DEVELOPMENT AND EVALUATION OF AN OPTIMIZED ENERGY RECOVERY SYSTEM FROM EXCESS HEAT OF A COMPRESSED AIR SYSTEM 

ANDREW S. MAÑEGO 1,2

DR. WARLITO M. GALITA 1

Bulacan State University, City of Malolos, Bulacan 1 

 Froneri Philippines, Incorporated 2

Abstract

The aim of this study is to build a bounded optimized energy recovery system from the compressed air system’s excess heat. It is important to concentrate on the use of products that satisfy the requirements for performance and sustainability, as well as the need for energy that will be optimized. Purposive sampling is used to select the respondents, using quantitative research, specifically both descriptive and developmental methods. The researcher utilized a decision support tool developed by Kolaitis et al., (2020) as the primary research instrument of the study. The adopted tool was slightly modified to suit the assessment needs of the developed energy utilization system. All the main criteria components are interpreted as highly sustainable. The researcher utilized log sheets to determine the performance of the study. Finally, paired t-test was used to determine whether there was a significant difference in the performance of the study. The performance of the optimized energy after the implementation of the project was statistically higher than the performance of the optimized energy before the implementation of the project. The researcher concluded that the performance of the optimized energy recovery system from excess heat of a compressed air system after the installation and operation was effective and efficient based on the ratings of respondents and descriptive measures on the log sheet. For this kind of innovation, the manufacturing company with the same equipment should adopt and sustain it for potential energy savings and protect mother nature.

Keywords: optimized energy; energy recovery; waste heat; compressed air; heat recovery; and energy efficiency

Introduction

Energy is one of the most important and necessary needs of every person especially in the age of globalization and modernization. It is often used lighting, running of household appliances, serving a variety of industries, and in other means of transforming electrical energy. There would have been no technology developments and life, in general, would have remained the same if the theory of electrical energy and the method of making it had not arisen.

Nevertheless, Dincer and Rosen (2021) presented a novel optimization of energy systems that explains the thermodynamic modeling, analysis, and optimization of several types of energy systems in a variety of applications. The optimization of energy recovery systems from excess heat of a compressed air system will bring a wider knowledge of the system and the process of identifying adequate safety functions. This is vital for determining the most appropriate design parameters for increased reliability, functionality, and applicability. Furthermore, Mahmoud (2019) believes that the issues of waste of energy and human needs have advanced, resulting in environmental problems and economic growth. Hence, the private entities had to do some updating and upgrading in terms of the optimization of its energy system.

Coal is the Philippines' primary source of energy. Coal-fired power stations, as sources of non-renewable energy, emit greenhouse gases, having a direct impact on global warming. Resulting in decreased water supplies because of global warming, the power generation capacity of renewable energy sources such as hydroelectric power plants become limited. The drastic solution to this problem is the adoption of the use of renewable energy at home and the optimization of energy in the industry.

Likewise, the most common energy source for industrial compressed air production is electricity. The entire cost of the installation is clearly dominated by energy expenses. As a result, it is essential to concentrate on implementing products that fit the requirements for performance and sustainability, as well as the needs for energy that will be optimized (Atlas Copco 2015).

According to the Department of Energy's 2019 Power Condition Survey, the Luzon grid experienced 46 Yellow Warnings and 16 Red Alerts in 2019. These were mostly caused by high demand, which was exacerbated by the moderate El Niño weather pattern. This raised the demand and reduced the usable capacity of hydroelectric power plants in the grid during the summer months. However, this would influence the country's economy due to a lack of energy capacity. Along with its significant effects on the environment and the economy, the appropriate approach to using resources efficiently and effectively is a very critical process in terms of energy optimization. In the area of electrical technology, innovation plays a major role as private entities, to be specific, are consuming energy in several ways.

There is relevant provision in the Energy Efficiency and Conservation Act, also known as Republic Act 11285, Rule VI. Energy End Users, Section 32. The role was used as a guide in the development of an optimized energy recovery system from the excess heat of a compressed air system. It states that: 

“All energy end users, including the end users defined under Republic Act No. 9513, otherwise known as the Renewable Energy Act of 2008, shall use every available energy resource efficiently and promote the development and utilization of new and alternative energy efficient technologies and systems, including renewable energy technologies and systems across sectors in compliance with the declared policies of the Act.” 

