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• Low GWP refrigerant selected from six candidates (R152a, R744, R1234yf, R1234ze(E), R170 and R290). • Design and build a DX-SAHP for domestic use, operating with low GWP refrigerant. • Develop a mathematical model based on 4E analysis and validated by DX-SAHP. • Investigate through simulations the influence of geometric parameters (evaporator area and condenser length) on the system's performance. The main objective of this study was to develop, validate and apply a mathematical model for analysing the performance of a Direct-Expansion Solar-Assisted Heat Pump (DX-SAHP) based on the energetic, exergetic, environmental, and economic (4E) analysis. The DX-SAHP produces domestic hot water using the low-global-warming-potential (GWP) refrigerant R290 which is the best candidate for energy, environmental, and logistical performance among six previously evaluated candidates (R152a, R744, R1234yf, R1234ze(E), R170, R290). Environmental and economic analysis are founded, respectively, on Total Equivalent Warming Impact (TEWI) and payback. The proposed model was validated using an experimental test bench developed for this study. Using the validated model, simulations were conducted to investigate the influence of geometric parameters (evaporator area and condenser length) on the system's performance. The results show that increasing the evaporator area yields the greatest increase in COP (117 and 80.4%) and the greatest decrease in TEWI (53.8 and 44.5%) for final water temperatures of 45 and 65°C, respectively. However, this also leads to a drop in collector efficiency (58.7 and 60.8%) but results in a shorter payback time (6.06 and 3.87 years) for final water temperatures of 45 and 65°C, respectively. The greatest increase in exergy efficiency (11.5 and 14.1%) occurs with an increase in condenser length for final water temperatures of 45 and 65°C, respectively. [ABSTRACT FROM AUTHOR]

• Elaborate a mathematical model based on the analysis of the 4E and validate it using infrared thermography in the DX-SAHP. • Investigate through simulations the influence of environmental parameters (solar radiation, ambient temperature, wind speed and relative air humidity) on the system. The application of renewable sources, such as solar energy, and the use of ecological refrigerants in refrigeration and heating systems contribute to more sustainable development and the reduction of global warming. With this perspective, the main objective of this work is to develop, validate and apply a mathematical model based on the energetic, exergetic, environmental, and economic analysis of a Direct-Expansion Solar-Assisted Heat Pump for the production of Domestic Hot Water operating with R290. Environmental analysis is based on Total Equivalent Warming Impact and economic analysis is based on payback. The proposed mathematical model was validated on an experimental bench with R290 through infrared thermography applied to evaluate the temperature distribution in the evaporator. The influence of environmental parameters on the system with R290 is investigated through simulations. Among the environmental parameters investigated, solar irradiance was the parameter that most contributed to the increase in energy (69.3 %) and exergy efficiency (8.72 %). In addition, the increase in ambient temperature contributed more to the reduction of greenhouse gas emissions (88.6 %) but promoted the longest payback time for the system. Finally, in the tests performed, heating the water at a lower temperature (45 °C) compared to the higher temperature (65 °C) increased energy (25.0 %) and exergy efficiency (2.86 %), contributed more to the reduction of emissions, but increased the payback time. [ABSTRACT FROM AUTHOR]

In present work, a flat plate collector assisted with reflecting system and desiccant wheel was used to dry oleaster fruit (Elaeagnus angustifolia L.). Three levels of air flow rate (0.025, 0.05 and 0.09 kg/s) and different dryer conditions: with reflectors (WR), with reflectors and desiccant wheel (WRD) and without reflectors and desiccant wheel (WORD) were considered to dry single layer of oleaster. The results indicated that the effect of using reflectors and desiccant system on extraction moisture from product was significant (P < 0.05). By using reflectors and desiccant wheel, the specific energy consumption for drying oleaster was decreased by 11.32–30.15%. The overall efficiency for WRD was obtained in the range of 33.21–39.64% which was higher than the system without reflectors and desiccant system. The results of the exergetic analysis showed that maximum exergy efficiency of drying system for WR, WRD and WORD was 38.8%, 56.7% and 32.1%, respectively. Solar thermal fraction rate for WRD was lower due to higher thermal energy inside of the drying cabinet. The payback time for system with optimized condition can be decreased about 15%. The quality consideration showed that the quality of oleaster (also the powder) dried by WRD is better than WORD and sun drying samples. • Drying kinetics of oleaster studied by a solar dryer with reflectors and desiccant. • Using reflectors and desiccant system accelerates the drying process of the samples. • A minimum value of specific energy consumption was achieved. • The exergetic analysis of drying cabinet and drying process was carried out. • Based on the initial condition economic optimization of collector was developed. [ABSTRACT FROM AUTHOR]

