Identifying iron-bearing nanoparticle precursor for thermal transformation into the highly active hematite photo-fenton catalyst

Funding: This reseach was funded by the European Regional Development Fund within the Activity 1.1.1.2 “Post-doctoral Research Aid” of the Specific Aid Objective 1.1.1 “To increase the research and innovative capacity of scientific institutions of Latvia and the ability to attract external financing, investing in human resources and infrastructure” of the Operational Programme “Growth and Employment” (No. 1.1.1.2/VIAA/1/16/157).The hematite photo-Fenton catalysis has attracted increasing attention because it offers strong oxidation of organic pollutants under visible light at neutral pH. In the present work, aqueous synthesis of hematite photo-Fenton catalysts with high activity is demonstrated. We compare photo-Fenton activity for hematite obtained by hydrolyzation at 60◦C or by a thermally induced transformation from iron-bearing nanoparticles, such as amorphous iron oxyhydroxide or goethite. A link between their structure and visible light photo-Fenton reactivity is established. The highest activity was observed for hematite obtained from goethite nanowires due to oblong platelet-like structure, high surface area and the presence of nanopores.European Regional Development Fund 1.1.1.2/VIAA/1/16/157; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Cost-Effective Pipelines Insulation of Solar Thermal System

Solar radiation intensity in the Baltic region is lower in comparison with the average European values. The average solar radiation intensity reaches 1100 kWh/m2 per year in Baltic region. And outdoor air temperature range is below average values in Europe. Range of outdoor air temperature in the Baltic region is -3 ºC in winter and +16 ºC in summer. Therefore, there is a particular need to optimize the solar thermal system in the Baltic region. A certain proportion of the solar thermal system generated energy is consumed as the heat loss in pipes between the solar energy absorbing devices to the heat-accumulation tank. Pipeline isolation of solar thermal system is necessary for both outdoor and indoor pipes. Outdoor heat pipe isolation reduces systems heat losses in the environment. While, indoor heat pipe isolation reduces value of unnecessary energy distribution indoors in the summer period. The amount of pipeline heat energy losses dependence on the pipeline isolation type of solar thermal system was determined with the PolySun simulation program models. The most popular heat pipe insulation materials in Baltic region were inspected and compared. They were compared and shown in table form by the thermal conductivity coefficient and the price. The amount of absorbing energy value and heat losses are calculated and displayed in the graphic form. As a result the method was created. The method can determine most cost-effective solar thermal systems pipe insulation type

Determination of Cost-Effective Pipelines Insulation of Solar Thermal System

Baltic States climate is colder than the average European climate, and solar radiation amount is less. This gives an increased need to optimize the overall solar thermal system for the Baltic States conditions. Solar thermal system manufacturers and vendors emphasize attention to solar energy absorption unit, but the rest of the system components remain in consumer choice. The publication describes a method for selection of the more energy effective and cost profitable pipe insulation type in solar thermal systems. A certain proportion of the solar thermal system generated energy is missed as the heat loss in pipes between the solar energy absorbing devices to the heat-accumulation tank. Pipe isolation is necessary for both an outdoor and indoor pipes of solar energy heating system. Outdoor pipes insulation should conformed to outdoor climate conditions and indoor pipes insulation accordingly should conform to indoor conditions. Amount of pipe heat losses mostly depends on pipe diameter, heat carrier temperature, air temperature of the room or environment. Solar systems heat carrier temperature depends on solar radiation intensity in a given period, and the outside air temperature changes throughout the year. Instantaneous pipeline heat losses are calculated according to the instantaneous heat carrier, outdoor and indoor air temperatures. Results of calculations using the average values are not correct. Therefore, it is necessary to use modeling programs with precise meteorological data. The amount of pipeline heat energy losses in accordance with the pipeline isolation type of solar thermal system was determined with the PolySun simulation program models. The most popular heat pipe insulation materials in Baltic region were inspected and compared. The amount of absorbing energy value and heat losses were calculated and displayed in the graphic form. As a result the method was defined. The method helps determine most cost-effective solar thermal systems pipe insulation type

