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According to the energy development strategy of Ukraine, implementation of energy efficient buildings is needed, in which external protections are converters of solar energy into heat. The article presents studies of solar coating with direct coolant supply. Studies of the average value of the heat loss coefficient of the solar coating were also carried out. As a result, the efficiency of the solar coating under the mode of forced circulation of the coolant is 0.67, at natural circulation of the coolant – 0.57 and at its direct supply is 0.71. Experimental researches of thermal and physical parameters of a solar covering and system of heat supply on its basis showed in the corresponding dependences influence on its thermal characteristics of dynamic modes of the heat carrier, energy, kinetic characteristics of the environment.

Lowering the exergy content of heat required for heating purposes decreases the primary energy consumption. District heating systems are often an important link between facilities that generate heat with low exergy content and consumers. Exergetic efficiency of heat distribution is an important performance criterion in heat supply to consumers. It can serve as a criterion for optimization, towards a more sustainable distribution-network design and operation. This paper presents a methodology for an exergy-based distribution-network analysis in a district heating system. Criteria for performance evaluations are defined. They can be used to evaluate heat supply to different points in the network, or individual system components. A case study is performed on an existing district heating system. Energetic and exergetic efficiencies of supply lines are analyzed. Exergy destructions and exergy losses are studied. Large differences in efficiency of heat supply to different points in the network are discovered. Over-dimensioned parameters of the distribution network are investigated.

One of the most important directions of Russia's economic and energy strategy is to increase the efficiency in the field of heat supply. One of the options for solving this issue is using preinsulated pipelines, such as steel pipes in polyurethane foam polyethylene insulation. The experience of their application indicates several disadvantages associated with defects in pipes in polyurethane foam insulation and installed pipelines. The studies carried out made it possible to identify the main defects and inconsistencies in the manufacture and installation of preinsulated pipelines and the reasons for their occurrence. Following this, the authors have developed a set of operations and control tools during the installation of pipes in polyurethane foam PE insulation, clarifying the requirements of the input, operational and acceptance types of control, which contribute to improving the quality of the finished product, which was the purpose of this work.

This article contains data on equipment failures at thirty-six centralized heating stations. In the process of operation of heating stations, the arising failures can lead to a significant decrease in air temperature in heated rooms. Data was obtained through the study of operational logs. When analyzing the data, we used the records of a five-year observation period (2012 to 2017) taking into account the preventive work that carried out annually as part of the preparation of equipment for use in winter conditions. Malfunctions of equipment elements, that arise during the operation of heat supply stations, have different meanings in qualitative and quantitative aspects. Different specialists of the same qualification may not represent the same quality characteristics of the same shortcomings. The presentation of faults in the form of sequences of numbers allows to formalize the analysis and reduce the influence of the subjective factor. Data on observations of equipment failures and restoration are the basis for determining the equipment reliability indicators at heat supply stations. The data can be used for repair planning, emergency services, financial planning and operational management focus. The obtained data are related to the research article "Monitoring of heating systems as a factor of energy safety of buildings" [1].

At present, specialists of foreign and domestic research organizations and industrial firms pay much attention to the use of steam compression heat pump plants (HPP) as an energy-saving technology. Modern compressor units allow receiving 3-4 kW for 1 kW of power consumed by HPP, and under certain conditions up to 5-6 kW of useful power. Today HPPs are most used in heat supply systems for residential and office buildings, especially in Scandinavia, Germany, Switzerland, USA, Japan, China. The paper discusses features of the operation of steam compressor heat pump plants as systems for improving energy efficiency with a description of the device of a heat pump plant; its main components are also listed. Review of the existing practice of introducing such systems in foreign countries is presented, including in Minsk - the Minsk metro, and in Russia - the Moscow Metro. The project, performed by specialists of JSC “VNIIZhT” and MIIT, is considered for the Moscow Metro (with reference to the heating systems of the Nagatinskaya and Pushkinskaya metro stations) for the use of dumping heat of ventilation shafts for heating and hot water supply, proposed by scientists of JSC “VNIIZhT” in 2012 within the framework of the exhibition of technical achievements. Authors presented information on the implementation of the pilot project at the station “Salar’yevo” (Moscow Metro) on the use of HPP in the heat and cooling supply system of the station for further comprehensive analysis of the effectiveness of the HPP application in the operating conditions of the metro. From the analysis of the data given in the work, it is concluded that metro systems are significant sources of low-potential heat, which can be used for the heat supply of stations and/or nearby urban sites by means of HPP. By now, there is a lot of experience (especially abroad) of the practical application of HPP in the heat supply systems of facilities. Nevertheless, for a reliable and comprehensive assessment of the feasibility and cost-effectiveness of projects using low-potential heat of metro systems as an energy-saving technology, a complex of studies is needed, including operational tests of currently implemented pilot projects.