• Economic analysis and design optimization of a DX-SAHP is presented. • The augment of collector size or solar radiation flux cause an increase in the COP. • The compressor with lower displacement has the highest COP and lower payback time. • There is an economic optimum size of collector area for the DX-SAHP. • The payback range was 1.77–3.34 years depends on the environmental conditions. One option to reduce the energy consumption to produce domestic hot water is to replace the electrical heaters by direct expansion solar assisted heat pumps. Although, there are many studies on the performance of this system, there are few studies on economic analysis of the equipment. In this paper, an economic analysis comparing the payback of heat pump over an electrical heater is carried out. The heat pump is modeled using lumped models for heat exchangers and a black box model for the compressor. The results show that the augment of collector size increases the COP, but it decreases the collector efficiency. The economic analysis showed that there is a collector size that minimizes the payback time. Additionally, the influence of the environmental conditions, the refrigerant, the costs and the heating capacity on the payback period and optimum collector size were investigated. The results showed that there is an economically optimum size of collector area for the DX-SAHP, which it is the same for different environmental conditions. A case study was made for three different cities and the payback time found is the range of 1.77–3.24 years. [ABSTRACT FROM AUTHOR]

Abstract The most important environmental issues caused by the textile industry are intensive water consumption, high amounts of wastewater generation with significant pollutant loads. Previous studies were focused on minimization of water consumption and wastewater amounts in cotton textile finishing-dyeing. There are very few real-scale scientific studies about water efficiency in woolen textile production. In this study, it was aimed to reduce water consumption, wastewater amount and its pollutant loads by appropriate techno-economical minimization techniques in an integrated woolen textile mill. In this context, water consumptions and wastewater generations in basic and other auxiliary processes of the mill were examined by detailed on-site investigations. Process based specific water consumption and wastewater values were calculated. Additionally, water and wastewater samples were collected at different periods and analyzed. Specific pollutant loads of wastewater were also calculated. Thus, reuse potentials of the process wastewaters were evaluated. Moreover, saving and reduction potentials of the mill were determined by comparing with similar textile mills. Total of 82 minimization techniques were identified and evaluated by using multi-criteria decision-making methods. As a result, it was decided to implement 9 minimization techniques in the mill. Thus, reductions in water consumption by 41–69%, wastewater amounts by 48–75% and wastewater chemical loads by 28–63% can be achieved by the implementation of the minimization techniques. Potential payback period was ranged between 24 and 60 months. Employed methodology and findings of the study may be useful to similar textile mills, stakeholders and regulators. Presented results may also provide a road map to textile industry for cleaner production applications. Graphical abstract Image 1 Highlights • A water efficiency study was carried out in an integrated woolen textile mill. • Total 9 priority techniques were identified for reduction of water and wastewater. • Water consumption can be reduced 41–69% after the implementations. • Wastewater and COD loads can be reduced 48–75% and 28–63%, respectively. • Potential payback periods ranged between 24 and 60 months. [ABSTRACT FROM AUTHOR]

It is anticipated that with the thrust towards use of clean energy resources such as electric vehicles, future distribution grids will face a steep increase in power demand, forcing the utility operators to invest in enhancing the power delivering capacity of the grid infrastructure. It is identified that the critical 5–20 km medium voltage (MV) underground ac distribution cable link, responsible for bulk power delivery to the inner urban city substation, can benefit the most with capacity and efficiency enhancement, if the existing infrastructure is reused and operated under dc. Quantification of the same is offered in this paper by incorporating all influencing factors like voltage regulation, dc voltage rating enhancement, capacitive leakage currents, skin and magnetic proximity effect, thermal proximity effect and load power factor. Results are presented for three different ac and dc system topologies for varying cable lengths and conductor cross-sections. The computed system efficiency is enhanced with use of modular multilevel converters that have lower losses due to lower switching frequency. A justified expectation of 50–60% capacity gains is proved along with a generalized insight on its variations that can be extrapolated for different network parameters and configurations. Conditions for achieving payback time of 5 years or lower due to energy savings are identified, while the socio-economic benefits of avoiding digging and installing new cable infrastructure are highlighted. The technical implications of refurbishing cables designed for ac to operate under dc conditions is discussed in terms of imposed electric fields, thermal profile and lifetime. A novel opportunity of temperature dependent dynamic dc voltage rating to achieve additional capacity and efficiency gains is presented. [ABSTRACT FROM AUTHOR]

