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The demand for renewable energy sources and the construction of new consumer capacities for forest biomass, combined with increasing demands for nature protection and disturbances caused by global climate change, present several technological and logistical challenges. This study aims to analyze the main logistical problems in the production and transportation of forest biomass for energy use. The input data for the study were obtained from the databases of the National Forest Center and the Ministry of Agriculture and Rural Development. In the production cycle, harvesting operations related to forest management, including tending felling and main felling, were considered. Service prices were sourced from the public price lists of both private and state forest managers, as well as forestry machinery operators. Costs were calculated for three key points in the logistics flow: the skid way in the forest, the biomass supplier’s warehouse, and the heating plant utilizing the biomass. Our results indicate that, regardless of the production location or the age of the forest stand, the largest cost component is primarily the transportation of biomass to the point of consumption. After establishing the optimization structure, it is also necessary to ensure the operational functionality and continuous biomass supply.

The paper presents results of the measurements of the sulfur dioxide (SO2) and nitrogen dioxide (NO2) concentration and meteorological parameters: temperature, air pressure, relative humidity and wind speed. The data were collected from January 2019 to December 2020 at two stations, namely Center and Heating plant, in the City of Bijeljina, Republic of Srpska, Bosnia and Herzegovina. SO2 and NO2 are one of the major air pollutants that could negatively affect the human health. Levels of SO2 and NO2 in air samples and meteorological variables from urban zone of Bijeljina were determined at both localities, which represent a highly-populated area with intensive traffic. This topic has not been studied up to now in Bijeljina, although the recent research data indicates that there is a correlation between meteorological parameters and air pollutants. Statistical analysis confirms direct corelation between SO2 and NO2 and meteorological parameters, specially temperature in locality Center (r = -0.639), the wind speed in locality Heating plant (r = 0.399) and relative humidity (r = 0.162). Correlation of NO2 with temperature is not confirmed in both localities. The wind speed increase is followed by rises of the NO2 concentration values and vice versa. Correlation of NO2 with pressure is confirmed in locality Center (r = 0.128) but it is not confirmed in locality Heating plant. Correlation between NO2 and relative humidity found to be negative in locality Center (r = -0.062). These parameters are the most important meteorological factors influencing the variation in SO2 and NO2 concentration in the air during the research. Depending on the obtained correlation, meteorological parameters had a positive or negative impact on air pollution. [ABSTRACT FROM AUTHOR]

The article explores the possibility of using nanotechnology to improve the efficiency of centralized and autonomous heating systems on the way to a new technological model. A logical sequence of the development of heat supply and heating is given, conservative equipment and technologies that are used to supply thermal energy to consumers is marked. In the context of the urgent tasks of heat supply and heating of buildings, the concepts of the use of nanotechnologies that meet the goals of maximum heat transfer intensification are considered. Heat conduction analysis, concentration, size, mass and velocity of nanoparticles assesses are the basis for assessing the possibility to use nanofluids as a coolant for improving heat exchangers and to reduce heat losses in heating systems to maximize efficiency of their work. It is shown that the use of nanostructures affects the saving of coolant flow as the main task of the qualitative and quantitative regulation of the heat supply system. Attention is focused on the application of nano-structured materials in low-temperature fuel cells used decentralized heating systems for heating houses.

The rapid deployment of district heating systems in local energy markets and increasing the number of small‐scale heat producers along with the expansion of local electricity markets increase the need for a transaction framework to manage the transactions between local participants in both heat and electricity markets. This paper presents a peer‐to‐peer thermal energy transaction framework to manage the transactions between small‐scale heat prosumers. This framework enables small‐scale thermal energy producers and consumers to participate in the market as price maker agents. Moreover, the optimal strategy of heat market participants is determined by proposing a linear profit function for each agent. This optimization problem enables the agents to determine their optimal participation strategy in electricity and heat markets by addressing the interdependencies of electricity market, gas price, and heat market. The numerical results successfully demonstrate the benefits and applicability of the proposed framework. [ABSTRACT FROM AUTHOR]