Кодкин Владимир Львович, д-р техн. наук, профессор кафедры автоматизированного электропривода, Южно-Уральский государственный университет, г. Челябинск; kodkina2@mail.ru. Аникин Александр Сергеевич, доцент кафедры теоретических основ электротехники, Южно- Уральский государственный университет, г. Челябинск; anikinas@susu.ru. Балденков Александр Александрович, аспирант кафедры автоматизированного электропривода, Южно-Уральский государственный университет, г. Челябинск; baloo@mail.ru. V.L. Kodkin, kodkina2@mail.ru, A.S. Anikin, anikinas@susu.ru, A.A. Baldenkov, baloo@mail.ru South Ural State University, Chelyabinsk, Russian Federation Results of studies of the automatic regulation system of a residential complex along the street of Academician Sakharov in the city of Chelyabinsk are given in article. The analysis of actual indicators of volumes of consumed gas within several months 2015–2017 is carried out depending on average daily temperature of external air. It is shown that the adjustment of the controller by the factory method does not ensure the effective functioning of the heat supply system, especially at ambient temperatures close to 0 °C. The comparison was carried out in two ways: by the method of equivalent trends and by the average temperature and consumption of gas per month. The conducted analysis convincingly proves that the control system with monotonic processes is not only more effective from the point of view of the operation of the equipment, but also from the point of view of energy efficiency. Приведены результаты исследований системы автоматического регулирования жилого комплекса по ул. Академика Сахарова в городе Челябинске. Анализ фактических показателей объемов потребляемого газа в течение нескольких месяцев 2015–2017 гг. осуществлялся в зависимости от среднесуточной температуры наружного воздуха. Показано, что регулировка контроллера по рекомендации завода изготовителя не обеспечивает эффективного функционирования системы теплоснабжения, особенно при температуре окружающей среды, близкой к 0 °C. Сравнение проводилось двумя способами: методом эквивалентных тенденций и средней температурой и потреблением газа в месяц. Проведенный анализ убедительно доказывает, что система управления с монотонными процессами не только более эффективна с точки зрения работы оборудования, но и с точки зрения энергоэффективности.

application/pdf, Article, Energy. 137, p.888-897

Solar systems are actively applied for heat supply of buildings in Europe. Usage of solar energy for heat supply of residential buildings is considered as rather efficient for the Republic of Belarus because total amount of direct and scattered solar radiation entering horizontal surface is equivalent to an average European index for the climate of Belarus. The paper analyzes an existing dependence on determination of solar system efficiency and proposes an amended formula for calculations while designing solar consumption systems and its legitimacy has been experimentally proved. A scheme of an experimental unit with explanations and a brief description for execution of experiments and main results of the completed investigations have been presented in the paper. Experiments have been carried out for solar systems with natural and forced coolant circulation. Attention has been paid to obtaining maximum possible temperature potential of the coolant during operation of the solar system within periods of high and low solar radiation intensity. Recommendations on practical application of solar systems for multi-storey residential buildings houses and mansion-type houses have been given in the paper. The paper presents technological principles of constructing “passive” solar heating devices. A comparison of traditionally applied and proposed alternative solar systems has been made for operational conditions in Belarus. The paper proposes a solar system for hot water supply of multi-storey buildings. The proposed system has found its first realization in the Republic while designing and constructing an energy-efficient demonstration 10-storey residential building in Mogilev within the framework of the UN Development Program project and Global Environment Fund “Improvement of energy efficiency for residential buildings in the Republic of Belarus”

This study aims to conduct a comprehensive life cycle assessment (LCA) of wood-based boards to support environmentally conscious design. The goal is achieved by the following objectives: to produce generic LCA data for production of wood-based boards (cradle-to-gate) and to evaluate the human health impacts through life cycle including the use stage (cradle-to-grave), based on the latest regulations for formaldehyde emissions in Japan. Production data of particleboard (PB), hard fiberboard (HB), medium-density fiberboard (MDF), and insulation fiberboard (IB) were obtained from major manufacturers of wood-based boards in Japan. We evaluated the impact categories of climate change, abiotic resource depletion, human toxicity (cancer and non-cancer effects), and ecotoxicity (cradle-to-grate assessment). For the human health impacts by formaldehyde emissions from PB and MDF in the use stage (40 years), we calculated the impacts through the life cycle (cradle-to-grave assessment), at all grades of formaldehyde emission rates set by the formaldehyde regulation. Cradle-to-gate assessment indicated that adhesives constituted 28–55% of the impacts in all categories for PB and MDF, whereas 74–98% of the impacts resulted from utilities supply for HB and IB. In particular, heat supply from wood boilers accounted for more than 92% of human health (non-cancer) and 71% of ecotoxicity impacts in HB. Cradle-to-grave assessment of PB and MDF, which satisfy strict regulations on formaldehyde emissions (