Brazil is a country with great agricultural potential due to its geographical position. All Brazilian states have a portion of their economy based on agriculture, which includes several activities, mainly farming and cattle and/or swine livestock, which generates a large amount of waste that can be used for energy production. When the waste is treated in biodigesters, the anaerobic bacteria produce biogas, which can be used as fuel for power generation. An alternative to produce energy in large scale is the combination of neighboring farms, forming agro-energy condominiums with a goal of accumulating the biogas produced and using it in power generation, however, studies on the financial viability of such projects are still scarce. Briefly analyzing the gradual increase of electricity consumption in Brazil, this study is justified by the need to reconcile the social, economic and environmental aspects. We verified the possibility of generating power by installing biodigesters on seven swine and cattle farms located in São Miguel do Iguaçu, Paraná, Brazil. We also aimed to reduce environmental impact and odors coming from the biodigesters, improve the quality of life of landowners and neighbors and use the biogas generated in the biodigesters for producing electricity to be used in those farms. We carried out field research in order to gather the necessary information for the feasibility study. Using the simple payback tool for financial return, the study showed a return of investment within 44 months, which is considered feasible. Several studies are still necessary regarding agro-energy condominiums, as there are many variables in these projects and different methodologies may be applied. [ABSTRACT FROM AUTHOR]

The main objective of the present work is to evaluate the potentials of the installed existing units of gas turbines for combined production of cooling, heating, power, and process heat. For this purpose a CCHPP cycle is proposed and simulated thermodynamically. The thermodynamical model is enriched with technical data extracted from the data sheets and operational manual and data of the gas turbine. The thermodynamic, economic, and environmental criteria of the CCHPP cycle are evaluated and impact of different parameters on these criteria is evaluated. For instant the impact of remaining lifetime of the gas turbine, ambient temperature, altitude, relative humidity, interest rate, and currency exchange value is investigated. In the economical valuations the conventional payback period is modified and a new formula that is more conservative is proposed. The results prove that fuel saving of more than 30% is achievable. Based on average consumption of natural gas in Iran, the amount of fuel saved can feed about 2450 and 5720 families in cold and hot climates respectively. The economical results show that for 1USD invested, about 0.5USD profit is achieved. Life analysis shows that for the existing gas turbines the minimum required life time for gas turbine to make the CCHPP investment profitable is about 15 years. Moreover the analyses show that the cycle characteristics are more sensitive to ambient temperature than relative humidity and altitude. The CO 2 , CO and NO x reduction of more than 52,000, 36 and 44 tons per year is estimated when using CCHPP. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to improve water-use efficiency and improve environmental performance with techno-economic water-use efficiency practices in an integrated textile mill that produces woven and knitted fabrics. In this context, detailed on-site investigations and data collection studies were carried out in the mill. All water consumption and wastewater generation points were determined. Specific water consumptions and specific wastewater amounts were calculated basis on the basic production processes, auxiliary processes, and non-process areas. Samples were collected from raw water, process water, process wastewaters, and composite wastewater at different periods and analyzed. Thus, reuse potentials of the process wastewaters were evaluated. Specific pollutant loads of process and composite wastewaters were also calculated. Moreover, saving/reduction potentials were calculated by comparing the specific water consumption, wastewater amounts, and pollutant loads of the mill with similar textile mills. It was decided to implement a total of 13 water-use efficiency practices to increase the water-use efficiency and environmental performance of the mill. Ultimately, it was found that reduction of 13.8–25.6% in the total water consumption, 18.2–32.9% in the total wastewater amount and 15.9–35.7% in the total chemical oxygen demand (COD) loads of the mill could be achieved after the implementation of suggested practices. The estimated payback periods were found to be between 2 and 45 months. This study shows that with low-cost water-use efficiency practices, significant reductions in water consumption, wastewater amounts, and pollution loads of wastewater can be achieved in similar textile mills. This study can be inspiring for other textile mills to improve their water-use efficiency performances. Also, it can provide significant contributions to industry stakeholders, policy makers and researchers in terms of presented water-use efficiency practices, obtained water-wastewater reductions/savings and applied methodology. • Water-use efficiency analysis were conducted in production and auxiliary processes. • 13 water use-efficiency practices were determined for the studied mill. • Water consumption can be reduced 13.8–25.6% after the implementations. • Wastewater and COD load can be reduced 18.2–32.9% and 15.9–35.7%, respectively. • Payback period was found between 2 and 45 months. [ABSTRACT FROM AUTHOR]

