## 1 Introduction
Recent research has concentrated on obtaining the heat transfer coefficient in an ice slurry maker, but due to the complex fluid flow and heat transfer resulting from forced convection, including phase change and agitation, the heat transfer correlation does not exist yet. Therefore, in order to compete with existing HVAC (Heating, Ventilation and air conditioning) and refrigeration technologies, the current ice slurry-making technology needs to be optimized for smaller, more efficient, and less costly processes by understanding basic crystal theories and heat transfer mechanisms. Figure 1: Photograph of crushed ice and ice slurry: (**a**) Crushed freshwater ice; (**b**) Seawater ice slurry. [PERSON] et al. [11] calculated the heat transfer coefficient in the SSHE heat exchanger during freezing of the aqueous sucrose solution and measured the amount of power required to rotate the scraper. As a secondary refrigerant, a solution of ethylene glycol was used. As a result, the heat transfer coefficient at the beginning of ice formation was 3 to 5 times larger than without phase change. When the ice growth started, the torque for driving the scraper continued to increase until the scraper stuck and stopped, and this was presented by numerical modeling. [PERSON] et al. [12] compared the heat transfer phenomena during ice-making of a sodium chloride aqueous solution using plate-type SSHE according to the arrangement, speed and logarithmic temperature difference of the scraper. The heat transfer coefficient decreases as the logarithmic temperature difference increases, which is explained with the result of ice layer growth as the speed of the scraper slows down. [PERSON] et al. [13] proposed an ice-maker in which a spiral scraper was inserted into a rotating type ice maker to scrape ice produced on the inside of a copper tube. The critical heat flux and the critical temperature at which it is possible to dehydrate the ice slurry continuously are collected through experiments and then modeled and verified. [PERSON] et al. [14] reported the characteristics of seawater ice formation using an evaporator including a wing type scraper and an orbital rod for fish cooling using seawater. The freezing point of seawater is lower than water because of its high salinity. The higher the salinity, the longer the time and the lower the temperature required for crystal nucleation. Therefore, when the salinity increases, the size of the ice decreases, and the enthalpy increases. [PERSON] et al. [15] investigated the optimum ratio of the expansion valve and the optimum operating condition of the drum rotation speed in order to develop an automation system capable of high-efficiency operation of the sea ice maker using the drum type evaporator. The Coefficient of Performance (COP) increases and the superheat decreases with the increase of the opening. The ice output is not influenced by the increase of the opening. Also, the rotational speed of the evaporator drum does not have a significant effect on COP and superheat. Although many research results have been reported on the heat transfer shape of various types of scraper type ice makers, the refrigerant used in the ice making is a secondary refrigerant without a phase change process, and therefore, it cannot be generally used due to its shape of the heat exchanger and the type of solution. In addition, data on the actual ice amount and the system according to the parameters affecting the heat transfer in the actual seawater application system are also insufficient. Therefore, the purpose of this paper is to provide basic data of the slurry type ice-making device using seawater by experimentally examining performance characteristics according to various conditions.