Energy Supply in the Environment-Friendly Buildings (Latvian Expirience)

In accordance with the Latvian “Law on the Energy Performance of Buildings” environmental and economic considerations, as well as binding regulations of the local government and other regulatory enactments, shall be taken into account in designing buildings, in order to evaluate the possibility to use as an alternative solution in these buildings systems, in which RES are used. Paper will describe good experience and practice of this Policy and Strategy how to use opportunities of the geothermal energy and solar energy in Latvian conditions. North Vidzeme Biosphere Reserve (NVBR) administration has finished the construction of an Environmental Education and Information Centre with a potential area of 675m2 in the town of Salacgriva. The education and information centre is expected to provide local residents, businesses, municipalities and state institutions with information about the natural assets of the reserve as well as about protection of natural resources and the use of innovative solutions in regional development

Solar Energy Systems for Hot Water and Air for Household

Introduction Today, solar energy is used both for generation of electricity and for production of hot water and air. The system’s costs for generation of any of the above mentioned processes are high. Methods Methods Households basically use systems operated by solar power for generation of electricity and hot water. However, it is exactly the heating that accounts for the largest part of costs incurred by households. The market offers hot air generation systems operated by solar power already now. Use of the said systems in the conditions of the temperate climatic area provides only for seasonal energy generation options. Combination of the solar energy systems, which generate hot air and hot water, permits operation of these systems throughout the year, thus increasing the system efficiency. Solar energy systems that generate hot water are currently being rather widely used. If such a system is installed separately its costs are high and its yield is long-lasting. Installation of a hot air generating solar energy system, in its turn, provides only for limited use depending on the seasonality because in summer air heating is not necessary. A market research showed that solar energy systems providing for simultaneous generation of hot water and hot air that would suit our climatic conditions are not available currently. Creation of a combined system will permit its use throughout the year, providing in its turn 100% use of sunny days for energy generation which is very important in our weather conditions. Today, the market offers only combined electricity and hot air generation solar energy systems basically intended for use in industrial objects. Considering the abovementioned, the research project plans to develop a new product – a combined hot air and hot water generation solar energy system usable in households. The project includes the industrial study and experimental development, and building of a prototype. The aim of the research is to conduct an industrial study and experimental development to work out a prototype of a new product - a combined hot air and hot water generation solar energy system usable in households. Conclusions The hot air and hot water generation solar energy system usable in households to be developed is a new product not only in Latvia. The new system will differ from the systems available on the market with that it could provide for simultaneous generation of hot air and hot water from solar power, thus increasing the building’s energy efficiency and decreasing the costs of use of the traditional energy, permitting use of the new system all around the year regardless of the season. Presently there are only the combined electricity and hot air generation solar energy systems available on the market intended basically for industrial use

Optimization of Solar Thermal System’s Pipelines Insulation

The paper will present the results of research work on the effective use of solar collectors which was realized in the solar energy testing polygon at the Institute of Physical Energetics. A certain proportion of the energy generated by solar thermal system is spent as the heat losses in pipelines between the solar energy absorbing device and the heat-accumulation tank. Insulation of solar thermal system’s pipelines is necessary for both outdoor and indoor pipes. Outdoor heat pipes insulation reduces systems heat losses outside, while, indoor heat pipe insulation reduces value of unnecessary energy distribution inside in the summer period. The dependence of pipelines’ heat losses from the pipelines insulation type has been determined with the PolySun simulation program. The most popular heat pipes insulation materials in Baltic region were examined and compared. The results of comparison were summarized in tabular form taking in account the thermal conductivity coefficients and the prices. The amount of absorbing energy values and heat losses have been calculated and presented in the graphical form. As a result the method for determination of the most effective insulation types for solar thermal system’s pipelines has been developed

Modeling of a Solar Collector’s Absorber

The paper gives a mathematical description for the heat conduction proceeding on the plane surface of a solar collector’s absorber divided into three parts for each of which the Laplace equation with boundary conditions is formed. Applying definite approximations the authors have completely described mathematically the heat conduction process initiating in the plane part of a collector’s absorber, then passing to a tube and from the tube to the liquid flowing through it. In all the three absorber’s parts the process is considered stationary, independent of time, and, therefore the temperature field is obtained in spatial coordinates

