Cost Recovery Period Research Articles

Performance and Economic Analysis of Two Types of High-Temperature Heat Pump Based on New Refrigerants

This paper proposes, for the first time, the research concept of comparing energy and economy between transcritical cycle high-temperature heat pumps and subcritical cycle high-temperature heat pumps with new refrigerants. Experiments and simulations are conducted to compare the system performance and economy of two heat pumps, and the effects of different factors on the performance of two heat pumps are analyzed. The results show that R744/R1234yf (90/10) and R515-1 are the preferred refrigerants for transcritical cycle heat pumps and subcritical cycle heat pumps, respectively. The COP of the R744/R1234yf (90/10) transcritical heat pump is generally higher than that of the R515B-1 subcritical heat pump, and compared to the R515B-1 subcritical heat pump, the cost recovery period of the R744/R1234yf (90/10) transcritical heat pump is about 9–15 years. Therefore, it is recommended that users who use heat pumps for a long time choose transcritical cycle heat pumps. Meanwhile, with the change of evaporation temperature, the system COP of the R515B-1 subcritical heat pump and R744/R1234yf (90/10) transcritical heat pump increases by 61.11% and 65.91%, respectively. In addition, the optimal charge amount for the R515B-1 subcritical heat pump is 81.8% of that of the R744/R1234yf (90/10) transcritical heat pump.

Reducing Carbon Footprint by Using Thermal Insulation Materials in Palestinian Buildings

Buildings account for 39% of emission worldwide. The study aims to clarify the effects of thermal insulation materials used in West Bank Palestinian buildings, to demonstrate their capacity to reduce emissions and saving cost. Using a variety of records from the Engineers Syndicate and the Palestinian Central Bureau of Statistics, a thorough study of buildings in the West Bank area was carried out to determine the number and area of buildings. Additionally, data from sources of energy was collected for the study years 2018–2021. Following the use of thermal insulation materials to the buildings, computations were then equipped with thermal insulation materials, and calculations to estimate the energy savings and reductions in carbon dioxide (CO₂) emissions. The results show, using insulating materials reduce energy consumption by 27.23% and CO₂ emissions significantly. It is anticipated that the cost recovery period for new construction is 0.39 to 1.09 years, and for repaired buildings it is between 4.34 and 7.2 years. Depending on the location and typical temperature of the area. The study recommends working for the widespread use of insulating materials in all new construction and for retrofitting existing structures. These initiatives will support international efforts to reduce emissions and achieve sustainable development goals in addition to improving energy efficiency.

An improved capacitance-resistance model for analysing hydrogen production with geothermal energy utilisation

The integration of geothermal and hydrogen energy through advanced predictive modeling not only enhances energy production efficiency but also contributes significantly to the global transition towards renewable energy sources. This study commences with the establishment of a geothermal hydrogen production model using Aspen Plus, incorporating physical constraints, derived from the Capacitance Resistance Model (CRM) model. Refinements to Long Short-Term Memory (LSTM) neural networks based on historical data and CRM constraints tailor them for geothermal reforming-based hydrogen production. Production analysis indicates that the hybrid CRM-LSTM model adeptly predicts heat and hydrogen production, improving system performance. The approach demonstrates superior accuracy, with hydrogen production predictions deviating by less than 2%. The comparison highlights the hybrid model’s advantage in handling nonlinear characteristics but it also shows the hybrid model requires longer training times. Sensitivity analysis reveals significant implications for investment decisions, with CRM predicting a 26-year cost recovery period under standard conditions, potentially underestimating actual outcomes by over eight months. Such discrepancies underscore the importance of accurate predictive models in guiding investment decisions for sustainable energy projects. This model contributes to achieving sustainable development goals by integrating geothermal and hydrogen energy, advancing the transition towards renewable and environmentally friendly energy sources.

