•Energy performance of three full-scale innovative HVAC systems for multi-family buildings renovation is assessed.•Life cycle cost analysis is performed based on true investment, maintenance and ...energy costs for the three alternatives.•Sensitivity analysis for different discount rate and energy price escalation is performed.•Economic feasibility versus building regulation requirements on primary energy is discussed.
The EU has adopted several policies to improve energy efficiency. One of these policies aims to achieve energy efficient renovations in at least 3% annually of buildings in EU. The aim of this study was to provide an accurate economic comparison between three similar multi-family buildings that have undergone the same energy efficiency measures, with essential differences regarding the installed ventilation systems. The selected ventilation systems were: 1) balanced mechanical ventilation with heat recovery; 2) exhaust ventilation with air pressure control; and 3) exhaust ventilation with an exhaust air heat pump. In the latter two cases, radiators pre-heat supply air. Life cycle cost analysis were conducted using real investment and operational costs for the three buildings. Sensitivity analysis was also made for different discount rates and energy price escalation patterns. It was found that the building with exhaust ventilation has the lowest life cycle cost. At 2% inflation rate, 3% real discount rate and 1% real energy price escalation, the building with exhaust air heat pump and the building with mechanical ventilation with heat recovery has 13% and 29% higher life cycle cost than the building with exhaust ventilation, respectively. The sensitivity analysis further showed that a lower discount rate gives higher future costs and gives more profitability of systems with heat recovery with lower future costs. Energy price assumptions have a crucial impact on the results and change the profitability of studied renovation packages.
•A methodology to find the best designs of heat and mass exchangers were introduced.•The best designs were found by optimization of all important performance criteria.•A comparative analysis of ...various kinds of heat and mass exchanger was presented.•Annual operation, as well as the ability to provide thermal comfort, was considered.•The best type of dew-point cooler was introduced at diverse climatic conditions.
The objective of this research is a comparative analysis of various kinds of heat and mass exchangers of dew point indirect evaporative cooler. Considering three key performance parameters of an evaporative cooler, namely life-cycle cost, annual water consumption and the annual average of the coefficient of performance as objective functions, the best design of two popular types of the dew-point evaporative cooler (counter-regenerative and cross configurations) for employing in small-scale residential buildings was found through a multi-objective optimization approach. Both operational and geometric characteristics of the coolers were selected as the design (decision) variables while proper constraints such as thermal comfort were imposed. Afterward, between the optimized counter-regenerative and cross configurations, the foremost one was selected for representative cities of four diverse groups within the Köppen-Geiger climate classification system. It was found that in very hot and dry areas, the counter-regenerative configuration was the ideal choice while in other investigated climates, using cross configuration was a better alternative. Moreover, the results showed that in comparison to the base case conditions by using the best-optimized configurations, 64.4, 86.4, and 1039.0% improvements in life-cycle cost, the annual water consumption, and the annual average of the coefficient of performance were achieved, respectively.
Life cycle assessment (LCA) and life cycle cost (LCC) are two primary methods used to assess the environmental and economic feasibility of building construction. An estimation of the building's life ...span is essential to carrying out these methods. However, given the diverse factors that affect the building's life span, it was estimated typically based on its main structural type. However, different buildings have different life spans. Simply assuming that all buildings with the same structural type follow an identical life span can cause serious estimation errors. In this study, we collected 1,812,700 records describing buildings built and demolished in South Korea, analysed the actual life span of each building, and developed a building life-span prediction model using deep-learning and traditional machine learning. The prediction models examined in this study produced root mean square errors of 3.72–4.6 and the coefficients of determination of 0.932–0.955. Among those models, a deep-learning based prediction model was found the most powerful. As anticipated, the conventional method of determining a building's life expectancy using a discrete set of specific factors and associated assumptions of life span did not yield realistic results. This study demonstrates that an application of deep learning to the LCA and LCC of a building is a promising direction, effectively guiding business planning and critical decision making throughout the construction process.
•Actual life span of building is vastly different from mainframe-based life span.•The computational models were trained to predict building life span using big data.•The proposed computational approach is superior over the mainframe-based approach.
Greening the urban environment can be an important strategy to tackle the problems of urban densification and meet the United Nations Sustainable Development Goals. Green infrastructures, like green ...roofs and green walls, have multiple associated environmental, social and economic benefits that improve buildings performance and the urban environment. Yet, the implementation of green roofs and green walls is still limited, as these systems often have additional costs when compared to conventional solutions.
Recent studies have been comparing these greening systems to other solutions, balancing the long-term benefits and costs. Also, there is significant research on green roofs and green walls benefits. Although, green roofs and green walls economic analyses don't include all benefits due to measuring difficulties. The associated uncertainty regarding the quantification of the benefit makes it difficult to compare the research outcomes.
