Simple Payback Period Research Articles

Energy audit and conservation of Dental college – A case study

Power is a lifeline for the industry as well as to the individual citizen. With industrial growth of about 10 %, the power demand is surging very rapidly from last decade. With limited resources of power generation and lack of planning resulted into power shortages throughout the states. Unprecedented powercrisis is hindering the socio-economical growth of almost all states. The remedy for this power crisis is seen by the planner at Centre and states only in the two option. Addition of power capacity. Enforcing disparate load shedding. There is total disregard shown to the time tested option of Energy Efficiency improvement at various stages. (Like in generation, T & D, and end use) Reduction of avoidable energy losses in distribution system. Demand side management. Implementation and Monitoring of Energy efficiency improvement program. Bharti Vidyapeeth University Medical campus, Dhankawadi includes many colleges i.e. Medical, Dental, Rajiv Gandhi Biotechnology, Ayurved, Homeopathy college. Being High Tension consumer having Contract Demand of 200KVA, its monthly average electricity bill is Rs. 6,84,908/-. Sanctioned Demand is 344KVA and connected load is 413kW. Some of the major electricity consuming systems are Illumination, Heating equipment, Water pumping system, Air Compressor, Air conditioners. So, the present paper represents the overview of energy audit and conservation programme carried out at Bharati Vidyapeeth University Dental college campus. This study has resulted in exploring the overall energy and thus cost saving potential of 10 % with simple payback period of months. The outcome of this study and the implementation of the suggestions are discussed with the management and other concerned staff. The suggestions incorporated in Energy Audit report are technically feasible as well as financially viable.

Design Analysis of an Optimal Microgrid System for the Integration of Renewable Energy Sources at a University Campus

The integration of renewable energy sources (RESs) is a strategic goal in Saudi Arabia. The energy source diversification plan comprises the penetration of various technologies, including solar photovoltaic (PV) and wind energy. In this research, an optimal microgrid system design is proposed and analyzed at the Islamic University of Madinah. The research intends to facilitate the decision-making process in the incorporation of RESs in Saudi universities. A pilot project has been established at the Faculty of Engineering and the measured load profile has been incorporated. Three alternatives are investigated, and their technical and economic performance is determined (i.e., PV system, wind system, and hybrid system). To enhance the accuracy of the simulated models, on-the-ground weather data have been utilized to formulate a typical meteorological year profile. The results demonstrate that a PV system of 1.5 MW installed capacity can cover up to 3.03% of the university’s annual electrical consumption, with a levelized cost of energy (LCOE) of 0.051 USD/kWh. The PV alternative can generate annual energy of 2.68 GWh with a capacity factor of 20.2% and a simple payback period of 18.6 years. The wind energy system has a capacity factor of 1.1 MW and yields a higher ratio of energy production to installed capacity, owing to a higher capacity factor at 29.5%, and annual energy of 2.71 GWh. However, due to the higher initial cost and insufficiency of wind resources at the proposed location, this wind energy alternative results in higher LCOE at 0.064 USD/kWh and a simple payback period of 23.6 years. The hybrid alternative facilitates the integration of diverse RESs. It has a capacity factor of 1.37 MW, leading to an annual generation of 3.27 GWh and a renewable fraction of 3.7%. The LCOE of the hybrid option is determined to be 0.061 USD/kWh and the simple payback period at 20.7 years. All alternatives help in the reduction of carbon dioxide (CO2), sulfur dioxide (SO2), and nitric oxide (NOx) between 0.11 million kg and 54.6 million kg annually. Each of the systems can provide opportunities at the technical, economic, and environmental levels. The implications of this research facilitate Saudi universities in supporting the integration of RESs, considering the strategic goals of Saudi Arabia.

Techno-economic analysis of the integration of flue gas dryer and steam-air preheater into biomass power plant

For a biomass power plant, which uses a biomass fuel having a high moisture content, flue gas drying is an effective method of increasing the overall power plant efficiency. However, this method requires flue gas that has a high temperature. Most biomass power plants, however, are designed so that flue gas temperature is already reduced to a low value through the installation of economizer and air heater. This paper investigates the use of steam-air preheater to raise both air temperature and flue gas temperature. Therefore, steam-air preheater enhances the potential of flue gas dryer, and both devices can be used in conjunction to raise the overall efficiency of a biomass power plant. Models of power plant, flue gas dryer, and steam-air preheater are used in this paper to demonstrate by simulation that the integration of flue gas dryer and steam-air preheater results in 2.52% increase in electrical power output of a reference power plant that consumes a fuel with 52% moisture content (wet-basis) if the fuel moisture removal rate in flue gas dryer is 7140 kg/h, and the total heating surface area of steam-air preheater is 2000 m2. The simple payback period for the investment in this integration is 3.3 years.