Energy saving and carbon reduction of the application of phase change materials in rammed earth heritage buildings

ABSTRACT The combination of conventional thermal insulation materials and phase change materials (PCMs) was proposed without damaging the appearance of REHBs, the internal insulation measures of four types of expanded polystyrene (EPS) and six kinds of PCM boards combinations were investigated, and 19 retrofit cases were obtained. By conducting detailed simulations of energy consumption and indoor temperature for different cases at different locations, and comprehensively comparing multi-objects (energy-saving, economic and low-carbon), the energy consumption, cost recovery period and carbon reduction of these cases are compared and analyzed. The results show that Case I (only EPS) has the best energy-saving performance, economy and carbon emission reduction, Case III (EPS and PCM) is the second and Case II (only PCM) is the worst. The energy-saving rate of Case I and Case III (16 ℃) differs by 5.65%, while the cost, incremental benefit and payback period differ by 9.34%, 10.2%, and 1.57 years, respectively. Case III is a new and better passive retrofit measure of the REHB. Its energy-saving, cost and carbon reduction are only about 10% lower than that of Case I, but it has better indoor comfort. The outcomes can provide a reference for the innovative energy-saving retrofit cases for REHBs.

Optimizing battery energy storage prototypes for improved resilience in commercial buildings: Gaussian mixture modeling and hierarchical analysis of energy storage potential

The increasing energy demand in commercial buildings has led to the adoption of photovoltaic (PV) systems as a viable solution. However, the gap between energy consumption and PV capacity in commercial buildings remains uncertain, and there is limited research on the potential for energy storage in different commercial building types. This study utilizes Gaussian mixture modeling to extract energy consumption and PV capacity patterns from diverse commercial buildings, using datasets provided by the Department of Energy. By employing hierarchical analysis, we investigate the energy storage potential of various commercial buildings based on the disparities between energy consumption and PV capacity patterns. Moreover, this study introduces innovative battery energy storage system (BESS) prototypes tailored to the specific needs of different commercial building types. These prototypes determine the optimal BESS capacity and charging schedules, providing an effective means of improving electrical resilience in commercial buildings. The findings reveal that medium offices, warehouses, and secondary schools require BESS capacities of 410kWh, 838kWh, and 349kWh, respectively, and recommend charging time windows of 9:00–17:00, 8:00–18:00, and 9:00–14:00, respectively. Additionally, the cost recovery period for Li-ion phosphate and ternary Li-ion batteries ranges from approximately 2.5 to 7.5 years and 4 to 8.2 years, respectively. The developed BESS prototypes based on energy storage potential offer resilience to commercial buildings during power outages caused by natural disasters and emergencies, helping to improve their electrical resilience. This study provides valuable insights into the potential for energy storage in commercial buildings and promotes the wider implementation of BESS in the commercial sector, contributing to the achievement of effective demand-side management.

Cost-benefit-analysis of coastal adaptation strategies and pathways. A case study in West Africa

Understanding the level of vulnerability of human and natural systems to climate variability and change, and how investing in adaptive capacity now will prevent losing billions of dollars in damages in the future are pivotal to making decisions and developing policies related to coastal adaptation. The research presented in this paper focuses on developing a methodological framework to perform a cost-benefit-analysis of disaster risk reduction and climate change adaptation strategies (i.e., protect, accommodate, or retreat options). The method is tested in pilot-site case-studies along the West African countries of Ivory Coast, Ghana, Togo, and Benin. The criterion used in the cost-benefit analysis is the Net Present Value (NPV) for the different risk management alternatives, according to different time horizons and dynamic adaptation pathways to 2100, discount rates and low- and high-cost estimates. Overall, the research makes evident that coastal protection investment costs ensuring the lowest residual risk (virtually zero risk) to 2100 are so high that they are unlikely to be paid back by avoided damages. Planned retreat (coastal setbacks and/or accommodation) allows to obtain most of the benefits (50%–98%) at a fraction of the protection costs (2%–12%). Furthermore, the research provides strong evidence that, when coastal risks are dominated by frequent coastal floods (10-year return period), the cost recovery period for climate-proofing of buildings is low (a few decades) compared to protect or setback measures. Finally, the research illustrates that disaster risk reduction and climate change adaptation strategies cannot be examined in general, but that location specific analysis of both costs and benefits is required.

