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To counteract possible corrosion, steel pipes are coated with a protective layer of zinc with a thickness of 20 to 85 microns, depending on the requirements of regulatory documentation. It is proven that hot-deposited zinc can effectively protect steel surfaces for 20 to 120 years. However, in centralized hot water supply (CHWS) systems, the period of protective action can decrease to two to three years, with further damage to the zinc layer and the appearance of fistulas. In order to counteract adverse factors, it is necessary to take into account the operating mode and design features of the system, the properties of the coating, and the environment in which the pipes operate. In this article, the main attention is paid to the study of the behavior of zinc coating. The protective properties and corrosion rate of zinc coating in tap water were evaluated. It was established that the protective effect of zinc is effectively manifested in the ratio of the protected area to the unprotected, as SZn/SFe ≥ 9:1. The influence of iron-containing sediment, when it accumulates in the pipes of a CHWS system, on the corrosion rate of the zinc coating was studied. It was also noted that the corrosion rates of the new zinc coating and uncoated steel pipe measured in short-term tests differed slightly. [ABSTRACT FROM AUTHOR]

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Several rural regions located in Africa are experiencing recurrent and even permanent problems in terms of energy production, supply, and distribution to citizens. This study was conducted to investigate the relevance of the use of a new solar technology that is gradually responding in Europe and in industrialized countries. It is about the use of hybrid photovoltaic thermal (PV/T) solar panels that co-produce electricity and hot water for local use. Furthermore, in Africa, local use of solar energy can provide a share in the energy mix. This work is motivated by the lack of studies on these hybrid solar panels in tropical climates. Hence, the paper examines the potential for integration of these systems in small households. A complete PV/T system consisting of solar panels, pump, storage tank, batteries, and controllers was tested and calibrated by using the TRNSYS simulation tool. A comparative study could thus be carried out for the performance of PV/T in a tropical climate (case of the city of Koua in the Comoros) to its performance in Mediterranean and continental climates (Marseille in the south and Longwy in the northeast of France). The results quantify the performance of the PV/T in the three climates and show that the performance in the town of Koua is 44% to 54% higher than in European climates. It can be concluded from this study that the Comorian market and more generally the sub-Saharan market for PVT systems has a good potential for development. [ABSTRACT FROM AUTHOR]

The task of determining the efficiency of operation of an absorption heat pump (AHP) with steam heating (COP conversion factor = 1.71) integrated into the thermal circuit of a PT-60/70-130/13 steam turbine that releases production steam and hot water during the partial heat load period (spring and autumn; also referred to as the inteheating period) is being solved in this paper. Variants of operation of the PT-60/70-130/13 with an integrated AHP with a capacity of ~17.25 MW in the partial heat load period were studied when steam with parameters of 1.296 MPa, 280°C was realised in the production selection of the adjustable turbine at flow rates of 20, 30, and 50 t/h with a variable heat load on hot water supply, which was determined by the return network water consumption task 1000–1400 t/h, while the ‘useful’ electrical power of the power complex was provided at ~30 MW. At electricity prices of 0.13 USD/(kWh) and standard fuel of 309 USD/t for Ukraine, the simple payback period of 17.25 MW AHP as part of the PT-60/70-130/13 steam turbine for the partial heat load period at a production load of 20–50 t/h of steam at the consumption of return network water of heat supply 1000–1200 t/h can decrease to two years. At the same time, during the partial heat load period, which lasts ~4404 hours in Ukraine, up to ~1.2% of fuel, up to 44% of technical water for feeding the circulation cooling system, and 0.4% of softened water for feeding are saved. A tangible environmental effect is achieved due to the reduction of harmful emissions – actual heat and hazardous gases – to the atmosphere: CO2 by 1118.7 tons, NOx by 5.87 t, thus saving ~41,000 of technical water. [ABSTRACT FROM AUTHOR]

To counteract possible corrosion, steel pipes are coated with a protective layer of zinc with a thickness of 20 to 85 microns, depending on the requirements of regulatory documentation. It is proven that hot-deposited zinc can effectively protect steel surfaces for 20 to 120 years. However, in centralized hot water supply (CHWS) systems, the period of protective action can decrease to two to three years, with further damage to the zinc layer and the appearance of fistulas. In order to counteract adverse factors, it is necessary to take into account the operating mode and design features of the system, the properties of the coating, and the environment in which the pipes operate. In this article, the main attention is paid to the study of the behavior of zinc coating. The protective properties and corrosion rate of zinc coating in tap water were evaluated. It was established that the protective effect of zinc is effectively manifested in the ratio of the protected area to the unprotected, as SZn/SFe ≥ 9:1. The influence of iron-containing sediment, when it accumulates in the pipes of a CHWS system, on the corrosion rate of the zinc coating was studied. It was also noted that the corrosion rates of the new zinc coating and uncoated steel pipe measured in short-term tests differed slightly.

