Design of Air Ventilation System for Cargo Hold Vessels using Solar Desiccant

One of the facilities and infrastructure of the vessel is the ventilation system in the cargo hold to maintain the quality. One attempt to avoid high moisture ratios is to provide a dry air supply by using desiccants. The purpose of this thesis is to design the system of air ventilation with solar desiccant by analysis the calculation with decrease air humidity ratio after passing desiccant rotor as well as fulfillment needs of heater and cooling system using heat of exhaust gas and seawater as well as fulfillment of electricity need using solar energy. From the result of analysis obtain to provide air supply in the cargo hold of 437.5 m3 / hour, the specification of rotor desiccant has a diameter of 550 mm with thickness 200 mm to decrease ratio of outside air humidity equal to 83.1% become 46.5%. Dehumidification air temperature of 47.7oC will be lowered to 35oC by using the sea water cooling media. As for the reactivation air heater requirement of 24.292 kW would be to fulfilled by utilizing the exhaust power of 498.12 kW. And for the electric power needs of the syetm is 34,488 wp will be supplied from the total solar module is 33 units with 345 wp per-capacity.


I. INTRODUCTION
Vessel s used as a logistics transport from a small port, to a port hub-port, the above function is a function of the people's voyage to ensure the availability of national logistics system to inland areas.The role of the people's sail in "Sea Highway" also plays an important role in safeguarding the stability and availability of logistics, especially in areas that are difficult to reach by land transport rice, cement, fertilizer, food are some of the freight carried by Pelayaran Rakyat vessels.In addition, Pelayaran Rakyat vessels are also used for river transport such as in Kalimantan, and Sumatra.One of the facilities and infrastructures of the Pelayaran Rakyat vessels is the air ventilation system in cargo hold which is useful to keep the cargo quality in good condition.
Natural air ventilation systems for cargo hold Pelayaran Rakyat vessels are considered less effective for some items such as rice, flour or other foods.
The region of Indonesia is in tropical climate with a range of temperatures in waters of 27 o C with a humidity level of 80%, while the normal temperature recommended for the charge is 43 o C with a relative humidity value of 65%.With the difference in environmental conditions, the charge will be affected by micro-climate elements, especially air humidity [12][13][14][15][16][17][18].
In addition to the use of renewable energy for the fulfillment of the heating system needs of the dehumidification system will use exhaust gas from the engine and the fulfillment of the electrical power needs used for the fulfillment of electrical power from the rotary desiccants system using solar thermal energy which is then converted through the system from photovoltaic [13].
Air ventilation system is the process of providing fresh air into the room or out of the dirty air of a room naturally and mechanically.The air venting system on the vessel has the function of maintaining chemical composition and humidity or keeping it as requirment in the vessel's room, by regulating the flow of air into out of the vessel in order to perform the process of replacing the already dirty air with fresh air and Adjust the temperature, pressure and chemical composition of the air inside the vessel [2].With the occurrence of the process will be able to fulfill the purpose of ventilation in the vessel.
Desiccant is one of the hygroscopic substances that can absorb moisture by put away water inside the capillary or surface of an item while maintaining the presence of water molecules.The most common substance used as a desiccant compiler is silica gel which is a form of silica dioxide (SiO2).The use of desiccants in dehumidifier is used to attract moisture from the air by creating low vapor pressure areas on the surface of the material [3].Calculation of exhaust heat is determined by estimating the mass of exhaust gas obtained through correction of optimation point on engine load curve and correction to ambient condition and exhaust gas pressure according to engine maker rules [4].The economizer that to transfer of exhaust gas heating is uses to supply hetaer of reactivation energi.The power generated by exhaust gas heat can be known by the following equation:  Calculation of heat load is performed by calculating the heat source of the ship's load space, which is the heat of solar radiation (∅s).Estimation of parameter values in determining heat load refers to ISO 7574 : Ship and Marine Technology -Air Conditioning and Ventilation of Accomodation Spaces [6].The solar heat burden (∅total) can be calculated based on the equation: (2) In determining the design of the cooling system can be done using calculations of energy equilibrium ie .[4].In the type of cooling use seawater as International Journal of Marine Engineering Innovation and Research, Vol.1(4), Sept. 2017.241-249 (pISSN: 2541-5972, eISSN: 2548-1479) 243 medium of cooling system.The system need to calculate flowrate the sewater is fulfill requirmnent of cooling capacity [14].The cooling capacity that uses to decrease the temperature is result for procces dehumidification of rotary desiccant.The flowrate of sewater that uses as medium of cooling system is to select the seawater pump with the requirment of system [15][16][17].The seawater pump have function to circulating supply cooling fluid.