Copyright of EMERG: Energy. Environment. Efficiency. Resources. Globalization is the property of Romanian National Committee of World Energy Council and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Graphical abstract Highlights • The economic and environmental impact of solar district heating systems is studied. • Multi-objective optimization is carried out in a wide range of EU climate zones. • A solar fraction above 90% can be achieved for all proposed EU climate zones. • High environmental performance is realized in solar district heating systems. • The future fuel prices growth supports the solar district heating economically. Abstract Aligning with the ambitious EU 2030 climate and energy package for cutting the greenhouse emissions and replacing conventional heat sources through the presence of renewable energy share inside efficient district heating fields, central solar heating plants coupled with seasonal storage (CSHPSS) can have a viable contribution to this goal. However, the technical performance variation combined with inadequate financial assessment and insufficient environmental impact data associated with the deployment of those innovative district heating systems represents a big challenge for the broad implementation of CSHPSS in Europe. In this context, our paper presents a comprehensive evaluation for the possibility of integrating CSHPSS in the residential sector in various EU member states through the formulation of a multi-objective optimization framework. This framework comprises the life cycle cost analysis for the economic evaluation and the life cycle assessment for the environmental impact estimation simultaneously. The technical performance is also considered by satisfying both the space heating demand and the domestic hot water services. The methodological framework is applied to a residential neighborhood community of 1120 apartments in various EU climate zones with Madrid, Athens, Berlin, and Helsinki acting as a proxy for the Mediterranean continental, Mediterranean, central European, and Nordic climates, respectively. The optimization results regarding the energy performance show that the CSHPSS can achieve a renewable energy fraction above 90% for the investigated climate zones. At the same time, the environmental assessment shows significant improvement when using the CSHPSS in comparison to a natural gas heating system, in those cases the environmental impact is reduced up to 82.1–86.5%. On the other hand, substantial economic improvement is limited, especially in the Mediterranean climate zone (Athens) due to low heating demands and the prices of the non-renewable resources. There the total economic cost of the CSHPSS plants can increase up to 50.8% compared to a natural gas heating system. However, considering the incremental tendency in natural gas prices all over EU nowadays, the study of future plant costs confirms its favorable long-term economic feasibility. [ABSTRACT FROM AUTHOR]

Highlights • Long-term operational experiences from two ORC cogeneration plants are reported. • Variability of operational parameters including biomass quality is explained in detail. • Key performance indicators are discussed. • Current macroeconomic and project profitability issues are presented. • SWOT analysis of the technology has been performed. Abstract This paper reports on operational experiences and performance of two municipal heating plants that were converted into cogeneration plants by the installation of biomass-fired modules based on the Organic Rankine Cycle technology (ORC). Two different plants of this type are presented. The text provides a review and discussion of critical issues related to implementation of the technology. Similarities, differences and operational characteristics are substantiated by the analysis of long-term measurement data. Particular attention is paid to variability of operational parameters, problems with determination of performance indicators, equipment characteristics, system sizing and its integration with existing heating plants. A special focus is put on profitability of investment projects under variable economic conditions. Finally, the technology is evaluated using Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis. The text fills the gap between the theoretical knowledge and required practical know-how. It also indicates areas of possible improvements and helps technological risk analysis in the future investment projects. [ABSTRACT FROM AUTHOR]

Copyright of Energy Policy Journal / Polityka Energetyczna is the property of Mineral & Energy Economy Research Institute of the Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nowadays biomass is widely used to produce electricity and heat. The growing demand for these stocks and their price results in the usage of low-quality biomass. In some cases, such biomass is mixed with herbaceous fuels and supplied to the heating plants. As such mix contains higher levels of volatile K, Na and Ca, there occurs ash-related problems such as slagging, fouling and agglomeration during combustion process. The aim of this work was to investigate the possibility to detect alkali-metals emission by chemiluminescence analysis during combustion in purpose to reduce the risk of ash-related problems. For experimental investigation, wood particle, wood pellet and wheat straw pellet were used. The chemiluminescence intensities of alkali species Na*, K* and Ca* and its variation during combustion of different biomass particle were evaluated. Results revealed that when fuel is changing during combustion, it is possible to predict the emissions of aforementioned radicals of different fuels and adjust appropriate regime of combustion. [ABSTRACT FROM AUTHOR]