The use of Primary Energy Factor (PEF) was chosen by European Union policy makers as an obligatory part of methodology for comparing the primary energy consumption of products, using different energy sources. Approaches for definition of primary energy differ in EU member states. Different methodologies and definitions of primary energy factors have impact on calculation of energy sector key indicators, including district heating (DH) sector. The aim of the research was collection, analysis and systematization of data about PEF and its calculation and definition methods for DH in EU Member states. Method used for data collection about EU Member States with adequate share of DH in heat supply is meta-analysis systematic review methodological approach, using as main data sources legislation and standards currently in force, which are used to regulate implementation of PEF in EU Member States with adequate share of DH in heat supply. The main criterion for the classification of DH PEF in different countries is PEF determination procedure. Based on this criterion three main groups were analysed: single fixed DH PEF, differentiated DH PEFs, DH PEF, calculated for each DH network independently.

Air pollution represented by haze in China has attracted great global attention in recent years. China has recently introduced a series of action plans to improve air quality and prevent air pollution. Remediation on small coal-fired boilers and the development of heat and power cogeneration (HPC) and centralized heat supply (CHS) are important measures for preventing air pollution. This paper introduces the above mentioned policies. An industrial park in Guangdong Province, China, is taken as an example to analyze the contributions of HPC-based industrial CHS to energy saving and environmental protection. The benefits to the heat supplier and user are also analyzed. Furthermore, this paper presents the difficulties and challenges in developing industrial CHS, including mismatching in the early phase, price dispute, measure dispute, and negative inter-effects. The reasons for these problems are analyzed and possible solutions are provided.

The paper suggests a methodology to determine optimal reliability parameters (failure and restoration rates) of heat supply system components, which provide the required level of heat supply reliability. The methodological approach consists in the economically rational distribution of the total effect of reliability improvement among the system components, which is calculated using the average reliability parameters of the components. This task, along with the task to ensure structural reliability, is one of the key reliability tasks within a more general problem of optimal synthesis of heat supply systems and is urgent for both the systems under design and the existing insufficiently reliable systems. The methodology of solving the stated problem is based on the methods of the theory of hydraulic circuits, nodal reliability indices, models of Markov random process and general regularities of heat transfer processes. The methodology also takes into account changes in thermal loads during the heating period and time redundancy of consumers related to heat storage. The results of the practical research based on the calculation experiment that confirms the viability of the presented methodology for the schemes of real heat supply systems are presented. The advantages of the proposed methodology compared to the existing approaches to solving this problem consist in joint optimization of the component reliability of heat source and heat network schemes, integration of procedures for the reduction in failure rates and the improvement in restoration rates of the components in one calculation pattern of search for the optimal system reliability, the absence of the need to conduct iterative calculations when using the average reliability parameters of components, considering the required levels of reliability indices.

This article describes a methodological approach to defining indoor air temperature in buildings heated by a power supply unit consisting of a boiler house and a wind-driven power plant (WDPP). We discuss a heating option for a residential building in the windy conditions of Murmansk city. We proved that, during the periods of strong wind, a WDPP can partially or fully satisfy the heat demand and sometimes even create a surplus of energy. During low wind weather, almost all loads are handled by the boiler house. We considered a possibility to accumulate the surplus energy obtained from a WDPP during strong wind by increasing the temperature in the whole building up to 25°C and further using the accumulated heat during the lowwind period when indoor air temperature may fall below 20°C. This allows saving organic fuel in the boiler house. We demonstrated how indoor air temperature in the building may change throughout the year when using the surplus energy from the WDPP due to thermal storage capacitance of the building. We also provided the results of study, showing favorable energy-related effects of using a WDPP along with the boiler house. It was determined that engaging a WDPP in fulfilling the diagram of heating loads promotes the decrease in the boiler house’s contribution to heat supply by 30 to 50%, and using the surplus energy from the WDPP and thermal storage capacitance of the building allows reducing the contribution of the boiler house by 5–15% more in certain months.

