Vol.4 No.3 2012

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Research paper : Demonstration test of energy conservation of central air conditioning system at the Sapporo City Office Building (H. Takeuchi )−138−Synthesiology - English edition Vol.4 No.3 (2012) In Japan, several basic researches have been conducted for the flow drag reduction technology, various agents were developed, and their fluid dynamic properties were studied. There were over 120 cases of use of agents in building circulation water. However, since they were conducted by private companies, the technical information is undisclosed, the accumulation of technology pertaining to flow, heat transfer, and long-term stability as well as energy conservation effects are lacking, and this technology has not spread widely. In this research, specialists took the role to integrate the elemental technologies for studying the occurrence of flow performance by agent addition, evaluation of the energy conservation effect, maintenance of heat transfer property, and long-term stability of the agent. Then, a demonstration test was conducted at a public facility to generalize the results, and attempts were made to enhance energy conservations in air conditioning of buildings. 3 Development of the elemental technologiesThe development of the flow drag reducing agent was conducted by the Yamaguchi University, the Shunan Regional Industry Promotion Center, and four companies in 1992, as part of an industry-academia-government collaboration, and a product was realized in 1995. The main components were: oleyl bis-hydroxyethyl methyl ammonium chloride, a surfactant; sodium salicylate, a counterion agent that promotes the formation of three-dimensional micelle network; rust inhibitor; and others[4] (hereinafter, this will be called the agent). In the Eco Energy Urban Project of the Ministry of Economy, Trade and Industry, the research mainly on the development of surfactant was conducted as an industry-academia-government collaboration for three years starting in 1997, and two research institutes under the Agency of Advanced Industrial Science and Technology also participated. For one year and a half from 1998, the project for the use of the agent in regional cooling/heating system was conducted as a NEDO project. Through these activities, detailed experiments were conducted at research institutes, and trials were done in actual buildings mainly by private companies.The installation of the agent commercialized by the Yamaguchi Prefecture to the air conditioning of buildings had been done to some extent, but it was far from becoming wide spread. In 2002, the research group for the realization of “smooth water” was established. Specialists of industry-academia-government of this technology convened to discuss how to grow this technology into a practical product, and the need for demonstration tests was indicated[5].The factors that affect the flow performance include the diameter of the pipes, length of the straight sections of the pipes, flow rate, water temperature, agent concentration, water quality and so on. In general, the pipes on site are very complicated, and it is not rare that the pipe arrangements are quite different from the initial plumbing diagram due to several repairs and renovations that have been done. Also, older sites tend to be without flow meters or thermometers, and this is a major inhibition in energy conservation management, let alone conducting tests. In many cases, it is difficult to utilize on site the flow performance data that was obtained at research institutes. For the maintenance of heat transfer performance, while it is reported that the agent reduces the heat transfer as well as flow drag in laboratory scale tests[6], such phenomenon has not been reported in the actual installation, and this difference must be solved. In addition, there is no disclosed data on the long-term stability or lifespan of the agent, and this is one of the priority issues for the on-site concentration management. 4 Air conditioning system of the Sapporo City Office BuildingBased on this scenario, it was necessary to conduct a demonstration of the integrated elemental technologies by actually injecting the agent to the water circulation system to see how much reduction of flow drag will be obtained, whether there will be any reduction in heat transfer performance, and whether long-term stable effect can be sustained. Since the data publication after the test was necessary, we decided to conduct the demonstration test in the cooling/heating water circulation system of the Sapporo City Office Building, a public facility, rather than a private one. This was possible as AIST and the City of Sapporo had signed a basic agreement and memorandum for the efficient use of energy. It was stated therein that: the City of Sapporo would provide test sites free of charge to AIST; AIST could install test equipment in such sites to conduct experiments; and the results obtained would be shared. Figure 4 shows the exterior photograph of the office building. The building was Fig. 4 Exterior of the Sapporo City Office BuildingCity Office Building・Built in 1971・2 basement floors, 19 aboveground floors・Installed stainless pipes in 2001・Circulating water about 32 tons

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