SOLAR ENERGY USE FOR SUSTAINABLE DEVELOPMENT

Solar energy use technologies are striving to deal with the fast-growing energy demand. Solar thermal systems are particularly important for solar heating, hot water preparing and even cooling that for many countries is very actual now. Solar thermal systems need a solar collector that guarantees substantially safe and effective operation. Besides the specific costs of the collector field also aspects like the resulting collector area and suitable collector technology for a specific system have an influence on the decision for a certain collector types. To select the suitable solar energy use equipment technology for a specific system properly, the weather conditions and the industrial load profiles or the characteristics of the solar energy use system always have to be taken into account by reliable and cost effective solution for sustainable energy consumption. For this purpose it was created testing polygon for the solar energy use equipment in Latvian climate conditions, which helps to meet these requirements. The paper presents the first results of the solar energy use equipment’s examination from the testing polygon that was build up on the roof of the Institute of Physical Energetics (IPE) and includes: -an autonomous system for PV elements testing; -a quasi-autonomous for PV elements testing; -a system for solar collectors testing; -devices for solar radiation and weather condition parameters measurement

Solar Energy Use for Sustainable Development

Solar energy use technologies are striving to deal with the fast-growing energy demand. Solar thermal systems are particularly important for solar heating, hot water preparing and even cooling that for many countries is very actual now. Solar thermal systems need a solar collector that guarantees substantially safe and effective operation. Besides the specific costs of the collector field also aspects like the resulting collector area and suitable collector technology for a specific system have an influence on the decision for a certain collector types. To select the suitable solar energy use equipment technology for a specific system properly, the weather conditions and the industrial load profiles or the characteristics of the solar energy use system always have to be taken into account by reliable and cost effective solution for sustainable energy consumption. For this purpose it was created testing polygon for the solar energy use equipment in Latvian climate conditions, which helps to meet these requirements. The paper presents the first results of the solar energy use equipment’s examination from the testing polygon that was build up on the roof of the Institute of Physical Energetics (IPE) and includes: -an autonomous system for PV elements testing; -a quasi-autonomous for PV elements testing; -a system for solar collectors testing; -devices for solar radiation and weather condition parameters measurement

Comparision of Solar Collectors Operation Methods

Solar collector’s operation methods investigated on the Institute of Physical Energetics (IPE) solar energy polygon according different parameters. The most common types of solar collector’s operation were investigated and compared: by the time, by the heat carrier temperature differences of input and output, by the solar radiation intensity and operation control methods in various combinations. Theoretical and practical advantages and disadvantages of using each control methods were analyzed. Currently, companies that offer solar collectors, offer solar collectors complete set with all necessary equipments for the solar collector connection for hot water supply system, or for home heating operation system by the temperature difference of input and output. And no one of them does not offer solar collectors operation systems by the various parameters. Except the manual operation system the worst solar collector’s operation system is the operation system by time. Usually equipments of the operation system are primitive and those could not used for individual program for each day, so one program is used for all days of the solar collector’s operation time. Thereby the fact that the weekly average value of solar radiation is changes, and changes the sun sunshine hours, then it is not possible fully use the obtaining solar energy in sunny days and fully use the solar collectors operation time of spring and autumn periods, in this time the heat storage tank will be more cooled than heated. The solar collector operation system by the flow and return temperature is one type of solar collectors for operational system. Through this system can provide instantaneous accession and if it is necessary can regulate solar collector operation system; by this operation the system can get instantaneous maximum efficiency. It is necessary to find the optimal speed of heat carrier flows speed. Solar collector’s operation system could be regulated in accordance with the solar radiation intensity, by the boiler lower temperatures and by the outdoor air temperature to determine precisely the solar collector efficiency of the parameter changes. This may help to avoid the previous operation systems testing regime deficiencies. The precision of solar collectors operation depends on the type of operation systems: heat losses and the collector efficiency calculation accuracy, the sensor is accuracy, the time between the regulation regimes, and the range of heat carrier pumps action operation sensors