Development of Heat Pump System Using Thermobank and Ejector for Heating Room and Cold Storage

Development of Heat Pump System Using Thermobank and Ejector for Heating Room and Cold Storage

Jong-Taek Oh (Chonnam National University, South Korea) and Cuong Ne Ngoc (Chonnam National University, South Korea)
DOI: 10.4018/978-1-4666-8398-3.ch021
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Abstract

In this study, heat pump system has been developed by CFD simulation and experimental investigation. It studies the thermal behavior of a thermobank and COP on heat pump system and cold storage. The thermobank stores the wasted heat of during refrigeration cycles and its energy is used for defrosting process and heating room. It also reduces defrosting time and condensation load so that the temperature regulation in the cold storage is constant. The system is investigated experimentally and CFD simulated under thermobank. The dimension L×W×H of cold storage is 3×1,6×1,4 m, thermobank is 600×300×400mm. The temperature of ambient on CFD simulation process is 150C.This heat pump system can be used to keep preservation of agricultural products in cold storage warehouse together with floor panel heating for room in winter. The ejector is used in system which the purpose increases in coefficient of performance (COP) and decrease in compressor displacement. As the calculated results, its COP is increased about 38% when using thermobank and ejector in heat pump system.
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Background

Refrigeration system has been used to remove heat from a source and discard it to other places. The refrigeration system applications include air conditioning, heat removal from chemical processes in petrochemical plant, medical equipment, special applications in the manufacturing and construction industries and processing and preservation of food. The processing and preservation of food uses refrigeration for their cold storage. The small size cold storage warehouse under 20 M/T that can preserve and trade agricultural, sea products in countryside and coastal areas in Korea. All of them are located inside or outside of house where is built closely from oil boiler equipment for heated rooms in individual house. A refrigeration unit in cold storage warehouse operates with electric power and heating room is heated with using oil boiler. Therefore spaces of those occupy much large in small house and energy is wasted doubly in spite of saving them in rural. Furthermore, it can reduce originated CO2 that the cause increase global warming potential (GWP). To overcome these problems, it need to develop heat pump system that can be used to keep preservation of agricultural products in cold storage warehouse together with floor panel heating for room in rural house. There are various numerical models with thermobank have been developed base on physical equations, empirical correlations using curve fitting method or combination of both. This model uses physical equations combined with the curve fitting empirical correlations to develop a model with simple and minimum input requirements. Based on the system operating conditions, refrigeration unit models can be divided into steady state (Hoffenbecker et al., 2005; Jolly et al., 2000; Aridiyansyah et al., 2007) and transient models. The steady state model is used because in the refrigeration systems of small size cold storage warehouse, the equipment is mainly intended to keep the refrigerated room in steady state conditions within the set temperature range. Preservation of agricultural products from producing district to the market and consumer forms an important parts of the product’s cold chain which is mainly distributed in market which is located at small, medium and large cities. In Korea, there are more than 792 units of cold storage warehouse over 50 M/T for food preservation and its total capacity is over 3.58 million M/T. The performance and efficiency of such refrigeration unit is essential to maintain good quality of the agricultural products and fishery foods, saving energy and minimize environmental impacts.

Key Terms in this Chapter

Heat Pump: A device that provides heat energy from a source of heat to a destination.

Energy Saving: That promotes energy saving with high efficiency.

High Efficiency: A high ratio of the energy delivered by a machine to the energy supplied for its operation.

Ejetor: A device using a jet of fluid, gas, steam to withdraw another fluid or gas from space.

Thermobank: A device for storing heat and using defrost.

CFD: Computational fluid dynamics, it is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows.

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