Answer

. PROJECT BRIEF

            The shipping industry is one of the oldest yet most important industry in the world. Since the construction of the first ship, these vessels have undergone a number of changes in order to accommodate the changing needs of the society. One of the systems that have undergone several changes in ships are the energy systems. Specifically, refrigeration systems have changed over time to allow more efficiency and output within the vessels. According to Metz (2005), refrigeration systems or plants consume up to 50% of the total electric energy in ships and for this reason, they have to perform effectively in order to ensure the power output is equal to the input. For this reason, this project develops a refrigeration system to be used in current and future shipping vessels. The project focuses on improving the refrigeration cycle and safety features towards better efficiency. 

            Basically, refrigeration is the process of moving heat energy from a single location to another and in ships, refrigeration can either be applied in air conditioning systems, freezers or refrigerators (Moons et al, 2014). Although this heat can be transferred by electricity, laser and magnetism, most of the refrigeration systems in shipping vessels use mechanical work to cool the ship or preserve their food cargo (Metz, 2005). These modes of heat transfer help to differentiate the different types of refrigerators in the market. In this study, a cyclic vapor-compression refrigeration system will be reviewed and improved to meet the desired goals. This four stage system consisting of a compressor, condenser, expansion valve and evaporator is designed for both household and large commercial refrigerators and therefore widely used in the shipping industry. This project will therefore describe the specific improvements to be made in the system, the materials to be used in the process, the tests to be done in order to ascertain the importance of each material and in conclusion, make recommendations for current seafarers and future adopters.

Fig 1: Simple illustration of the cyclic vapor-compression refrigeration.

Fig 2: An example of a ship refrigeration system

2. PROJECT SPECIFICATION

            As already noted, cyclic vapor-compression refrigeration systems are widely used in shipping vessels (Metz, 2005). Accordingly, these systems have five important components that facilitate the refrigeration process and therefore have to be improved for the overall better performance of the system (Leducq, Guilpart & Trystram, 2003). These components include: the refrigerant, compressor, condenser, evaporator and the expansion valve. To begin with, the refrigerant is a chemical substance that undergoes transitions from liquid to gases interchangeably causing the transfer of heat from various parts of the system. Brookhaven National Laboratory,  Andrews and USDOE Office of Energy Research (ER) (2001) note that an ideal refrigerant is one that exhibits good thermodynamic properties, non-corrosive to the refrigeration systems, safe (non-flammable and non-toxic) and finally safe to the ozone. Pragmatically, there is no ideal refrigerant in the market and for this reason, the authors say that refrigeration companies only attempt to identify refrigerants that meet most of the required properties for their systems. Since the 20th Century, chlorofluorocarbons have been used as refrigerants since they have most of the recommended properties (Metz, 2005). Nonetheless, as of 2004, the European Union developed new regulations discouraging the use of chlorofluorocarbons like R22 since it rapidly and excessively depletes the ozone layer. In this regard, this project will utilize R290 (propane) as an alternative to the R22.

            The compressor is the second component and basically compresses the refrigerant from the evaporator before transferring it to the condenser (Althouse, Turnquist & Bracciano, 2013). The refrigeration compressor can either be reciprocating, centrifugal or rotary. In this case, a reciprocating compressor will be considered. This is a piston unit that compresses by displacement of the refrigerant within the piston chamber (Bloch & Geitner, 2012). Since this process depends on a motor, the first method of increasing the performance of the compressor is reducing or eliminating any losses within the motor. The other factors that will be considered are the elimination of gas leakages in the compressor system, managing the pulsation within the system, reducing the frictional forces and lastly, gas pre-heating and pre-expansion losses. The next component is the condenser which eliminates the latent heat of condensation within the refrigerant causing it to change into liquid (McCauley, 2000). Condensers can either be air or water cooled and in this case, the research will describe how seafarers can utilize sea water for cooling in the condensers. Another important component is the evaporator which allows the transfer of heat from the hot object to make it cold in order to preserve it for later use or remove the heat to make the environment cool as preferred by the inhabitants (Metz, 2005).  The evaporator is always stationed in the region where cooling is required and is designed to meet the evaporative standards. This research will therefore propose the use of multilayer circuits leading to better transfer of heat in the ship. Lastly, the project will discuss how the expansion valve, as a flow control component will be able to detect the heat in the refrigerant better. The diagram below illustrates how all the components are set up in the fulfillment of the refrigeration process.

Fig 3: Schematic diagram of the refrigeration process (Yeh, 1999).

