Executive Summary
All over the world, there is a rising need for sustainable energy production. In the recent past, human development has led to more energy demands and this has had the effect of increasing pollution as well as global warming. Most of the power around the world is obtained from the combustion of fuels and as such, there is a production of carbon dioxide and other chemicals that affect the planet. Regardless of this effect, the use of power will never cease and it is therefore imperative to come up with new ways through which power can be produced.
This report presents one of the best technologies that has been developed for power production. The technology has the advantage of reducing the emissions that are common in the conventional fuel combustion power generation technology. Furthermore, there is a reduction in the losses due to heat wastage. Most power generation plants and equipment have the disadvantage of having a tremendous amount of energy lost as heat but this can be reduced by using trigeneration.
The technology is aimed at using the heat that is produced as waste by most power generation plants for other purposes and more to this, it has a system that purifies the carbon dioxide that is produced. The technology is a great investment to the world because of its many advantages. All this is explained in this report.
The report focuses on trigeneration, how the system works, a comparison with other sustainable technologies and the pros and cons of the technology.Trigeneration can be compared to other sustainable methods of energy production such as a cogeneration and this presents a major vantage point in the development of sustainable power generation technology. As such, all this, will be looked at in detail but with the main focus on the trigeneration technology.
Regardless of the unknowns about the technology, the findings are likely to be more positive than negative. The technology saves on the cost of production of heat power as well as reduces carbon emissions. It is a sustainable approach to energy production as compared to the conventional methods.
Introduction
There has been an increased emphasis on the use of sustainable energy (Dempsey, et al., 2011). This refers to energy that has little or no effect on the environment and meets the needs of the users. However, the energy should not lead to depletion of the oil reserves as this is one of the main agendas of sustainable use and development: intergenerational equity (Cuthill, 2010). Intergenerational equity is an agenda whereby the present demand should ensure that there is sufficient reserves for the other generations to utilize. Therefore, basing the argument on the fact that most of the energy and power is generated from oil, it is important to consider the needs of the present as well as those of the other generations.
Trigeneration refers to the production of electricity as well as the utilization of the heat energy for either cooling or heating (Engle, 2004). Therefore, the heat energy that may be deemed as waste in other energy production technologies is useful in this technology.It may also be known as the combined heat, cooling and power technology. The two most common sources of all the aforementioned are fuel and heat collected from solar energy (Al-Ali & Dincer, 2014).
In line with the energy and heat conservation measures that are integrated in the trigeneration technology, it is important to consider cogeneration. Cogeneration is also known as combined heat and power (CHP) and it refers to the process through which heat and power generation techniques maybe used to develop power and energy simultaneously (Chen & Ni, 2014).However, the major difference between cogeneration and trigeneration is the fact that latter uses the excess heat produced for cooling as well as heating purposes, unlike the former. The two most common technologies that may be used in the production of power as well as useful energy are heat engines and power generating stations.
It is the development of power and heat that makes cogeneration an important part of trigeneration (Chiccho & Mancarella, 2006).Trigeneration may also be defined as the method through which the heat produced by cogeneration technology may be used to produce air that is chilled for use in air conditioning as well as refrigeration. However, the functionality is only achieved when there is a link from the system. The link may be provided by an absorption cooler.
However, the system may be developed in such a way that there is the addition of a purifying technology. Combustion of fossil fuels leads to the generation of humongous amounts of carbon dioxide and the quadgeneration technology has been developed so that this gas is purified and therefore reduces the emissions (Engle, 2004).By looking at the various technological developments that surround trigeneration, the report will provide some of the basic background and detailed information for use by scholars as well as researchers. All this will provide a platform from where research can be conducted and as such, emphasis on these sustainable energy production approaches.
Some of the areas to be looked at in detail are centered on the sustainability of the technology and the factors that advocate for its use. Therefore, the advantages as well as the disadvantages will be weighed against each other with the main agenda the sustainability of the technology. The methods through which the combustion of fossil fuels leads to the generation of power as well as heat are looked at but the main emphasis is on energy conservation.
Besides comparing these sustainable power generation approaches, this report looks at the differences between trigeneration and the conventional power and energy approaches. In this, the technology has been developed mainly because of the shortcomings of the conventional approaches and as such, it is important to observe the major upgrades of the system. The heat and power losses that are associated with the conventional methods are the main factors that call for an upgrade to trigeneration and therefore, the report will look at the difference in specifications between the two systems. All of the above are obtained through research and experimentation and provide a blueprint for more research.
Literature Review
There is increasing need for sustainable energy production all over the world. Production of energy should be combined with environmental protection and this has been neglected over the past decades (Chicco & Mancarella, 2008). However, with the increasing pressure on sustainable energy production, various technologies have been developed with the most notable example being trigeneration. Trigeneration combines the aspects of sustainable development with technology and the result, is a system that meets the energy and power needs of the current generation without affecting the next generation (Hernandez-Santoyo & Snachez-cifuentes, 2003).
Trigeneration, as stated before, refers to the technology that ensures that there is combined and simultaneous production of heat as well as electricity. In this, the heat that is produced through cogeneration may be used for constructive purposes such as air conditioning and even refrigeration (kibert, 2016). It is a sustainable approach to energy use and prevents the wastage of energy that would otherwise be useful to the human population while destructive to the environment. However, other definitions of trigeneration are centered on the production of heat, electricity and chemicals for use in industries. In this, trigeneration is defined as the method through which the three aforementioned may be produced by power systems. One of the gases that may be produced by trigeneration is syngas (Angrisani, et al., 2012).
The technology provides a platform through which thermal energy may be used for productive purposes such as heating and cooling. These combined heat and power systems may be decentralized to ensure that there is proper delivery of heat as well as cool air during the cold and warm seasons respectively (giz, 2016). Furthermore, the energy that is derived from these systems may be used in refrigerators for the purpose of cooling. However, the energy produced should be at a moderate temperature of about 180 degrees Celsius (Meunier, 2002).
Trigeneration is a development of cogeneration whereby the earliest power systems depended on cogeneration because of heating needs of some of the buildings as well as industries (Ortiga, et al., 2011). The technology was mainly emphasized by organizations and industries that used to generate their own power. The excess heat that was developed in these power generation facilities was used to heat steam that was used in heating the overall building structure (Raj, et al., 2011). The concept also applied to hotels, buildings and schools that used to develop their own power prior to the grid supply system.