Several rural regions located in Africa are experiencing recurrent and even permanent problems in terms of energy production, supply, and distribution to citizens. This study was conducted to investigate the relevance of the use of a new solar technology that is gradually responding in Europe and in industrialized countries. It is about the use of hybrid photovoltaic thermal (PV/T) solar panels that co-produce electricity and hot water for local use. Furthermore, in Africa, local use of solar energy can provide a share in the energy mix. This work is motivated by the lack of studies on these hybrid solar panels in tropical climates. Hence, the paper examines the potential for integration of these systems in small households. A complete PV/T system consisting of solar panels, pump, storage tank, batteries, and controllers was tested and calibrated by using the TRNSYS simulation tool. A comparative study could thus be carried out for the performance of PV/T in a tropical climate (case of the city of Koua in the Comoros) to its performance in Mediterranean and continental climates (Marseille in the south and Longwy in the northeast of France). The results quantify the performance of the PV/T in the three climates and show that the performance in the town of Koua is 44% to 54% higher than in European climates. It can be concluded from this study that the Comorian market and more generally the sub-Saharan market for PVT systems has a good potential for development.

The article describes the prerequisites for development of methodology for integrated assessment of options for transition to a closed hot-water supply scheme. For analysis of promising options for transition to a closed system of hot water supply, criteria have been proposed that influence the choice of possible solutions. Block diagrams of boundary conditions and independent variables were created. A pyramid of indicators which affect the operating costs of heating system over 25 years of its operation was formulated. A method and a program for selecting the optimal transition scheme to a closed hot-water supply system with calculation of weighting factors have been developed.

Charge climatic daily data for the annual period is made for the set location, primary analysis of the obtained data and detailed visualization of position of the Sun within a year, the choice of optimum technical parameters of system of a solar collector on the basis of climatic data for the chosen location (Omsk). The technique of selection of a solar collector is given.

The progress of work on the revising of building codes and regulations of the "Solar Hot Water Installations", operating in the territory of the Republic of Uzbekistan is shown. The goal of the work is to create a modified republican regulatory document that meets modern requirements and provides an increase in the energy efficiency of designed solar hot water installations by 30%. The analysis was conducted with domestic and foreign experience in the design, and construction and operation of solar hot water installations for various purposes was studied and summarized. The selection of advanced technical achievements and scientific research of different countries in the field of energy saving and efficient use of solar energy has been carried out. In the process of revising the regulatory document, outdated regulations were excluded; new regulatory requirements were included, taking into account the current level of scientific and technological achievements, design and construction practices, and regional features of the Republic of Uzbekistan. The article introduces and substantiates main changes made to the previously existing building codes and rules, developed on the basis of the analysis of generally accepted results of completed research, development and experimental work, the study and synthesis of domestic and foreign experience in designing, building and operating solar hot water installations for various purposes. [ABSTRACT FROM AUTHOR]

The problem of modernization of the heat module (HM) with two-stage mixing scheme connection of hot water supply (HWS) by installations of the heat pump (HP) during interheating period is considered. Heating water of the in-house circuit of the building heating system is used as heat source for HP. The district cooling of the residential areas is possible through heaters during summer. R600 refrigerant is chosen for HP as a most environmentally freindly and as one that has low-pressure evaporation and condensation. The economic calculation is made for interheating period with and without HP. This paper advanes selection of optimum amount heat to be recovered during low potential heat utilisation and targets for heating and cooling capacities. Almost all residential buildings connected to the district heating and that have heat module with two-stage mixing scheme HWS system have market potential. Climatic conditions for such modernization are quite broad and include virtually all residential buildings in Europe. Primary energy consumption is taking place during daytime, when the cost is high. And so promising direction of development of the proposed approach to use HP in the in the heating system with hot water supply tanks, which charged at night. The results of this work may be used for in Total Site methodology development allowing heat recovery for district heating needs of both new designs and as retrofits to existing sites to ensure fast, widespread and cost-efficient industrial deployment. It leads to carbon footprint reduction and energy efficiency improvement of regions with heating and cooling demands during winter and summer seasons.