Investigating the Energy-Efficient Structures Using Building Energy Performance Simulations: A Case Study

The use of energy efficient structures in the local construction industry assists in promoting green building concepts, leading to economical and eco-friendly solutions for self-sustained structures. The main aim of this study was to examine and compare the energy performance of various local buildings. Detailed 3D building models (house, office, and warehouse buildings) were constructed and investigated for their cost and energy savings using building energy simulation tools (green building studio and insight). Moreover, the effects of various building materials for walls, window panels, and roof construction were explored, and a life-cycle cost analysis was performed. It was observed that the effect of the window-to-wall ratio was less severe in term of energy use in office buildings compared to normal houses due to the larger amount of space available for air circulation. Furthermore, the most efficient location for windows was found to be at the middle of the wall in comparison with the top and bottom positions. The effect of the orientation mainly depended on the symmetry of the building. More symmetric buildings, i.e., tested warehouse buildings (rectangular structure), showed an energy use difference of around 7 MJ/m2/year for a 360° orientation change. Tested house buildings exhibited an energy use difference of up to 25 MJ/m2/year. Three-pane glass windows also showed major improvements, and the total energy consumption for houses was reduced to 14%. Furthermore, wood walls showed comparable energy performance with brick walls without the use of insulation. According to US-LEED guidelines, the tested house, office, and warehouse buildings achieved 79, 89, and 88 points, respectively. The cost recovery period for house, office, and warehouse buildings was estimated to 54, 13, and 14 years, respectively, including running and maintenance costs. It can be argued that the Insight and Green Building Studio packages can assist construction stakeholders to determine the energy efficiency of the modeled building as well as to help in the selection of materials for optimized and improved design.

Prospects for environmentally safe mechanical biological treatment of municipal solid waste in Ukraine

Improving waste management is currently one of the priorities for Ukraine in the environmental safety. EU experience in the use of mechanical biological waste treatment technologies should be applied now in connection with the development and implementation of Regional Waste Management Plans in Ukrainian regions. The aim of the paper is to analyse the benefits and the preconditions of using mechanical biological waste treatment technologies in Ukraine, as well as barriers that may hinder the construction of mechanical biological waste treatment plants. The analysis of the eight drafts of the Regional Waste Management Plans showed that the mechanical biological waste treatment technologies market is free in Ukraine and the best option for the regions where there are cement plants operating is production of solid recovered fuel. Such types of projects could be affordable for Ukrainians with the cost recovery period more than 8 years. On the other hand there are significant obstacles of economic, organizational and technological nature to their immediate implementation i.e. low rates on waste disposal tax, partly compliance on air emissions monitoring system, absence of necessary standards etc. The priority actions to speed up mechanical biological waste treatment technologies implementation have been defined.

Design and Optimization of Underground Logistics Transportation Networks

With the burden of city transportation system becoming bigger and bigger, it is imperative to develop reliable and efficient underground logistics. The appropriate location of cargo transshipment centers in underground logistics system is selected using the Set Covering Problem Model, Weighted Set Covering Problem Model, and the reasonable prediction of the freight volume data of major cities to ensure the maximum numbers of service nodes are covered by the least transshipment centers within a reasonable range. The timing of the construction of facilities in the system is proposed, considering the construction cost and cost recovery period of the underground logistics system. The design and optimization plan of the urban underground logistics system, based on the above, is given to achieve the purpose of relieving urban traffic congestion and increasing freight volume.

A Mathematical Model Development for Assessing the Engineering and Economic Improvement of Wave and Wind Hybrid Energy System

All aspects of human life require some source of energy. Fossil fuels are predicted to be exhausted in some decades. Moreover, their consumption is known to be very harmful to all living species. Wind and wave powers, as renewable energy sources with no emissions, represent better alternatives for electricity generation. The aim of the present study is to develop a model to assess a wave–wind hybrid energy system. The idea of adding a wave energy harvester to a floating or a fixed-support wind turbine structure contributes to increase the system reliability. Thus, a mathematical model was used to assess not only the components of the wind–wave hybrid system (e.g., wind turbine, wave converter, and foundation), but also the system costs and the cost recovery period. The wave energy converter selected for the hybrid device was a Wavestar prototype combined with a wind turbine. The engineering and economic improvements of the system and associated costs were calculated. Two case studies of the proposed hybrid system in the eastern Mediterranean Sea and the North Sea were assessed. It was concluded that the annual energy production from the wind–wave hybrid device in the North Sea was 64.3% higher than that in the Mediterranean Sea. As a result, the cost of energy (in USD/kWh) in the North Sea was lower than that in the Mediterranean Sea, making the hybrid technology commercially feasible.