This work refers to a case study on sugar cane mill from Sao Paulo State, in Brazil. It will be analysed the financial benefit acquired through sugar cane bagasse usage as energy source, studying the transformation of this inlet into electrical power, highlighting the greenhouse gas emissions throughout the manufacturing processes of sugar and alcohol. Also, a relationship between power generated and gases emitted will be established and a financial analysis of the project cash flow through the analysis of net present value (NPV), internal rate of return (IRR), and payback will be done. The high profitability calculated on Santa Candida Mill was evaluated, which becomes even greater when implementing the cogeneration system. This one may also consider the sale of surplus energy and carbon credits as two more products to sell to the plant. [ABSTRACT FROM AUTHOR]

To reduce the consumption of freshwater in the laundry industry, a new trend of closing the water cycle has resulted in the reuse/recycling of water. In this study, the performance of a full-scale submerged aerobic membrane bioreactor (9 m 3 ) used to treat/reuse industrial laundry wastewater was examined over a period of 288 days. The turbidity and total solids (TS) were reduced by 99%, and the chemical oxygen demand (COD) effluent removal efficiencies were between 70% and 99%. The levels of COD removed by the membrane were significantly greater than the levels of biodegraded COD. This enabled the bioreactor to sustain COD levels that were below 100 mg/L, even during periods of low wastewater biodegradation due to bioreactor sludge. An economic evaluation of the membrane bioreactor (MBR) system showed a savings of 1.13 € per 1 m 3 of water. The payback period for this system is approximately 6 years. The energy and maintenance costs represent only 5% of the total cost of the MBR system. [ABSTRACT FROM AUTHOR]

Abstract: Air filtration systems implemented in large sow herds have been demonstrated to decrease the probability of having a porcine reproductive and respiratory syndrome virus (PRRSV) outbreak. However, implementation of air filtration represents a considerable capital investment, and does not eliminate the risk of new virus introductions. The specific objectives of the study were: 1) to determine productivity differences between a cohort of filtered and non-filtered sow farms; and 2) to employ those productivity differences to model the profitability of filtration system investments in a hypothetical 3000 sow farm. Variables included in the study were production variables (quarterly) from respective herds; air filtration status; number of pig sites within 4.7km of the farm; occurrence of a PRRSV outbreak in a quarter, and season. For the investment analyses, three Scenarios were compared in a deterministic spreadsheet model of weaned pig cost: (1) control, (2) filtered conventional attic, and (3) filtered tunnel ventilation. Model outputs indicated that a filtered farm produced 5927 more pigs than unfiltered farms. The payback periods for the investments, were estimated to be 5.35 years for Scenario 2 and 7.13 years for Scenario 3 based solely on sow herd productivity. Payback period sensitivity analyses were performed for both biological and financial inputs. The payback period was most influenced by the premium for weaned pig sales price for PRRSV-negative pigs, and the relative proportions of time that filtered vs. unfiltered farms produced PRRSV-negative pigs. A premium of $5 per pig for PRRS-negative weaned pigs reduced the estimated payback periods to 2.1 years for Scenario 2 and 2.8 years for Scenario 3. [Copyright &y& Elsevier]