    The Act promotes the development and utilization of alternative energy-efficient technologies, energy optimization, and conservation of energy, which provide the need for energy recovery and significant environmental guidance in the undertaking of this study. It is reassuring that when it comes to environmental protection and resource preservation, private entities, as end users, have a major role to play. 

    Any establishment that utilizes hot water, steam boilers, and compressed air systems, especially industries and manufacturing companies, may benefit from this study. And, where the proponent is presently connected with the same equipment, and it has promoted energy conservation as the centerpiece of its continuous improvements and innovations. In fact, the output of the study may be included in the innovation program of any company, where the current practices may be in consonance with the thrust of the study. Such companies must comply with and sustain an energy management program since the Department of Energy (DOE) has the authority to inspect the establishments, as specified in Section 33 of the Republic Act 11285:

“The DOE shall monitor all energy end users' compliance with the relevant standards and requirements under Chapters of the Act, as well as the EEC-IRR. The DOE, through Energy Utilization Management Bureau (EUMB), shall have the authority to visit energy end users to inspect energy-consuming facilities, and evaluate energy management.”

    The DOE is working to ensure that energy is well managed for its optimum use that utilizes equipment and technology efficiently in terms of energy recovery systems. A keen analysis was conducted to ensure that a company's energy supplies will be optimized in terms of heat waste recovery from compressed air. This is based on the government's policy declaration that is necessary to be complied accordingly. 

The provision relevantly reiterates the importance of this study since it concentrates on increasing the outlet temperature of the water supply before it reaches the feed-water tank of a steam boiler, using excess heat from an air compressor to optimize the energy recovery system while supplying additional heat transfer. Growth will be attributed to the constant flow and heat transfer of water, with a direct effect on the cooling system. Thus, this study may also serve as a reinforcement to the cooling tower.

On the other hand, failing to utilize the waste heat energy properly will lead to high operational costs and, as an inevitable fact of life, energy prices will continue to rise. In this age that is dominated by industries, factories, and manufacturing companies around the world, it is vital that energy will be used sparingly and efficiently as possible for the sake of both the economy and the environment.

    Therefore, recovering the heat energy will have a large impact on the industry in terms of energy-saving initiatives. The pipe and heat exchangers can be used as heat recovery systems by analyzing the appropriate information by designing the pipe layout and electrical control system to maximize the recovery of heat energy study. Furthermore, it is a thermodynamic fact that approximately 10% of the electricity consumed in the industry accounts for the use of an air compressor for manufacturing processes, with the remaining energy converted into waste heat. Heat energy released by compressed air systems can be addressed naturally by using cooling fans, but with an additional cost. However, some processes in the factory can use power to generate heat for hot water processes and heating applications. This latter principle serves the purpose of this study.

    The proponent investigated the process of recovering waste heat to conserve energy and minimize carbon dioxide emissions in the company's operations through this research. The study implemented a modification in the control system and piping layout to achieve the desired result by interconnecting the constituent components. Spare parts such as electrical, electronic, and instrumentation devices were also used. The researcher pursued this present investigation to contribute to the body of knowledge, particularly in waste heat recovery systems.

1.1 Relevant Theory and Related Literature

    Innovation is the conversion of a concept into something useful to produce new things or its development as used in the optimization of energy recovery systems. The theory seeks to describe users' intent to utilize an information system as well as eventual use behavior. In a private company like Froneri Philippines, passion for excellence is one of the core values.

    Acceptance behavior, on the other hand, explains many other variables such as user satisfaction and user involvement. These are vital to provide an overall theory in order to explain acceptance behavior and system implementation success of the unified theory of acceptance and use of technology. Following that, the attempt to establish a relationship between this theory and personal innovativeness and user involvement as antecedents by presenting certain arguments (Williams et al. 2015). Therefore, by combining these ideas that describe technology use behavior in this research will be substantial in terms of energy efficiency.

    In this case, the researcher's firm was optimizing energy recovery systems from excess heat of compressed air systems as in line with the company's core values. According to Sengupta et al., (2014), the economic theory of innovation focuses on the technological component and its implications for economic growth. The business paradigm has shifted drastically in today's world due to advances in technology and the understanding of new concepts.

    Dincer and Rosen (2021) presented a novel optimization of energy systems that explains in detail the thermodynamic modeling, analysis, and optimization of several types of energy system. Luo et al. (2017) support that a novel heat recovery device has been developed to recuperate the heat that is removed from the surface of equipment. This study would reduce carbon dioxide emissions and avoid global warming.

