Secondary Energy Resources Research Articles

Electricity Generation at Gas Distribution Stations from Gas Surplus Pressure Energy

At gas distribution stations (GDSs), the process of throttling (pressure reduction) of natural gas occurs on gas pressure regulators without generating useful energy. If the gas expansion process is created in a turbine, to the shaft where an electric generator is connected, then electricity can be obtained. At the same time, the recycling of secondary energy resources is provided, which is an important component in the efficient use of natural resources. The obtained electric power can be supplied to the external power grid and/or used for the GDS’s own needs. The process of generating electricity at the GDS from gas overpressure energy is an environmentally friendly, energy-saving technology that ensures an uninterrupted, autonomous operation of the GDS in the absence of an external energy supply. The power needs of a GDS with regard to electricity are relatively small (5 ÷ 20 kW). Expansion in throttling devices or turbine flow paths leads to gas cooling with a possible hydrate formation. It is prevented via gas preheating or vortex expansion equipment that keeps the further gas temperature at a necessary level. Turbogenerators can be created on the basis of vortex expansion turbomachines, which have many advantages compared to turbomachines of other types. This article studies how gas pressure (outlet: gas distribution station) and gas preheating (inlet: vortex expansion machine) influence turbogenerator parameters. Nine turbogenerator variants for the power needs of gas distribution stations have been assessed.

КАФЕДРЕ ЭНЕРГЕТИКИ ТЕПЛОТЕХНОЛОГИИ – 35 ЛЕТ

The article is dedicated to the 50th anniversary of the Department of Processes and Apparatus of Chemical Technology and the 35th anniversary of its renaming, in connection with the opening of a new specialty, to the Department of Energy engineering of heat technologie. Since 1990, the department has graduated more than three thousand specialists (engineers, bachelors, masters) for the energy sector, housing and communal services, the building materials industry, engineering and design centers. More than a third of graduates completed full-time education, and every tenth graduate received a diploma with honors. The department is implementing programs of additional professional education in the field of energy saving and increasing energy efficiency; 1,300 specialists have undergone advanced training at the department. The educational and scientific work of the department is aimed at basic heat engineering and heat and power education, energy saving and increasing energy efficiency, recycling of secondary energy resources, and the use of renewable and alternative energy sources.

Gas turbine modification: A review

Energy is a vital part of life today and it is utilized by humans to carry out work. Energy is required in different forms e.g. chemical, mechanical, electrical etc. Electricity is a secondary energy resource due to its dependence on other primary energy resources like coal, natural gas, wind, solar, hydro etc. and it is one of the most important energy source needed today because man relies on it for a lot of processes and activities. Electricity generated by renewable means have zero effect on the environment while electricity generated by non-renewable means generate pollution to the atmosphere and deplete energy resources. 51% of the electricity generated in the world today is derived from fossil fuel which is a nonrenewable energy resource. Natural gas power plants account for 23.1% of electricity generation in the world while gas turbines makes up a large percentage for natural gas plants in power generation. Gas turbines can be modified to increase their generation capacities with the aim of reducing pollution associated with combustion of fossil fuel. Nigeria relies mainly on gas turbine to supply electricity to the grid. 81% of power plants in Nigeria are thermal power plants while 17.59% are hydro-power plants. Gas turbine power plants make up 89% of the thermal plants in Nigeria today and they mostly operate using simple cycle. This data shows that there is a lot of potential to increase gas turbine efficiency in the Nigerian electricity space while reducing pollution and reducing fuel consumption.

Вплив згодовування пробіотика «Субалін» на показники продуктивності гібрида осетрових (Acipenseridae) бестера першого року вирощування з використанням теплої скидної води енергетичної установки

