*2.1. Description of Engine and Hot Water Demand*

The investigated luxury resort is located at the island which is a popular tourist place. It has the hotels and restaurants with five stars standard and a nice quiet beach. There are many travelers from all over the world are coming here. Beside the tourist demands, this place is used for organizing the national and international events. This resort has 300 high level rooms for 400–500 visitors at the present time, about 80–90% of the rooms are occupied daily and 100% in the holidays. It has 3 restaurants with about 1000 seats and has 01 canteen for about 200 staffs. This resort is on offshore islands, farther from the land, and the main transportation is by the ship, the electric power was generated by ICE combined with generator. The demand for hot water and steam are quite high, hot water is used mainly for bathing and steam is used for hot water heating and laundry. At the present, the hot water is supplied by the heat of boiler using DO fuel. So, if we utilize the waste heat from EGH of the ICE to replace a part or fully the steam from the boiler, the cost of fuel consumption will be decreased. The average exhaust gas temperature of ICE is about 400–500 ◦C. Current temperature is not enough for the engine cycle, but very suitable for another heat process. The specifications of ICE were investigated in this study as shown in Table 1. It has a close cooling system by an inside solution and outside by air cooling, so we cannot utilize this waste heat source. Thus, we only can utilize waste heat source from exhaust gas of this ICE. The used fuel of ICE is DO, the fuel consumption and exhaust gas temperature changed according to the ICE load as shown in Table 2. It is obvious that the DO fuel consumption increases as the engine load increases which results into increase in the exhaust gas temperature. This is because increase in the heat carrying capacity of exhaust gas with increase in the DO fuel consumption. The data presented in Table 2 show that the waste heat percentage is more at the higher engine load. So, increasing hot water demand at the resort could be satisfied by running the engine at the higher loads.

**Table 1.** Engine specifications.



**Component Specification** Manufacturer Mitsubishi Rated output 1530 KVA

Fuel consumption 273.5 L/h at 75% load

Number of cylinders 16 Bore/stroke (mm) 170/180 Total displacement 65.4 L

Maximum back pressure in exhaust gas system 12 in H2O = 3000 Pa

Engine model S16R-PTA, 4cycle, air cooler

**Table 2.** Fuel consumption and exhaust gas temperature according to the load. **Table 2.** Fuel consumption and exhaust gas temperature according to the load.

*Symmetry* **2021**, *13*, x FOR PEER REVIEW 4 of 15

**Table 1.** Engine specifications.

At the resort, the requirement of hot water temperature is ensured in range of 50–55 ◦C. The real data of daily hot water volume for 7 months including summer months (July and August), Christmas and new year (December and January) was collected. Figure 1 presents the daily hot water consumption volume of four months higher number of tourists. It can be observed that the hot water volume changed daily, monthly, and average demand is about 50–55 m3/day. The hot water demand changes due to fluctuation in the number of tourists on daily and monthly basis. However, there are some peak days with the hot water volume increases to 80–90 m3/day. From these collected results, the volume flow rate and its ratio with maximum hot water volume flow rate per day were determined, as shown in Table 3. The hot water demand of resort for three volumes namely, maximum, minimum and average is evaluated from the collected data of real system. Considering the average hot water demand as the baseline, the maximum and minimum hot water demands are 180% higher and 42% lower, respectively. At the resort, the requirement of hot water temperature is ensured in range of 50–55 °C. The real data of daily hot water volume for 7 months including summer months (July and August), Christmas and new year (December and January) was collected. Figure 1 presents the daily hot water consumption volume of four months higher number of tourists. It can be observed that the hot water volume changed daily, monthly, and average demand is about 50–55 m<sup>3</sup> /day. The hot water demand changes due to fluctuation in the number of tourists on daily and monthly basis. However, there are some peak days with the hot water volume increases to 80–90 m<sup>3</sup> /day. From these collected results, the volume flow rate and its ratio with maximum hot water volume flow rate per day were determined, as shown in Table 3. The hot water demand of resort for three volumes namely, maximum, minimum and average is evaluated from the collected data of real system. Considering the average hot water demand as the baseline, the maximum and minimum hot water demands are 180% higher and 42% lower, respectively.

**Figure 1. Figure 1.** Daily hot water consumption volume for months with higher number of tourists. Daily hot water consumption volume for months with higher number of tourists.

**Table 3.** Volume flow rate and its ratio with maximum value per day.