Performance analysis of solar vacuum membrane distillation regeneration

This paper proposes a novel solar vacuum membrane distillation (VMD) regeneration for liquid desiccant air conditioning (LDAC) system, and establishes a mathematical model of the VMD regeneration process and traditional thermal (TH) regeneration process based on the heat and mass balance. The corresponding simulation model was established by using Matlab software, and the model was verified by previous experiments. The results show that: the model results are consistent with the previous experimental results, and the maximum error is less than 6%. Model simulations are carried out to study the regeneration performance under various operating parameters and climatic conditions, meanwhile the comparison the solar power consumption for regenerating one kilogram desiccant between the VMD regeneration and TH regeneration. Results demonstrate that when the air temperature is less than 32 °C, the humidity ratio is higher than 19 g/kg, and the air flow rate is less than 0.13 kg/s, the VMD regenerator solution regeneration effect is better than the conventional thermal regenerator. VMD regeneration is more suitable for solution regeneration in wet areas than TH regeneration. Furthermore, when the solution temperature is lower than 60 °C, VMD regeneration outlet concentration is higher than TH regeneration. VMD regeneration is more suitable for low-grade energy. Analyze the solar power consumption for regenerating one kilogram desiccant found that the VMD regeneration saves 10–37% energy than TH regeneration. Through economic analysis, it is found that the VMD regenerator can save 582.4 kWh of electricity per year compared to the TH regenerator. According to the cost recovery calculation formula, the cost recovery period can be calculated as 13.8 years.

Annual thermal evaluation of a double pane window using glazing available in the Mexican market

The annual thermal evaluation of a double pane window (DPW) is presented; the DPW is modeled using three different types of panes commercially available in Mexico. Hourly climatic data of the coldest and the warmest day of each month of 2016 were used to model the behavior of the DPW in a warm region of Mexico (Chetumal, Q. Roo). The simulations were carried out using an in-house code based on the finite volume method. To carry out the annual thermal analysis of the DPW, four cases were defined; Case C1: corresponds to single clear glazing window (reference case); Case C2: clear glass + air gap + clear glass; Case C3: clear glass + air gap + reflective glass and Case C4: clear glass + air gap + Low-ε glass. Results showed that case C3 reduces the heat flux to the inside about 72.6% regarding case C1. Besides respect to case C1, cases C2 and C4 showed an energy saving of 12 and 28.6% respectively. On the other hand, case C3 resulted to be the best option for energy savings, where a saving of $30.73 USD a year was computed with respect to case C1, with an approximate cost recovery period of 3.5 years. Hence, the use of a reflective pane in a DPW is highly recommended for warm weather conditions in Mexico.

Estimation of the Economic Efficiency of Blueberry According to the Production System

Abstract Currently, the blueberry crop systems are continuous diversifing due to the growing demand for fruit on the market as well as the willingness of farmers to invest in profitable blueberries business. The need to extend the fresh-consumption period of blueberry fruits has made crop protection systems be considered appropriate for high-quality and valuable fruits. In the present work, we have proposed to compare the economic efficiency of three blueberry production systems as follows: the normal intensive cultural system in beds, the superintensive cultural system in pots and the superintensive cultural system in pots and plastic covered (high tunnel). The analyze of the cost and profitability of blueberry has been done according to the crop system, taking into consideration several elements such as: the number of plants per hectare, the total duration of the exploitation, the value of the investment, the yield and the cost of production etc. Further more, considering the average sale price of the blueberry fruits in Romania, we have calculated the net annual return, the annual return rate, the cost recovery period, total operating profit, economic return on investment, and average return on investment. We observed that as much the degree of intensification has increased, the value of investment was higher and the spendings has increased too. Blueberry pot production systems with or without plastic protection are especially recommended for smaller surfaces, which in this way can boost the value and their economic potential.

Thermoelectric generator with air-cooling heat recovery device from wastewater

A lot of waste water has not been recovered in China. The waste water emissions also cause thermal pollution and damage to the ecological environment. This paper presents a waste heat recovery solution based on thermoelectric power generation technology. The general structure of an air-cooling heat recovery device is designed. The physical model is established and solved. The temperature changing law along the flow direction is obtained. The effects of main factors such as thermoelectric module geometry, heat sink geometry and wastewater flow rate are analyzed. The results show that the heat sink design is the most key factor affecting the performance of air-cooling thermoelectric power generation device. The wastewater temperature decreased 0.19°C per meter in the flow direction with a 120mm wide square pipe. The area power density of the thermoelectric module is about 0.30kW/m2 and the efficiency is about 1.28%. The cost recovery period of the equipment is about 8years. The main reason for the uneconomical is the low temperature of the wastewater.