The system has mainly been advocated for because of the numerous economic as well as sustainable benefits that can accrued. To begin with, the system reduces the amount of fuels that are used in the manufacture of heat and power. In return, the system ensures that the costs of power are maintained at a minimal. Secondly, the system employs an onsite method of power and heat generation. Moreover, the system is very efficient which means that it is very reliable. Thirdly, the technology ensures that the rate of electricity usage is kept at a minimal during the peak summer demand times. The technology provides a cooling mechanism that ensures the houses are within the desired temperature ranges and as such, prevent the use of other cooling technologies. Fourthly, the technology ensures that there is a minimization on the rate at which greenhouse gases are produced. The other advantage of the system is the fact that there is a reduction in the pollution associated with chemicals since the refrigerant used is usually water. Last, but not least, the technology may be used as a means through which hot water can be produced for use at the site.
Regarding the heating requirements of a building, the technology is very important in raising the ratings of energy efficiency in Australia (Thompson & Maginn, 2012). The rating of a building depends on the heating as well as the cooling requirements and these can be drastically reduced by the trigeneration technology.
There are three ways through which trigeneration  may be used in the distribution of energy. The energy may be distributed as electricity, heat or water that is chilled (Boukhanouf, et al., 2018). However, the absorption chillers act as a sustainable replacement to the conventional refrigeration systems that tend to use chemicals as refrigerants. It is one of the most sustainable approaches to energy generation and usage since it reduces the emissions, increases the efficiency and reduces the usage of harmful chemicals. There are three configurations of the absorption chiller that may be used to distribute the energy: a system that operates using hot water, a system that uses stream and finally, a system that works by combustion.
The other configuration that ensures that the energy from trigeneration is used effectively is the refrigeration compression. In this, there are two types with one using direct power while the other uses electrical power. The two systems that have been stated are used for the efficient as well as sustainable energy usage and therefore play a pivotal role in sustainable energy usage.
In line with the energy distribution and usage of the absorption chillers, the main consideration is usually the excess heat that can be used for cooling. Heat energy is usually utilized by reducing the time interval between cooling and the generation of power for other systems. The water that is usually used in the cooling circuit usually has excess energy which can be properly utilized and this comes to play in the chillers.
The chiller may also use the hot gas that is emitted from the gas engine. It acts as a means through which steam may be generated from the steam engine (Wang, et al., 2008). The steam can be used as means of energy generation which means that the water may be chilled without the need for a refrigerant chemical as well as extra energy. It therefore provides a means through which the energy efficiency of the building as well as the cooling requirements are met throughout the year at a reduced cost.
The major advantage of using chillers over the conventional refrigeration system is mainly centered on the cost reduction. In this, the excess and extra energy is used in conditioning houses which means lower expenses. Secondly, these systems have very low maintenance costs because they do not have moving parts. Thirdly, the extra heat that may be produced by these absorption chillers may be used during the cold seasons to ensure that the house is well conditioned. Finally, there is a reduction in the chemicals that result to the destruction of the ozone layer. Reduction in the ozone destroying substances is a sustainable development approach that prevents global warming.
There are two methods through which trigeneration technology may be implemented; the absorption technology and the adsorption one. However, the underlying principle of these technologies lies with the cogeneration principle of the technology as well as the supply of heat energy, cooling energy as well as electricity generation. The technology works by converting the energy to chilled water either by adsorption or absorption.
It is a proven technology that has been widely applied in the market since it converts low waste energy to sufficient levels that meet the cooling needs of the society. It has been widely used in the trigen market because of the efficiency that comes along with the chilled water. The downside with the technology is mainly centered on the high maintenance costs that come with it. Maintenance costs are mainly due to the usage of the highly corrosive Lithium Bromide in the chillers (Chandra, et al., 2013). These salts are highly corrosive and require frequent maintenance which raises the costs of the absorption technology.
The capacity of chillers that use this technology is very high and ranges between hundreds of kilowatts to several megawatts (Chen & Ni, 2014). However, there are smaller scale chillers whose capacity is a few hundred kilowatts. The technology is highly adaptable because of the flexibility measures and as such, it can be used in both the warm and cold seasons to meet the energy demands of the population.
(Boukhanouf, et al., 2018)
 In comparison to the absorption technology, it is relatively new and has not been implemented on a huge scale. Moreover, the technology that is applied in such a technology depends on the interaction between solids and gases with the main focus on the adherence of molecules on substances, rather than dissolution (Lian, et al., 2010). Working from the principle of adsorption, the technology has a solid filled chamber, usually neutral in state that adsorbs the refrigerant.
The second step is when the solid is heated. Heating the solid which has adsorbed the gas results to the release of the vapor through desorbtion (Chiccho & Mancarella, 2006).The desorbed vapor is then cooled which means that it liquefies and it is during this process that there is cooling of the evaporator. The process then repeats itself when the vapor cools and is readsorbed to the solid material. The cooling effect that is obtained in the evaporation chamber is usually because of the heat that is adsorbed during the condensation process.
The technology is relatively simple and has a lower maintenance cost as compared to the absorption technology.It is however very attractive for the trigeneration technology because of the simplicity that is associated with its operation. The power and electricity requirements of this technology are relatively lower ranging between 2kW to 20MW (Nosrat & Pearce, 2011).
(Boukhanouf, et al., 2018)
Therefore, considering all these aspects of trigeneration, the main aim of this report is to investigate the amount of carbon dioxide that may be produced from trigeneration.The use of fossil fuels and production of carbon dioxide are simultaneous processes but with proper analysis, the production can be lowered. Besides conserving energy, trigeneration may also be used in the reduction of the carbon dioxide gas that leads to global warming. In line with this, there are statistical methods that are presented to analyze the amount of carbon dioxide produced in an experimental set up.
RESEARCH QUESTIONS
Trigeneration plays a fundamental role in optimizing the use of energy. The simultaneous use of waste energy for the heating as well as cooling requirements of a building as or a factory has many positives particularly because of the reduction in heat pollution. However, the design has to consider the carbon production which needs to be minimized.
Considering this design and the hypothesis, the research question formulated will be: what are statistical methods and formulas that are used in estimating the carbon dioxide removal. This report considers the importance of the removal of carbon dioxide on the environment.
 