By reviewing the listed components, the refrigeration cycle will fully be tackled and additional information will be provided in regards to the safety features of the components that will be used in towards ensuring the entire system is able to work effectively. This research is therefore important at ensuring the energy consumption in ships is effective and able to sustain the growing demands of the shipping industry.

3. PROJECT OBJECTIVE

This project is aimed at developing and improving the refrigeration systems in ships. Other objectives are as follows:

1. To utilize better materials in the manufacture of refrigeration systems in ships.
2. Improve the cycle of the refrigeration system for better performance in vessels.
3. Introduce better safety features and equipment in the new improved system.
4. Develop a refrigeration system that can match the standards of modern shipping vessels.
5. Use the learnt technical skills to improve various concepts in the engineering field.
6. Complete the project in time through the provision of accurate information and data.
7. To provide resourceful recommendations for future adopters in the shipping industry.

4. PROJECT SCHEDULE

Gantt Chart

5. SELECTED SOLUTION

            Refrigeration systems are important in the shipping industry as they help in air conditioning, freezing of cargo and for other preservations within a ship. As energy systems that rely on the ships' engines to operate, these systems have to be in good conditions and able to meet all the demands of the ship. Consequently, modern shipping companies have began to install improved systems with better efficiency. Although some of these systems are expensive to install and maintain, they are effective in the long term thus justifying the investment. As part of the selected solution, this research will identify common faults in current refrigeration systems and offers suggestions for improvements of the system. To begin with, the refrigerant R22, HCFC-22 or diflouromonocloromethane has been used for a long time due to its good refrigeration properties. unfortunately, when exposed  to the atmosphere especially when it leaks in the system or is extracted for replacement, the gas directly depletes the ozone layer. Fannou  (2015) also notes that during its production, it leads to the generation of HCFC-23 which according to the author, leads to global warming. Consequently, different economies have started limiting the production of these gases and for this reason, alternative gases like R290, R410A and R407C are being produced. This study will apply R290 or propane (C₃H₈) as the preferable alternative to the R22.

            According to Tian et al (2015), R290 can be described as a natural refrigerant since it is safe to the ozone as it does not destroy it in any way, it has limited potential for global warming, improves the efficiency of a system due to its good thermodynamic properties, easily compatible with different refrigeration systems in the market and due to its low charges, allows air conditioning and refrigeration companies to develop small-sized piping systems and heat exchangers. On the other hand, it can be applied in both commercial and household refrigeration equipment and air conditioners. In contrast, this refrigerant is highly flammable and therefore when installing it is a system, the operators have to exercise adequate caution to prevent accidents. Tian et al (2015) add that chances of flammability are highest when replacing R290 with another refrigerant like R22. This is because one may ignore or forget the chemical properties of this gas and therefore technicians should be careful when undertaking this process. Lastly, R290 is purer than R22 and other chlorofluorocarbons and if supplied by a good vendor, Tian et al (2015) say that propane can have up to 97.5% purity with limited moisture content which reduces chances of corrosion and reduced amounts of hydrocarbons like Sulphur thereby reducing chances of corrosion.

            Despite these quality features of R290, an effective refrigeration system also requires effective components. For this reason, the compressor, as an important component in the system should also be optimized. The refrigerant arrives to the compressor prior to distribution to the external areas. There are several reasons why the compressor efficiency may decline or generally remain low causing loss of energy. First, the suction strainer that stops and collects solid particles within the system may be blocked due to the accumulation of solid particles leading to a decline in the pressure of the refrigerant in the system. For this case, this research proposes continuous checking of pressure within the system and routine cleaning of the strainer. In the former case, Bloch and Geitner (2012) advice that the technician should be keen on the downstream pressure more specifically along the crankcase. Second, since the compressor in use is a reciprocating type, pressure difference within the system may cause breakage of discharge valves. This would cause a decline in pressure efficiency and therefore technicians should be able to monitor the load capacity and control sequence momentarily. Similarly, when using the refrigeration system for small processes like air conditioning of a single room, the compressor of the refrigeration system has to apply an equally low load. Consequently, the load sequence has to be checked consistently for effective functioning.