New low temperature industrial waste heat district heating system based on natural gas fired boilers with absorption heat exchangers

To efficiently recover low temperature industrial waste heat, a new low temperature industrial waste heat district heating system based on natural gas fired boilers with absorption heat exchangers was proposed, and also analyzed from the perspective of thermodynamics and economics. In heating substations, absorption heat exchangers are used to greatly decrease the return water temperature of the primary heating network. The lower temperature return water helps to efficiently recover waste heat in heating station and greatly increase economic heat transmission distance. Annual primary energy efficiency and product exergy efficiency of the new district heating system are 215.0% and 42.5% respectively. When waste heat price and heat transmission heat distance are 25¥/GJ and 60km respectively, its heating cost and investment recovery period are 6¥/GJ and 0.7years respectively lower than that of current district heating systems based on natural gas fired boilers. Characterized by better thermodynamic performance and economic benefit, the new district heating system would be promising for low-temperature industrial waste heat recovery.

As Iran Ramps Up Production, Industry Views Contract Terms

Middle East Special Section Iran has surprised many global market experts with how rapidly it has increased crude oil production, following the January international agreement that lifted nuclear-related sanctions against the country. Production rose by 25% to hit the pre-sanctions level of 3.6 million B/D in April, shattering major analysts’ predictions that it would take a year to do so, and increased to 4 million B/D during the summer. Exports have doubled to more than 2 million B/D. However, notwithstanding Iran’s early success, most market observers believe the country will be challenged to sustain a 4 million B/D output for the rest of the year. And for Iranian production to grow to 4.8 million B/D in 5 years, a goal that Petroleum Minister Bijan Zangeneh stated in June, the country will require a large infusion of capital from international oil and gas companies. To keep its ambitions on track, Iran has set an objective of attracting USD 180 billion in international investment for its oil and gas sector. Of this amount, between USD 70 billion and 100 billion is needed for upstream projects, and Iran hopes to bring in from USD 20 billion to 30 billion of that for projects in its initial tendering round for licensing projects. The Iran Petroleum Contract Understandably, the global industry has been paying close attention to the Iran Petroleum Contract (IPC), the new framework approved by the Iranian government in early August for signing agreements with international operators to explore for and develop oil and gas resources in the country. While the framework was approved, questions remain over numerous details. For priority projects under the IPC, Iran worked from a technical services contract model, under which an operating company bears all capital costs up to first production, or targeted incremental production, and begins to recover its costs from production proceeds. The percentage of proceeds from which costs can be recovered may be negotiated field by field but will not exceed 50% for oil fields and 75% for gas fields. Previously, Iran used a system of buy-back contracts. Under these, the operator’s capital investment level and cost-recovery period were negotiated with the government and a fixed rate of return was set. If exploratory drilling led to a viable project, the operator’s capital expenditure for exploration and development was considered a loan to the state. The government compensated the company through annuity payments that began when production started, or a production target was met, and continued for the life of the contract. Iran is likely to continue using buyback contracts for lower priority projects. An important question is where it will draw the line between IPC projects and those on a buy-back or other contractual basis.