METHODOLOGY
The research is based on the two most common trigeneration technologies that are employed: the absorption technology. The maintenance costs of these requirements are very high but the returns are numerous. Furthermore, this technology is the most common ad therefore, can be easily modified to meet the needs of a particular environment.
Research will be conducted through research. In this, the internet as well as books and journals that are obtained from the library will be fundamental in provision of the necessary information. However, the literature will be limited to recent research and developments in the trigeneration technology.
The limitation of the research will be mainly centered on the available literature. Recent developments in the technology are not well documented and as such, pose a challenge to the research. However, calculation as well as the necessary statistical equations will be used in developing the proper solutions.
 
Experimental set up
The experimental set up to be used in simulation of the trigeneration technology was made up of the following components: heat and power unit, the cooling system that is controlled by the emanating heat, the heat exchanger, the condenser and the vapour separator. These are the basic components of a trrigeneration system and as such, will be fundamental in the experimental set-up.
The research may also be based on computer simulation. However, a computer model provides the optimal heat as well as power generation capabilities of the system and as such, is not highly recommended for research purposes. Regardless, it provides a platform through which the various components of the system can be visualized and will enable the necessary system modifications.
(Chiccho & Mancarella, 2006)
There are two components that are considered in this research: the combined heat and power unit as well as the equipment that circulates the heat. The combined heating and power unit may be attached to a heating equipment to minimize the waste of heat energy emission. However, it should be oriented to the power grid and should be built around an engine for power and heat generation.
The second aspect that considers the heat circulation system focuses on the amount of power used. There are different types of cycle mechanisms that can be used but all this depends on the amount of power that is used. Furthermore, the cycle depends on the amount of heat required as well as the type of energy source used.
Analysis
To begin with, the formula that is used in the analysis of the power, heat and temperature capacity of the system is described by the following formula:
Hot water return=hot water input+
The coefficient of the system performance is the ratio of the heats that are available in the generator as well as the evaporator and can be calculated from the following formula:
 