An elementary arrangement is considered for heat supply of residential buildings with dependent connection to external heating systems, providing reliable heat delivery and required comfort indoors due to admixing of water from the heating system return line at an outdoor temperature exceeding the breakpoint temperature. Basic equations are analyzed describing dependence of the temperature of water in the trunk lines on the outside air temperature, and an overview is presented of possible ways to regulate heat delivery and prevent oversupply of heat near the beginning and the end of the heating season with consideration of requirements of the current Russian Federation regulations. Calculations are performed, which enable to determine the desired admixing ratio in conditions of application of an arrangement with buildings connected to a heating system involving use of mixing pump based on linearization of the equation of the temperature curve in the heating system in a close proximity to the breakpoint temperature. Analysis is given of results obtained, and conclusions are drawn regarding the feasibility of the arrangement under consideration. It is found that the value of the current dimensionless diff erence of temperatures of indoor and outdoor air at the breakpoint does not depend on climatic parameters of the construction area, and the required admixing ratio is almost directly proportional to the excess of outdoor temperature compared to the breakpoint temperature. It is shown that the higher the estimated water temperature in the return line of the heat network at the breakpoint is, the higher the value of the admixing ratio. Recommendations are given on sharing the elevator and the mixing pump in order to minimize variations at reconstruction of the heat entry to eliminate oversupply of heat.

Кодкин Владимир Львович, д-р техн. наук, профессор кафедры автоматизированного электропривода, Южно-Уральский государственный университет, г. Челябинск; kodkina2@mail.ru. Аникин Александр Сергеевич, доцент кафедры теоретических основ электротехники, Южно- Уральский государственный университет, г. Челябинск; anikinsasha@gmail.ru. Балденков Александр Александрович, аспирант кафедры автоматизированного электропривода, Южно-Уральский государственный университет, г. Челябинск; baloo@mail.ru. Качалин Андрей Юрьевич, аспирант кафедры автоматизированного электропривода, Южно-Уральский государственный университет, г. Челябинск; kachalin89@inbox.ru. V.L. Kodkin, kodkina2@mail.ru, A.S. Anikin, anikinsasha@gmail.ru, A.A. Baldenkov, baloo@mail.ru, A.Y. Kachalin, kachalin89@inbox.ru South Ural State University, Chelyabinsk, Russian Federation Results of trial operation of system of heat supply of the residential building with the optimized processes of regulation of temperature of the heat carrier are given in article. The actual indicators of volumes of the consumed gas for several months 2015 and values of temperature of external air are analyzed. It is shown that “factory” settings of controllers don't ensure effective functioning, especially at temperatures of external air close to 0 °С. The data, which showed that the optimization of processes in heating systems developed techniques for increasing their efficiency by 10–15 %. On the basis of pilot studies in a suburban boiler room with considerable losses in a heating main, the method of increase in their energy efficiency by increase in giving of the heat carrier is offered. The method is realized by means of the converter of frequency installed for control of the network pump. The experiments have confirmed efficiency of the offer. Приведены результаты опытной эксплуатации системы теплоснабжения жилого здания с оптимизированными процессами регулирования температуры теплоносителя. Проанализированы фактические показатели объемов потребленного газа за несколько месяцев 2015 года и значения температуры наружного воздуха в это же время. Показано, что заводские настройки регуляторов не обеспечивают эффективной работы, особенно при температурах наружного воздуха, близких к 0 °С. Приведены данные, показавшие, что оптимизация процессов в системах отопления по разработанным методикам повышают их эффективность на10–15 %. На основе экспериментальных исследований в пригородной котельной со значительными потерями в теплотрассе, предложен метод повышения их энергоэффективности путем увеличения подачи теплоносителя. Метод реализован с помощью преобразователя частоты, установленного для управления сетевым насосом, и эксперименты подтвердили эффективность предложения.

The scheme of equalization of heat-transfer agent temperature expansion in independent heating system without temperature tank is viewed. To equalize heat-transfer agent temperature expansion regulating and safety valves are used in this scheme instead of temperature tank. The valves provide heat supply and heat rejection in- and out of heating system. The proposed scheme permits to equalize heat-transfer agent temperature expansion in heating systems with a large amount of heattransfer agent and with minimal capital cost.