Abstract: Green roofs have been used as an environmentally friendly product for many centuries and considered as a sustainable construction practice. Economic and environmental benefits of green roofs are already proven by many researchers. However, a lifecycle net benefit-cost analysis, with the social dimension, is still missing. Sustainable development requires quantitative estimates of the costs and benefits of current green technologies to encourage their use. This paper is based on an extensive literature review in multiple fields and reasonable assumptions for unavailable data. The Net Present Value (NPV) per unit of area of a green roof was assessed by considering the social-cost benefits that green roofs generate over their lifecycle. Two main types of green roofs – i.e. extensive and intensive – were analyzed. Additionally, an experimental extensive green roof, which replaced roof layers with construction and demolition waste (C&D), was assessed. A probabilistic analysis was performed to estimate the personal and social NPV and payback period of green roofs. Additionally, a sensitivity analysis was also conducted. The analysis demonstrated that green roofs are short-term investments in terms of net returns. In general, installing green roofs is a low risk investment. Furthermore, the probability of profits out of this technology is much higher than the potential financial losses. It is evident that the inclusion of social costs and benefits of green roofs improves their value. [Copyright &y& Elsevier]

Abstract: In this study, the possibilities to decrease energy consumption are analyzed in a thermally non-insulated old house in Belgrade, Serbia. By using EnergyPlus software, the space heating inside the old and refurbished houses is simulated for the single and combined refurbishment measures. The retrofitted houses are the house with thermal insulation of the external wall (H-IW), house with thermal insulation of the ceiling (H-IC), and house with lowering of the ceiling (H-LC). The houses with the combined refurbishment measures are house with the lowering of the ceiling and the modified thermal insulation of ceiling (H-ILC), and house with the lowering of the ceiling, modified thermal insulation of ceiling, and thermal insulation of the external wall (H-ILC&IW). The obtained results were analyzed for energy savings, investment, and investment return. It is found that the best single refurbishment measure has H-IW. The H-ILC gives the higher energy saving than that expected by the rule of thumb. The H-ILC&IW gives the lower energy saving than that expected by the rule of thumb. [Copyright &y& Elsevier]

Abstract: Large quantities of low grade heat (LGH) are generated within many process industries, and the recovery of LGH is a potentially significant means of improving process efficiency, but it is often difficult to find an appropriate internal heat load. One alternative is to use appropriate technologies to convert the low grade heat to electricity for use onsite. This paper describes the environmental and techno-economic evaluation of a case study examining the potential application of an Organic Rankine Cycle (ORC) to generate electricity from LGH from the stacks of a coke oven used in steel production. 21MW of LGH was available for recovery at the plant and resource accounting and life-cycle analysis methods were used to evaluate the environmental and economic benefits of the operation of an ORC. The results showed that between 1 and 3% of the CO2 emitted directly through the production of coke would be offset by installation of an ORC, with life-cycle environmental impacts, (including different coal production processes) of coke production reduced by less than 1%, although this was sufficient to offset over 10,000t CO2 annually. However, the amount of electricity generated was sufficient to replace all currently imported electricity and economic analysis indicated a relatively attractive discounted pay-back period of between 3 and 6 years, suggesting this may be a commercially viable option, which could present a relatively cost effective method of achieving greenhouse gas savings in the process industries. [Copyright &y& Elsevier]

Abstract: In this paper, the global market potential of solar thermal, photovoltaic (PV) and combined photovoltaic/thermal (PV/T) technologies in current time and near future was discussed. The concept of the PV/T and the theory behind the PV/T operation were briefly introduced, and standards for evaluating technical, economic and environmental performance of the PV/T systems were addressed. A comprehensive literature review into R&D works and practical application of the PV/T technology was illustrated and the review results were critically analysed in terms of PV/T type and research methodology used. The major features, current status, research focuses and existing difficulties/barriers related to the various types of PV/T were identified. The research methods, including theoretical analyses and computer simulation, experimental and combined experimental/theoretical investigation, demonstration and feasibility study, as well as economic and environmental analyses, applied into the PV/T technology were individually discussed, and the achievement and problems remaining in each research method category were described. Finally, opportunities for further work to carry on PV/T study were identified. The review research indicated that air/water-based PV/T systems are the commonly used technologies but their thermal removal effectiveness is lower. Refrigerant/heat-pipe-based PV/Ts, although still in research/laboratory stage, could achieve much higher solar conversion efficiencies over the air/water-based systems. However, these systems were found a few technical challenges in practice which require further resolutions. The review research suggested that further works could be undertaken to (1) develop new feasible, economic and energy efficient PV/T systems; (2) optimise the structural/geometrical configurations of the existing PV/T systems; (3) study long term dynamic performance of the PV/T systems; (4) demonstrate the PV/T systems in real buildings and conduct the feasibility study; and (5) carry on advanced economic and environmental analyses. This review research helps finding the questions remaining in PV/T technology, identify new research topics/directions to further improve the performance of the PV/T, remove the barriers in PV/T practical application, establish the standards/regulations related to PV/T design and installation, and promote its market penetration throughout the world. [Copyright &y& Elsevier]