Highlights • We look into internal structures of a production system to assess its performance. • We present a common-weights DEA method for two-stage structures with fuzzy data. • We assess the efficiency of the system and component processes. • The new approach is illustrated through a numerical example. Abstract Data envelopment analysis (DEA) has been genuinely known as an impeccable technique for efficiency measurement. In practice, since many production systems such as broadcasting companies, banking institutions and R&D organisations include two processes connected in series, we have need of utilising two-stage DEA models to identify the sources of inefficiency and explore in turn appropriate options for improving performance. The lack of the ability to generate the actual weights is not only an ongoing challenge in traditional DEA models, it can also have serious repercussion for the contemporary DEA models (e.g., two-stage DEA). This paper presents a common-weights method for two-stage structures that allows us to consider equality of opportunity in a fuzzy environment when evaluating the system efficiency and the component process efficiencies. The proposed approach first seeks upper bounds on factor weights and then determines a set of common weights by a single linear programming problem. We illustrate the developed approach with a data set taken from the literature. [ABSTRACT FROM AUTHOR]

Copyright of Geological Exploration Technology, Geothermal Energy, Sustainable Development / Technika Poszukiwan Geologicznych is the property of Mineral & Energy Economy Research Institute of the Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geological Exploration Technology, Geothermal Energy, Sustainable Development / Technika Poszukiwan Geologicznych is the property of Mineral & Energy Economy Research Institute of the Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With energy efficiency regulations coming into force, the retrofitting of existing plants has become mandatory in many European countries. The application of thermostatic radiator valves is a cheap, effective solution in case of radiator-based hydronic plants, but it requires the distribution system to be re-engineered and, in some situations, further adjusting devices to be added. In this paper, the behaviour of a vertical distribution heating system has been simulated with the aim of analysing the outcome of different hydraulic balancing strategies and proposing a method to identify the most suitable option. The common problem of noisy valves has been examined and the cost impact of the different solutions has also been considered.Practical application: This paper applies simple calculation tools to explore the impact of different balancing solutions to a real building, using an approach that could valuably assist the practitioner in the decision process. [ABSTRACT FROM AUTHOR]

The most critical component of an absorption heat transformer (AHT) is the absorber, by which the exothermic reaction is carried out, resulting in a useful thermal energy. This article proposed a model based on improving the performance of energy for an absorber with disks of graphite during the exothermic reaction, through an optimal strategy. Two models of artificial neural networks (ANN) were developed to predict the thermal energy, through two important factors: internal heat in the absorber (QAB) and the temperature of the working solution of the absorber outlet (TAB). Confronting the simulated and real data, a satisfactory agreement was appreciated, obtaining a mean absolute percentage error (MAPE) value of 0.24% to calculate QAB and of 0.17% to calculate TAB. Furthermore, from these ANN models, the inverse neural network (ANNi) allowed improves the thermal efficiency of the absorber (QAB and TAB). To find the optimal values, it was necessary to propose an objective function, where the genetic algorithms (GAs) were indicated. Finally, by applying the ANNi-GAs model, the optimized network configuration was to find an optimal value of concentrated solution of LiBr-H2O and the vapor inlet temperature to the absorber. The results obtained from the optimization allowed to reach a value of QAB from 1.77 kW to 2.44 kW, when a concentrated solution of LiBr-H2O at 59% was used and increased the value of TAB from 104.66 ° C to 109.2 ° C when a vapor inlet temperature of 73 ° C was used. [ABSTRACT FROM AUTHOR]

Flat plate collectors have relatively low efficiency at the typical supply temperatures of district heating networks (70–95 °C). Parabolic trough collectors retain their high efficiency at these temperatures. To maximize the advantages of flat plate collectors and parabolic trough collectors in large solar heating plants for a district heating network, a hybrid solar collector field with 5960 m 2 flat plate collectors and 4039 m 2 parabolic trough collectors in series was constructed in Taars, Denmark. The design principle is that the flat plate collectors preheat the return water from the district heating network to about 70 °C and then the parabolic trough collectors would heat the preheated water to the required supply temperature of the district heating network. Annual measured and simulated thermal performances of both the parabolic trough collector field and the flat plate collector field are presented in this paper. The thermal performance of both collector fields with weather data of a Design Reference Year was simulated to have a whole understanding of the application of both collectors under Danish climate conditions as well. These results not only can provide a design basis for this type of hybrid solar district heating plants with flat plate collectors and parabolic trough collectors in the Nordic region, but also introduce a novel design concept of solar district heating plants to other high solar radiation areas. [ABSTRACT FROM AUTHOR]