High efficiency heating/cooling networks have a main role in economy decarbonisation. Evaluation of the potential for cogeneration district heating systems at regional level requires environmental, economic and regulatory analyses at different levels. This paper defines a top-down/bottom-up methodology for the analysis of potential cogeneration district heating systems at regional level as tool for supporting energy policies. It is based on the analysis at four levels for the regulatory framework, resources, infrastructures and demands: national, regional, municipality and district. As case study the methodology is applied to the analysis of cogeneration heating networks in the Spanish continental area. For the case study, cogeneration heating networks of small power (5MWe) were shown as the most interesting option with heat supply capacity for 1300–1400 houses. The application of the methodology to this region shows a potential for 589 new fully viable cogeneration district heating systems. It implies the installation of 3000 MW of high efficiency distributed power. For each single module annual savings above 0.5 Million euros are expected with market prices for gas and electricity. Results show the opportunity for an annual CO 2 emissions savings above 4 Million of CO 2 tons and a business generation above 3000 Million of euros.

The need to solve problems of planning and justification of the rational level of centralization and concentration of sources' heat capacity was noted in the law “About a Heat Supply”. For the solution of these tasks, the complex methodology was developed; it allows us to define locations of heat sources and the border of their action at the predesign level of heat supply schemes' development of settlements. In presented complex methodology, standard values of heat load density per unit of the area (heat load density) and per unit of the pipelines' length (linear heat density) are criteria of scales restriction of the systems. The important task is to find their standard values. Authors offer dependences for determination of standard values of heat density indicators for carrying out a predesign analysis of heat supply systems. The analysis carried out showed that heat supply from chosen heat source of part of consumers isn't economically feasible if values of heat density indicators are less than their standard values. The less value of heat density in the system, the higher specific costs for generation, distribution and transmission of heat energy.

Correlations of resultant heat transfer efficiency criteria with length of flat flames are obtained for various gaseous and liquid hydrocarbon fuels by mathematical modeling of complex heat transfer in narrowchamber tube furnaces using zonal method. Thanks to this, such temperature fields can be created in the furnace by varying the length of flat flames as would ensure the required uniformity of heat supply at nearmaximum value of integral heat received by a tubular screen.

This contribution introduces an innovative, sustainable heat supply concept. This concept, which is based on solar thermal and geothermal heat generation and advanced heat storage technologies, will be realized for the first time as a heat supply system for new apartment buildings. The key feature of the system is the fact, that on an annual basis only 1 kWh of electricity will be required to generate 10 kWh of heat. This contribution is focused on the presentation of the above described, newly developed system concept as well as first results of the design and simulation studies for a pilot heat supply system that is planned to be realized in a complex of three multi-family houses within a total living area of over 3 500 m 2 in the German city Crailsheim, which is located 80 km north-east of Stuttgart. The development of the concept is part of the research project ‘1to10 – Development, testing and demonstration of a sustainable, standardized solar-geothermal heat supply concept’. In the conceptual design phase of the project, theoretical work for the realization of such systems is performed.

The European funded cooperative research and demonstration project PITAGORAS is focused on efficient integration of city districts with industrial parks through smart thermal grids. The overall objective of the project is to demonstrate a highly replicable, cost-effective and greatly energy efficient large-scale energy generation system for sustainable urban planning of low energy city districts. As part of the project two demonstration plants namely in Brescia, Italy and Kremsmunster, Austria are being designed and will be built and tested during the project. The demonstration plant in Austria focuses on installing a large-scale solar thermal system of 10,000 m 2 ; including seasonal storages with a total capacity of 60,000 m 3 in order to supply the local district with heat and to reduce the gas consumption of a large combined heat and power (CHP) plant nearby. Additionally, to the demonstration plant in Austria the collector efficiency of several different collector types of different collector manufacturers is being tested under real outside conditions, which may give valuable insights on these collectors in order to choose the most efficient collector for the demonstration plant and ultimately on the future development of solar collectors.

In spite of the large potential, the market development of solar heat for industrial or commercial applications is rather slow so far. An important barrier for the market development is the large effort to carry out a feasibility assessment including the pre-dimensioning of a suitable solar process heat system. Especially to facilitate the identification of suitable integration points for solar heat in Industry, tools and guidelines are required. To reduce the effort for identification of a suitable integration point within Industry, comprehensive research on the food and beverages sector was performed to highlight the possibilities for integrating solar heat. The analysis shows that the utilized process installations and especially the current equipment for heating are of particular importance for the integration of solar heat. Based on the results of the analysis of several sectors of the food and beverage industry and conventional process heating technologies, a classification for the integration of solar heat in industrial processes and heat supply systems was developed. This classification is sector independent and contains concepts for the hydraulic integration of solar heat for the majority of all industrial processes and operations. Finally, an approach is presented to simplify the choice of a suitable integration point for solar heat in industry. This approach includes the identification and assessment of possible integration points as well as the utilization of the developed classification and other important steps within the feasibility assessment.