The Cost Benefit Analysis of Commercial 100 MW Solar PV: The Plant Quaid-e-Azam Solar Power Pvt Ltd.

The energy crisis in Pakistan has crippled the country’s economy with an energy shortfall reaching up to 6000 MW. Fortunately, Pakistan lies close to the Sun Belt and therefore receives very high irradiation. To this end, in the beginning of 2014 the Pakistani government sanctioned a solar photovoltaic project namely Quaid-e-Azam Solar Park which was rated at 1000 MW. In this study, a cost benefit analysis for the Quaid-e-Azam Solar Park has been developed. The model uses RETScreen software. In fact, a literature review pointed out that most of the previous research work with reference to cost benefit analysis for solar projects has been mainly carried out on smaller power plants. The outcome of the study shows promising results with the simple payback period coming out at 5.6 years. Furthermore, this analysis can serve as guideline for future solar photovoltaic projects in Pakistan and can help in the development and utilization of the huge solar potential of the country, thus aiding in the reduction of energy shortage. In its proposal, our research is unique and innovative in the Pakistani context. The results aim to serve as a guideline for decision makers and researchers interested in this topic.

Improvement of a liquid air energy storage system: Investigation of performance analysis for novel ambient air conditioning

Liquid air energy storage (LAES) is a grid-scale energy storage technology that utilizes an air liquefaction process to store energy with the potential to solve the limitations of pumped-hydro and compressed air storage. A challenge it faces itself is its high compression work during the charging process. Thus, attempts to increase the performance of the system need to include reducing the compression work. This study investigates the possible performance improvement of a LAES system through inlet air dehumidification and cooling. A simulation is performed on a 40 MW/320 MWhe LAES system which uses a desiccant wheel dehumidifier and a cooling coil for inlet air conditioning. The results show that the system can save 9521 MWhe in compression work annually which will translate to $761,680 annual cost savings in charging the system. The maximum performance improvement achieved during the summer period when the ambient conditions are unfavorable is 11.7%. Financial analysis also shows that the simple payback period of the desiccant wheel dehumidifier modification is 11.5 years and the levelized cost of storage (LCOS) of the LAES system is $237/MWh which is competitive compared to other storage systems.

Passive Strategies for Building Retrofitting: Performances Analysis and Incentive Policies for the Iranian Scenario

A large amount of the Iranian energy demand is related to the building sector, mainly due to its obsolescence. In this paper, a second-skin system has been implemented as a retrofit action for an office building, evaluating the effect of a tensile material as second-skin in terms of primary energy saving, carbon dioxide equivalent emissions, and simple payback period. The analysis was carried out through numerical simulations across a whole year and for four Iranian cities (Tabriz, Teheran, Yazd, and Bandar Abbas) in four different climates (cold, temperate, hot-dry, and hot-wet), and with the building aligned at either north-south or east-west. Moreover, an economic analysis was carried out suggesting different incentive policies to promote building energy refurbishment. The simulation results highlighted a favorable orientation for buildings in Iran, suggesting a guideline for new constructions. Indeed, the best results were achieved for an east-west orientation of the building (up to a primary energy saving of 13.6% and reduction of carbon dioxide equivalent emissions of 45.5 MgCO2,eq, in Yazd), with a decrease of the annual specific total (cooling and thermal) energy demand of 37.9 kWh/m2/year. The simple payback period values were also lower in the east-west orientation than the north-south one.

An explanatory parametric model to predict comprehensive post-commissioning building performances

Existing building commissioning (EBCx) is a promising approach to save energy and improve indoor environmental quality (IEQ) without sufficient attention yet. However, the uncertainty of building performance post-retrofit leads to a low adoption rate of EBCx, as the commissioning outcomes are dependent on various factors and difficult to model. To facilitate decision-making on EBCx, this paper introduces PECCO, a parametric mathematical model enriched with years of commissioning engineering experience to predict comprehensive EBCx outcomes for various types of public buildings, along with a mobile-based tool to automate the prediction process. An 8-min questionnaire is used to collect building parameters regarding general, management, HVAC, smart system, IEQ, electrical, water supply, and building envelope. Then, a mathematical model predicts commissioning outcomes including energy-saving potential, annual cost saving, asset value increase, comfort-improvement potential, operation risk, commissioning cost, simple payback period, and difficulty in commissioning, and provides overall commissioning strategies, specific commissioning suggestions, and benchmark figures compared with other buildings. Three case studies suggested that PECCO's prediction on the simple payback period achieved a mean absolute percentage error (MAPE) of 15.47%, which is acceptable and comparable to other related studies. By providing various perspectives of information to building owners and managers, PECCO is helpful to foster the industry to undertake EBCx, leading to a more energy-efficient, low-carbon building industry.