This paper shows the model of five possible states of components of steam turbines in thermal power plants and heating plants. The introduced model represents an upgrade of Marcovian model of four states, because a new (fifth) state is introduced -- the diagnosis state. This model can be applied directly to determine optimal intervals of maintenance, and to use standard data and engineering experience. Using this model, one can determine the probabilites of state of work regime in observed moment, applying the Markovian modeling -- Markovian chains, i.e. the transition rate from one state to another. Calculation of probabilities of five possible states determines reliability and risk of work of the five possible states. The paper also offers the implementation of the stationary model of states on the observed steam turbines. [ABSTRACT FROM AUTHOR]

The possibilities of using an inexpensive sorbent for dyes removal from waste waters after textile dyeing were investigated in this work. Ashes from city heating plant that arise as a by-product in the burning process during the city central heating operated were sorbent. After chemical modification of the ashes it were transformed to the efficient sorbent. Based on the results from this paper, it can be said that the sorbent produced from ashes has potential for the textile dyes removal from aqueous solutions and emission reduction of toxic dyes. A metal complex textile dye was used and the adsorption thermodynamics were studied. On the basis of obtained results, it can be concluded that the natural sorbent is an efficient sorbent for metal complex removal dye from aqueous solution and has a potential for use on an industrial scale. Characterization of other similar, solid waste materials can help explain adsorbate-sorbent interactions in order to optimize and increase efficiency of adsorption process as an environmentally acceptable process. Negative values of free energy change indicate a spontaneous nature of adsorption, negative values of free enthalpy change indicate an exothermic adsorption process and negative values of free entropy change indicate a decrease of disordered system at solid - liquid interface during adsorption. Based on adsorption, kinetic and thermodynamic parameters it can be concluded that chemisorption of the dye on the sorbent is also present together with physical adsorption. [ABSTRACT FROM AUTHOR]

The integration in a district heating network of renewable energies, waste heat or cogenerated heat is one of the key point of the 2012/27/EU Energy Efficiency Directive issued by the European Union (EU), to contribute to lower primary energy consumptions in final energy uses. The availability of an adequate set of indices that can efficaciously be used to evaluate the performance of hybrid district heating systems, in which traditional, cogenerative and renewable energy sources are integrated, becomes therefore a key aspect to assess the effectiveness of these systems. The aim of this paper is presenting a comparative analysis of different performance indices, applied to a real small-scale district heating network in operation in Turin, Italy, fed by a natural gas cogeneration plant and some boilers. All calculations are based on the experimental data of the real plant and show as the commonly employed indices for the assessment of performance of CHP units can overestimate to a great extent the real performance of the whole system, as do not take into account the heat transportation losses and the pumping electrical requirements. The results of these analyses are presented in detail in the paper. [ABSTRACT FROM AUTHOR]

The use of solid biofuel for energy in heating plants has increased drastically during the last decades. This substantial and increasing demand has placed focus on delivering biofuel to the plants, as logistics issues are considered one of the key challenges for further increased use of biofuel. Problems in sourcing enough fuel locally due to the increasing size of power plants and environmental concerns has sparked an interest in using multimodal road-rail transport as a cost effective and environmentally friendly way of long-haul transport. A case study is performed at a Swedish district heating plant to investigate the potential of introducing multimodal transport. Extensive calculations are performed in the design and operation of a multimodal system, showing both costs and CO2 emissions. This is analysed in relation to key logistical challenges in the industry. A best case scenario is identified. Conclusions are that the potential for multimodal transport is greatest among the largest plants with large volumes to achieve high resource utilisation of the transport equipment. A shift from road to multimodal transport is facilitated by that a large share of the current road transport flows already pass through a terminal, which improves multimodal transport competitiveness against road transport as this reduced the cost difference. This study leads to better understanding of the strengths and weaknesses of multimodal biofuel transport and has practical implications for anyone in the process of designing such systems. [ABSTRACT FROM AUTHOR]

The gas-liquid two-phase flow is characterized by continuous and local change of surface separation of phases and by their mutual interactions. Due to the instability of the flow, heat transfer and mass, a precise analytical approach is difficult to achieve. Despite these difficulties, efforts are underway to progress from the more frequent empirical studies to reliable analytical models. This requires an accurate research of the processes involved in the two phase flow and how they interact with one another. This paper aims to determine the pressure drop for a two-phase flow in a horizontal pipe of a heating plant. The author would like to to compare the results obtained by numerical simulation with existing results in the domain. The mixture is air-water, at an environmental temperature of 25 C. [ABSTRACT FROM AUTHOR]