    When an inventor knows nature's rules, he can make greater use of them. Deeper understanding may lead to new ideas that might not be apparent at first glance. For example, thermodynamics' fundamental law must be revealed in the field of applications to appreciate its functions. After that, the person who experiences these fresh concepts and convincing arguments will emerge. New information will be created and enhanced in performance. It would result in innovation (Struchtrup, 2014).

    Energy recovery is an instrument to improve fuel consumption in thermal engines (Sciubba et al., 2016). All the energy provided to a compressor system is transformed into heat. The better the system's efficiency, the more energy may be recovered and used in other operations. Energy recovery is simple to implement with standard oil-free compressors. This air compressor is excellent for use in a hot water heating system as it maintains the appropriate temperature for effective energy recovery (Atlas Copco, 2015).

    According to Pesiridis (2014), the issue of fuel economy and pollution reduction has a timely impact on both diesel and gasoline engines regarding emission management and exhaust energy recovery. Xu et al. (2019) assume that the waste heat recovery applications in automotive, as well as residential and industrial zones, are highlighted. According to studies, optimizing heat recovery systems results in considerable energy savings. Moreover, Jouhara et al. (2018) postulated that industrial waste heat is energy created in industrial operations that are not used and are lost, squandered, or thrown into the environment. Various waste heat recovery systems may be used to collect waste heat and provide important energy sources while reducing total energy usage.

    Warnes (2017) states that the electrical and mechanical system or unit must first be connected to an electrical circuit and mechanical modification before it can be used. In addition, Irwin and Nelms (2020) propounded that circuit analysis expertise can only be attained via practice. Also, complex devices can be modeled by basic components that, when assembled into the correct circuit, can be evaluated, and thereby predict the machine's behavior. As a result, circuits are at the heart of every analysis of electrical and mechanical technology. The research begins by describing basic circuit components, then integrating them into electrical circuits and mechanical modifications for study using a variety of laws and theorems.

    Luo et al. (2017) presented a novel heat recovery device developed to recuperate the heat that is removed from the surface of the equipment. The provision of the development of such a study from waste heat is to recover and reuse that energy, as this study would reduce carbon dioxide emissions and avoid global warming. In another study, Sandre-Hernadez et al. (2017) supported the solution in optimizing the performance of industrial processes by means of continuous improvement in the design and method used in the development of a waste heat recovery system in order to increase its energy efficiency. Since then, these studies have been hypothesized, implemented, and tested using the Model Predictive Control MPC in a laboratory-based prototype to determine the performance and accuracy in terms of energy savings. 

    Meanwhile, Cai et al. (2019) assumed that the energy-saving and emission-reduction (ESER) plan is a critical approach for increasing manufacturing industry sustainability in the green transition. This study presents a novel concept called lean energy-saving and emission-reduction (LESER) and a strategy to efficiently enhance energy efficiency and reduce waste emissions by analyzing current practices and limits of ESER in the manufacturing industry. In addition, Gao et al. (2017) supports that the individual energy-saving behaviors at the workplace are significant for reducing energy usage and carbon emissions. A manufacturing philosophy is primarily concerned with reducing waste. Nowadays, various manufacturing industries must keep pace with all new technologies, innovations, and equipment to compete successfully and efficiently in the worldwide economy (Nallusamy et al., 2015).

    On the other hand, Sapingai (2017) states that the nature of the information requested as well as the manner of entry are carefully chosen and is called the data collection log sheet. A data collection log sheet is a structured form that must be filled out with certain details. Moreover, Lawson (2014) pointed out that the method of sampling and collecting data parameters is reliable for monitoring the system of several pieces of equipment in running conditions that will be determined in the operational log sheet. The parameters of machinery will also be measured with the use of the aforesaid log sheets.

    The quantitative method answers research problems by using numbers, quantity, and statistics. It entails measuring and quantifying abilities, efficiency, points of expertise, aptitude, and commitment. The gathered information is then examined with statistical techniques, and the results are utilized to generate study findings (Roever and Phakiti 2017). However, the utilization of statistical techniques and how quantitative research results are conveyed leaves much to be desired. In contrast, Kothari (2020) states that the importance of research is determined by its quality rather than its inquisitiveness. Those involved in research must pay close attention to creating and sticking to a suitable approach. It is envisaged that this modest effort may aid in the completion of exploratory and result-oriented research investigations.