Abstract: Conception of combination of gas-engine-driven heat pump (GHP) and water-loop heat pump system (WLHPS) is firstly presented in the paper in order to reduce the energy consumption of air conditioning system further. Design of the new system is introduced through an actual project in China and compared with a conventional air-conditioning system (CACS) and conventional WLHPS (EHP-WLHPS) in terms of technical characteristics and payback period. It is found that the payback period of GHP-WLHPS is about 2 years when compared with CACS and 2.6 years with EHP-WLHPS on the average. So it is worth being more widely applied. And several barrier to application are also discussed. [Copyright &y& Elsevier]

Buildings have become a major concern because of their high energy use and carbon emissions. Thus, a material-efficient prefabricated concrete element (PCE) system was developed to incorporate construction and demolition waste as feedstock for residential building energy renovation by over-cladding the walls of old buildings. By conducting life cycle assessment and life cycle costing using the payback approach, this study aims to explore the life cycle performance of energy conservation, carbon mitigation, and cost reduction of the PCE system in three European member states: Spain, the Netherlands, and Sweden. The results show that the energy payback periods for Spain, the Netherlands, and Sweden were 20.45 years, 17.60 years, 19.95 years, respectively, and the carbon payback periods were 23.33 years, 16.78 years, and 8.58 years, respectively. However, the financial payback periods were less likely to be achieved within the building lifetime, revealing that only the Swedish case achieved a payback period within 100 years (83.59 years). Thus, circularity solutions were considered to shorten the PCE payback periods. Using secondary materials in PCE fabrication only slightly reduced the payback period. However, reusing the PCE considerably reduced the energy and carbon payback periods to less than 6 years and 11 years, respectively in all three cases. Regarding cost, reusing the PCE shortened the Swedish payback period to 29.30 years, while the Dutch and Spanish cases achieved investment payback at 42.97 years and 85.68 years, respectively. The results can be extrapolated to support the design of sustainable building elements for energy renovation in Europe. • Novel technological systems for recycling mineral construction and demolition waste were introduced. • A novel prefabricated concrete element system for renovating existing building (PCE2) was presented. • Comprehensive assessment of the PCE2 system under three EU member states was investigated. • How will material circularity strategies influence the energy-carbon-investment payback of the PCE2 was explored. [ABSTRACT FROM AUTHOR]

The textile industry has a high share in the total energy consumption of the manufacturing industry, especially in global textile supplier countries. Energy consumption and air emissions can be reduced at the source with detailed cleaner production and energy efficiency applications in textile production processes. In this study, energy efficiency studies were carried out in an integrated woolen textile facility. In this context, energy consumptions were analyzed based on the main production and other preparatory processes by detailed onsite investigations. Specific electricity, thermal energy, and air emissions were calculated based on the production processes of the facility. In addition, specific energy consumption values were compared with similar textile facilities to evaluate energy saving potentials and opportunities. A list consisting of 85 energy efficiency techniques was prepared to reduce energy consumption and air emissions in the facility. These techniques were evaluated and prioritized in terms of techno-economic feasibility, potential savings, and environmental benefits using a systematic decision-making model. Ultimately, it was decided to apply the following priority energy efficiency techniques (a total of 13): process optimization, the establishment of a process-based energy monitoring and control system, the recovery of waste heat, the optimization of steam boilers, the modification of radio frequency (RF) dryers, the modification of fan motors in the ventilation-humidification system, the proper positioning of compressors, the installation of a compressor monitoring system, and an air emission treatment system. It was found that with the application of such techniques, electricity, thermal energy, and air emissions could be reduced by 8–27%, 12–28%, and 23–45%, respectively. Based on the financial analysis, the payback periods of the priority energy efficiency techniques were found to be generally less than 36 months. • Energy efficiency studies were carried out in an integrated textile facility. • A total 85 techniques were identified to reduce energy consumption. • Finally, 13 techniques were identified and decided to implement. • Electricity and thermal energy savings were 8–27 and 12–28%, respectively. • The payback periods were shorter than 36 months.. [ABSTRACT FROM AUTHOR]