Thesis Proposal

Air-conditioning Systems Simulation and Energy Saving and Economic Analysis for Waiting Hall of Tianjin Railway Station

Introduction
Energy saving of buildings is ever-increasingly emphasized by modern society. With the emergence of innovative technologies, new materials, and sophisticated architectural design, designers are hard to know the energy consumption of a building. It will reduce the real meaning of building's energy consumption test if we conduct this test on a building already built. Therefore, it is recommended to simulate a building's energy consumption within project design stages. Owing to the complexity of the air conditioning process and the mechanism of thermal components, the work of analysis and computation is time-consuming. Meanwhile, simulation software advantages over the traditional way in the application of design compare and equipment selection. In a nutshell, building energy simulation softwares play a vital role in the analysis of building energy consumption.

Tianjin Railway Station is the main railway transport hub of Tianjin city. With the help of software to simulate its air conditioning system and conduct energy analysis, we can obtain some salutary design advices, which are beneficial to the energy saving of Tianjin Railway Station.

Introduction to Waiting Hall of Tianjin Railway Station
Tianjin Railway Station is located in the center of Tianjin, at the junction of Heping District, Hedong District and Hebei District, and is the most important railway transport hub of Tianjin. Tianjin Railway Station is the largest railway station in Tianjin.

In January 2007, Tianjin Railway Station expanded its scale. New Tianjin Railway Station was officially put into use on August 1, 2008. New Tianjin Railway Station includes north station building of inter-city trains, elevated waiting hall, underground entrance hall, no-platform-pillar canopy and high platform, south station building and so on. The total construction area of Tianjin Railway Station is about 200,000 m2. Passenger traffic will reach 40,000,000 per year in the future.

In the north station building of Tianjin Railway Station, the first floor is an entrance hall, and the second floor is the elevated waiting hall. Roof structure applies large-span steel grid. External decoration adopts new stone and glass curtain wall. The east-west direction appears in the shape of unilateral concave dumbbell, and the total construction area is 26,700 m2. The north end of elevated waiting hall is connected to north station building, and the south end is connected to south station. Elevated waiting hall lies in the northeast direction, and the north station building and south station building lie in the northwest direction. The total construction area of elevated waiting hall is 19853m2, the floor elevation is 8.739m, the roof plane elevation is 28.120m, and the averaged storey height is 19.381m. The height between the roof plane of the entrance hall and the roof plane of elevated waiting hall is about 1m. The east side and west side of elevated waiting hall each have 10 rainproof canopies.

Tianjin Railway Station adopts fan coil+ dedicated outdoor air system, floor heating and cooling system, etc. In summer, the cooling area is the lower part of the space. The heating area in winter is the lower part, too. Therefore, we need to consider different layer when we calculate loads. Air outlets on side walls are 7.9m above the second floor of the waiting hall. Fresh air units are located around the toilets.

Introduction to building energy simulation software DeST
DeST provides a platform for building environment and HVAC system simulation. DeST is created by Tsinghua University. Combining with ten-year accumulated researches, DeST is reliable for researches related to building environment, building environment simulation and performance evaluation, and acts as an advanced tool for HVAC system simulation, predication, and optimization.

Topic Research
This graduation thesis mainly includes the following works.

1. Establish the building model of the Waiting Hall of Tianjin Railway Station by DeST-c;
2. Set building technical parameters, and divide air conditioning systems into different section;
3. Simulate building shade, lighting and natural room temperature;
4. Simulate all-year hourly dynamic load calculation of air conditioning systems;
5. Simulate air conditioning system and conduct analysis of comfort;
6. Simulation and energy analysis of air handling systems;
7. Simulation and energy analysis of cold and heat source equipment and water system;
8. Economic analysis of several main design stages.

The building model of the Waiting Hall does not include the north station building and the south station building, and only consider the elevated second floor of the waiting hall. Besides, the building model of waiting hall’s roof is composed of two sloping roofs, of which east and west sides are lower than the central intersected part. This model is quite similar to the real situation. Based on the building model, technical parameters are set to simulate building shade, lighting and room temperature, and then conduct all-year hourly dynamic load calculation of air conditioning systems. With the help of DeST, this project would install different air conditioning system, including air handling system, cold and heat source equipment, water system and so on, on the waiting hall, and then simulate and analyze these systems to figure out which one is most suitable to the elevated waiting hall, and offer advices for energy saving.