1.2 Statement of the Problem

   The general problem of the study is: How may an optimized energy recovery system from excess heat of a compressed air system be developed and evaluated? Specifically, this study sought answers to the following questions:

• How may an energy recovery system from the excess heat of a compressed air system be developed?

• How may the level of sustainability of the optimized energy recovery system be evaluated in terms of applications; safety; functionality; environmental impact; industry/company approval; and financial requirements?

• What is the performance of the system before and after the installation and operation of the equipment based on the optimized energy? 

• Is there a significant difference in the performance of the optimized energy recovery system before and after the implementation of the project?

• 
  

1.3.1 Hypothesis of the Study 

        From the problem stated, the following hypotheses were formulated:

• Ho1: There is no significant difference in the performance of the optimized energy recovery system before and after the installation and operation of the equipment. 

• Ha1: There is a significant difference in the performance of the optimized energy recovery system before and after the installation and operation of the equipment.

1.3.2 Assumption of the Study

        The following assumptions guided the researcher in correctly drawing conclusions from the analysis of the results:

• Energy recovery system can be optimized from compressed air system’s excess heat. Specifically, reducing the steam injection for preheating of the feed water tank will have a direct impact on reducing fuel consumption as the fuel was utilized to produce steam.

• The optimum technology regarding energy utilization system can be best assessed by a support tool consisting of the following criteria: application, safety, functionality, environmental impact, industry / company approval and financial requirements.

• The effectiveness of the developed optimized energy recovery system can be determined if a significant difference in the performance of the equipment is detected before and after its installation and operation using the optimized energy as parameter.

METHODOLOGY

    The study utilized the quantitative method of research where numbers, quantification, and statistics are used to solve research challenges. It comprises assessing and measuring skills, effectiveness, areas of competence, ability, and dedication. Here, the data obtained is then analyzed statistically, and the outcomes are used to develop scientific studies. As presented in this study, quantitative methods are analytical, mathematical, and computing tools that help researchers solve a wide range of problems, notably those in private enterprises. Moreover, both the descriptive and developmental research methods were also used in this study. In using the developmental and descriptive research methods, the researcher seeks to develop and evaluate the optimization of an energy recovery system from excess heat of a compressed air system. Development is the act of revealing what is uncertain; a progressive development process in which everything will be constructed, such as a plan or technique. Descriptive, on the other hand, are represented by information resources or descriptions.

    The study was conducted at the Bulacan State University-Main Campus with selected faculty experts in Electrical Technology and company experts from Froneri Philippines, Incorporated, where the study was implemented. The participants in the study consisted of five (5) management staff, seven (7) associates, and eight (8) instructors in electrical technology. The respondents were purposively selected considering the expertise to evaluate the developed system of the study. The following attributes characterized the respondents: (a) the faculty experts; minimum of five years of experience in their field of specialization, experts in the field of industrial technology and graduates of either master's or doctoral degree; and (b) company experts; bachelor’s degree holder and licensed electrical technology or mechanical engineering. The survey respondents were asked to respond to an evaluation form that defines the sustainability of the energy recovery system that was developed and optimized. The responses consisted of the data that were used in the last section of the report for data processing. The adopted and modified evaluation tool were sent to each respondent. The researcher also utilized log sheets to determine the performance of the energy recovery system in terms of the operational parameters such as outlet temperature, pressure differential, and optimized energy, as these would serve as the indicating factors for future references of the study.

    The researcher utilized a decision support tool developed by Kolaitis et al. (2020) as the primary research instrument of the study. The adopted tool was slightly modified to suit the assessment needs of the developed energy utilization system. The slightly modified evaluation tool was content validated by two (2) faculty experts unrelated to the study and two (2) company experts unrelated to the project. The specific criteria adopted in the selection procedure have been selected to highlight the contribution of each proposed technology based on the concept of sustainability. As previously mentioned, the set of factors to be used in the evaluation of the innovation consists of the following: applications; safety; functionality; environmental impact; industry approval; and financial requirements.

    The Optimized Energy Recovery System from Excess Heat of a Compressed Air System was evaluated quantitatively. The data that were collected for the study were processed statistically to produce the desired outcome.In rating and assessing the level of sustainability of the Optimization of Energy Recovery System from Excess Heat of a Compressed Air System, the weighted average of each factor was computed and interpreted using the five-point Likert scale developed for the purpose. Finally, a paired sample t-test was used to determine whether there is a significant difference in the performance of the optimized energy recovery system before and after the implementation of the project.