Hot water supply is one of the leading consumers of energy in the building sector in cold climate areas. The use of woody biomass is effective in reducing CO2 emissions in hot-water supply systems. This report deals with a system that combines a wood pellet boiler (PB) and a heat pump system with CO2 (CO2HP) that is used in a facility for disabled people. The following research was conducted. The operation of a hybrid system combining a PB and CO2HPs was investigated. While operating the system, four specific operations were developed as countermeasures to save on costs and reduce system troubles while reducing CO2 emissions. The processes and results are introduced. Numerical simulations were carried out to optimize the operation. The hot water temperature, water volume, and hot water loads were simulated. The influence of the water volume ratio on the cost and primary energy consumption under the requirements for safe system operation was studied. The regional economic ripple effects (REREs) of this system were studied. The wood pellet boiler is not only a measure for reducing primary energy consumption but can also play an important role in a regional economy for sustainable development in countries that import energy resources such as Japan.

Centralized hot water systems widely used in Russia and Belarus are characterized by a considerable length and branching which inevitably leads to increased heat losses and to an unstable hydraulic system. The operation of the domestic hot water system in the circulation mode can be characterized by several parameters; one of which is the specific ratio of the cost of thermal energy for heating a cubic meter of hot water. The parameter is often regulated by law in Russia; exceeding this parameter is considered as administrative violation. The aim of the research is to determine the design and actual costs of thermal energy for hot water supply (hot water heating) and their comparison, analysis of the data obtained. The methodology for determining the design and real costs of thermal energy for hot water supply was to study the operation of the hot water supply system of a residential 144-apartment 9-storey building. The research showed that the actual circulating flow rate is much less than the calculated circulating flow rate. The authors note that in order to optimize the standard for heating a cubic meter of water it is necessary to observe the calculated circulation modes. This will require stabilization of the hydraulic systems of both the external and internal networks which is a difficult but feasible task. The research results are supposed to be taken into account when setting up existing hot water supply systems.

The paper presents a comparative analysis of design and thermal parameters of various types of solar collectors, including Russian-manufactured ones. It is shown that over the last 15 years, the massdimensional characteristics and thermotechnical excellence of flat-plate solar collectors have remained virtually unchanged, the manufacturing technologies of such collectors have not sufficiently improved, the collectors have reached parameters close to limiting ones. In terms of thermal excellence, Russian-manufactured collectors are highly competitive with foreign models. Evacuated tubular solar collectors currently on the market can be divided into several types, of which the most efficient are U-shaped heat removal pipe Sydneytube collectors. Popular heat pipe Sydney-tube collectors, which are considered promising, are significantly less efficient. [ABSTRACT FROM AUTHOR]

Planet Earth is facing challenge of Environment degradation which could be checked by usage of Green technology in order to achieve Energy Conservation. Usage of Renewable energy resources would meet energy demand without compromising the need of future generation and would replace conventional fuels. Adoption of decentralized approach such as solar thermal technology based products like Solar Water Heating System (SWHS). MNRE had introduced SWHS scheme under National Solar Mission as the economic benefits of the utilization of SWHS in both domestic and industrial sectors can lead to savings in fuel costs for water heating and by reducing environmental issues. The main objective of paper is to explore the development of SWHS in Punjab state installed under subsidy provided by State Nodal Agency of Punjab i.e. Punjab Energy Development Agency (PEDA). This paper had examined the assessment of role played by PEDA in process and functioning of installation and release of subsidies for SWHS and also analyzed the perspective of beneficiaries towards use of SWHS from three districts of Punjab. The analytical study showed that the installation of SWHS has saved energy in providing hot water supply in domestic and commercial areas. The results of study highlighted that there is lack of maintenance provision by private companies. There is need to monitor Private companies, initiate feedback mechanism, provide more government rebates and benefits which will help the small scale manufacturers to flourish more by maintaining quality assurance. [ABSTRACT FROM AUTHOR]