            Nonetheless, the stop valve at the discharge end of the compressor can block the discharge of refrigerant and therefore this valve should be listed in the routine checklist for technicians to confirm that it is always completely open except when there is need to close it. On the other hand, Leducq, Guilpart and Trystram (2003) notes that other causes of decline in compressor efficiencies are; if the internal temperature exceeds the recommended level or the suction vapor contains the refrigerant in liquid forms. In these cases, maintaining the compressor temperature is important. Accordingly, I recommend the application of temperature sensors on the compressor suction and discharge areas. These will help to understand the pressure changes within the system leading to the application of corrective measures. The third component is the condenser which is a heat exchange system designed to cool the refrigerant before returning it to the evaporator. Since ships operate on seas and other huge water bases, I believe that sea water is an important resource that can be used in cooling refrigerant in the condenser. Although some cruise ships were already using this sea water to cool their condensers, smaller ships were concerned about the salinity and purity of the water. In fact,  Althouse, Turnquist and Bracciano  (2013) state that sea water does not have much implications to the system since it is used in a separate pipe that runs concurrently with the refrigerants pipes. There is no contact between the refrigerant and the sea water. Nonetheless, chances of fouling within the internal parts cannot be ignored and for this reason, the condenser should be cleaned on a routine basis. Fouling leads to pressure drop within the water system and this increases the cooling period. In a system that relies on adequate cooling, a high cooling period leads to loss of energy as the cooling water is pumped to the condenser by an engine which equally consumes power.

            The use of propane as a refrigerant in this case is also beneficial to the condenser as it eliminates the formation of non-condensable gases. Moons et al (2014) acknowledge that condensers mostly experience a build-up of non-condensable gases when HCFC-123 gases are used. Propane is therefore a better alternative and therefore the need to purge the air within the condenser is eliminated. Lastly, Metz (2005) adds that sea water can be very cold especially in deep seas thereby eliminating the need for extra cooling systems. For these reasons, it should be used as a better alternative for the expensive fans and wet-bulb systems which require high attention when using it. After the cooled refrigerant leaves the condenser, it heads to the expansion valve which relies on pressure difference of the refrigerant to cause the opening or closing of the valve to allow the refrigerant into the evaporator through the lines. Accordingly, the refrigerant has to leave the condenser at high pressure in order to cause the valve to expand and open. Metz (2015) notes that most refrigeration systems use thermostatic expansion valves which detect the temperature of the refrigerant and open when it meets the set low standards or remain close until the refrigerant temperature declines to the recommended state. According to Althouse, Turnquist and Bracciano  (2013), these valves have lower response times which may delay the refrigeration process especially when the expansion valve fails to open in case the refrigerant fails to attain the recommended temperature. In such a case, it is also difficult for the technician carrying out diagnosis to detect the failure in the condenser system and for this reason, the problem identification process may take too long. For this reason, Althouse, Turnquist and Bracciano  (2013) recommends the use of electronically controlled valves. These systems are able to detect the temperature and respond instantly depending on the needs of the system. Besides, these systems are able to display the temperature of the refrigerant at within the expansion valve and upon reviewing this temperature against the expected standards, the technician or operator is able to realize the condenser is defective and thereby take corrective action immediately.

            Lastly, the evaporator, also known as the heat exchange chamber allows the refrigerant to absorb all the heat within the chamber causing a cooling effect. There are various ways in which the evaporator can be improved towards better performance and efficiency. In this study, the first initiative would be to increase the tubing system of the evaporator. This involves introducing extra tubing or increasing the number of coils on the existing systems. This is an important process that increases the surface area of the refrigerant in contact with the interior of the cooling chamber. As more refrigerant comes into contact with the heat within the cooling chamber, more heat is absorbed allowing faster refrigeration. Nonetheless, In Dinis,  In Silva and IGI Global (2015) note that the air coolers which operate at temperatures below the freezing point have to be defrosted consistently so that their operation is not limited by the frozen liquid in the system. there are various methods of conducting the defrosting process, electric, hot water and hot gas defrost. This study recommends the application of warm water through the cooling system in order to defrost the internal parts. Warm water is selected because it allows gradual defrosting that can take place without much supervision since the system gains the heat from the water and gradually defrosts unlike in electric defrosting which is instant causing rapid change in temperature that weakens the structure of the piping system due to the change in size during expansion and contraction. Metz (2005) also notes that electric heating is costly as the heating equipment has to be hired or bought which may be difficult to do while at sea. Consequently, the warm water option is most viable.