RESULT AAND DISCUSSION

3.1 Development of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System

    The development of the system begins by describing basic circuit components, then integrating them into electrical circuits and mechanical modifications by using circuit analysis.  

    Circuit Analysis. Warnes (2013) states that the electrical and mechanical system or unit must first be connected to an electrical circuit and mechanical modification before it can be used. Furthermore, Irwin and Nelms (2020) propounded that circuit analysis expertise can only be attained via practice. Also, complex devices can be modeled by basic components that, when assembled into the correct circuit, can be evaluated, and thereby predict the machine's behavior. As a result, circuits are at the heart of every analysis of electrical and mechanical technology.

    Piping and Instrumentation Diagrams (P & ID) are essential for maintaining and modifying the processes that they graphically describe. During the design stage, the diagram also serves as the foundation for the study's development as illustrated in Figure 1.

    The Mechanical Scope of Work. The third-party contractor provides the labor and materials necessary to install pipes and fittings locally and easily in accordance with the Piping and Instrumentation Diagram (P & ID) as above-mentioned. Figure 2 depicts the pipework and fittings as they were before the alteration.

    Electrical ladder diagrams are specialized schematics used to depict industrial control logic systems. The level controller is presented in Figure 4. The power supply is shown in Figure 5 and the automated refilling-recirculating with off-time delay is shown in Figure 6. These are utilized in the research's development.

    Firstly, in Figure 4, the level controller contact is shown as the signal in control relay main (KO) connected to 220 Volts of Alternating Current. This wiring connection will be responsible for the sequence operations of recirculating and refilling water before it enters the feed water tank. 

    Secondly, in Figure 5, the full wave; bridge-type connection is shown as the power supply connected to an input of 440 Volts of Alternating Current; a 5 Ampacity Double Pole, Double Throw (DPDT) Circuit Breaker in the primary coil of a step-down transformer with an output of 24 Volts of Alternating Current in the secondary coil connected to the bridge-type connection of four (4) diodes with two (2) electrolytic capacitors connected in series and parallel connections with the resistor (R1) in order to produce an output of 24 Volts of Direct Current; Full Wave Power Supply. 

    This power supply will be responsible for reducing the voltage for safety purposes to utilize low-voltage equipment.

    Thirdly, in Figure 6, the automatic refilling of the feed water tank and recirculating of water by means of two (2) solenoid valves with an off-time delay is shown as the main electrical interlocking system to optimize energy recovery system from excess heat of a compressed air system. 

    Automatic Refilling of Feedwater Tank Interlocking System. The positive supply of the main circuit is connected to a 5 Ampacity Single Pole, Single Throw (SPST) Circuit Breaker as thermal overload protection. The negative power supply is connected to the normally closed contact 1 of control timer 1 (T1NC1), which is connected in series to the normally open contact 1 of control relay main (KONO1) and in parallel connected to control relay 1's normally open contact 1 (K1NO1) as a holding coil connected to negative coil A1 and coil A2 to the positive supply of control relay 1 (K1). The negative power supply is connected to the normally closed contact 1 of control relay main (KONC1), which is connected to the normally open contact 2 of control relay 1, (K1NO2), which is connected to negative coil A1 and coil A2 to the positive supply of Timer 1 (T1). Timer 1 (T1) Off Delay is set to 5 seconds. The negative power supply is connected to control relay 1’s normally open contact 3 (K1NO3), which is connected to negative coil A1, and coil A2 is connected to control relay 1's normally open contact 4 (K1NO4) to the positive supply of solenoid operated valve 1 (SoV1).

    Automatic Recirculating Water Interlocking System. The positive supply of the main circuit is connected to a 5 Ampacity Single Pole, Single Throw (SPST) Circuit Breaker as thermal overload protection. The negative power supply is connected to the normally closed contact 1 of control timer 2 (T2NC1), which is connected in series to the normally closed contact 2 of control relay main (KONC2) and in parallel connected to control relay 2's normally open contact 1 (K2NO1) as a holding coil connected to negative coil A1 and coil A2 to the positive supply of control relay 2 (K2). The negative power supply is connected to the normally open contact 2 of control relay main (KONO2), which is connected to the normally open contact 2 of control relay 2, (K2NO2), which is connected to negative coil A1 and coil A2 to the positive supply of Timer 2 (T2). Timer 2 (T2) Off Delay is set to 10 seconds. The negative power supply is connected to control relay 2’s normally open contact 3 (K2NO3), which is connected to negative coil A1, and coil A2 is connected to control relay 2's normally open contact 4 (K2NO4) to the positive supply of solenoid operated valve 2 (SoV2).

