheat

Fűtött, többhajós, többtechnológiás fóliaházak néhány fontos, egymásra ható fizikai paraméterének vizsgálata = Research of some significant interaction of physical parameters of a heated plastic greenhouse using multitechnology

A kutatás célkitűzéseinek megfelően az alábbi eredmények születtek: - A Magyarországon használatos növényházi burkolófóliák spektrális fényáteresztő képességének összehasonlítása - A Magyarországon használatos növényházi burkolófóliák szilárdsági paramétereinek vizsgálata a fóliák típusának, az adalékanyagok függvényében - Fóliaház tartószerkezet erőhatásainak vizsgálata alapján ajánlás vázszerkezetre A mért paraméterek alapján a kettős burkolatú fóliaházak kedvező vázszerkezetére, valamint a fóliapár optimális kiválasztására vonatkozó ajánlások születtek. | Regarding the objectives the research resulted the following outcomes: - Comparison of spectrale light transparency of different cladding plastic materials used in Hungary - Strength test of the cladding plastic materials in dependency of the type of the plastic thickness of the cladding material additives - Analysis of the different greenhouse structures regarding to the marginal conditions and suggestion to the optimal structure The research can additionallz contribute to the following results - theoretical statements from the interrelation between the measured parameters, - Give a help for choosing the proper structure and cladding material coupling for different plant-cultures in the Hugarian circumstances

Food safety and energetics analysis of the heat treatment of milk

The food safety and energy efficiency of the heat treatment of cow’s milk was investigated by our research group. Of the known heat treatment processes, the results of our investigation are presented in the case of a cow’s milk treated at 75 °C and held for 5 minutes. Proper treatment of cow’s milk is probably the most pivotal issue in food production, but from the point of view of the manufacturing plant, food safety and the amount of energy used for the production are important as well. Our measurements were carried out using the PG 015 pasteurizer of the Department of Food Hygiene of the University of Veterinary Medicine. The electricity input and the amount of heat used during the technology were measured. The efficiency of food production was defined as the ratio of the utilized energy to the energy invested. To verify the adequacy of the heat treatment, peroxidase enzyme inactivity tests were performed untreated milk, and for treated milk, without and with holding it at the given temperature for the proper length of time. Based on our measurement results it can be stated that a heat recovery zone built into the technology keeps the COP (coefficient of performance) value above one. By optimizing the length of the heating and the heat treatment, by adjusting the desired technological temperature precisely, and by the application of food safety limit values and analyses, the efficiency of a larger system can be improved significantly as well

Élelmiszerek mirohullámú dielektromos jellemzőinek vizsgálata és alkalmazása a technológiai fejlesztésben és minőségbiztosításban = Research of microwave dielectric properties of foods, their use in technological development and in the quality assurance

A kutatás első fázisában üregrezonátoros és csőtápvonalas mérőrendszereket fejlesztettünk ki élelmiszerek dielektromos jellemzőinek vizsgálata céljából. Mérési és számítási eredményeink alapján algoritmust állítottunk fel, amellyel gyorsan és egyszerűen tudjuk megbecsülni különböző nedvességtartalmú és halmazsűrűségű gabonák dielektromos állandóját. Tej és sör mikrohullámú pasztőrözése céljából folyamatos üzemű laboratóriumi hőkezelő berendezést fejlesztettünk ki. A folyamatos üzemet a mikrohullámú készülékbe helyezett üveg-spirál segítségével alakítottuk ki. A technikai jellemzők vizsgálatán túl mikrobiológiai vizsgálatot is végeztünk hőkezelt tej és sörmintákon. A vizsgálatok eredményeként megállapítható, hogy a spirálcsöves mikrohullámú hőkezelő berendezés alkalmas pasztőrözésre. A kutatómunka keretében kisérletet tettünk palackozott sör mikrohullámú hőkezelésére alkalmas folyamatosüzemű berendezés kifejlesztésére.A kifejlesztett változat a megengedhetőnél nagyobb háttér sugárzást okoz,ezért továbbfejlesztése szükséges. A kutatás befejező fázisában tojáslé mikrohullámú pasztőrözésével kapcsolatos vizsgálatokba kezdtünk, ezek eredménye és további fejlesztése folyamatban van. | A measuring system with a resonant cavity and with a rectangular waveguide was set up to investigate the dielectric properties of food products. Based on the results of the measurements and calculations an algorithm was set up, which makes possible the quick and simple estimation of the complex permittivity of wheat samples of different moisture content and bulk density. A laboratory pasteurizations device was developed for the continuous microwave heat treatment of milk and beer. Continuous operation was achieved by putting glass spiral insets in the oven. In addition to the measurement of physical attributes some microbiological examinations were also carried out on the pasteurized milk and beer samples. The results of the investigations show that the microwave heat treatment device with spiral pipes is suitable for pasteurization. In the framework of this research an attempt was made to set up a continuously operating device that is suitable for the microwave heat treatment of bottled beer. However the background radiation of the device exceeds occupational safety limits, thus it is not appropriate for investigations in its current form. In the final stages of this research some investigations were carried out related to the microwave pasteurization of liquid eggs. The determination of results and the further development of the method is still underway