Optimal Placement of SVC Incorporating Installation Cost

As the FACTS controllers are an inequitable part of power system due to their fast and very flexible control. With the enhancement of FACTS technology, their role in the marginal cost determination should be considered taking their cost function into account. The aim of this paper is to compare the optimal performance of static VAR compensator (SVC) in voltage stability enhancement problem. During last decade, FACTS devices are broadly used for maximizing the margin of voltage stability and loadability of existing power system transmission networks. To get the optimal system, cost analysis might be necessary. In the cost analysis of SVC, authors analyzed the installation cost of SVC devices in USD, the cost of SVC in USD/KVAR and the average value of installation cost for given systems. Here, the voltage stability enhancement problem is solved applying Gravitational Search algorithm incorporating SVC. The following conditions are investigated with the incorporation of SVC: the role of SVC for improving the voltage profile, loss minimization and the approximate analysis on cost recovery and payback period with SVC in voltage stability enhancement problem. With this motivation, the location of SVC is finalized through weak bus identification methods. Voltage stability indices namely Fast Voltage Stability Index (FVSI) is utilized to identify weak buses in the systems. For calculation of the Size of SVC, an optimization routine Gravitational Search Algorithm (GSA) is established. The main purpose of optimization is to minimize the FVSI. The proposed approach has been tested on three standard IEEE bus systems with different loading scenarios. General Terms: Flexible AC Transmission System (FACTS), Marginal Cost, Voltage Stability Assessment, Static VAR Compensators.

A combined system utilizing LNG and low-temperature waste heat energy

This paper has proposed a combined system, in which both the exergy of liquefied nature gas (LNG) and low-temperature waste heat energy can be effectively utilized. A multi-objective optimal model containing four factors: net output power, total investment cost, heat availability and dynamic investment recovery period has been built. Based on it, a thermodynamic and thermal-economic analysis on the system has been conducted with eight organic working fluids. Cycle performance of both the novel system and separated LNG and ORC system has been comparatively analyzed. The results show that the combined system has more net output power, lower total investment cost and larger heat availability factor than separated systems. And n-pentane emerges as the most suitable working fluid. Meanwhile, the influence of temperature and LNG parameters on F(X) is also analyzed. Moreover, the turbine's share is the largest; accounting for 43% to 50% of the total cost, and the condenser's exergy loss in the combined system is the most.

Energy conservation and waste utilization in the cement industry serve the green technology and environment

The cement industry is one of the most energy-intensive industries consuming 4 GJ/ton of cement, i.e. 12–15% of the energy use in total industry. Energy cost accounts for 30% of the total cost of cement production. Seventy-five per cent of this energy is due to the thermal energy for clinker production. It is also found that 35% of this supplied thermal energy is lost in flue gas streams. Most modern kilns use pet coke or coal as their primary fuel. Instead, the municipal waste in landfills offer a cheap source of energy and reduce the environmental effects of dumping solid waste. The calcination and drying processes and the kiln need large quantities of thermal energy. About 40% of the total energy input is lost in the hot flue gases and cooling the stack plus the kiln shell. Hence, it is suitable to use an organic Rankine cycle (ORC) to recover the exhaust energy from the kiln. Alternatively, a 15 MW gas turbine engine combined with a steam turbine could be utilized. It was found that ORC produces 5 MW with a capital cost recovery period of 1.26 years. However, the gas turbine combined system produces 21.45 MW with a maximum recovery period of 2.66 years.

Cost benefit analysis on SVC and UPFC in a dynamic economic dispatch problem

Purpose – The aim of this paper is to compare the performance of static VAR compensator (SVC) and unified power flow controller (UPFC) in dynamic economic dispatch (DED) problem. DED schedules the online generator outputs with the predicted load demands over a certain period so that the electric power system is operated most economically. During last decade, flexible alternating current transmission systems (FACTS) devices are broadly used for maximizing the loadability of existing power system transmission networks. However, based on the literature survey, the performance of SVC and UPFC incorporated in the DED problem and its cost–benefit analysis are not discussed earlier in any of the literature. Design/methodology/approach – Here, the DED problem is solved applying ABC algorithm incorporating SVC and UPFC. The following conditions are investigated with the incorporation of SVC and UPFC into DED problem: the role of SVC and UPFC for improving the power flow and voltage profile and the approximate analysis on cost recovery and payback period with SVC and UPFC in DED problem. Findings – The incorporation of FACTS devices reduces the generation cost and improves the stability of the system. The percentage cost recovered with FACTS devices is estimated approximately using equated monthly installment (EMI) and non-EMI scheme. It is clear from the illustrations that the installation of FACTS devices is profitable after a certain period. Research limitations/implications – In this research work, the generation cost with FACTS devices is only taken into account while calculating the profit. The other benefits like congestion management, cost gained due to land and cost due to stability issues are not considered. For future work, these things can be considered while calculating the benefit. Originality/value – The originality of the work is incorporation of FACTS devices in DED problem and approximate estimation of recovery cost with FACTS devices in DED problem.