Mass equilibrium
Early + Procces = End Solar energy is energy derived from the process of converting solar heat through certain equipment into a resource in anotherenergi.Solar energy is one source of power generation other than water, steam, wind, biogas, coal, and petroleum [13].
The development of the use of solar energy reappeared in 1958.Silicon cells used to convert solar energy into resources began to be taken into calculation as a new method, since it could be used as a resource for space satellites [8].
The equation used to determine the capacity of the solar system: Where : ET =Total energy power (Wh) =Correction factor (1,1)

II. METHOD
In supporting to make this research it is needed a sequence of methods that become the framework of reference in the completion of this research.The methodology of this thesis contains steps to solve the problem in the work of this thesis.Starting from the formulation of the problem until later concludes the conclusion on the work of this thesis.The methodology used in this thesis is through the four main stages, the first is to design the dehumidification system using rotary desiccants, the second phase is to design the heating and cooling needs, the third is to design the electricity needs fulfillment system, and the last stage is to do the design condition suitability analysis.
The first step in this thesis is to determine the design schema and initial condition as a reference in determining the calculation parameters.Furthermore, it calculates the volume of vessel loading space and determines the value of air changes per hour in accordance with the recommendation of BKI, to obtain the air capacity to be supplied as well as the technical specifications of the rotor desiccant.
The next step is to design the need for reactivation air heaters for the desiccant rotor and the dehumidification air conditioning system requirements.Heating needs planning is done by calculating the required power from the heaters to be designed.Next is the calculation of the power generated by the heat from exhaust gas from the main engine.To determine the cooling system is done by calculating the cooling load from the dehumidified air desiccant dehumidifying process adjusted to the initial design temperature for cargo hold.In the cooling system can be determined the estimation of the compressive capacity that can be produced by utilizing sea water as a cooling medium.
The next step is the designing of the electrical system.The electrical system on this system uses modul photovoltaic that utilize solar energy as a source of energy.In determining the solar panel to be installed it needs to calculate the power load on the solar desiccant system.After that it is necessary to estimate the selection of equipment specification to be used in the system.
The final step is to analyze the suitability of design conditions.The analysis is conducted to determine is the design of designed to maintain the cargo hold condition

A. Design Desiccant System
Here is the flow diagram design of the solar desiccant system used:

B. Design Condition Determination
The outside air at 38.The total volume of cargo hold ship (vol.)Based on data capacity plan is 437.5 m 3 .While the value of air changes per hour (n) based on BKI Ventilation is 6 air changes per hour.The calculation from that obtained of requirment capacity to fulfill the system.Capacity is the air of quantity that must be in the supply into the system.So the air capacity (Q air ): (2) 6x437.5 2625 m 3 /h

C. Dehumidification Procces
Determination of specification from rotor desiccant is done with the assisted of the Desiccant Wheel Simulation Program.The desiccant diameters are selected based on the availability of space in the accommodation space and the ability to lower the humidity ratio [16].To selected desiccant rotor need to known quantity of air flow, temperature, reactivation of temperature and humiduty rasio.Input parameters to determine the desiccant specification are shown in Table 2.

D. Design Heater Requirment
Based on the result of dehumidification procces, is the requirment of temperature heater for rotary desiccantis 66 o C. The air flow for the regeneration process starts from the air of cargo hold to the desiccant wheel.Input parameters to determine the design heater of energi reactivation system shown in Table 4.
As a fulfillment of requirment heater is used heat from main engine exhaust gas as amedia reactivation air heater with a heat transfer medium therma oil.The power generated by exhaust gas heat is obtained through estimation calculation of the mass and the exhaust gas temperature by engine exhaust gas data from your project Nissan NKC-RH10C used.To determine the temperature and mass flowrate exhaust gas of main engine shown in Table 5.Thus, the capacity of the exhaust gas flow( ), the heat power of the exhaust gas is calculated by equation 1 so thatis : = 1.39x1.054x 340 = 498.12kW Power generated by exhaust gasof 498.12 kW can be used to supply the heater requirement of 24,292 kW.

E. Calculation Cooling Capacity
Based on the dehumidification process that has been done, the air temperature after passing the desiccant wheel increased to 47.7 o C.This air temperature will be let off to 35 o C before entering into the loading space.The first step is to find the value of cooling power needs with parameters that can be seen in Table 6.From the Table 6 it was found that the cooling requirement of 10.306 kW will be supplied with a cooler that uses the medium of sea water as a heat transfer.

F. Design Cooling System
Cooling system design begins by calculating the flow capacity of the cooling system with the sea water medium.Then we calculate the temperature change in the cargo hold due to the heat load from the solar radiation.

kg/s
So the flow capacity needed to supply the water cooling from seawater is 0.553 m 3 /h Obtained from calculating the cooling system seawater flow rate requirements to supply the cooling system amounted to 0.553 m 3 / h.The flow rate of seawater will be used for the selection of seawater supply pump as a coolant from the solarsystem dehumidification.

G. Heat Load Calculation
The heat load that affects the cargo hold conditions comes from the heat generated by solar radiation (∅s).In this calculation process in accordance with ISO .With these results can be observed that the ability of existing cooling system in the solar dehumidification system is able to fulfill a requirment of the system and heat load from solar radiation..