Purpose. To assess the effect of supplementing the feeds with the probiotic “Subalin” on the productive parameters of bester on the first year of cultivation using waste water from an energy installation (power plant) under conditions of elevated water temperature. Methodology. The study was conducted in 2023 in the conditions of an industrial-type farm “Biosila” created on the basis of warm waste water of a thermal power plant. Growing of age-0+ bester was carried out for 65 days in plastic tanks. They were fed with compound feeds manufactured by a well-known European manufacturer with a crude protein content of 54% and crude fat content of 15%. In addition to the main diet of the fish, a probiotic based on Bacillus subtilis “Subalin” was introduced at the rate (% of the weight of the feed): 0.02 (variant 1); 0.03 (variant 2); 0.04 (variant 3); 0.05 (variant 4). In the control variant of the experiments, the fish received the same compound feed without the probiotic. The stocking density of fish with an initial average weight of 22.8 g in all variants of experiments and control was 100 individuals in each tank (about 56 ind./m2). Determination of productive parameters and study of physico-chemical factors of the environment were carried out according to generally accepted methods. Findings. During the cultivation period of bester, water temperature fluctuated between 23.8–32.5°C. For 39 days, water temperature exceeded 30°C, which is uncharacteristic for sturgeon aquaculture. The content of dissolved oxygen varied from 4.0 to 5.7 mg O2/dm3. Other hydrochemical parameters met the requirements for growing sturgeons. As a result of intensive breeding, bester juveniles in various experimental variants reached an average weight of 166.8 to 195.4 g. In the control, it was 145.4 g, which was 12.8–25.6% less than in the experimental groups of fish. In all variants of the experiments and control, fish survival rate was 100%. The fish productivity of tanks was in the range of 6838.9–9588.9 g/m2. The highest productive parameters of bester were obtained in the variant where their main feed was supplemented with “Subalin” at the amount of 0.04% of the weight of the compound feed. Originality. The results of the use of probiotic “Subalin” as a supplement of the main feed of bester juveniles in the conditions of an industrial-type farm with the use of heated waste water from a power plant were studied. Practical value. The results are of interest for the development of sturgeon aquaculture technologies in the conditions of industrial-type farms, primarily with the use of secondary energy resources in thermal power generation. Keywords: sturgeon, bester of the first year of cultivation, industrial fish farming, feed, probiotic “Subalin”, productivity parameters.

Determining heat and mass exchange kinetic in a column heat exchanger with direct phases contact

The object of this study was the processes of heat and mass transfer in a column heat exchanger with direct phases contact. The investigated problem is related to the need to determine the estimates of the kinetic characteristics of heat exchange during the concentration of solutions in a contact heat exchanger equipped with dual-flow trays. In particular, it was assumed that the determination of the influence of the gas velocity in the apparatus and the density of liquid irrigation of the plates, as well as the geometry of the plates, on the kinetic coefficients would make it possible to reveal the patterns of heat and mass exchange between the liquid and the air in contact with it in the column apparatus. It was determined that to increase the intensity of mass transfer in the gas and heat transfer in the liquid, it is necessary to increase the gas velocity and irrigation density. Then the gas velocity and irrigation density have approximately the same effect on the intensity of mass transfer in the gas and heat transfer in the liquid. When studying the effect of the geometry of the plate on the kinetic coefficients of heat transfer in the liquid and mass transfer in the gas, it was established that the value of the portion of the free cross section of the plate has a decisive influence on the value of the considered kinetic coefficients. A generalized equation was built, which makes it possible not only to calculate the enthalpy transfer coefficient during the interaction of sodium chloride solution with air but also to determine the limiting stage of this process. The results could be used to design a unit for concentrating a hot solution of sodium chloride by evaporating water during blowing with air in a contact heat exchanger. This would make it possible to obtain crystalline sodium chloride using secondary energy resources and other non-traditional sources of thermal energy

Повышение энергетической эффективности газопоршневой ТЭС за счет комплексного использования тепловых вторичных энергоресурсов

Recently, the advantages and prospects to use piston gas internal combustion engines for the combined generation of electrical and thermal energy have become increasingly obvious. The range of single capacities of gas piston units (GPU) ranges from 0,1 MW to tens of MW, which makes them more attractive when designing various power facilities. Most brands of gas piston units can operate in co-generation mode, that is, as a combined heat and power plant that simultaneously generates electrical and thermal energy. The purpose of this study is to substantiate the possibility of integrated use of heat of the cooling systems of the gas piston engine of a thermal power plant (TPP). The studies conducted are carried out using well-known methods of thermodynamic calculation of the internal combustion engine cycle, of determination of the components of its thermal balance and thermal calculation of the equipment for utilization of secondary thermal energy resources. The results of the analysis of the heat losses of the GPU drive engine have showed that the total losses during its operation are about 11544,5 kW. Average potential heat losses with flue gases are 45,87 %, and low-potential heat losses with water in cooling systems and oil in lubrication systems are 53,14 %. A schematic diagram is proposed for the integrated utilization of thermal renewable energy resources (RES) at a gas piston thermal power plant. The main difference between the proposed scheme and the existing technical solutions is the utilization of the heat of the low-temperature charge air cooling system after the second section of the compressor and the heat of the engine lubrication system. An analysis of the expenditure part of the energy balance of the drive engine in case of the integrated use of thermal RES in the GPU cycle, has showed that the implementation of energy-saving measures will make it possible to usefully use up to 93,05 % of the supplied energy in the generation of electrical and thermal power.