The article contains important issues about functioning of technical means and engineering systems of cities as sources of the human impact on the surrounding ecosystem, namely, the study of the functioning of boiler plants as sources of the human impact on a condition of the atmospheric air located near urbanized areas. So, we solved the problem of improving standardization systems, licensing, certification, environmental safety requirements, design and research activities in the building and operation of municipal services, in particular, improving methods of forecasting air pollution by solid particles contained in emissions released from the production of heat and electricity by burning coal. We made studies and mathematical treatment of the dispersed composition of dust emitted from the organized (boilers) and unorganized (ash dumps) boiler emissions sources, we established that solid particles are entered in the atmospheric air and most of them has a size up to 20μm. We got expressions for determining the sedimentation rate of fine particles of ash and slag.

The following article describes the designed and implemented mathematical model of the distribution model of heat consumption in an urban agglomeration. The model is intended for the prediction of heat supply, which can be applied in the regulation system. Depending on the structure of a given real-life system it is usually required for the heating water temperature to be predicted.For the purposes of describing the heat consumption characteristics a function characterizing the heat consumption fluctuation has been established. The fluctuation is defined by number of variables such as outdoor temperatures, solar radiation etc.

Reverse cycle defrosting is the most widely used standard defrosting method for air source heat pump (ASHP) units. It was suggested in previous experimental studies that downwards flowing of the melted frost over a vertical multi-circuit outdoor coil in an ASHP unit has negative effects on reverse cycle defrosting performance. To quantitatively study the negative effects, an experimental study and a modeling study on draining away locally the melted frost for an experimental ASHP unit with a three-circuit outdoor coil were carried out and separately reported. However, for exiting ASHP units, it is hardly possible to install water collecting trays between circuits. To alleviate uneven defrosting for a vertical multi-circuit outdoor coil in an existing ASHP unit, an effective alternative is to vary the heat supply to each refrigerant circuit by varying the opening values of modulating valves installed at an inlet pipe to each circuit. In this paper, a modeling study on varying heat (via refrigerant) supply to each refrigerant circuit in a three-circuit outdoor coil to alleviate uneven defrosting is reported. Finally, in the designed three study cases, defrosting energy use could be decreased to 94.6%, as well as a reduction of 7 s in defrosting duration by fully closing the modulating valve on the top circuit when its defrosting terminated.

The work studies the problems arising at calculation of reliability indicators in relation to thermal networks of the large cities. Techniques of determination of reliability of heat supply deadlock and ring systems are analysed. Calculation of indicators of reliability of two cities (Kazan and Naberezhnye Chelny) having various structures of thermal networks is executed. The problem of reliability assessment at the moment and in the future is solved in the paper with the account of complication of heat supply schemes, development of new residential and industrial regions, changes such as laying of pipelines. The received indicators of reliability of the existing structure of thermal networks will allow one to define an optimum zone of connection of new consumers.

Exergy concept is applied on district heating systems with different network temperature levels in their distribution networks. These district heating systems use a combination of renewables and heat recovery from other primary processes. The aim is to show simplicity and value of using exergy concept when comparing current and future temperature levels. Both the traditional exergy factor and the novel exergy utilisation rate are used in these analyses. Exergy utilisation rate expresses the ratio between the exergy delivered to customer heating systems and the exergy content in heat supply input to the distribution network. The analyses are performed on four different generations of district heating technologies, two national groups of district heating systems in Denmark and Sweden for revealing variations among systems, and two municipal systems for revealing variations within systems. The main conclusions are simplifications can be introduced in order to analyse the network temperature levels, current exergy factors reveal that current temperature levels can be reduced, and that almost two thirds of the exergy content in heat supply input are lost in the heat distribution chain. These conclusion will be vital input in developing the future fourth generation of district heating systems using both renewables and heat recovery.

High temperature gas-cooled Reactor (HTGR) is expected to extend the use of nuclear heat to a wider spectrum of industrial applications such as hydrogen production, high efficiency power generation, etc., due largely to high temperature heat supply capability as well as inherent safe characteristics. Japan Atomic Energy Agency has been conducting research and development with a central focus on the utilization of High Temperature engineering Test Reactor (HTTR), the first HTGR in Japan, towards the realization of industrial use of nuclear heat. On the basis of licensing experience through the HTTR construction, JAEA initiated an activity to establish an international safety standard for licensing of commercial HTGR cogeneration systems fully taking into account safety features of HTGRs. This paper explains a roadmap towards licensing of commercial HTGR cogeneration systems. A test plan using the HTTR to support the establishment of safety standards and safety analysis methods is also presented.