    The materials and equipment needed to install the electrical and instrumentation parts came from the company because those are considered slow-moving or non-moving stock items, so the researcher found a way to utilize them. 

    Testing and Validation of Measuring Instruments. Without a well-planned testing effort, the development will surely fail and have an influence on the overall operational performance of the solution. Validation studies assist researchers in identifying mistakes that occur while examining thoughts and behaviors, allowing these faults to be mitigated or removed for research studies to deliver more precise and valid results.

    All the activities, inputs, materials, methods, and information above are used for the development of the optimized energy recovery system from excess heat of a compressed air system.

3.2 Evaluation of the Sustainability of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System

   This part presents the evaluation of the sustainability of the research in terms of the following main criteria: (1) application; (2) safety; (3) functionality; (4) environmental impact; (5) industry/company approval; and (6) financial requirements.

    Application. According to Sengupta et al., (2014), the current economic theory of innovation focuses on the technological component and its implications for economic growth. The business paradigm has shifted drastically in today's world due to advances in technology and an understanding of new concepts. 

Table 1. Evaluation of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System in terms of Application.

    Automatic Refilling of Feedwater Tank Interlocking System. The positive supply of the main circuit is connected to a 5 Ampacity Single Pole, Single Throw (SPST) Circuit Breaker as thermal overload protection. The negative power supply is connected to the normally closed contact 1 of control timer 1 (T1NC1), which is connected in series to the normally open contact 1 of control relay main (KONO1) and in parallel connected to control relay 1's normally open contact 1 (K1NO1) as a holding coil connected to negative coil A1 and coil A2 to the positive supply of control relay 1 (K1). The negative power supply is connected to the normally closed contact 1 of control relay main (KONC1), which is connected to the normally open contact 2 of control relay 1, (K1NO2), which is connected to negative coil A1 and coil A2 to the positive supply of Timer 1 (T1). Timer 1 (T1) Off Delay is set to 5 seconds. The negative power supply is connected to control relay 1’s normally open contact 3 (K1NO3), which is connected to negative coil A1, and coil A2 is connected to control relay 1's normally open contact 4 (K1NO4) to the positive supply of solenoid operated valve 1 (SoV1).

Automatic Recirculating Water Interlocking System. The positive supply of the main circuit is connected to a 5 Ampacity Single Pole, Single Throw (SPST) Circuit Breaker as thermal overload protection. The negative power supply is connected to the normally closed contact 1 of control timer 2 (T2NC1), which is connected in series to the normally closed contact 2 of control relay main (KONC2) and in parallel connected to control relay 2's normally open contact 1 (K2NO1) as a holding coil connected to negative coil A1 and coil A2 to the positive supply of control relay 2 (K2). The negative power supply is connected to the normally open contact 2 of control relay main (KONO2), which is connected to the normally open contact 2 of control relay 2, (K2NO2), which is connected to negative coil A1 and coil A2 to the positive supply of Timer 2 (T2). Timer 2 (T2) Off Delay is set to 10 seconds. The negative power supply is connected to control relay 2’s normally open contact 3 (K2NO3), which is connected to negative coil A1, and coil A2 is connected to control relay 2's normally open contact 4 (K2NO4) to the positive supply of solenoid operated valve 2 (SoV2).

The materials and equipment needed to install the electrical and instrumentation parts came from the company because those are considered slow-moving or non-moving stock items, so the researcher found a way to utilize them. 

  Testing and Validation of Measuring Instruments. Without a well-planned testing effort, the development will surely fail and have an influence on the overall operational performance of the solution. Validation studies assist researchers in identifying mistakes that occur while examining thoughts and behaviors, allowing these faults to be mitigated or removed for research studies to deliver more precise and valid results.

  All the activities, inputs, materials, methods, and information above are used for the development of the optimized energy recovery system from excess heat of a compressed air system.

3.2 Evaluation of the Sustainability of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System

  This part presents the evaluation of the sustainability of the research in terms of the following main criteria: (1) application; (2) safety; (3) functionality; (4) environmental impact; (5) industry/company approval; and (6) financial requirements.

  Application. According to Sengupta et al., (2014), the current economic theory of innovation focuses on the technological component and its implications for economic growth. The business paradigm has shifted drastically in today's world due to advances in technology and an understanding of new concepts. 