Purpose. Heat consumption for heating and hot water supply of housing and industrial facilities is an essential part of heat energy consumption. Prerequisite for development of energy saving measures in existing heating systems is their preliminary examination. The investigation results of campus heating system of Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan are presented in the article. On the basis of the analysis it is proposed to take the energy saving measures and assess their effectiveness. Methodology. Analysis of the consumption structure of thermal energy for heating domestic and hot water supply was fulfilled. The real costs of heat supply during the calendar year and the normative costs were compared. Findings. The recording expenditures data of thermal energy for heating supply of residential buildings and dormitories in 2012 were analyzed. The comparison of actual performance with specific regulations was performed. This comparison revealed problems, whose solution will help the efficient use of thermal energy. Originality. For the first time the impact of climate conditions, features of schemes and designs of heating systems on the effective use of thermal energy were analyzed. It was studied the contribution of each component. Practical value. Based on the analysis of thermal energy consumption it was developed a list of possible energy saving measures that can be implemented in the system of heat and power facilities. It was evaluated the fuel and energy resources saving.

A multi-functional heat pump system has been proposed to effectively utilize waste heat and heat capacity in gray water for heating and cooling of residential buildings. Condenser heat recovery is integrated into the system. This system was tested in two environmental chambers that mimic the outdoor and indoor environments, respectively. In this paper, the investigation of the optimized system is focused on the system optimization and performance in cooling mode. The drawbacks of the initial prototype are analyzed and fixed. The system performance in the initial and optimized prototypes are compared and analyzed. At outdoor temperature 35 °C, compared to initial type, the COP of optimized prototype increases up to 20.07% for space cooling mode and up to 21.51% for space cooling with hot water supply mode. This system is tested and analyzed at space cooling mode, space cooling with hot water supply mode and hot water supply only mode. [ABSTRACT FROM AUTHOR]

“Design regime for current water consumption” is proposed to use when performing calculations of water consumption in hot water supply systems in multi-family buildings. Design regime is a simplified mathematical description of all ordered sets of time costs expected in the current period of hot water system operation. The design regime of water consumption is described by the ratio of total hourly irregularity at 98% supply (security). When choosing a water flow counter in the hot water supply of multifamily buildings value of the operational water flow counter must comply with the parameters of water consumption of the building to the greatest extent. The methodology is proposed and an example of calculation of the amount of water per day passing through the water flow counter when water flow is below threshold values, the smallest and the transitional costs for the flow counter is made. [ABSTRACT FROM AUTHOR]

The object of research is frost-protected shallow foundations.The article focuses on a technique of solving the nonstationary and nonlinear problem of freezing/thawing of soil in a 2D target setting, using software based on the finite-element method. The COSMOS/M package from Structural Research & Analysis Corp. is used as an example. The article also mentions some peculiarities of data input, caused by the non-linearity and nonstationarity of the problem.

One of priority directions in modern building is maintenance of energy efficiency of buildings and constructions. This problem can be realized by perfection of architectural, constructive and technical decisions. The particular interest is represented by an influence estimation of temperature and moisture mode of enclosing structures on a thermal performance and energy efficiency of buildings. The analysis of the data available in the literature has shown absence of effective calculation methods of temperature and moisture mode in edge zones of enclosing structures that complicates the decision of this problem.The purpose of the given work is an estimation of edge zones influence on a thermal performance and energy efficiency of buildings. The design procedure of energy parameters of a building for the heating period, realized in the computer program is developed. The given technique allows settling an invoice power inputs on heating, hot water supply, an electrical supply. Power inputs on heating include conduction heat-losses through an envelope of a building taking into account edge zones, ventilation heat-losses and leakage air (infiltration), internal household thermal emissions, heat-receipt from solar radiation. On an example it is shown that the account of edge zones raises conduction heat-losses through an envelope of a building on 37 %, the expense of thermal energy on building heating on 32 %, and the expense thermal and electric energy on 13 %. Consequently, thermal and moisture mode in edge zones of enclosing structures makes essential impact on building power consumption. Perfection of the constructive decision leads to decrease of transmission heat-losses through an envelope of a building on 29 %, the expense of thermal energy on building heating on 25 %, the expense of thermal and electric energy on 10 %. Thus, perfection of edge zones of enclosing structures has high potential of energy efficiency.

