Simulation and Analysis of Building Energy Consumption in Port passenger Stations

Port passenger station buildings (PPSD) are an important part of transportation buildings in China, which is characterized by large human flow, long operating time, high load of equipment and lighting. The characteristics and functions of PPSD lead to the high energy consumption. However, the energy consumption analysis of PPSD was deficient. In this paper, the characteristics of energy consumption of port passenger stations in cold regions and hot summer and warm winter regions in China were analyzed. Based on eQUEST, the building models of port passenger stations are established. The influencing factors of the building energy consumption were analyzed through orthogonal experiment with SPSS. Results show that the factors such as summer indoor design temperature, heat source form, air conditioning form, window to wall ratio and lighting control mode are the key factors affecting the energy consumption of port passenger station.


Introduction
As an important part of public buildings, the traffic architecture has the characteristics of large space span, complex function, large passenger flow and long working time. [1,2,3] A large number of literatures at home and abroad have studied the energy consumption and energy saving potential of transportation hub buildings.
Song et al. [11] investigated the energy consumption of 36 railway stations in north China, and found that the average annual energy consumption per unit area of the high, medium and low grade railway stations was 423 kWh/m 2 , 222 kwh/m 2 and 101 kwh/m 2 . Huang et al. [12] studied the thermal comfort of the waiting room of a railway station in Harbin. Balaras et al. [13] investigated the energy consumption of 29 airport terminal buildings in three climatic zones in Greece, and obtained that the annual energy consumption per unit area of each climatic zone was 376.0kWh/(m2·a), 244.6kWh/(m2·a) and 168.3kWh/(m2·a). Perdamaian et al. [14] use building energy consumption simulation software to analyze Jakarta international airport terminal 3 building annual energy consumption and CO2 emissions.
There are few studies to analyze energy consumption of port passenger station. Existing studies mainly focus on energy consumption of cargo ports. Wu Peisen [4] discussed the production monitoring method during the construction of the green port in Tianjin Port. Zhang Rongxiang [5] comprehensively analyzed the influencing factors of port energy consumption and constructed the influence factor system of port energy consumption respectively.
At present, there is a lack of research on the energy consumption of port passenger station buildings, and the energy structure and energy consumption of port passenger station buildings in China is still unclear.
In this paper, eight port stations were investigated and tested to obtain the basic information and energy consumption of the port stations. the building models of the port passenger stations are established to analyze the influence factors of the port passenger station through orthogonal experiment.

investigation result
In this paper, eight port passenger stations were investigated and tested to obtain the basic information and energy consumption of the port passenger stations. There is basic information of the port station recorded in Tab.1. S1~S5 are 5 port passenger stations in cold regions and S6~S8 are 3 port passenger stations in hot summer and warm winter regions. Fig.1 shows the energy consumption of the port stations.  As can be seen from Figure 1, there is a big difference in annual comprehensive energy consumption per unit area of port passenger station buildings in cold regions. Among them, S1 and S5 passenger stations use municipal hot water for heating and they are completed later and have better insulation performance of envelope structure, so the annual comprehensive energy consumption per unit area is relatively low. S4 passenger station also uses municipal hot water for heating in winter, but its completion time is earlier, and the insulation performance of the enclosure structure is poor, so the annual comprehensive energy consumption per unit area is higher than S1 and S5, while S2 and S3 passenger stations all use electricity for heating, so the comprehensive energy consumption is much higher than S1, S4 and S5.
Compared with the cold region, the difference of annual energy consumption per unit area of port passenger station building in hot summer and warm winter is relatively small. S8 passenger station has the lowest annual comprehensive energy consumption per unit area, which is due to the later completion time, good insulation performance of the envelope structure, and the use of energy-saving lamps, so the lighting energy consumption is low.
The comprehensive energy consumption per unit area of port passenger stations in cold regions ranges in 42.70~153.26kWh/(m 2 ·a), with an average of 81.02kWh/(m2·a).
The comprehensive energy consumption per unit area of port passenger stations in hot summer and warm winter regions ranges in 71.05~106.19kWh/(m 2 ·a), with an average of 93.86kWh/(m2·a).