Table 1. Evaluation of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System in terms of Application.

The perfect mean rating of 5.0 can be interpreted to mean that the respondents agree that the developed optimized energy recovery system is "highly sustainable" in terms of its applications.

Safety. Hollnagel (2018) states that safety is calculated by the number of cases in which it fails rather than the number of circumstances in which it succeeds. It is the state of being safe from damage or other unfavorable consequences.

Table 2. Evaluation of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System in terms of Safety.

  A brief analysis of the tabular data reveals that in statement # 3, which relates to the characteristic of ease of shutting down, the system received a perfect mean rating of 5.0, which is read as "Highly Sustainable." It can be claimed with confidence that the respondents give careful thought to the fact that the level of influence of the random shutdown is very important. This is followed by the item referring to the hazard risk obtaining a mean rating of 4.90, also interpreted as "Highly Sustainable". This finding shows that in the conceptualization of its development, careful consideration was also given to the inherent risk that the innovation or process may possess. The item pertaining to most of the processes required in the innovation received the lowest mean rating of 4.85, which was interpreted as "Highly Sustainable." Despite this, the rate is still favorable. According to the findings, respondents believed that the complexity was still limited. Finally, the overall mean of 4.92, with a verbal interpretation of "Highly Sustainable," demonstrates that all respondents believe the research is safe.

  Functionality. This is the property of basic function or performance, especially in terms of practical use. This refers to the extent to which the optimized energy recovery system can be used properly by the respondents. 

  Table 3. Evaluation of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System in terms of Functionality.

      For item # 2 on control or adjustment simplicity, the developed system received a mean value of 4.90, which has a verbal interpretation of "Highly Sustainable." This is followed by item # 1 on process sensitivity, with a mean value of 4.80, interpreted as "Highly Sustainable". The overall mean of 4.85, with a verbal interpretation of "Highly Sustainable," demonstrates that all respondents believe the research is functional.

Environmental Impact. The frequency and descriptive measures of the evaluation of the respondents regarding the optimized energy recovery system from excess heat of a compressed air system in terms of its impact on the environment are presented in Table 4. 

Table 4. Evaluation of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System in terms of Environmental Impact.

     The frequency distribution showed that for the flue gas volume, the project received a mean score of 4.95, having a verbal interpretation of "Highly Sustainable." The second statement, which is on the solid residue form, in turn, received a mean score of 4.90, also interpreted as "Highly Sustainable." The overall mean of 4.93, with a verbal interpretation of "highly sustainable," shows that all respondents think the study is ecologically beneficial.

Industry/Company Approval. Table 5 shows the frequency and weighted mean values of the responses of the respondents regarding their evaluation of the optimized energy recovery system from excess heat of a compressed air system in terms of industry or company approval. 

Table 5. Evaluation of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System in terms of Industry/Company Approval.

      As shown in the table, respondents viewed positively the impact of the innovation's installation in the industry/company. A perfect mean score of 5.0, interpreted as "highly sustainable," was received by the developed system, which indicates that the respondents think that this innovation has a significant influence on the industry.

Financial Requirements. The frequency and descriptive measures of the evaluation of the respondents regarding the optimized energy recovery system from excess heat of a compressed air system in terms of its financial requirements are presented in Table 6. 

Table 6. Evaluation of the Optimized Energy Recovery System from Excess Heat of a Compressed Air System in terms of Financial Requirements.

       A cursory examination of the tabular data indicates that item number 1 is related to the study sub-criterion of energy efficiency. Estimated overall efficiency obtained the highest mean rating of 4.95, which is regarded as "highly sustainable," indicating that respondents carefully consider energy efficiency as a highly important contribution of the optimized energy recovery system. Following that is the item pertaining to the running cost, which received a mean rating of 4.90. This is similarly understood as being "highly sustainable." This co-attribute of the system indicates that the cost efficiency of the operation and maintenance was carefully considered throughout its inception. On the other hand, the item referring to the cost efficiency of the installation of the innovation got the lowest mean rating of 4.85, but was still characterized as "Highly Sustainable," indicating that respondents believed that the installation cost, although restrictive, is reasonable and practical. The overall mean of 4.90, with a verbal interpretation of "Highly Sustainable," shows that all respondents feel that the project study is financially feasible.