This paper aims to provide a research review of existing benefits and costs of different types of green roofs and green walls. These were divided between building scale benefits, urban scale benefits and life cycle costs, focusing on the identification of results variability and assessment of their average quantification.
The analysis shows that in general, there are few data regarding intangible benefits, as the promotion of quality of life and well-being. Also, there are still few studies quantifying green walls benefits and costs. High variability in data is mostly related to the different characteristics of systems, buildings envelope, surrounding environment and local weather conditions.
•Review of existing research on green roofs and green walls benefits and costs.•Focus on building scale benefits, urban scale benefits and life-cycle costs.•Variability identification and average quantification assessment.•Fewer studies have quantified green walls benefits and costs.•There is high variability in data across all benefits and costs.
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•A comprehensive review of the application of solid waste in building insulation materials.•Solid waste mainly comes from municipal, industry and agriculture.•Life cycle cost, annual ...power consumption and pollutant gas emissions were calculated.•Based on the decision analysis method, the most promising building insulation material was determined.
The effective application of solid waste in building insulation materials is of great significance to the global economic and social development, because energy shortages and environmental pollution are two global problems that need to be solved urgently. However, unfortunately, there are few, or no systematic studies on this aspect. In order to fill this gap, solid waste was divided into municipal solid waste, industrial solid waste and agricultural solid waste according to the source. The bulk density, thermal conductivity, water absorption and compressive strength of three types of solid waste recycled building insulation materials were systematically evaluated. The relationships between bulk density and thermal conductivity and compressive strength were given, respectively. For solid waste recycled building insulation materials with poor thermal performance and flame retardancy, corresponding improvement suggestions were put forward. Taking a city as an example, the life cycle cost (LCC), energy consumption and gas emissions were discussed in detail. Based on the decision analysis method, the most promising building insulation material was selected. Finally, in view of the shortcomings of the existing study, the future study direction in this field was proposed.
•The socio-economic aspects of plasma gasification were assessed.•A comparison to the conventional incineration option was performed.•A hybrid importance-fulfilment matrix combining different aspects ...was developed.•Plasma gasification depicted high capital costs while enabling higher revenues.•The technical aspects were the most significant and the social sphere ranked last.
Fossil fuels contribute to climate changes, negatively affecting the environment. Waste has been seen as a possible resource for energy production, constituting a cleaner alternative to replace non-renewable fuels through waste-to-energy (WtE) techniques. Plasma gasification is a procedure that decomposes the molecules at high temperatures, affording a synthetic gas (syngas) that can further produce electricity, fuels and chemicals. Within the most used WtE technologies, plasma gasification is recent and therefore not yet widely applied. Thus, a viability study to support the thorough understanding and implementation of this treatment is required.
This paper assesses the socio-economic aspects of plasma gasification promoting a more sustained waste management system, also taking advantage of the commodity assets granted by the technique. To the best of the authors’ knowledge, this is the first time that an importance-fulfilment matrix is specifically developed to appraise the socio-economic viability of plasma gasification, combining environmental, technical, economic and social aspects. Although depicting high capital costs, plasma gasification enabled high revenues, rebating the operational costs. The sensitivity analysis exhibited a descending impact in the profitability of the plant for varying electricity sales price, landfill fee, discount rate, vitrified slag sales price and initial investment.
Given that energy-efficiency policies focus on meso- or macro-scale interventions, it is imperative to establish a macro-scale evaluation approach for building retrofits to support policymaking in ...building energy conservation, management and sustainability. This study applies the generic idea of optimising the energy, economic and environmental outputs to propose a facile framework for evaluating the prospects of building retrofits on a macro-scale. Here, an extensive optimisation approach integratinglife cycle cost evaluation and an environmental assessment is formulated, involving coordinated on-site survey, modelling and data analytics. The model framework is corroborated by a case study analysis focused on identifying the optimal retrofit solution for low-rise office buildings in Shanghai. Simulation results show that modifications in occupancy regime, improvements in natural ventilation, heating and cooling systems, cool roofs insulation and installation of renewable energy systems (such as geothermal and solar/photovoltaics) are the basic retrofit measures for a macro-scale intervention to attain maximum life-cycle benefits. Individually, an estimated investment cost for each retrofit project varied within RMB 1 – 5 million with a payback period < 13 years, depending on the building characteristics. Overall, an investment estimated at RMB 1.7 billion (with a payback period of 6 years) is required to achieve ~ 80% energy reduction with a carbon dioxide savings of ~ 243 Gg-CO2/yr. In summary, this study provides a guidance framework for stakeholders to evaluate investments on retrofit projects, including existing and prospective ones.
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•Three water/power generation configurations were designed, modeled, and optimized.•Damage to human health and the ecosystem caused by diesel generator were estimated.•Division ...algorithm was more accurate and faster than the genetic algorithms.•Desalination with photovoltaic panel/wind turbine was environmentally efficient.•Desalination with the photovoltaic panels was economically the best configuration.