Performance Analysis of Bio-Energy Based Power Generation System in Nigeria Using Rice Husk Feedstock

Bio-energy which is the energy resources derived from organic matter has contributed significantly to primary energy supply in most developed countries of the world. The extensive use of biomass for electricity generation started recently as a more efficient option of providing energy. To encourage investment in this area, detail analysis on the prospect of Biomass energy generation system in Nigeria context need to be carried out. In line with this, this study assesses the viability of setting up a Biomass Energy Plant in Nigeria using rice husk. It determine the availability of rice husk for the project and identify the economic advantage of using rice husk as a feedstock in generating electricity while evaluating the energy conversion technology adopted with consideration on its environmental impact. The proposed plant location is Abakiliki Rice Mill complex and Gasification technology was adopted for the bio conversion process. Data on the feedstock availability was collected by direct measurement of the resources at the various mill dump site in the Rice Mill Complex and analyzed using Python analytical and visualization tools (Numpy and Seaborn). The primary source of data for the analysis is data gotten from the field and Nigeria Energy Regulatory Council (NERC) while the secondary source of data is data from related work over the internet. The outcome of the study showed that the Rice Complex have the capacity to produce the quantity of rice husk required to generate 499,320KWh of electricity per year using Bio-Energy plant. Also, the mass of rice husk produced is significantly higher in the month of October, November and December due to the weather condition (dry season) and the high demand of rice as the result of the festivity (Christmas celebration). When the performance of the existing system and the proposed Bio-Energy plant was compared in terms of per Kilowatt cost of energy generation, it was observed that the new system outperformed the existing one. This is traceable to the good caloric value of rice husk and its availability in very large quantity at no cost. To determine the system’s sustainability, the financial feasibility of operating a Biomass plant in Nigeria was also carried out; levelised cost, simple payback period and return on investment (ROI) as important financial metrics were calculated using real data.

Impacts of large chilled water temperature difference on thermal comfort, equipment sizes, and energy saving potential

The heating, ventilation, and air-conditioning system accounts for nearly half of the building's total electricity consumption, and chillers are the biggest consumer. Optimizing the design and control of chiller plants is critical for building decarbonization. This study evaluated the impacts of large chilled water temperature difference (CHW-DT) on the equipment sizes, thermal comfort, and energy saving potential. An office building in Beijing was modeled in EnergyPlus and calibrated by measured data. Three retrofit scenarios of chilled water systems were studied. Firstly, the impacts of large CHW-DT on occupants' thermal comfort were presented. The equipment was sized based on 5 °C CHW-DT and operated at larger CHW-DT. Secondly, the impacts of large CHW-DT on equipment sizes were studied. The equipment was sized based on the operating CHW-DT to maintain thermal comfort. Thirdly, an optimal CHW-DT control strategy was developed to save energy consumption without changing the equipment sizes. The uncertainty analysis of Fanger model inputs was done for the first two scenarios. The results showed that using large CHW-DT without changing terminal sizes caused a significant decrease in occupants' thermal comfort. The uncomfortable hour percentage during the cooling period changed from 0.48% to 37.50% when CHW-DT increased from 5 °C to 10 °C. It was costly to increase the terminal sizes to maintain occupants' thermal comfort when applying large CHW-DT. The simple payback periods ranged from 10.7 to 27.7 years. Compared with baseline, the proposed daily optimal CHW-DT control strategy reduced annual energy consumption by 12% without changing terminal sizes and thermal comfort. The case study demonstrated that the proposed daily optimal CHW-DT control strategy had a high energy saving potential for chilled water systems.