            All these improvement suggestions also promote the safety of the system through adequate monitoring, application of alternative refrigerants, detection of leakages, increasing efficiency through the utilization of quality tools and the introduction of more convenient valves. On the other hand, the piping system should also be considered or reviewed. In this regard, refrigeration systems should be fitted with the correct sizes of pipes. This according to IOR (2003) would help to reduce unnecessary pressure drops in the systems and limit the cases of oil return especially along bends. Additionally, the control systems and components should only be limited to the required sizes and numbers. Unnecessary controls and control systems should be avoided. Some of these unnecessary systems include: "hot gas bypass of compressors, throttling valves between evaporators and compressors, evaporator control by starving refrigerant supply, too frequent defrosts, condenser head pressure controls except when necessary" (IIR, 2003).

6. VERIFICATION STRATEGY

            The effectiveness of the proposed improvements can best be determined through verification or testing. In this regard,  a number of tests can be implemented. According to Li and Wang (2000), one of the methods that can be used to verify the efficiency of a refrigeration system is the application of sensors to detect various parameters. For instance, to detect pressure, a pressure detector has to be fitted along the system. Accordingly, pressure sensors have to be fitted at the suction and discharge ends of the pressure vessels like the compressor and condenser. Temperature changes are also part of the system's cycle since the system is a thermodynamic process.  Temperature sensors and thermometers should be fitted before and after all the system components. Apart from measuring the temperature of the refrigerant, the temperature sensors will also measure the temperature on the surface of the components. This helps to understand whether the heat exchange process occurs at the required standards. Based on these parameters, the moisture content and defrosting properties can best be described. The information obtained is then tabulated in the table below:

Table 1: Sample of data collection for verification table featuring all tested parts.

7. CANDIDATE FEEDBACK

            The aforementioned verification process offers good insight into the performance of all system components right from the compressor to the evaporator. By detecting the temperature into and out of the compressor, the average operating temperature of the component can be determined in relation to the previously stated ambient temperature. Accordingly, with the improved system, the compressor efficiency is increased leading to better performance and utilization of energy. The pressure parameters also indicate closeness to ambient standards thus illustrating that the valves which act as the control systems work effectively within the system. The adoption of electric valves within the system also allowed faster reaction to the various thermodynamic changes in the study.  In conclusion, the verification strategy is convenient and therefore allows us to understand the impact of the improved strategies based on actual data or feedback. 

8. ACCESSING MATERIALS

            The most important material in any refrigeration system is the refrigerant. In this study, the proposed refrigerant is the R290 or propane and comes with various benefits including, but not limited to: it is safe to the ozone unlike other HCFCs, has good thermodynamic properties that make it efficient as a refrigerant, its good compatibility properties allow it to be used as a replacement in other refrigeration systems and finally, allows the utilization of small-sized piping systems and heat exchangers which can allow the utilization of more piping circuits in heat exchange areas leading to better performance. However, this product is highly flammable and users should be trained on its applications and handling prior to utilizing it. Although this seems like a critical threat to the utilization of the refrigerant, the long-term benefits of the product make it ideal despite the concern. On the other hand, it is also the concerns raised about the exposure of propane to the environment are similar to those raised about the exposure of R22 as the latter also has negative impact to the environment (depletion of the ozone layer) and should therefore be prevented from leaking. The average price of propane in the UK as of November 2015 is £3.7 per kg which accounts for about £0.209 per KWh of energy. Although this is relatively high compared to gases and coal as sources of energy, the long-term effects of propane justify its applications in the ship refrigeration systems.

            The compressor shell is made of steel metal due to its property as a strong metal that can resist heavy loads or impacts. Within the compressor are: a shut-off system that stop the compressor immediately its operational temperatures exceed the normal operating temperature or restart it whenever the internal temperature is lower than recommended; a semi-hermetic sealing arrangement that has both the motor and compressor within one casing but has bolts connecting the casing of the compressor and motor to allow for servicing when necessary and finally; a speed adjustment system that adjusts the running speeds of the motor and compressor whenever necessary. On the other hand, condensers as heat exchange components are fitted with materials that allow easier and faster heat exchange just like in the evaporator. In this case, brass is used due to its relatively high thermal conductivity. Although copper has better conductivity, it is susceptible to corrosion and therefore brass is a better alternative since it is made from the mixture of copper and zinc to make it less corrosive. Nonetheless, Metz (2005) warns that the amount of zinc added to make the alloy has to be limited since zinc reduces the thermal conductivity property of the alloy (brass). Since water will be used as the coolant, brass will be able to resist corrosion to a greater extent compared to while using copper thereby ensuring the refrigeration system serves the ship for a long time without the need for replacements.