      Presented in Table 7 is the summary of the respondents’ responses in the evaluation of the sustainability of the optimized energy recovery system from excess heat of a compressed air system. 

      It can be gleaned from the summary of the responses in table 7 that all indicators of the sustainability of the optimized energy recovery system from excess heat of a compressed air system were rated favorably by the respondents, with mean ratings ranging from a high of 5.0 to a low of 4.85. Two (2) of the six (6) main criteria were scored identically with a perfect mean rating of 5.0, and they were Application and Industry Approval, followed by Environmental Impact, Safety, Financial Requirements, and Functionality with a mean rating of 4.93, 4.92, 4.90, and 4.85, respectively. All the main criteria components are interpreted as highly sustainable. Overall, the optimized energy recovery system from excess heat of a compressed air system was rated "Highly Sustainable," as evidenced by a grand mean of 4.93. The project study is strongly recommended for adoption and future improvement, according to the company and faculty experts’ responses.

3.3 Performance of the Optimized Energy Recovery System Before and After the Installation and Operation of the Equipment

 Table 8 displays the number of days, the equivalent mean values of the outlet temperatures, optimized energy, and the weighted mean of the performance of the system before and after the inclusion of the equipment based on the optimized energy. The mean optimized energy in mega-joules prior to installation and operation of the equipment is 365.20, while the mean optimized energy after implementation of the developed equipment is 730.15. There was a significant increase of 364.95. This implies the efficiency of the developed and optimized energy recovery system.

       Moreover, Figure 7 shows the summarized graphical presentation to visualize the trend and comparison of optimized energy recovery from excess heat of a compressed air system before and after installation and operation.

     Meanwhile, Table 9 shows the descriptive measures of the optimized energy recovery system from excess heat of a compressed air system before and after the implementation of the study. 

     Table 9 simply shows that the variance of the optimized energy after the implementation of the system is greater than the variance of the optimized energy before the system was installed.

3.4 Significance of the Performance of the Optimized Recovery System 

      Table 10 shows the results of a paired-samples t-test conducted to compare the optimized energy before and after the utilization of the developed equipment. The mean difference of 364.95 was found to be significant between the two measures; the optimized energy before (M = 365.20, SD = 48.19) and the optimized energy after (M = 730.15, SD = 90.55); t(25) =-17.384, p = 0.000, which is less than. It means that the t-value of -17.384 is less than the p-value of 0.00. 

      These findings suggest that the null hypothesis stating that the optimized energy before and after the utilization of the developed equipment is not significantly different is thus rejected. The performance of the optimized energy after the utilization of the equipment was statistically higher than the performance of the optimized energy before the utilization of the developed equipment.

CONCLUSION

The study was developed in line with the circuit analysis, by combining the mechanical and electrical modifications, creating a log sheet and procedures, installing instrumentation components, and coming up with an effective and efficient system. The optimized energy recovery system from excess heat of a compressed air system was rated "Highly Sustainable" by the company and faculty experts. It provides the potential for energy savings and energy efficiency, resulting in less pollution in terms of environmental impact, thereby benefiting the environment significantly. There is a significant difference in the performance of the optimized energy recovery system before and after the installation and operation of the equipment.

The researcher concluded that the performance of the optimized energy recovery system from excess heat of a compressed air system after the installation and operation was effective and efficient based on the ratings of respondents and descriptive measures on the log sheet. For this kind of innovation, the manufacturing company with the same equipment should adopt and sustain it for potential energy savings and to protect mother nature.

4.1 Recommendations

      The study found that the development of an optimized energy recovery system from compressed air system excess heat revealed the following recommendations, which are now presented: Since the optimized energy recovery system from excess heat of a compressed air system was effective and efficient. It may apply to any establishment that utilizes hot water, steam boilers, and compressed air systems, especially manufacturing companies and industries. The results of the study may give the company experts: the management and the associates who served as respondents to this research, another insight on how to further improve the efficiency of machinery in the process. The study may be used as part of the learning materials for the students who will be taking the fundamentals of heating. It may serve as an example of how heat energy transfers and how to modify electrical control systems interact with one another in a complex process used in industrial applications. The faculty experts may use the findings of the study as basis on how to further improve the efficiency of machinery in terms of electrical control systems, as in line with industry. The research output may be used to promote energy efficiency and conservation, thereby benefiting the environment significantly. The study may provide add-on information to guide future studies associated with energy management systems. The study may contribute significantly to the body of knowledge on waste heat recovery systems for future researchers.

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