The district heating system (DHS) is an efficient way for heat supply in urban areas. The efficiency of the DHS is considerably increased with the modern developments of technology, introducing 4th and 5th generations of centralised DHS. The existing DHS in Ukraine needs energy-efficient modernisation, where the reduction of heat losses at buildings and pipelines, the low temperatures of heat carriers, the use of heat pumps and individual heat substations with measuring devices and automated control are needed. The work proposes a novel methodology of transition to 4th generation DHS that allows its implementation with limited funds for investment. It consists of the step-by-step realisation of required innovations that allow optimising investments schedule and payback time. The methodology is illustrated by two case studies. In one of them, the university administrative building built 50 years ago is considered. The proposed improvement method can decrease the total energy consumption by 85%, with investments lower by 47% compared to traditional simultaneous realisation. The introduction of a new generation of DHS in Ukraine can be performed by gradual additions of new elements to existing DHS and integrating individual heat substations with heat pumps and renewable energy sources. • The step-by-step retrofit approach for district heating systems is proposed. • Modernisation of Ukrainian district heating system to 4th generation is analysed. • The retrofit of office and multi-store residential building is discussed. • The proposed approach can reduce payback period from 7.5 to 6 years for office building. • The decrease of more than 50% of total consumed heat was obtained for residential building. [ABSTRACT FROM AUTHOR]

Ante tres casos de legionelosis asociados a un establecimiento balneario se inició la investigación para confirmar la fuente de infección, determinar el riesgo y controlarlo. Entre el 26 de noviembre de 2008 y el 16 de septiembre de 2009 se realizaron seis inspecciones, con toma de temperaturas y muestras de agua para el aislamiento de Legionella pneumophila en todos los puntos de la red de agua caliente sanitaria y en las piscinas climatizadas. Se confirmó la presencia de L. pneumophila del serogrupo 1 con el mismo patrón molecular que la cepa clínica en el circuito de agua caliente sanitaria (de bajo riesgo de proliferación). La tasa de ataque bruta fue del 0,34% (intervalo de confianza del 95%: 0,09-0,94). Solo se obtuvieron muestras de agua sin presencia de L. pneumophila tras realizar cambios estructurales. Las temperaturas del agua entre 25 y 30ºC, el estancamiento del agua y la exposición a primera hora de la mañana serían factores participantes en la agrupación de casos.After three cases of legionellosis associated with a spa were identified, an investigation was conducted to confirm the source of infection, determine the risk factors, and establish control measures. Between November 26, 2008 and September 16, 2009, six inspections were carried out, samples were collected for Legionella pneumophila isolation, and water temperature was determined at all the sampling points of the hot water system and at the spa pools. The presence of L. pneumophila serogroup 1 with the same molecular pattern as that found in the clinical isolate was confirmed in the hot water system (with a low proliferation risk according to legislation). The crude attack rate was 0.34% (95% CI: 0.09-0.94). Samples without L. pneumophila were obtained only after structural changes were carried out. Possible factors participating in the cluster were water temperatures between 25ºC and 30ºC, stagnant water and early morning exposure.

This investigation deals with the issues of resource-saving in buildings, to wit, power saving in heat supply systems. The IAHSU was considered as one of the solutions. The article gives an example of selecting an IAHSU for a 16-storey residential building and calculates the parameters required for making a HSU. [ABSTRACT FROM AUTHOR]

For the climatic condition of a tropical country like Bangladesh, solar heat driven adsorption cooling seems to have great prospect. Installation cost is one of the foremost drawbacks of such a system. Although, once installed, system maintenance and operation cost is negligible. Besides, the solar unit can not only support as a cooler for adsorption space cooling purpose during summer season but also as a source of hot water supply for domestic use during the winter season. A conventional two bed basic adsorption chiller, driven by solar heat run by silica gel-water pair as adsorbent and adsorbate respectively, has been investigated for the climatic condition of Dhaka 23°46′N (latitude), and 90°23′E (longitude). 30 enhanced compound parabolic concentrator (CPC) collectors each of area 2.415 m 2 along with a hot water storage tank of volume 2.197 liters is optimum for considered climatic condition. With such a unit 30.27 °C continuous water supply during the peak hours can be assured, with the storage of 44.77 °C of hot water in the month of January. [ABSTRACT FROM AUTHOR]