Techno-environmental analysis to valorize the secondary energy resources from refuse-derived fuel-based waste to energy plant.

The present study quantifies the environmental and sustainability impacts associated with municipal solid waste management (MSWM) in India which plays a vital environmental issue in recent times. The upsurge in population has resulted in massive waste generation, leading to a concerning rise in the level of greenhouse gas (GHG) emissions. Therefore, the sustainable management of MSW has been discussed and highlights the conversion of MSW into refuse-derived fuel (RDF) to identify its potential for generating electricity in waste-to-energy (WtE) plants. The life cycle assessment (LCA) study has been done to identify and compare the environmental impacts associated with different scenarios (SC) as SC1: landfilling without energy recovery, SC2: open burning and SC3: processing of RDF in WtE plant by considering the nine impact categories from the inventory data obtained over a period of 12 consecutive months (Jan 2021-Jan 2022). The results exhibited that the global warming potential caused by emissions of GHG are in the order of SC1 (1188kg CO2 eq) > SC2 (752kg CO2 eq) > SC3 (332kg CO2 eq), respectively from 1 t of MSW. It is concluded that the WtE plant can help in the reduction of environmental issues, strengthening the capacity of electricity generation and improving the aesthetic view of the city which is socially acceptable as well. Thus, WtE technology can help in achieving sustainable development goal 12 to regenerate the sustainable secondary resources for the twenty-first century and minimize global climate change.

Heat recovery with low pressure loss for natural ventilation

Regenerative heat exchangers are widely used in life support systems, gas turbines, boilers and other high-temperature industrial installations. These heat exchangers are used for cooling and heating gases, humidification and dehumidification of gases, heat recovery from high-potential heat carriers. Today, the increase in energy consumption and the increase in energy prices require a large-scale energy-saving policy in the creation of modern engineering structures – residential, commercial and industrial facilities alike. When designing and creating life support systems to save energy, it is advisable to use secondary energy resources, such as, for example, the heat of the air removed from the room. The energy intensity of conventional ventilation systems is on average 50–80% of the total energy intensity of the engineering systems of the facility where they are operated. The use of rotating regenerative heat exchangers in ventilation and air conditioning systems makes it possible to return up to 85% of heat to the system at a relatively low capital investment. In this regard, when improving such systems, considerable attention should be paid to the calculation, optimization and increase in the efficiency of heat exchangers. Thus, this work is about increasing the efficiency of rotating regenerative heat exchangers in ventilation and air conditioning systems.

Поєднання енерго-ресурсозберігаючих та екологічно безпечних технологій в проєктах ДП «ГИПРОКОКС»

DOI: 10.31081/1681-309X-2024-0-1-21-26 Specialty 161. U.D.C. 621.311 COMBINATION OF ENERGY-SAVING, RESOURCE-SAVING AND ENVIRONMENTALLY FRIENDLY TECHNOLOGIES IN THE PROJECTS OF THE SE "GIPROKOKS" © T.F. Trembach, M.V. Mezentseva, I.O. Radychuk (STATE ENTERPRISE "STATE INSTITUTE FOR DESIGNING ENTERPRISES OF COKE OVEN AND BY-PRODUCT PLANTS'' (SE "GIPROKOKS''), 61002, 60 Sumska str., Kharkiv, Ukraine) The article deals with the issues of energy efficiency and implementation of environmental technologies in coke production, which is one of the most energy-intensive and environmentally hazardous, but at the same time has a great potential of fuel and energy resources. The experience and achievements of SE GIPROKOKS in the use of modern technologies aimed at reducing energy and resource consumption, as well as ensuring environmental safety, are reflected. Particular attention is paid to innovative approaches to the development, design and implementation of environmentally friendly technologies in production, which help reduce emissions and negative impact on the environment. The article analyses the application of organisational, technical, design, technological and other energy saving measures in the projects of SE “GIPROKOKS” for metallurgical and coke-chemical enterprises. The most effective of these are technological: improving the quality of coke, what, when used in the blast furnace process, leads to a reduction in energy consumption; using less energy-intensive technologies and secondary energy resources. These technologies primarily include the coal charge stumping technology. Flue gas heat from the coke oven battery heating system has a significant energy potential that is released into the atmosphere, leading to irreversible heat losses and causing a negative impact on the environment. The use of a heat recovery unit with thermal flue gas treatment will significantly reduce emissions of harmful components in flue gases into the atmosphere. In its projects, SE “GIPROKOKS” pays considerable attention to the use of secondary resources generated in coke production processes, which is a vivid example of combining energy-saving, resource-saving and environmentally friendly technologies. Keywords: coke production, secondary products, utilisation, energy saving, resource saving, environmental safety, technological measures. Corresponding author: T.F. Trembach, e-mail: ozos@giprokoks.com

