ASSESSMENT PRACTICES OF GOBAS IN CHINA

Transcription

1 - ASSESSMENT PRACTICES OF GOBAS IN CHINA Borong Lin Dr. Qin Ouyang Ph.D Candidate Daojin Gu Ph.D Candidate Lei Tian Ph.D Candidate School of architecture, Tsinghua University, Beijing, 8, China, School of architecture, Tsinghua University, Beijing, 8, China Keywords: GOBAS, Assessment practices, Green building, Green Olympic Summary GOBAS (Green Olympic Building Assessment System), a project sponsored by Chinese Ministry of Science and Technology and developed by Tsinghua University and other eight organizations, was published in August. Its aim is to explore the idea and content of green buildings in China, found the framework of an assessment system for green buildings and to do some trial evaluation practices in the Olympic buildings. In this paper, four different types of buildings, including gymnasium, residence and office, were evaluated by GOBAS in different phases such as detailed design, construction, and commissioning and operation phases. Afterward, some issues, such as how to collect necessary information evaluated, how to establish a more reasonable weight coefficient system for different type of buildings and how to make the assessment process easier and more operable, are proposed and discussed. Background China is during a booming age of urban construction. Based on the statistics, the urbanization level of China in is 7%, and it will be over % in as planned, which means in the next or years, a large-scale construction will appear in China. In recent years, the annual completed urban construction area consecutively exceeded billion sq. meters, higher than the total amount of completed area in all other countries around the world. With such a fast-track development, here comes big challenges for the urban constructors that how to realize sustainability in the urban development, land conservation, resource-saving and environmental protection and to build a friendly human settle for our life and work, instead of wasting resources destroying the land and creating a city wasteland. However, the sustainable growth did not become a key rhyme of the urban development recently. More and more large-scale construction projects in China adopted an international bid method to decide a final scheme of the building; however, during this process a poor trend or taste, which simply pursues the strangeness and novelty of the shape instead of the basic sustainable development principle, is extended widely. Therefore, the function of design competition has been misconstrued. However, from other hand, it seems we should do something to assure the design competition have a sound work. In order to correct this bad trend, and considering the slogan Green Olympic is a promise made by China to the world, green building becomes one of the most important tasks. Funded by China Ministry of Science and Technology (MOST), the research of GOBAS was launched from Nov. in order to assure all the Olympic construction projects meet the sustainable principle. Consigned by MOST, Beijing Municipal Science and Technology Commission (BMSTC) was the supervisor of the project, and Tsinghua University took charge of the research. The first version of GOBAS was published in August resulted from the efforts of experts from nine organizations. The aim of GOBAS is to explore the idea and content of green buildings in China, found the framework of an assessment system for green buildings and to do many trial practices in the Olympic buildings. In addition, the main characteristics of GOBAS are process control; evaluate phase by phase, total amount argumentation and scale control, and a Q (Quality)-L (Load) -D evaluation and rating []. In this paper, four different types of buildings, including gymnasium, residence and office, were evaluated by GOBAS in different phases

2 . Application of GOBAS. Evaluation of a gymnasium Evaluated project is a gymnasium for athletes training. The first floor is for weightlifting training and the second floor is for basketball or volleyball training. The building style is to pursue a combination of modernism and location culture and climate. From the bird view, we could find a grant view is founded with lots of large area of blinds and clean solid wall. Here the building is evaluated by GOBAS in detailed design phase (Phase II). As one of the basic design principles, barrier-free is fully realized here. An external insulation system and a double glassing with low-e membrane are adopted here to insure the building meet and exceed the energy efficient regulation. At the same time, the double glassing could keep quieter indoor environment relatively. In mid-season, all the space could utilize the outdoor fresh air with a -level fan ventilation system. The HVAC system is designed with DDC control mode and integrated into the BAS system to realize energy saving. However, generally speaking, this building does not show more impressive feature in green strategy and technologies. Building type: Gymnasium Floor Area:,968m Floors: + Height:.9m Use: Sports training, including weightlifting, basketball, volleyball, etc. Main features: Low-e double glassing, mid-season fresh air utilization, grey water, rainwater collection, DDC control for refrigerators, barrier-free design. LR:Water resource LR:Material & resources Q: Outdoor Environ. Quality Q: Indoor Physical Environ. Q: IAQ LR:Energy LR: Atmosphere pollution Q:Service & function LR: Influence to environ Envelope Energy-saving System Efficiency Renewable energy usage Waste disposal Rain utilization Water for Services & Greening & pipe landscape (e) details in energy saving evalution (f) details in water resource evalution Figure Evaluated result of a gymnasium (Phase II)