Thermal cooling systems are particularly attractive in locations supplied by district heating based on cogeneration heating plants (CHP). Moreover, solar thermal energy is a major renewable source for the provision of thermal energy, fulfilling demands for space heating, domestic hot water, process heat, and cooling. This energy source can be suitably used also in Nordic Countries. The presented paper focuses on two configurations of a cooling solar-driven thermal system for an office building located in Finland. Dynamic simulation approach has been used through TRNSYS software. In particular, the configurations differ from the connection between the hot storage tank, the solar collectors and the chiller. Particularly, in the first configuration only the tank can supply the chiller (Case 1), while in the second, the chiller can be supplied either by the tank or the solar collectors directly (Case 2). System performance indexes, in case of district heating as main building heating supply system in winter and as auxiliary heating system for the chiller in summer, have been evaluated as a function of the tank and solar thermal field sizes. Results show that Case 2 has better performance than Case 1, because of the versatility shown in summer. Particularly, when the solar irradiance is low, Case 2 solutions perform far better than Case 1 solutions, benefitting from the direct connection between the solar collectors and the chiller. This study has highlighted also the potential of this technology in cold climate areas supplied by means of DH based on CHP plants. Indeed, the adoption of such cooling technology, in addition to reduce both heating and cooling consumed energy and to shave summer electricity peaks, can potentially allow some CHP plants to operate also in summer, fulfilling the future energy networks aims: being able to provide electricity, heat and cooling energy. [ABSTRACT FROM AUTHOR]

The use of solid wood biofuels for energy production in heating plants has increased drastically during the last decades. Great interest has been shown in replacing unsustainable road transport of wood fuel with more sustainable intermodal transport. This paper maps the common business models for biofuel transport in Sweden and suggests how these models may be developed to accommodate intermodal transport. A view of the biofuel supply chain as five overlapping networks (industry, material, operations, transport, and infrastructure) connected by four transaction markets (sourcing, operations, transport, and traffic) have been used. Four typical business models have been found: Regional/National Biofuel Company, Local Biofuel Company, Heating Plant Own Account, and Wood Processing Industry. Cooperation and vertical integration among the actors are important to reach the large transport volumes required for intermodal transport. Key issues to increase the intermodal potential are: increased vertical integration and cooperation, sharing of transport resources and infrastructure, joint purchases, outsourcing to expert actors, building trust and open communication, and not underestimating the complexity of intermodal transport. The results have implications for any actor interested in developing intermodal transport or policy measures. The contribution includes the new approach of developing business models by using the five-layer network-market model. [ABSTRACT FROM AUTHOR]

The article presents the reliability analysis of subsystem of heat supply in the example of 47 thousand inhabitants' city. The analysis was made on the basis of operational data made available by the Municipal Heating Company, between the years 2001 ÷ 2012. To describe the quantitative reliability of heat supply subsystem reliability indicators are used. Main times between failure and unitary failure rates including the month of their occurrence, type and diameter of the heating network, thermal power region were working out. Knowing the characteristics of the time to repair for the heating network, the reliability of heat supply subsystem for different thermal power region, considering the district heating system configuration can be determined. [ABSTRACT FROM AUTHOR]

The paper analyzes the economic aspects of geothermal heating plants in Poland—selected plant operating costs, prices of geothermal heat, and economic efficiency of geothermal heating plants. All six geothermal heating plants operating in Poland are analyzed including the oldest plant established in 1994 and the newest plant established in 2013. The cost structure of geothermal heating plants tends to significantly; however, amortization is the principal operating cost at close to 55% in some cases. Other key costs include use of materials and energy. A comparison of the net price of 1 GJ of heat produced by selected heating plants shows that heat produced by brown coal (lignite) plants is the least expensive, while that produced by black coal (anthracite) plants is more expensive. The prices of heat produced by geothermal heating plants are less competitive, but still more competitive than those of heat produced using natural gas, biomass, and fuel oil. An analysis of the economic efficiency of geothermal heating plants shows that this source of heat has significant potential for profitability, which is also shown by its positive EBITDA. A notable part of the revenue of geothermal heat companies comes from various types of subsidies and grants. A large number of difficulties of estimate risks and high start-up costs along with a low rate of return have thus far discouraged private entrepreneurs from pursuing this line of investment. As a result, virtually every geothermal heating plant in Poland is owned by the government at the local or national level. [ABSTRACT FROM AUTHOR]