Enhancing technical solutions to reduce fuel energy consumption of drilling equipment during well drilling with air cleaning

Efficient fuel and energy resource utilization in drilling equipment can be attained through strategies such as decreasing the relative consumption in technological systems during well drilling, enhancing the integration of secondary energy resources in the equipment's power supply system, and refining the design of drilling equipment and technologies. This article showcases the outcomes of pilot studies conducted on a diesel power plant within a drilling rig and a device designed for recycling secondary energy resources from a compressor.

ВОПРОСЫ ОБЕСПЕЧЕНИЯ ЭКОЛОГИЧЕСКОЙ БЕЗОПАСНОСТИ ГОРОДСКОЙ СРЕДЫ НА ОСНОВЕ РЕСУРСОСБЕРЕГАЮЩЕЙ МОДЕЛИРЕМОНТНО-СТРОИТЕЛЬНЫХ РАБОТ

The relevance of the study is caused by unresolved problems of preventing the negative impact of production and consumption waste generated in the process of life support of settlements. According to the authors, the most promising area for the study of such a life–threatening technosphere object as waste is the sphere of construction and urban management and its most important sector - construction, reconstruction, repair, renovation of real estate. During the study, it was found that the waste of repair and construction production, most of its mass, which are low-hazard and practically harmless to the environment, serve as a source of various types of valuable secondary raw materials. This raw material can be used in the production of a wide range of construction and other products, the production of works for various purposes, as sources of alternative energy sources. The purpose of this study was to form the configuration of a resource-saving model of repair and construction works as a mechanism for ensuring the environmental safety of the urban environment, preventing natural emergencies, their adverse consequences for the life of the population, the sustainable functioning of economic facilities, conservation and protection of the natural environment and natural resources. The scientific approach proposed in the work is aimed at obtaining two important scientific and practical results: preventing the negative impact of waste on the environment at the source of their formation: the processes of repair and construction work and, at the same time, the technological transformation of useful resource components of waste into secondary material and energy resources. This ensures the second important result: the preservation of the country's natural resources by replacing them with secondary raw materials and alternative energy sources. The research is applied in nature, its results can be used in the implementation of measures for the transition of the construction and urban management system to a resource-saving technological way of environmentally safe life support for settlements.

Energy efficiency analysis of caustic soda production process

The increase in the cost of fuel and energy resources motivates industrial enterprises to introduce new technical solutions for their effective use. At the same time, as a result of the production ac-tivities of industrial enterprises, a significant amount of waste is generated that negatively affect human health and the environment. Such enterprises include caustic soda production plants, the technology of which is associated with the formation of thermal and combustible secondary energy resources in the form of steam, condensate, process water, etc. Such types of resources may be useful to use for the production of thermal energy for the company's own needs, or heating of raw materials or material flows involved in the technological chain. The technology of caustic soda production is considered it this paper, the basic structure of production is discussed, the material balance is given, options for improving the efficiency of energy resources are proposed.

