| The problem of environment pollution and energy shortage has become the focus of the world, the energy consumption of air conditioning, heating and hot water supply system is an important part of building energy consumption, how to reduce the energy consumption of this part is of great significance to adjust the energy structure and realize the sustainable development. Seawater is an ideal cold and heat source of air conditioning system because of the ocean contains large amounts of renewable energy and the specific heat of seawater is bigger than air. To find a new heat exchanger with high efficiency, low cost and can be used in many different sea areas is the main problem to be solved.A new type of front-end heat exchange system for seawater source heat pump is presented in this thesis, the capillary front-end heat exchanger is fixed within the concrete caisson in flowing seawater, this form can effectively solve the problem of the heat exchanger’s fixation and prevent the impact of the waves. The material of capillary heat exchanger is plastic, this type of material is anticorrosive and inexpensive. But it’s heat transfer characteristics is very important for the design and operation of seawater source heat pump system. The core research content for the capillary front-end heat exchanger is numerical simulation, then it’s heat transfer performance is evaluated and the cold and heat load of a practical engineering is calculated, at last the seawater source heat pump with capillary as front-end exchanger is analyzed by thermo-economic analysis method. The Specific research contents include the following aspects:(1) The theoretical model of the capillary front-end heat exchanger is established, and the heat transfer analysis is carried out.(2) The feasible arrangement scheme of capillary front-end heat exchanger is determined according to the actual situation, the three-dimensional(3D) model of different length of the capillary front-end heat exchanger is established after a reasonable simplification, the model is vertified according to the experimental results of literature [84]. We can ascertain the key parameters such as temperature and velocity of seawater through consulting relevant literature.(3) The 3D model established previously is simulated by CFD numerical simulation software according to the relevant physical parameters after the working and boundary conditions of the simulation ascertained, then the import and export temperature distribution of heat exchanger in different capillary length and different media flow velocities are acquired.(4) The important paramenters such as the heat exchange amount per unit capillary mat and per unit capillary volume are calculated by formulas and analyzed, then the prospect and feasibility of capillary front-end heat exchanger placed in the flowing seawater for seawater source heat pump is evaluated.(5) The cold and heat load of a building which selected is calculated by the DeST all-year hourly load simulation software, then the annual heating and cooling capacity is obtained and the equipments of heat pump are chosen. Thermo-economic analysis method is adopted to compare seawater source heat pump system with the capillary as front-end heat exchanger and traditional air conditioning system, to guide the popularization and application of sea water source heat pump system. |
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