In the above formula, are defined as the vapor enthalpies at the exit of the evaporator as well as the generator. On the other hand,   refers to the enthalpy of the liquid at the condenser exit.
In analyzing the efficiency of the system performance, the following formula is used:
Where Qg is the calorific value of the fuel is the output of electricity from the system, and y is he fraction of heat available.
Finally, the emissions that may be attributed to the system can be calculated from the following formula:  where Etri is the emission factor.
Results, outcomes and relevance
The removal of carbon dioxide determines the efficiency of the trigeneration process. However, this removal and the amount of carbon dioxide produced depends on the type of fuel that is used. Fossil fuels have a higher emission factor than other forms of power such as electricity. The fuels that have higher proportions of hydrocarbons are more likely to produce more carbon dioxide gas than those that are partially made up of hydrocarbons.
Increase in carbon content of fuels requires more heat to produce energy. This means that fossil fuels require more power to produce higher amounts of energy.
Gantt chart and project planning
The Gantt chart is a platform that is used to monitor the rate of job progress. In this study, the whole project will be divided into 6 tasks with the final task being the documentation. The whole project will take a total of 14 weeks and 5 days. Weekly analysis will be conducted to determine the relevance and the rate of progress of each task. The Gantt chart and the list of activities are as indicated below.
Conclusion
Technological developments have led to the increase in power demands and this has an undermining effect on the environment.However,trigeneration is one of the most ecofriendly electricity, heat and cooling strategies applied throughout the world. The technology utilizes the waste energy from power generation for cooling and heating purposes.
The two common technologies applied in trigeneration are adsorption as well as absorption. Absorption is one of the most commonly used methods but it is very expensive and requires frequent and proper maintenance. On the other hand, adsorption is not that common but it is relatively cheaper. Selection depends on the cooling and heat requirements of the user and the capital available.
Finally, there are various formulas that have been developed in the analysis of trigeneration technologies. The formulas determine the efficiency of the system, the power requirements, the heat and cooling energy outputs as well as the carbon emissions. All these formulas provide a benchmark for further research on eco-friendly technologies.
 
 
 
 
 
 
 
 
 
 
 

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