This article aims to define the energy and economic performance of district heating considering the impact of cost-optimal refurbishment solutions of the connected buildings. The possibility to shift to low-temperature district heating is considered as a feasible solution to compensate for the loss of performance of the network in combination with a systematic approach to the refurbishment of the connected buildings. For this purpose, an integrated model for both buildings and network has been developed. Several refurbishment measures for the existing buildings have been investigated, and a multi-objective (energy and economic) optimization has been conducted, by means of a genetic algorithm to reduce the computational time. The results highlight that building refurbishment strongly influences both the energy and economic performance of the district heating system. The distribution efficiency is considerably low during summer—only domestic hot water need—and when a high number of refurbished buildings is considered in the district heating network. Nevertheless, the implementation of the minimum network temperature allows partial compensation for both the energy and economic losses deriving from the refurbishment. Although an incentive to promote the use of heat at lower temperature has been considered, the economic loss deriving from the incentive could not be paid back. [ABSTRACT FROM PUBLISHER]

This study provides a country level estimate of geographically available agricultural land area which has been out of production for more than two years and has not been converted into forest or urban area, and is suitable for short rotation woody crop (SRWC) production to meet EU 2020 renewable energy targets in Latvia. Geographic information system (GIS) was used to estimate the total amount and location of agricultural land suitable for SRWC. Several criteria of restrictions were applied in the assessment process, such as agricultural land use status, soil and slope restrictions, designated territories of protection, minimum size of agricultural land within each tax parcel and minimum tax parcel distance from the roads. A total estimated amount of agricultural land that meets the minimum criteria is 261,710 ha. Most (42%) of the suitable agricultural land for SRWC is in the range from 10 to 50 ha. The greatest proportion (29%) of that land is located in the Latgale region. If only 5% (13,085 ha) of the estimated agricultural land were used for SRWC with yields of 7–10 Mg dry ha −1 yr −1 , it could produce 485,475–693,532 MWh of biomass energy annually, which is roughly 412,653–589,502 MWh of delivered energy if the heating systems are 85% energy efficient. It would result in 13–18% of the total heat energy produced by heating plants in Latvia in 2012. [ABSTRACT FROM AUTHOR]

This study compares the life cycle impacts of three heating plant systems which differ in their source of energy and the type of system. The following heating systems are considered: electric water-water heat pump, absorption water-water heat pump and natural gas fired boiler. The heat source for heat pump systems is low temperature geothermal source with temperature below 20 °C and spontaneous outflow 24 m 3 /h. It is assumed that the heat pumps and boiler are working in monovalent system. The analysis was carried out for heat networks temperature characteristic at 50/40 °C which is changing with outdoor temperature during heating season. The environmental life cycle impact is evaluated within life cycle assessment methodological framework. The method used for life cycle assessment is eco-indicator ‘99. The functional unit is defined as heating plant system with given amount of heat to be delivered to meet local heat demand in assumed average season. The data describing heating plant system is derived from literature and energy analysis of these systems. The data describing the preceding life cycle phases: extraction of raw materials and fuels, production of heating devices and their transportation is taken from Ecoinvent 2.0 life cycle inventory database. The results were analyzed on three levels of indicators: single score indicator, damage category indicators and impact category indicator. The indicators were calculated for characterization, normalization and weighting phases as well. SimaPro 7.3.2 is the software used to model the systems’ life cycle. The study shows that heating plants using a low temperature geothermal source have lower eco-indicator than a gas boiler unit. In comparison of two heat pumps the absorption heat pump has a lower environmental impact rather than electrical heat pump. However, in spite of high level eco-indicator, gas boiler has the lowest damage to human health. [ABSTRACT FROM AUTHOR]

Seasonal input–output efficiencies of two heating plants with condensing boilers in cold climate institutional buildings (3300 m2 school and 12,000 m2 university building) were evaluated. Plant efficiency remained about the same or declined with load, contrary to typical lab boiler ratings, which show efficiency increasing at lower loads. These results occurred when the boilers were operated with return water temperatures largely in the condensing range. Heating plant load was often 25% or less of the rated load of a single boiler, resulting in heating plant input–output efficiencies well below rated boiler efficiencies.Practical application: In-situ boiler plant input–output efficiencies can differ widely from manufacturer's boiler efficiency curves. For applications such as simulation for energy-efficient design, effective decision-making depends on accurately estimating real-world performance. [ABSTRACT FROM AUTHOR]