Research On Some Heat Transfer Characteristics Of AC (Air Conditioning) Refrigeration Systems And Thermal Control Of Buildings

The heat transfer characteristics of the refrigeration systems and thermal control of buildings are studied in this thesis. This thesis is divided into three parts: Part 1 - Heat transfer characteristics of the LiBr/H₂O absorption machine system. Part 2 - Heat transfer characteristics of the vapor-compression cycle with ice-storage system. LiBr/H₂O absorption machine system and vapor-compression cycle with ice-storage system may be obtained wide applications in near future in Libya. Part 3 - Thermal control of buildings. Many examples of buildings by using passive control or passive and active control may be found in Libya.Part1Some heat transfer problems of the LiBr/H₂O absorption machine are studied theoretically and experimentally.The literature survey of the LiBr/H₂O absorption machine is given in the chapter 1.In chapter 2, the experimental research works for LiBr/H₂O solution pool boiling heat transfer are presented.In chapter 3, theoretical and experimental research on a new extended surface for air cooling is given. Water is the best choice as cooling fluid in absorption machine. Libya lacks of the fresh water, so air may be choiced instead of water.In chapter 4, the feasibility of the LiBr/H₂O absorption machine using heat pipe heat exchanger is analyzed. An example of a 581.5 kW absorption machine using separate heat pipe in high pressure generator is given.Part 2Some heat transfer problems of the ice storage system are studied theoretically and experimentally.In chapter 5, the cool storage designs, such as cool storage media and types, cooling load calculation, system equipments, operating and control strategies, etc., are introduced in general.In chapter 6, one kind of advanced ice storage capsules (double-core ice storage cylinder) and its systems are introduced in detail. Forced convection heat transfer with its correlation outside double-core ice cylinders in packed bed is discussed systematically.In chapter 7, exact solution of phase change problem is discussed firstly. The approximate analytical solution (integral solution) and some useful results of phase change process in double-core ice storage cylinder are obtained.In chapter 8, numerical solutions of phase-change heat transfer in double-core ice storage cylinder by using enthalpy method and control volume approach separately are proposed. Solidification and melting process are studied separately with different considerations such as the effects of core and natural convection. Valuable results were gotten.In chapter 9, several types of ice storage capsule are studied experimentally. An ice storage air conditioning system with double-core ice storage cylinders in operating was tested. Comparison between theoretical and experimental results is made.Part 3In chapter 10, the literature survey for passive and active thermal control of buildings is given. The passive control together with active control may be used in Libya.In chapter 11, the research on artificial thermal environment is given. An environment by using multilayer envelop consisted of a 25 mm thermal insulation layer and a 600 mm heat storage layer was established theoretically and experimentally by present author and co-workers of Zhejiang University.