Heat pump technology for utilizing the heat of secondary energy resources in the catalytic method of obtaining biodiesel

Heat pump technology for utilisation of heat of secondary energy resources in catalytic method of production of biodiesel fuel is implemented. Algorithm for control of technological parameters at all stages of production of biodiesel fuel is proposed and analysis of parameters of its quality is performed. Heat pump system is represented in the form of two recirculation circuits of low-potential and high-potential heat carriers, preparation of which was carried out in stages of low and high pressure of heat pump. Exergetic analysis was performed, functional dependencies of exergy flows coming out of the considered types of process equipment were obtained. The obtained hybesel fuel complied with the requirements of GOST 23513-79. The proposed heat pump technology reduced specific energy consumption by 13-14%; improve environmental safety at all stages of the process; maximum reduction of spent heat carriers emission into the ambient atmosphere.

A modern foundry is a prototype of energy–efficient, environmentally neutral production of the future

The article discusses the tasks of the development of foundry production at the present stage, the issues of its energy efficiency, material consumption and environmental friendliness. It is shown that advanced achievements in the field of foundry technologies, purification of dust and gas emissions, recycling of secondary energy resources (SER), recycling of metals, regeneration of materials, processing and use of man‑made waste, allow us to talk about a modern foundry as a model of energy‑efficient, environmentally neutral production of the future.

Моdern heat and steam supply systems of industrial enterprises using deep utilization of the technological steam energy potential

Steam supply systems of industrial enterprises, as a type of heat supply system, are a large consumer of primary energy in national energy balances. In turn, due to the specificity of thermodynamic steam processes, steam supply systems of industrial enterprises in practice have significant unused potential of secondary energy resources (SEP). Modern steam supply systems should be built exclusively when evaluating their exergetic efficiency, which will make it possible to evaluate the effectiveness of such systems grossly in all elements of the life cycle of the project: energy, economic, ecological and even social. The article shows modernized thermal schemes of steam supply systems, for which it is possible to achieve additional electrical power at the level of 135-250 kW/(kg/s) when devices with a relative internal efficiency of up to 60-70 % are operating. In combination with an increase in the percentage of condensate return and the utilization of secondary energy resources (SRP), the increase in energy efficiency of the system is 2-4 %, and the absolute value of exergetic efficiency is 16-22 %, taking into account the exergetic efficiency of the boiler unit. Low-potential "tail" consumers: the heating system, the hot water supply system - increase the exergy efficiency of the steam supply system of an industrial enterprise by 0.2-0.6 % in the case of joining on the steam side of secondary boiling. Any processes of generating electrical energy are associated with obtaining a significant amount of thermal energy, and must be accompanied by its utilization; enterprises that use steam as an energy carrier (the same applies to energy enterprises such as thermal power plants and nuclear power plants) for the deep utilization of hydroelectric power plants must have thermal energy consumers in their composition, which can act as communal household consumers (if they exist), as well as new technological consumers of thermal energy.

The “Smart Home” Heat Supply System Based on District Heating with the Utilization of Secondary Energy Resources Using a heat Pump

One of the most important aspects of a “smart home” is its heating system, which should provide comfortable living conditions for residents while also being energy-efficient. This article discusses an innovative approach to heating systems in “smart homes” based on centralized heating with the utilization of secondary energy resources using a heat pump. The proposed heating system combines the advantages of traditional centralized heating and the efficiency of heat pumps. The article presents a calculated scheme, for which a temperature chart was developed. A methodology for calculating heat loads for both the traditional heating scheme and combined heat and power (CHP) with heat pumps is also proposed, and the necessary calculations were carried out. For clarity of the obtained data, a graph depicting the total steam load required for heating as a function of ambient temperature is constructed, as well as a graph showing the steam load as a function of the duration of the ambient temperature. The analysis of the data revealed that the use of heat pumps in CHP schemes reduces electricity generation by eliminating its production in the steam flow in the condenser. This facilitates the coverage of the electricity consumption schedule during periods of low demand for the integrated energy system. Additionally, integrating a heat pump into the heating system of the centralized heating system helps reduce energy dissipation and greenhouse gas emissions into the atmosphere, making heating more sustainable and environmentally friendly. Moreover, the proposed heating system for a “smart home” demonstrates high technical and economic performance, ensuring the investment attractiveness of such a project.