            The expansion valve comes assembled with a spring that allows the valve to shut and open whenever necessary. On the other hand, the evaporator is a cabinet designed with pipes. In this system, the evaporating pipes are made of copper which allow high exchange of heat due to their good thermal conductivity. Although brass was used in the condenser, the evaporator will require the use of copper for better and faster heat exchange since the component is mostly enclosed. Unlike the evaporator the condenser is always exposed to the atmosphere to enhance the cooling or may be fitted with fans especially when used to cool large facilities. The other exterior parts of the refrigeration system can be enclosed so as to make it a single unit. Consequently, metal sheets can be used to enclose the system depending on the design and size of the ship. The materials used in the design of the exterior parts do not affect the actual design of the system to a great extent but other factors like the use of the refrigeration system and the convenient aspects must be considered. For instance, the interior and exterior parts of the refrigeration system will be separated with fiberglass as it is relatively strong yet light in weight.

9. PRODUCT/ INVESTIGATION CONSTRUCTION

            The assembly and construction of the improved refrigeration system for ships and other water vessels begins with the identification of the location or products to be cooled and the available size for the installation of the system. Second, all components are assembled and analyzed to ensure they meet the recommended standards. In this regard, the compressor has to has to come pre-installed with the motor and the expansion valve has to include the spring and the electric components. The remaining parts are assembled according to the design specifications. The internal refrigeration system is fitted prior to the installation of the external parts. The metal parts are welded for better fastening whereas moving parts are fitted with hinges for easier movements in the desired directions. The basic installation set up should allow the flow of refrigerants as illustrated below:

10. TESTS/DATA CHECKS

            Since the verification process was also a data collection process, this section will describe how the data will be utilized towards understanding the performance of the system. As a thermodynamic process, refrigeration involves understanding the relationship between heat and work. Accordingly, there are important terms that have to be described prior to the explanation of tests. First is enthalpy which is the internal heat energy generated as a product of pressure and volume. According to ...it is the heat formed at constant pressure. Both authors agree that it is denoted by "h" and its metric units are in KJ/Kg. The quantity of heat into or out of a system is also a separate entity and is denoted by "q_in" or "q_out" respectively. Lastly, the amount of work done in the system is also important. Given a refrigeration system like the one represented below:

The individual enthalpies at the various stages can be described as: h₁, h₂, h₃, h_i

Consequently, the enthalpies between stage 1 to 2 are approximately equal since the refrigerant in the expansion valve is released at an equal temperature as it was received from the compressor. The term approximate has been used to imply that there may be some disparities in the  two enthalpies but the deviation is not large.

Therefore; h₁ α h_2.

In stage 2 to 3, heat is exerted into the system as the cooling process in the chamber begins. The equation for this process is therefore: q_in = h₃ - h₂ which is also equivalent to h₃ - h₁.

At the compressor (Stage 3 to 4), work is done and therefore; Work = h₄ - h₃

From stage 4 to 1, the condenser releases heat within its system thus giving the equation: q_out = h₄ - h_1.

Based on these formulae by Birtwistle  (2013), the co-efficient of performance (COP) which describes the evaporator efficiency in relation to the work input is given by; W = h₃ - h₁ or h₄ - h₃.

11. INTERPRETATION OF DATA OR TEST RESULTS

            For proper understanding of the improvements made in the systems, the test results of the system have to reflect improved efficiency. Efficiency of thermodynamic systems is best reviewed based on the coefficient of performance or COP (Wang, 2001). This parameter helps to relate the energy input to the energy or work output. In this case, the energy input is given by the compressor and condenser work while the output which is the amount of heat extracted through the evaporator. Wang (2001) also argues that COP is not necessarily the actual efficiency since its value is more than 1. Accordingly, the COP of the improved system = h₃ - h₁ or h₄ - h_3. Based on the first thermodynamic law, the compression process is an isometric process (stage 3-4), condenser releases heat at constant pressure (stage 4-1) and the evaporator gains heat at constant pressure (stage 2-3). Based on these data, the COP can also be given as: h₃ - h₂ over h₄ - h₃. In his tests, these COP give a positive outcome of more than 1 implying that the energy input is almost equal or less to the output representing effective utilization and saving of energy.

