Research Of Thermal Discharge Based On Heat Pump Systems

In the 21st century, the energy issue has become increasingly prominent. The sea water-source heat pump (SWHP) system's coming into China is a very important significance for the energy efficiency in buildings. At present, there're only several experimental projects in China, and environmental impact assessment is one of the most important issues to resolveSWHP system uses seawater as heat source and sink, and discharges the same quantity of water into local oceans after use. The temperature of the discharge water is higher in the summer than the local water temperature around 10℃, and lower in winter about 3-5℃ than the receiving water body. The discharge temperature elevation of seawater will not only have a certain impact on the local marine environment, but also affect the local micro-climate, the local marine life and fishing economy, etc. When the large-scale application of SWHP systems come into reality in the coastal cities in China for district cooling and heating, these impacts may become particularly prominent.Apart from the environmental issues, another problem should be considered in design scheme phase. If an intake and an outfall are close together (not necessarily of the same plant), the specific problem of recirculation may occur, as the suitability of the water at the intake for the SWHP process may be reduced by the nearby discharge. However, if the distance between intake and outfall is too far, there'll be investment issues.To solve the above two issues, in this paper, based on Navier Stokes equations and shallow water assumption, non-linear shallow water equations are established. By solving the momentum equations and transport equation, the current field and the temperature field are given and studied.Firstly, the depth averaged two-dimensional hydrodynamic model is established, including the effects of earth's rotation, bottom friction, wind shear and surface heat exchange. Heat exchange model uses the measured variables as meteorological parameters. The control equations formed by ADI method are solved on a staggered grid.Then the current of Heishijiao Bay is simulated, and the computed results are compared with observed values of several stations. And Following, the nested method is used to simulate the thermal discharge of Xiaoping Island SWHP project. Simulation and description on the discharge of this SWHP project show that, the temperature rise/drop extends to certain area, but according to the Quality Standard for State Oceanic Water in China, the temperature change does not exceed prescriptive ranges. And the negative impacts between outfall and intake can be considered negligible at the current phase.Next, two SWHP projects in Heishijiao Bay, Xiaoping Island project and Xinghai Bay project, both running under maximum load conditions are simulated. The results show that...