Thermal environment and comfort test
In this paper, the Port S2 and S7 are selected for the thermal comfort survey. Results of thermal environment data of the waiting hall are shown in Tab According to the thermal comfort survey results, the linear regression line between the average thermal sensation vote (MTS) of port passenger station and the operating temperature was obtained by fitting, as shown in Figure 2. The thermal neutral temperature in the waiting hall of S2 passenger station was 26.7℃, close to the average temperature of 26.32℃ in the test area, indicating that passengers were comfortable with the thermal sensation in the waiting hall. The thermal neutral temperature in the waiting hall of S7 passenger station was 27.5℃, 0.65℃ higher than the average temperature in the test area, indicating that the thermal sensation of passengers to the waiting hall was slightly warmer. The results were consistent with the thermal sensation voting results of passengers.
The thermal sensation voting values within -1~+1 were regarded as satisfaction with the thermal environment. The passenger satisfaction rate within each temperature range is calculated, and the quadratic equation regression is obtained, as shown in Fig.3. The thermal environment with 80% satisfaction rate is defined as comfort environment. The acceptable temperature ranges for passengers in the waiting hall of Port S2 and S7 are 25.6~27.9℃ and 26.8~28.8℃, respectively. The temperature acceptance range of passengers in the waiting hall of port passenger stations is large, which is due to the adaptability and tolerance of passenger to the waiting thermal environment of ports. The actual temperature in the waiting hall of the two ports is lower than the thermal neutral temperature. The indoor temperature in the waiting hall can be improved appropriately to reduce the energy consumption of air conditioning.

Building model
Using eQUEST, the building model of Port S2 in cold region and Port S7 in hot summer and warm winter region are established [6,7], as shown in Figure 4.  The building model of S2 passenger station has 5 floors above ground, with a north-south orientation, a building size coefficient of 0.196, and a total area of 73,48 m 2 . The building model of S7 passenger station has 2 floors above the ground, with a north-south orientation, a building size coefficient of 0.19, and a total passenger station area of 6200m 2 . The density of personnel is calculated by passenger transport volume, daily ship times and waiting hall area of passenger station. The lighting power density is selected according to the actual situation. The power density of equipment refers to the Public Building Energy Conservation Design Standard [8].
The heating period of S2 passenger station is from November 15 to March 15 of the next year, and the cooling period is from June 15 to September 30. Air conditioning system is used for heating and cooling. The air conditioning system adopts the separated type air conditioner. S7 passenger station operates all day. The cooling period of the building is set from April 15 to November 15, and there is no heating period. The air conditioning system also adopts the separated type air conditioner, and the interior design temperature is 26℃.

Results and validation of simulation
The simulation results show that the annual total energy consumption of S2 port passenger station model is 719,290kwh, among which heating and air conditioning energy consumption is the highest, accounting for 53% of the total energy consumption, electrical equipment energy consumption is the second, accounting for 35%, lighting system energy consumption is the lowest, but still accounting for 12%.The total annual energy consumption of S7 port passenger station is 6,886,70kwh, among which the energy consumption of air conditioning system is the highest, accounting for 37% of the total energy consumption. The energy consumption of electrical equipment and lighting system is similar, accounting for 30% and 33% of the total energy consumption respectively. The comparison between model results and actual survey data is shown in Tab. 3. The relative error of the total energy consumption is less than 5%, and the maximum relative error of each item of energy consumption is within 10%. which indicates that there is a good agreement between the simulated result and the actual energy consumption.

Orthogonal test method 4.1 Orthogonal test
Orthogonal test design is a kind of method of analyzing the multiple factors. According to the test factors, the number of levels and the interaction among the factors, the orthogonal

Results
The building model is used to simulate the building energy consumption of the port passenger station model under different parameters. SPSS software was used to analyze the results of the orthogonal test to determine the significance levels of each factor of total energy consumption of the buildings of the port passenger station. The results are shown in Tab.5. According to the results of F test, the ranking of significance of the total energy consumption impact factors can be obtained: Cold area: heating design temperature > frequency conversion control > window wall ratio > equipment power density > lighting power density > roof heat transfer coefficient > cooling design temperature > window heat transfer coefficient > wall heat transfer coefficient > window shading coefficient.
Hot summer and warm winter area: equipment power density > frequency conversion control > cooling design temperature > lighting power density > window shading coefficient > roof heat transfer coefficient > wall heat transfer coefficient > window heat transfer coefficient.

Conclusion
( 1) The investigation shows that the port passenger station buildings have the characteristics of long operation time, large fluctuation of energy consumption and high building energy consumption. The average comprehensive energy consumption per unit area of investigated port passenger stations in cold regions and hot summer and warm winter regions are 81.02kWh/(m 2 ·a) and 93.86kWh/(m2·a), respectively.
(2)The result of thermal comfort test indicates that appropriately lowering indoor temperature can reduce the energy consumption of air conditioning and buildings.
(3) By analyzing the results of orthogonal experiment, the ranking of factors of building energy consumption is obtained, which can provide ideas for energy saving of port buildings.