The article presents special characteristics of mathematical modeling of the process control a resource efficient heat supply system of industrial buildings and facilities, where constant temperature maintenance is especially critical for the process. A functional diagram of the operation of the continuous heat supply process is provided. The dependence of temperature at the point of heat-transfer fluid mixing on environmental is analyzed and control system operation algorithm is proposed.

One of the main obstacles for more widespread introduction of heat pumps to the sphere of heat supply is the high cost of systems on their basis. The paper considers the measures capable to reduce cost and to increase efficiency of the heat pump installations using warmth of surface water, first of all warmth of watercourses, due to improvement of selection methods of low-grade heat from the water environment. The paper gives the example of a design of the submersible water-brine heat exchanger designed according to the described measures and recommendations about a choice of optimum medium of a low-temperature contour.

This article deals with applying numerical methods of thermal condition modeling of buildings and their component parts in heat-and-power engineering. Some research results in this area are also presented. The main purpose of the study is to improve energy efficiency of buildings’ thermal power on the basis of thermal conditions analysis. The object of the study is the thermodynamic parameters of the thermal state of the buildings heated by radiators of radiative-convective type. This article presents methods of modeling of aerodynamic and heat transfer processes in the buildings with the help of software package ANSYS CFX. The research results can be applied by energy auditors in the field of heat-and-power engineering to assess compliance of the comfortable conditions inside the building, to analyze its thermal state, to assess the effectiveness of various energy-saving measures.

This work presents the method of failures forecasting in district heating systems on the basis of time series analysis. Statistical data concerning the frequency of damage in communal heat distribution networks from a ten-year time period have been used in the article. The data were subjected to statistical analysis. The methods of exponential smoothing, ARIMA, homologous period trend estimation and seasonal indicators were applied as the most adequate for this type of data. Four forecast models of damage in district heating systems were formulated and the best optimal model for the system was selected. After verification, the methods of failure prediction in district heating systems can be applied in the operating process of a heat supply system. These methods give us answers to many questions about planning of repairs, maintenance emergency service, planning of finances and purposefulness of operational control.

In this paper, district heating is described and its operation process is considered in varying operation conditions over time. Taking into account the ordered thermal power which affects the amount of heat supply to consumers, the system operation states are introduced. Heat supply to consumers is carried out by means of a heat-carrying agent having the necessary parameters: required quantity, temperature and pressure, in a specific location, under certain operational conditions and timeframe. To model the system operation process and describe the changes between the operation states the semi-Markov process is applied. The identification of the district heating operation process is performed on the basis of real operational data obtained from the District Heating Company in the city of Rzeszow. Using the data and considering the specific character of the system, the main characteristics describing the safety of heat supply to consumers were determined.

The article describes the heat transfer and air movement that occur in the ventilated air gap of a building's passive solar heating system under winter and summer conditions. The physical and mathematical models of these processes are presented for the Trombe wall with and without venetian blinds arranged in the air gap. The mathematical models allow for the determination of the heat and air stream distribution and the surface temperature change of the constructive elements in both cases. The transfer of heat by radiation and convection are considered separately, making it possible to estimate in an analytical way the influence of constructive materials and covering properties on the heat flow distribution and regulate it. The mathematical models were developed on the basis of the analysis of the heat transfer and air movement and therefore they can be complemented and improved depending on the constructive and climatic conditions. Examples of comparative calculations of the heat transfer and air movement in the air gap of the conventional Trombe wall and the Trombe wall equipped with a venetian blind for regulation of heat supply are presented. For the winter period the comparative calculations were carried out with a different intensity of solar radiation.

This paper aims to explain and analyze the test results of the fire behavior of real-size bed mattress products when subjected to an open flame burner system with a total heat supply of 27 kW accor...

A life cycle assessment of greenhouse gas (GHG: CO2, CH4, N2O) emissions for woodchip-paved walkways using tsunami salt-damaged wood was conducted in Otsuchi, Iwate Prefecture. The GHG emissions for woodchip-paved walkways from the raw material procurement process to the construction process were 2.62 kg-CO2-eq/m2/year. Of these, most were for the raw material procurement process (88 %), with the production process accounting for 7 %, the transportation process

Automatic regulators of coolant temperature have found broad application in modern heat supply systems. These systems implement the oscillatory processes of regulation. Changes of the parameters of regulators in accordance with the instructions don’t practically change anything and the instructions don’t include the procedures of manual identification of buildings as the objects of regulation. Attempts of substantial (tenfold) changes in the controller parameters are very dangerous in real thermal systems. In order to obtain a qualitative picture of the influence of the selected parameters on the processes in control systems, it is advisable to use a mathematical model of the thermal system that is adequate to the real thermal system. The article presents a model of the heating system with reference to commercially available controllers flow temperature for heating and hot water developed by the authors. It is shown the adequacy of the model to the real heating system.