H. Electrical System Design
In the design of solar desiccant electrical system there are several considerations that needsto be considered such as insolation of the sun in an area.For electrical system design parameters using solar panels on the system required a process of changes from solar energy to the distribution of electrical energy generated.Here is the process of solar panel distribution for theneeds of the required power load solar desiccant system.From the above scheme can be determined needs of the power load required by the system by looking for specifications of each equipment required for each system.Specification of equipment used can be seen in Table7.From the Table 7 it is found that the total energy required by the system is 34488 Wh.Of the total solar module of 33 units then the required area required for 55.44 m 2 .While the extent of existing solar module placement on the vessel of 9.5x8.5 = 80.75 m 2 , then the extent that still exists.

IV. CONCLUSION
From the calculation and analysis of data that has been done to design air ventilation system using solar desiccant, it can be concluded that: 1.From result of calculation analysis to dehumidification process of cargo hold volume equal to 437.

( 4 )
International Journal of Marine Engineering Innovation and Research, Vol.1(4),Sept.2017.241-249  (pISSN: 2541-5972, eISSN: 2548-1479)   244 based on the type of cargo transported.The suitability of the cargo hold condition is determined by considering the air dehumidification parameters of the dehumidification process.And its relation to the cooling ability before being supplied into the cargo hold.

Figure. 4 .
Figure. 4. Flow diagramsolar Desiccant SYSTEM (A: Desiccant wheel; B: Electric Motro C: Cooling; D: Sea Water Pump; E: Cargo Hold; F: Solar Radiation; G: Heater ; H: Thermal Oil Pump; I: Exhaust Fan; J:Supply Fan) 7574 regarding : Ship and Marine Technology -Air Conditioning and Ventilation of Accomodation Spaces.With these calculations can be observed the results of the cooling system's ability to keep the condition of the cargo hold according to the initial design of the heat load caused by solar radiation.To calculate the value of the solar radiation heat load used equation 2.. From the above calculations obtained heat generated from solar radiation of 4.816365 kW.This heat causes temperature changes in the cargo hold vessel to conditioned by the system.The calculation of temperature changes due to solar radiation heat can use the formula: o C o C From the above calculation of temperature changes due to the present of heat energy from solar radiation of 0.5717 o C.So the final temperature of the cargo hold is 35.5717o C . ET = EA+(15%EA) losses equipment 15% ET = 34488 + (15%x34488) ET = 39661.2Wh Energy requirements of the calculated system, which amounted to 39661.2WH.The lowest monthly solar insolation was in January 2015 ie 3.91.For the adjustment factor the installation is 1.1.Power module capacity = = 11157,88 wp The photovoltaic module to be used has the following specificationsBecause the solar power module capacity is 11157.88Wp and the power capacity of 1 unit of photovoltaic 345 WP can be made equation: ∑m= = 33 unit.

TABLE 1 .
STANDARD TEMPERATURE AND RELATIVE HUMIDITY STORAGE OF STAPLES LOAD Figure. 5. KLM Pesona Bahari Figure.6. Intenational Ship Surveying Letter of KLM.Pesona Bahari

TABLE 2 INPUTS
PARAMETERS FOR THE DESICCANT PROCCES So, we need to cooling to reduce the air temperature into the outside air temperature of 35 ° C.The specification of rotor desiccant can be supply the system.The spesicification of rotor desiccant are shown in Table3.

TABLE 6 .
PARAMETERS OF DESIGN COOLING

TABLE 7 .
SPECIFICATIONS OF DESICCANT SOLAR SYSTEM EQUIPMENT 5 m 3 at 6 air changes / hour got desiccant wheel specification which best compatible with diameter 550 mm and thickness 200 mm.2. The ratio of outside air humidity at 38,5 o C temperature of 83.1% can be decreased to 46.5% at 35.6 o Ca cargo hold temperature after passing the desiccant wheel.3. To requirment desiccant heating requirement of 24.292 kW, heat exhaust gas from main engine with temperature of 350 International Journal of Marine Engineering Innovation and Research, Vol.1(4), Sept. 2017.241-249 (pISSN: 2541-5972, eISSN: 2548-1479) 249 heater energy, economizer with thermal oil fluid as heat transfer medium.The required cross-sectional area is 0.1828 m 2 .While the use of sea water as a cooling medium can reduce the temperature of 12.7 o C with the flow of sea water flow of 0.553 m 3 /h.4. To fulfill the electric power requirement of solar desiccant system 34.488Wh with 1 day storage capacity obtained amount of module power requirement equal to 11.157,88 wp.From the module's power capacity requirement, the solar module is required for 33 units with a capacity of 345 wp each.
o C and produce power equal to 498.12 kW.Therefore, it is requirfor the economizer to transfer heat energy from the exhaust gas meter.With the requirement of 24.292