Analysis of energy, exergy, environmental and economics (4E) on photovoltaic-thermal collector system

In this paper, a novel thermal absorber based photovoltaic-thermal system is presented. The thermal absorber is attached at the rear surface of photovoltaic, and water is re-circulated to extract heat. The outdoor experimentations are performed at Pune, India (18.7611? N, 73.5572?) on clear sky day, and water temperatures, surface temperature, radiation and flow rate are measured to analyse techno-economical performance at different operating conditions. The surface temperature of the photovoltaic module plummeted from 54.65?C to 47.9?C with the incorporation of a thermal absorber with flipside water cooling at a ranging flow rate of 0.03 to 0.06 kg per seconds. The result shows an average enhancement of 4.2 % in the electrical power output of the photovoltaic-thermal system. The maximum thermal and electrical efficiencies were 47.82 % and 9.88 %, respectively, at 0.06 kg per seconds. The exergy efficiency was found in the range of 9.85-14.30%. Based on the experimental evaluation, uncertainty analysis was performed. The results revealed that the annual CO2 mitigation for photovoltaic and photovoltaic-thermal system was 225.46 kg annual and 464.8 kg annual, while simple payback periods were 4.53 years 3.03 years, respectively. The analysis offers an efficient estimate of experimental features of photovoltaic and photovoltaic-thermal systems from an energy-exergy, environmental and cost-benefit standpoint.

Potential of Using WVO for a Restaurant EV Charging Station

Abstract This research comprised an evaluation study for a charging station based on waste vegetable oil or biodiesel fuel. The biodiesel was produced from waste vegetable oil (WVO) and will be used (or the WVO) to charge electric cars for restaurant’s customers in their car park. The main concept behind the charging station is to be part of a restaurant that serves its customers and then uses its WVO or biodiesel to fuel a diesel engine that generates electricity to charge their electric vehicles (EV). The economic and environmental impacts of the direct use of WVO-EV charging station are promising because the costs associated with purchasing WVO are lower than those of purchasing crude oil or gas. There are several options and scenarios when selecting the perfect sized generator; using charging up to a maximum rated power of 6.6 kW is more feasible despite its higher initial cost as the simple payback period will be less than 3 years and the internal rate of return of the project is 44 %. The total saving at the end of the project for a generator with maximum rated power of 10 kW (option B) is $ 58 000. Conversely, for a generator with maximum rated power of 6.6 kW (option A) the project will cover its initial cost in around 4 years and the internal rate of return is 26 %. The total saving at the end of the project is $ 52 000. Furthermore, lower amount of greenhouse gases is produced from the burning of WVO directly. The final results showed that WVO is more feasible as it is available for free and could be burnt directly in the diesel engine. In economic terms, the project is feasible for both WVO and biodiesel as it has a high net present value and short payback period. A WVO-EV charging station can also improve the national economy by preparing it for the electric car era and, if applied to a large number of restaurants, will save a significant amount of electricity and reduce the expected strain on the electricity grid caused by the increasing number of electric cars.

Technical and economic feasibility assessment of hybrid renewable energy system at Kenyan institutional building: A case study

This study focused on the technical and economic feasibility assessment of hybrid renewable energy system for powering institutional building in Kenya – a case study of the School of Engineering, University of Nairobi. The study aimed to determine the optimum hybrid renewable energy system that can supply reliable and affordable power to the school. The load profile of the site was determined using power and energy logger (PEL) with data analysis carried out in DataView™ software. The total energy demand and consumption of the establishment were found to be 84.59 kW and 1172 kWh/day, respectively. Grid/wind/photovoltaic/diesel/battery/converter configuration was simulated and optimized in HOMERTM Pro microgrid analysis tool using local meteorological data. The total net present cost was calculated for 25 years to find the lowest cost of energy for the systems. Grid/Photovoltaic/Diesel was found as the optimum system configuration with the system having Cost of Energy (COE) of Ksh 7.89, Net Present Cost (NPC) of Ksh 69,512,100.00, Initial capital cost of Ksh 30,264,100.00, a renewable fraction of 71.6%, simple payback period of six years, discounted payback period of eight years, present worth of Ksh 12,819,300.00, annual worth of Ksh 965,700.00, excess electricity generation of 2.48% etcetera. This result shows that the system is technically and economically viable. The system proved to have reduced the power purchase from the grid by approximately 77% and reduce the electricity bill by approximately 84%. In addition, nine (9) sensitivity cases were used for sensitivity analysis and the result gave the same configuration except in cases where the sizes and prices of some components were changed.