The condensing heat recovery in air conditioner is attractive because of its great economical and environmental value. This paper presents theoretical and experimental investigations of a novel solar thermoelectric air conditioner with hot water supply (STACHWS). The system can implement different working modes according to the building users’ requirement. Experiments were carried out under different operating conditions in order to investigate the performance of the system. Results show that the STEACWS can reliably be used to heat hot water without losing its cooling capacity when it is controlled well in different operation conditions. The system has relatively remarkable coefficient of performance (COP int ) which can be as high as about 4.51 in space cooling and water heating mode. When the system works as a water source thermoelectric heat pump, the coefficient of performance (COP) of the system can be about 2.59 in cooling mode and 3.01 in heating mode. This simple and environmentally friendly system can reduce indoor cooling and heating load and provide a continuous hot water supply for householders. [ABSTRACT FROM AUTHOR]

This work evaluates the possibility of meeting a single family household's need for hot water and heat year round, using solar collectors as the sole energy source. The main flaw of energetic systems based on solar energy is that the energy supply is usually insufficient in winter, when it is most needed. This work is going to show that, for a house surface of 150 m² and base dimension of 10x10 m, it is possible to supply sufficient heat for everyday purposes with solar energy only, using a thermally insulated thermal storage unit of 200 m³ volume, filled with water or paraffin wax. [ABSTRACT FROM AUTHOR]

Highlights: [•] Drawbacks of the initial prototype are analyzed and remedical measures are proposed. [•] Optimized prototype provides better performance than the initial prototype. [•] Optimized prototype shows the superior performance in future practical use. [•] Impacts of outdoor air and gray water temperature on system performance are studied. [•] Supplying hot water improves the COP and has limited impacts on space heating. [ABSTRACT FROM AUTHOR]

Abstract: A field survey on energy consumption by hot water supply and cooking was conducted in two cities in China, Nanjing, and Hefei. In each city, 5 housing complexes were selected, and approximately 100 or 200 residential units were selected from each of them. The following items were surveyed: (1) fundamental information, such as number of family members, data on residents, etc., (2) bathing style, and (3) frequency of cooking and cooking time. Most of the residents take showers seven times a week in the summer, but less frequently in the winter. In contrast, the frequency of taking baths increases to several times a week during the winter, compared with 0 or 1 times a week in the summer. These results differ slightly depending on the heating and cooling systems used in the houses. The frequency with which people cook in their own houses ranges from 4 to 7 times a week, which means that “eating out” is relatively frequent, although the result differs significantly among the housing complexes. Distribution of the cooking time has usually two peaks at 20 to 30min and 50 to 60min (or 30 to 40min and longer than 60min) for lunch and dinner, respectively. The high energy consumption for cooking might be due to the long cooking time. [Copyright &y& Elsevier]

A solution is given to the problem of heat supply to multi-storied residential and office buildings with the use of solar insolation as the principal energy source making it possible to do away with the district heating of towns and settlements and to reduce expenditure of energy on heating and hot water supply by more than 85%. [ABSTRACT FROM AUTHOR]

A district heating and hot water supply system is presented which synthetically utilizes geothermal energy, solar thermal energy and natural gas thermal energy. The multi-energy utilization system has been set at the new campus of Tianjin Polytechnic University (TPU). A couple of deep geothermal wells which are 2 300 m in depth were dug. Deep geothermal energy cascade utilization is achieved by two stages of plate heat exchangers (PHE) and two stages of water source heat pumps (WSHP). Shallow geothermal energy is used in assistant heating by two ground coupled heat pumps (GCHPs) with 580 vertical ground wells which are 120 m in depth. Solar thermal energy collected by vacuum tube arrays (VTAs) and geothermal energy are complementarily utilized to make domestic hot water. Superfluous solar energy can be stored in shallow soil for the GCHP utilization. The system can use fossil fuel thermal energy by two natural gas boilers (NGB) to assist in heating and making hot water. The heating energy efficiency was measured in the winter of 2010-2011. The coefficients of performance (COP) under different heating conditions are discussed. The performance of hot water production is tested in a local typical winter day and the solar thermal energy utilization factor is presented. The rusults show that the average system COP is 5.75 or 4.96 under different working conditions, and the typical solar energy utilization factor is 0.324. [ABSTRACT FROM AUTHOR]