USE OF SECONDARY ENERGY RESOURCES TO PROVIDE HOT WATER SUPPLY TO BUILDINGS AND CONSTRUCTIONS

The paper assesses the possibility of using secondary energy resources to provide hot water supply to buildings and constructions. The introduction of recovery systems by using previously unused cheap waste heat energy helps to reduce the amount of energy produced and consumed, increase energy efficiency, and reduce greenhouse gas emissions, which correspond to the development strategy of the construction industry and housing and communal services in the field of environmental protection and energy saving. A method for using the waste heat energy of refrigeration plants to provide hot water supply to an apartment building is proposed. This method makes it possible to ensure uninterrupted supply of hot water to consumers with minimal dependence on the operation of centralized heat supply systems. The minimum power of waste thermal energy sources necessary for the organization of such systems is calculated, and possible sources of secondary energy resources are proposed.

Feasibility Study of Polygeneration Turbine Plants Based on Carbon Dioxide

Schemes of polygeneration plants based on carbon dioxide are presented, in which the energy source are secondary energy resources and a gas turbine plant. These polygeneration schemes make it possible to simultaneously produce electricity, heat, cold, carbon dioxide in liquid and gaseous aggregate state, as well as to dispose of part of the carbon dioxide emitted into the atmosphere, due to its absorption from combustion products and use for commercial and technological purposes. The structure of the mathematical model of the program that has been developed for the exergetic analysis of polygeneration schemes is presented. With the help of the program, an exergetic analysis of polygeneration schemes was performed, in which polygeneration turbine units with different parameters of carbon dioxide in front of the turbine, as well as single and double overheating of carbon dioxide were compared. The exergetic electrical efficiency of polygeneration plants as a whole and its individual elements were taken as the criteria to be compared. Polygeneration plants with double overheating and supercritical parameters of carbon dioxide in front of the turbine have the greatest efficiency. A method for calculating of the economic indicators of polygeneration schemes is presented, which makes it possible to take into account the influence of double overheating and carbon dioxide parameters in the cost of a polygeneration plant. The economic efficiency indicators of various versions of polygeneration schemes, such as the internal rate of return, net discounted income, static and dynamic payback periods are obtained. It has been established that all variants of polygeneration schemes have acceptable indicators of economic efficiency, the static payback period of the proposed polygeneration schemes does not exceed 5 years, while the internal rate of return does not decrease by less than 22,8%.

Energy security performance evaluation revisited: From the perspective of the energy supply chain

The previous research on energy security performance (ESP) has often treated the energy security system as a “black box,” meaning that it has not explored the internal composition structure of the system or the linking relationships of the energy supply chain. This study proposes a comprehensive evaluation framework and a comparative study of ESP evaluation in 32 OECD countries over 20 years, dividing the energy system into four processes. A dynamic network Data Envelopment Analysis (DNDEA) model is used to analyze the energy system's overall performance and each process's performance, considering their internal structure and dynamic characteristics. The ESP results show that half of the 32 OECD countries had perfect efficiency scores, while the other half had scores ranging from 0.0222 to 0.74. The study also found more progress in the second half of the 20-year period. In terms of the four individual processes, the total primary energy supply (TPES) and total final energy consumption (TFEC) processes had consistently high scores, while the secondary energy resources (SER) process had room for improvement. Based on a cross-check of the various ESP results over the past 20 years, as well as the ESP in the most recent decade, seven countries (Austria, Canada, Finland, South Korea, Luxembourg, Norway, and Switzerland) were identified as benchmarks for their strong performance, and the study examined the indicators underlying their success. The study also identifies areas for improvement in underperforming countries and determines future directions for improvement.

Increasing the efficiency of drilling exploration wells with air bleeding based on the use of recovered heat of the compressor

To date, the practice of drilling shows that the use of compressed air to clean the bottom of the cuttings is the most effective in difficult and unfavorable conditions for the use of drilling mud: when drilling in absorbing zones of flushing fluid, when it is impossible or difficult to supply water, when drilling in areas with negative ambient temperature. However, when drilling with bottomhole cleaning with air, the fuel and energy costs of drilling operations are significantly increased due to the use of compressor units, the drive energy costs of which are greater than pumps used in similar conditions. An analysis of the operation of mobile compressor units shows that a significant part of the energy losses falls on the internal combustion engine of the compressor drive, since not all of the combustible fuel is converted into useful power. Most of the thermal energy is removed from the engine to the cooling system and carried away with the exhaust gases. In this article, the energy losses of the internal combustion engine of the compressor are investigated and the possibility of increasing the energy efficiency due to the use of the recovered heat of the compressor drive and secondary energy resources is presented.