Energy performance and economics assessments of a photovoltaic-heat pump system

In the previous few decades, the demand for heating and cooling systems has notably increased besides the requirement to get energy in a more efficient and sustainable method. Consequently, the thought of solar photovoltaic powered heat pumps has become more good-looking to match the heating demand with a renewable and environmentally friendly energy supply. In this present work, the performance of using a photovoltaic - heat pump system has been experimentally studied by installation the solar photovoltaic on the rooftop of the Ayla hotel building in Jordan which is seemly simpler than that of solar thermal to be utilized to supply heating demand and can supply any available electric load associated with the building or directly to the grid, As a result by identified the key performance indicators of the system the simple payback period is calculated to be about 1.94 years where the net profit that yearly saved is about 185,850 JOD.

Evaluating the Impact of Energy Efficiency Building Codes for Residential Buildings in the GCC

In arid climates, almost half of the urban peak load of energy demand is used to supply cooling and air-conditioning in the summertime. The pressure placed on energy resources to satisfy inhabitants’ indoor comfort requirements is mounting due to accelerated urbanisation rates in developing countries and has led countries such as those in the GCC (Gulf Cooperation Council) to establish sustainable building codes to enhance their environmental performance. Using the extensive parametric energy simulations provided by DesignBuilder, this study addresses the potential of applying different GCC energy efficiency measures to reduce annual energy consumption and carbon emissions in a typical residential dwelling in the Kingdom of Bahrain. To do so, first, a base case validation simulation model was generated, followed by four design scenarios addressing the minimum requirements for Bahrain’s Energy Conservation Code, Abu Dhabi’s ESTIDAMA 1, Saudi Arabia’s code, and Kuwait’s building code. Then, a feasibility study was conducted using the simple payback period (SPP) and lifecycle cost (LCC) analysis. Overall energy and carbon emission (CO2) reduction showed the potential for building sustainable codes to improve building environmental performance throughout the year. In terms of energy performance and CO2 reduction, Abu Dhabi’s ESTIDAMA 1 code recorded the best energy savings at a 24.4% and a 26.3% reduction in carbon emissions, followed by the Saudi code with a 14.6% annual energy savings and 12.3% less carbon emissions. Regarding the economic analysis, although the SPP indicates the Bahraini code offered payback in just under two years for subsidised energy and half a year for unsubsidised, the LCC analysis suggests that applying Abu Dhabi’s ESTIDAMA 1 code was the most feasible, followed by the Saudi building code. Consequently, the study suggests a comprehensive evaluation of the relationship between the sustainable building codes and their economic feasibility in order to enhance and promote the wide application in the GCC based on the code’s capabilities and their benefits for residential households and the overall economy.

Design and Analysis of Solar Water Pumping for Salt Production in Indonesia

Salt production farmers in Patutrejo Village, Purworejo Regency, spend nearly Rp. 10 million per year for diesel water pump operational costs. The cost of fuel is the heaviest financial burden for the farmers. Not only is it expensive, but fuel scarcity is also a serious issue causing the salt production capacity target cannot be assured, and the increasing demand for salt cannot be met. This study proposes using a solar water pump system (SWPS) as an alternative solution for the farmers to ensure and increase salt production. For a group of farmers in Patutrejo who require pumping around 35 m3 of seawater each day, a photovoltaic (PV) panel of 900 Wp and a DC pump of 700 Watt can perform the task sufficiently. The total capital cost of the SWPS is Rp. 90 million, with a simple payback period (SPP) of 9.5 years. The SPP would be shorter if future fuel price increases were taken into account. With a lifetime of up to 25 years, SWPS promises a long-term, practical, reliable, and sustainable solution for salt farmers in Patutrejo.

Design and Analysis of a Solar-Powered DC Irrigation System: A Case Study of a Shrimp Pond

In this paper, a new approach for supplying water to shrimp production ponds in Purworejo, Indonesia, is proposed. The paper covers the design of a solar-powered DC water pump system (SWPS), system performance analysis, and economic analysis by comparing it with the existing fossil-fuel-powered pumps. The mathematical approach for the designing process is shown and Lorents Compass alternative tool is introduced. By taking into consideration the daily water demand of 50 m3/day, the annual-averaged local solar irradiation of 4.7 kWh/m2 per day, and the available components in the market, an SWPS in Purworejo would comprise a 1200 Wp PV panel and a 600 W DC pump submerged in a borehole in the seashore. The SWPS would be able to meet the daily water demand with small seasonal variations. The financial analysis shows high feasibility to install SWPS in Purworejo with a 1,6 years simple payback period, which is very short. The SWPS would provide more than 20 years of free energy for the farmers to draw seawater to the pond each day when the sun shines. It can provide not only environmental and social benefits but also significant economic advantages, both at the farm and the national levels.