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.

The regional integration of variable wind power could be restricted by a strong coupling of electric power generation dispatch and heat supply of combined heat-and-power (CHP) units. The coupling in cold seasons precludes CHPs from providing the necessary flexibility for managing the wind power dispatch. The lack of flexibility problem can be tackled by exploiting the energy storage capability of a district heating network (DHN) which decouples the strong linkage of electric power and heat supplies. In this paper, a combined heat and power dispatch (CHPD) is formulated to coordinate the operation of electric power system (EPS) and district heating system (DHS). The proposed CHPD model which is solved by an iterative method considers the temperature dynamics of DHN for exploiting energy storage as an option for managing the variability of wind energy. The simulation results are discussed for several test systems to demonstrate the potential benefits of the proposed method in terms of operation economics, wind power utilization, as well as the potential benefits for real systems.

© 2017 Elsevier B.V. In recent years, the application of district heating systems for the heat supply of residential districts has been increasing in Germany. Central supply systems can be very efficient due to diverse energy demand profiles which may lead to reduced installed equipment capacity. Load diversity in buildings has been investigated in former studies, especially for the electricity demand. However, little is known about the influence of single building characteristics (such as building envelope or hot water demand) on the overall heating peak load of a residential district. For measuring the diversity, the peak load ratio (PLR) index is used to represent the percentage reduction of peak load of a district system from a simple sum of individual peak loads of buildings. A total of 144 residential building load profiles have been created with the dynamic building simulation software IDA ICE for a theoretical analysis in which the PLR reaches 15%. Within this study, certain district features are identified which lead to higher diversity. Furthermore, these results are used in a district heating simulation model which confronts the possible advantage of reduced installed capacity with the practical disadvantage of heat distribution losses. Likewise, the influence of load density and the district́s building structure can be analyzed. This study shows that especially in districts with high load density, which consist of newly constructed buildings with low supply temperature and high influence of the hot water demand, the advantages of load diversity can be exploited.

District heating (DH) is a cost-effective method of heat supply, especially to area with high heat density. Ultra-low-temperature district heating (ULTDH) is defined with supply temperature at 35-45 degrees C. It aims at making utmost use of the available low-temperature energy sources. In order to achieve high efficiency of the ULTDH system, the return temperature should be as low as possible. For the energy-efficient buildings in the future, it is feasible to use ULTDH to cover the space heating demand. However, considering the comfort and hygiene requirements of domestic hot water (DHW) preparation, supplementary heating devices should be combined, which can affect the return temperature in different extents. This study analysed the return temperatures of different types of substations for DHW preparation with ULTDH, and developed improvements in the substation for better energy efficiency. Both the instantaneous and storage-type electric heating methods were Long-term measured as supplementary heating for ULTDH in the case substations in Denmark. We analysed the seasonal impacts of the return temperature from the DHW loop on the overall return temperature of district heating. To achieve lower return temperature and higher efficiency for DHW supply, an innovative substation was devised, which replaced the bypass with an instantaneous heat exchanger and a micro electric storage tank. The energy performance of the proposed substation and the resulting benefits for the DH system by the lower return temperature were investigated (C) 2017 The Authors. Published by Elsevier Ltd.

The domestic energy demand of buildings is responsible for one third of the world's final energy consumption. To increase the sustainability of new housing areas, the identification of innovative heat supply concepts based on renewable energy sources (RES) is required. For the new housing area “Zum Feldlager”(Kassel, Germany), various supply concepts are studied. Main objective is the development of an innovative and efficient supply concept based on RES and low temperature district heating (LTDH) for practical implementation. In the course of different studies, centralised and decentralised supply strategies are analysed. The most promising supply concept is based on a central ground source heat pump in combination with LTDH and decentralised solar thermal systems. In comparison to a reference concept the annual heating costs and the CO 2 -emissions are lower. This project is a cooperative activity and of the Fraunhofer IBP, Institute for decentralized Energy Technologies (IdE), Kassel University, City of Kassel and Staedtische Werke Kassel AG. The paper covers a topic from IEA DHC Annex TS1.