12. PROJECT REPORT

            Ships and other sea vessels utilize refrigeration systems for air conditioning, cooling and preservation. Although this practice or the use of refrigeration systems has had a positive impact since their first utilization in these vessels, most shipping companies were still utilizing the old refrigeration systems which give limited benefits in comparison to the energy consumed. Based on this realization, modern ships are being manufactured with improved refrigeration systems that are able to meet the  refrigeration needs of the vessel better. Althouse, Turnquist and Bracciano (2013) adds that these new systems are equally expensive but have better savings in the future as ships can utilize the systems for a long time without unnecessary breakdowns as they are designed with better equipment and materials. This research therefore explores the various improvements that can be made on refrigeration systems in ships. These improvements aim at reducing the number of faults in the current systems, offering alternative methods of achieving recommended refrigeration standards and utilizing better materials and equipment towards safe operating standards of the refrigeration system. In summary, this project was able to effectively meet its objective by: replacing the use of ozone-depleting R22 with R209 which is safe to the ozone; reducing leakages, enhancing better monitoring and fitting a variable speed system to the compressor system; encouraging the use of sea water as a coolant in the condenser and using the less corrosive brass as the main material for constructing the condenser piping system; adopting an electric expansion valve for instant and accurate response and finally, the utilization of more copper circuits within the evaporator to increase the surface area of heat exchange leading to better transfer. The report also includes other system improvement techniques that involve elimination of unnecessary system parts like the heat exchange by pass fitted in some compressor system. Based on the test results and data analyses of the improved system, the solutions provided effectively contribute to better performance of the system leading to effective utilization of the ships energy.

13. NEW KNOWLEDGE AND SKILLS

            By improving or developing various ways of improving the refrigeration systems of ships, the project provided me with an opportunity to utilize my class work knowledge to solve societal issues. In the process, I gained adequate knowledge on the entire refrigeration systems as applied in ships. To begin with, despite the fact that I had known HCFCs deplete the ozone, I was not informed that regulators in various parts of the world had began phasing out the use of HCFCs as refrigerant. This compelled me to research on which refrigerant would offer better alternative. For this reason, I chose R209 as the best alternative due to its thermodynamic benefits that meet the recommended standards. Despite this R209 is safe for the ozone but highly explosive. The latter factor leads to the need for better leak detection and mentoring of the system but does not disqualify the refrigerant as a whole since by the use of HCFCs, technicians were already aware of its impact to environment and thus always applied adequate care when handling it. This same care should be applied to the propane system for safe operations.

            Other than the operational system of the refrigeration system, I also gained knowledge on the design assembly process. In assembling the system, I learnt that the term "cyclic" used when describing the system is generated from the arrangement of the main components of the refrigeration system which make a cycle. Basically, from the evaporator, the refrigerant goes to the compressor, then the condenser, expansion valve and later back to the compressor. Despite having other control parameters in the system layout, this cyclic arrangement has to be maintained for a vapor-compression refrigerator. In contrast, this does not imply that this is the only arrangement of the refrigeration systems in use since there are other arrangements that can be used to facilitate the refrigeration process. Lastly, through this project, I have been able to improve my research techniques towards the development of existing knowledge and generation of new insights. These are important skills I can utilize later in the profession.

14. NOVEL FEATURE

            There were both positive and negative challenges in the development of this project. The positive aspects that contributed to the timely completion of the research were the availability of adequate sources of information on refrigeration systems. Selecting the improvement procedure and other accessories was therefore effective and helped to meet the desired standards. On the contrary, the testing stage was challenging due to the high number of parameters that had to be tested or evaluated in this stage. The testing stage was therefore time consuming as accuracy of the data had to confirmed. Nonetheless, the process was completed successfully thus conclusions about the improvements made were drawn as described in the report.

15. ADITIONAL RESEARCH

            The improvements made in the ship refrigeration systems in this research are part of the continuous improvements that will be made even in future. According to ... refrigeration systems will continue improving with the discovery of better materials and refrigerants. For instance, in future, more ozone friendly gases like the R410a will be used in newer systems. With equally appropriate thermodynamic properties, these refrigerants will offer better alternatives for the refrigeration systems. In most ships, the refrigeration system is mostly powered by the auxiliary generator since they are at times utilized for air conditioning and simple cooling purposes, however, with continuous improvements and reduction in losses along the system, the refrigeration systems can be powered by the main generator thereby limiting the use of the auxiliary generator to power back up and other operations that require less energy like lighting the ship. The utilization of explosive gases like R209 as future refrigerants due to their environmental safety has led to the improvement and enhancement of leak detection technologies which will be able to guarantee better safety. Such safety concerns have also led to the realization of the importance of training to the technicians handling this process and therefore these personnel have to be skillful and well-trained to handle these refrigerants. The refrigeration components can also be improved further through the utilization of better equipment or facilities and for this reason, future piping systems will be have non-corrosive properties, better thermal conductivities and reduced fouling. These will increase the energy utilization of the system.