Although freshwater is necessary for the well-being of humankind, increasing population growth and limited resources lead to a serious crisis to supply freshwater. Since the Earth is surrounded by seawater, desalination based on electrical power is introduced as a promising technology to provide freshwater. It is well documented that the connection of remote areas that usually do not have access to freshwater into the electricity grid is not affordable and eco-friendly. Hence, the efforts to design and construct high reliability, cost-effective, and eco-friendly stand-alone hybrid renewable energy system in remote areas. In line with this, this paper describes a novel energy management system for the optimized operation of a stand-alone hybrid energy system based on photovoltaic panels, wind turbines, batteries, and diesel generator. For this purpose, a multi-objective optimization problem is formulated by combining three objective functions, i.e., minimum the total life cycle cost as well as environmental impacts on human health and ecosystems and the maximum system reliability that can conflict with each. To solve the multi-objective optimization problem, a division algorithm is proposed that is more flexible and faster compared with conventional algorithms such as genetic algorithm. In order to show the proposed framework, a real case study in Larak Island, Iran, with appropriate solar and wind is considered. The effectiveness of the applied approach compared with optimization results of genetic algorithm and the artificial bee swarm optimization algorithm that was previously used successfully to solve optimization problems related to desalination integrated with the renewable energy system. The optimization is performed based on different diesel fuel price amounts (0.2, 0.5, and 1 $/liter). It is seen that at fuel price set to 0.2 and 0.5 $/liter, the seawater reverses osmosis desalination/photovoltaic/diesel generator/battery is the most cost-effective energy system, and when fuel price is 1 $/liter, the seawater reverses osmosis desalination/photovoltaic/wind turbine/diesel generator/battery is the most cost-effective hybrid system. While at fuel price set to 0.2, 0.5, and 1 $/liter, the seawater reverse osmosis desalination /photovoltaic/wind turbine/diesel generator/battery is the most eco-friendly. Finally, the results of this study show proposed algorithm is faster and more accurate (100 iterations, 98.36% accuracy) than the genetic algorithm (1000 iterations, 83.03% accuracy) and the artificial bee swarm optimization (300 iterations, 95.49% accuracy).
Ground source heat pump systems (GSHP) for residential building heating, cooling, and hot water are highly energy efficient but capital intensive when sized for peak demands. The use of supplemental ...sources of energy with GSHP systems enables improved life-cycle economics through the reduction in the size and cost of the GSHP components. This paper investigates the life-cycle economics of hybrid solar-assisted ground source heat pump systems (SAGSHP) using simulations validated from field data. The economics and optimal sizing of SAGSHP systems for heating dominant climates in four locations in Australia and ten locations elsewhere are evaluated in order to explore the suitability and relative merits of SAGSHP systems in a range of heating dominant climates. In locations having high or moderate levels of solar irradiation, high electricity prices, and high or moderate gas prices, SAGSHP systems are shown to have the lowest life cycle cost amongst alternatives, with predicted savings of up to 30%.
•A comprehensive investigation of the design and performance of hybrid GHSPs.•A comparison of hybrid GSHPs and conventional systems on cost and CO2 emissions.•Effects of local climatic and economic conditions are evaluated for 14 global cities.•Hybrid GSHPs have shown to be the most economical system for 10 out of 14 locations.•Local energy price is a key factor that influences the feasibility of hybrid GSHPs.
•4E analysis of a building integrated photovoltaic thermal system is investigated.•The scenario is based on the variation via glass windows and PV module surface area on the outer façade.•A scenario ...with the highest PV module surface area with a payback time of 1.58 (years) has been suggested.•The life cycle revenue of 55,157 ($) is suggested as a feasible retrofit measure as a result of the (4E) analysis.
In this research paper, energy, exergy, economic and environmental analysis of a building integrated photovoltaic thermal system is investigated. To cover the aim of the research, the impact of a system as a retrofit solution for the existing office building has been evaluated in different scenarios through various key performance indicators including generated electricity, energy and exergy efficiency, greenhouse gas emission reduction and life cycle cost. The scenario development for the analysis is based on the variation between glass windows and photovoltaic module surface area on the outer façade. According to the results of the study, a scenario with the lowest photovoltaic module and highest glass windows surface area has been suggested due to the highest energy efficiency, lowest initial investment, lowest energy consumption and emission for manufacturing. Besides, a scenario with the highest photovoltaic module and zero glass windows surface area has been suggested because of the highest lifetime generated and avoided energy and emission reduction, lowest payback time and greenhouse gas rate as well as highest life cycle revenue. In conclusion, a scenario with the highest photovoltaic module surface area with a payback time of 1.58 years and a life cycle revenue of 55,157 (USD) has been suggested as a feasible retrofit measure as a result of the energy, exergy, economic and environmental analysis.