3 . Evaluation of office building A Office A is designed as a demo building for energy saving and other eco-technologies. Firstly, the building shape is decided by carefully energy and daylighting simulation with DOE-. The U value of external wall is controlled below.6 W/m K, and the high thermal performance glassing is designed as.6 W/m K with Low-e membrane and vacuum cavity. All south windows are implemented external blinds and internal reflectors. The HVAC system for office area is VAV fresh air system plus FCU except a rising floor ventilation system serviced for nd floor. A wheel heat recovery device is used here to collect the waste heat of exhaust air. In order to use the night cheap electricity, an ice storage system is designed. In the roof, there is a 9 kw PV system. All the lighting in the building is control by lots of precise sensors and a BAS. When there is no occupant, the BAS would power off the lamp automatically. Moreover, there is a special grey water reuse system combined with a rainwater collection measure. The daily garbage is collected by bag and translated to dumping site by special cleansers. The main shortage is that the utilization of recyclable materials is not sufficient. Building type: Office A Floor Area:,m Floors: +8,- Plot ratio:. Height:.m Greening ratio:.9% Main features: U value of ex-wall:.6 W/m K; U value of window:. W/m K, SHGC=.8, TVIS=.; adopt VAV fresh air ventilation, ice storage system, wheel heat recovery, 9 kw PV panel and south blinds and daylighting reflectors. Grey water system and rainwater collection. LR:Water resource LR:Material & resources Q: Outdoor Environ. Quality Q: Indoor Physical Environ. Q: IAQ LR:Energy LR: Atmosphere pollution Q:Service & function LR: Influence to environ Envelope Energy-saving System Efficiency Renewable energy usage Waste disposal Rain utilization Water for Greening & landscape Services & pipe (e) details in energy saving evalution (f) details in water resource evalution Figure : Evaluated result of Office A (Phase II)

4 . Evaluation of office building B Here office B is evaluated by GOBAS in phase III, namely the construction phase. In the construction process, the construction company has carried out lots of measures to insure the construction quality, protect around environment, save water and energy and assure the safe and health of the workers. For example, the ground water is only taken out from the base pit of building, which could avoid waste the ground water resource and decrease the water level in the ground. In addition, the construction rubbish is dealt with by category and used close car to transport to the city dumping site. Other measures please see Fig.(b). Building type: Office B Floor Area:,7m Floors: +,- Plot ratio: 9. Height:.m Structure: Concrete steel Main features: save ground water, control construction noise and light pollution, rubbish collection by category, waste water reuse for construction, worker health supervision, etc. LR:Water Resource Q: Occupants' safety and health LR:Influence around Enviro LR:Material & Resources LR:Energy Figure : Evaluated result of Office B (Phase III). Evaluation of a residential complex This project is also the demo building for energy saving 6% aim (baseline is the level of 98) in Beijing area since its heating load is less 6% of the energy-saving design standards. The most impressive characteristics of it are the high thermal performance of envelope and the HVAC systems. The filed measured U value of external wall is.7 W/m.K, and the mean U value of windows is.7 W/m.K and.89 W/m.K when the external curtain closed. The building is designed with external aluminum rolling screen, which could effectively block sunshine into the room in summer. The measured summer PMV is -. and the corresponding PPD is 9%, and these two indexes in winter are -. and 8% relatively. The indoor IAQ is satisfied. A displacement system and a radiant cooling and heating system are adopted here and the fresh air is designed in charge of the latent load of the buildings. Moreover, there is noise-against system for the occupants. It includes an