Performance improvement of CO2 air conditioner by integrating photonic radiative cooler as sub-cooler or/and roof envelope

Passive radiative cooling, which creates a direct in-situ cooling effect, along with a natural refrigerant-based vapor compression system, could be a potential alternative for building air conditioning to reduce the heat island effect and global warming. Hence, the radiative cooler is integrated with transcritical CO2 air conditioner as a sub-cooler or/and roof envelope. Three configurations of radiative cooler integrated CO2 system (Case 1: radiative cooler as roof envelope only, Case 2: radiative cooler as sub-cooler only and Case 3: radiative cooler as sandwiched roof envelope and sub-cooler) are proposed and simulated for tropical Indian summer climate. Energy, exergy and economic analyses along with gas cooler pressure optimization are performed. The Monte Carlo method is used to calculate annual energy savings for all three cases. Results show that case 3 exceeds the performance of other cases. Case 3 also reduces the variations of optimum gas cooler pressure and cooling load, leading to the smooth operation of the CO2 air conditioner. COP increment of 33.8% and exergy efficiency improvement of 29.1% are observed for case 3. A simple payback period of 5.3 years is worked out for case 3. Annual energy saving per unit area for case 3 is found comparable to solar photovoltaic integration.

A Novel 10 kW Vertical Axis Wind Tree Design: Economic Feasibility Assessment

A novel, small-scale vertical axis wind turbine tree was designed using turbines combining both Darrieus and Savonius blades. We tested for economic viability using wind data collected at a site in Surat Thani, Thailand. The Weibull distribution and Monte Carlo modeling with financial indices (Levelized Cost of Electricity (LCOE), Net Present Value (NPV), Internal Rate of Return (IRR), and Simple Payback Period (SPP)) were used to analyze data. We found that monthly mean wind speeds varied from 2.35 m/s in October to 2.84 m/s in February, corresponding to a wind power of 28.43 W/m2 and 42.68 W/m2. The average annual power output was 1446.1 kWh for May 2019 to April 2021. Results show that for turbine cut-in to cut-out speeds (2 m/s to 15 m/s), the prototype has potential economic feasibility (NPV > 0 for 64.93%), although the small capacity of the wind tree, in combination with the low average wind speed at the Surat Thani test site, showed a lack of economic viability at this specific location (NPV = USD − 20,946.29). A higher-wind-speed location (Chiang Mai) showed viability, especially at a 10 m height (NPV > 0 for 84.83%). We discuss potential conditions that would make broader use of the prototype feasible.

ENERGY SAVINGS IN AUXILIARY VENTILATION SYSTEMS OF UNDERGROUND MINES

Energy is a basic need for industries around the world. In recent years, electrical power costs have risen considerably and this rise is likely to continue in the future. Meanwhile, the increasing cost of ventilating mines safely and efficiently is of vital importance. Ventilation on demand has the potential to optimize electrical consumption while maintaining the safety of mines. This paper investigates the energy efficiency enhancement through ventilation on demand in underground mines by installing variable speed drives on the auxiliary mine ventilation fans to provide variable airflow control. Variable speed drives are cost effective and manageable and require low maintenance. It has been estimated that a total electrical energy saving of 324,300 kW, or 53%, can be achieved in 1 year by using variable speed drives. Therefore, it is possible to reduce CO2 emissions by 155.6 tons per year with a simple payback period of 5 months 220 days.

Efficiency of Installation of an Additional Gas-Air Heat Exchanger When Operating a Steam Boiler on Gas and Liquid Fuel

The article presents the results of calculating the efficiency of reconstruction of the gas and air paths of a steam boiler when working on gas and liquid fuel due to the installation of additional gas-air heat exchangers. Due to the utilization of the thermal energy of the flue gases in the newly installed heat exchangers, the air is heated in front of the boiler air heaters and the fuel efficiency is increased by increasing the boiler efficiency. The increase in the efficiency of the "gross" boiler during the operation of the considered TGM-84 boiler on fuel oil with an average annual operating mode was 2.81 %. The flue gas temperature after the boiler air heaters was 178 °C, and the air temperature at the inlet to the air heaters was 99 °C at the average annual load of the boiler, which ensures an almost corrosion-free operation of the air heater packing. It is revealed that when the liquid fuel boilers, installation of new heat exchangers and their strapping on the side of the air and flue gas has a shorter payback period than the boiler gas fired. The simple payback period of the considered technical solution was 6,82 years when working on gas fuel and 1,35 years when working on liquid fuel.