Energy systems for consumers' supply with sanitary hot water can be considered as a separate category of the system with many similar functions, performances and integral elements. This similarity of energy systems for sanitary hot water supply and the way in which they are used enable systemic planning, proposing and undertaking measures for improvements and advancements. This is possible not only by the reconstruction and modernization of existing technological solutions but also by their replacement with new, modern and more efficient solutions. The basic idea and the aim of this paper is the development of a concept for integrated and upgraded system of sanitary hot water supply for different types of buildings from residential to more complex buildings intended for different purposes. The analysis is based on the application of a systemic approach adapted to the conditions in urban communities and includes only modern but commercial technologies. This paper presents the results of a net energy analysis of integrated central and solar hot water supply system and compares it with the conventional sanitary hot water system in the City of Novi Sad, Serbia. The proposed methodology is demonstrated through a simulation example. It is shown that 23% reduction in the total system's costs can be achieved as compared to the existing solution. Also, the methodology is applied to a residential block as a unit and obtained results indicate that investments in the development and construction of integrated systems are justified. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the evaluation results of conventional solar water heater (SWH) systems and solar assisted heat pump (SAHP) systems for hot water production in Hong Kong. An economic comparison and global warming impact analysis are conducted among the two kinds of solar thermal systems and traditional water heating systems (i.e. electric water heaters and towngas water heaters). The economic comparison results show that solar thermal systems have greater economic benefits than traditional water heating systems. In addition, conventional SWH systems are comparable with the SAHP systems when solar fractions are above 50%. Besides, analysis on the sensitivity of the total equivalent warming impact (TEWI) indicates that the towngas boosted SWH system has the greatest potential in greenhouse gas emission reduction with various solar collector areas and the electricity boosted SWH system has the comparative TEWI with the SAHP systems if its solar fraction is above 50%. As for SAHP systems, the solar assisted air source heat pump (SA-ASHP) system has the least global warming impact. Based on all investigation results, suggestions are given on the selection of solar thermal systems for applications in Hong Kong. [Copyright &y& Elsevier]

This paper presents a mathematical model for the collection and efficient use of solar energy in hot water systems at permafrost regions. A case study was presented for northern territories of the Russian Federation in the Republic of Sakha (Yakutia). Daily maximum diffuse solar radiation on a horizontal and inclined surface was predicted during the year taking into account cloud coverage. The cloud coverage data was taken from the results of five-year monitoring on the heliometric station of the Yakutsk city. The modelling of the hourly, daily, monthly, and annual amount of solar radiation was performed. The mathematical model was turned and finally proved by experimental data obtained from the testing rig. The modelling of the domestic hot water supply system of particular northern territories was performed using solar energy and energy storage. Both models were integrated and verified by experimental data accounting a seasonal fluctuation. The estimation of the solar energy potential for practical application in Yakutia was executed. The operating features of permafrost regions were analysed by the developed experimental unit. The application of solenoid valve reduces the heat losses during the night by 57% in June and by 69% in November. The case study provides the results of modelling and efficient use of solar energy for different daily water flow rates during January and June. The results of the case study show the possibility to use of solar energy in a hybrid energy system at permafrost regions, decarbonize the energy input and contribute regional sustainability of northern territories. • A modelling of solar energy for DHW in permafrost regions was performed. • Experimental unit for solar energy harvesting in northern territories was developed. • The mathematical model was proved by experimental data. • A case study presents the solar energy use in permafrost region. • The operating features of solar energy at permafrost regions were analysed. [ABSTRACT FROM AUTHOR]

Hot water supply is one of the leading consumers of energy in the building sector in cold climate areas. The use of woody biomass is effective in reducing CO2 emissions in hot-water supply systems. This report deals with a system that combines a wood pellet boiler (PB) and a heat pump system with CO2 (CO2HP) that is used in a facility for disabled people. The following research was conducted. The operation of a hybrid system combining a PB and CO2HPs was investigated. While operating the system, four specific operations were developed as countermeasures to save on costs and reduce system troubles while reducing CO2 emissions. The processes and results are introduced. Numerical simulations were carried out to optimize the operation. The hot water temperature, water volume, and hot water loads were simulated. The influence of the water volume ratio on the cost and primary energy consumption under the requirements for safe system operation was studied. The regional economic ripple effects (REREs) of this system were studied. The wood pellet boiler is not only a measure for reducing primary energy consumption but can also play an important role in a regional economy for sustainable development in countries that import energy resources such as Japan. [ABSTRACT FROM AUTHOR]