Energy-saving And Comfort Study Of Low Temperature Geothermal Water Heating Using Water Source Heat Pump

With the deteriorism of the energy crisis, the rising price of traditional energy, and more consciousness of environment protection, the utilization of renewable energy like solar energy and geothermal energy plays a more and more important part. At present, a new upsurge of terrestrial heat directly using appears in our country, especially in the colder district of high latitude. Well equipment support for low temperature geothermal water heating is provided by heat pump and floor radiation. But, the temperature of geothermal water at about 40℃is higher than what's demand at the inlet of evaporator in the general water source heat pump. Now, one solution is mixing the geothermal water with the back water of the heat pump before entering into the evaporator, another is gradient utilization, which means geothermal water enters into the radiator to lower temperature before into evaporator. The exergy analysis method is used and exergy efficiency models of the two methods are built in this paper. These two methods are analyzed combined with the rebuilding project of Tianjin Zoo, and the result indicates that the exergy loss of mixing water method is higher than gradient utilization; the latter has more advantage of energy-saving.At present, energy-saving of building has already been an emphasis to energy-saving job in our country, so the analysis of all-year building energy consumption is especially importance. Nowadays, there are many analysis softwares of energy consumption in the world; EnergyPlus is one of them which applied extensively. Gradient utilization of low temperature geothermal water is analyzed with EnergyPlus in this paper, and it is compared with the fact. The agreement between the simulation and the fact is quite well, which indicates EnergyPlus can accurately predict energy consumption. Energy consumption of these two methods is simulated by the software, and the result indicates gradient utilization heating system can get well energy-saving effect.The main heating purpose is meeting with the animal's comfort in the rebuilding project of Tianjin Zoo. Some animals need higher temperature, and there are only two thirds of floor radiation coils on the ground disposed, so that the animals can live in different ground temperature. The temperature can't be satisfied while heating with both the cast iron radiator and the floor radiation coil. Therefore, two methods of adding fan coil and adding radiator to the orang room are introduced, and the temperature field is simulated separately with Airpak software. The result indicates that the temperature field below two meter in the condition of adding fan coil is more uniform than adding radiator; the ground temperature is different but the temperature of the space is almost same when floor radiation is partly deposed. During system operation, the accuracy of the simulation is validated through testing on the spot. The result can be referred by project design.