A Study on Industrial Waste Heat Recovery Compression/Absorption High-Temperature Hybrid Heat Pump System

Recently, skyrocketing oil prices and the depletion of energy resources due to industrialization are the most important issues in the world. In order to solve these problems, the efficient use of various types of waste heat and renewable energy should be promoted. This can reduce the dependence on fossil fuels immediately. In addition to the development of new energy sources and improvement of the efficiency of existing systems, the research on various technologies for harnessing unutilized energy is needed. In the industrial process plants, there is a large amount of waste energy that will not be utilized because the water temperature is too low. Compression/absorption hybrid heat pump system technology is capable of upgrading post-processed waste heat into 90Ԩ of reheated water for industrial process. The purpose of this research is the development of a 10 kW-class compression/absorption hybrid heat pump system with two-stage compressors, absorbers, a desorber, a de-superheater, a solution pump, a rectifier, and a liquid/vapor separator. The system was designed to produce plant process water over 90 Ԩ from heat source temperature around 50 Ԩ. In this study, initial startup and operation of the 10 kW-class hybrid system was carried out to identify the characteristics of the experimental study. RESERCH BACKGROUND In particular, a large amount of waste heat exists in wastes that are discharged in some industrial processes. There is a large amount of waste energy that will not be utilized because the temperature is too low. Moderate- to high-temperature industrial waste heat can be recovered, using a simple heat exchanger structure. However, if the heat source is less than 50 ℃, a processing temperature of 90 ℃ or higher is required, so re-heating is necessary. Previous studies indicate that excellent efficiency is obtained when low-temperature waste heat is used as a heat source for heat pumps. As a result, a simple boiler and heat supply are more expensive than a heat pump, but the complex structure of heat pumps imposes some restrictions on where they can be installed. Despite these constraints, the installation of industrial heat pumps makes sense. They can offer many advantages arising from energy conservation as well as better process control and reduced emission of pollutants, and they reduce the temperature of the exhaust heat and use the amount of coolant. In addition, heat pumps can be used for heating and cooling year-round, as opposed to achieving only short periods of economic advantage when operation is possible. In this study, we examine various ways to use low-temperature industrial waste heat for heating water. In particular, we performed basic research into the development of a compression/absorption hybrid heat pump that uses a complementary ammonia/water mixture. General waste water temperature is 20-50°C, but useful high temperature heat for industrial processes should be at least 90 °C. Therefore, Hybrid heat pump technology is capable of upgrading post-processed waste heat into 90 ℃ of reheated water using 20-50°C waste heat.