5 excellent glassing system, a rising and elastic floor and a back-exhaust drainage system. The garbage handling system, which consists of food handle device, central suction machine and a classified garbage collection box, could avoid the second pollution of the rubbish and insure recyclable rubbish could be reuse. The main shortage of this building is that there is not an independent control device for the occupants to control the indoor temperature, humidity, airflow and so on; it is not reasonable for energy-saving and individual comfort. In addition, the window could not be open without the central permit. Building type: High-level apartment Floor Area:,m Floors: +8,- Plot ratio:.8 Greening ratio: % Main features: low energy consumption index (.W/m ), high performance envelope (U of wall is.7 W/m.K, U of glassing is.89 W/m.K), high efficient HVAC system, noise-against measures, rubbish handle system. LR:Greening management LR:Water resources Q: Outdoor Environ. Quality Q: Indoor Physical Environ Q: IAQ LR:Energy LR: Effects to environment Q:Service & function Q:Green Management Greening Rubbish CommissioningWater quality constrol (e) details in quality control evaluation (f) details in resource saving L evaluation Figure : Evaluated result of a residential complex (Phase IV) Energy saving control Water saving

6 . Discussion From the assessment practices of GOBAS, it shows good performance to evaluate the green building from different aspects of what the green building care. In addition, the evaluation method phase-by-phase is proved feasible and could tell different information to us. Until now, in fact GOBAS has been applied to about projects include gymnasium, diving hall, office buildings and residential buildings except Olympic buildings. During case studies, scoring system and weighting coefficients are examined and adjusted. Recently, Beijing Municipal Construction Committee (BMCC) has issued official document to adopt GOBAS as the Beijing local green building standard. With the support from BMCC, Beijing Green Building Association is establishing to put GOBAS into practice more widely. And as we suggested, the idea of process control should also be implemented into the general construction process, especially for the high-level, large scale buildings. Therefore, we have designed four new phases, where a scheme phase evaluation is proposed to instead the planning phase. Its aim is to focus on the major issues of sustainability during the beginning of a design, which would be omitted in the bid competition phase, such as the unreasonable structure, poor building shape design and poor energy, water and resources efficiency performance. However, some issues, such as how to collect necessary information evaluated, how to establish a reasonable weight coefficient system, and how to make the assessment process easier and more operable, are still need to study. For example, the relationship between Q and L is not always clear. Under the study of criteria in Q and L, we can find that there could be positive relationship, negative relationship and irrelevance three different kind of relationship between Q and L. When improving some criteria in Q category, the corresponding environment impact does not be expressed in L category. One possibility is to carry out some simplified version for real developers and let them do some self-evaluation first, and then the rd part, which is authorized by the government, could finish the final evaluation and award corresponding green level for them. Moreover, if hope to extend this evaluation system to whole country, such as a national standard for green building, more dada investigation and research are still needed to finish.. Conclusion Next years is the key decade of urban construction in China. Developing green building is the key step to realize sustainable growth of the urbanization. The practices of Beijing green Olympic building would provide rich experiences for the spread of green building around the country, the same function would be done when the th World Exposition will be hold in Shanghai at. Moreover, more concrete and scientific matters relating to work should be finished gradually. We belief all above would be efficiently promote the sustainable growth of the construction enterprises and assure the completion of the urbanization process more healthy, scientifically and stably. Reference [] Jiang Yi, Qin Youguo, Zhu Yingxin etc.. Green Olympic Building Assessment System. China Architecture and Building Press. August, Beijing.