تجزیه و تحلیل حساسیت در بهینه سازی ساختار سیستم های تامین انرژی برای یک بیمارستان

In this paper, the method of rationally determining the system structure and operational strategies is proposed for the energy supply system for a hospital based on the optimization approach. First, energy demands are estimated hourly, daily, and seasonally through one year for the hospital with total floor area of 25,000 m2. Second, miscellaneous kinds of equipment are listed up such as refrigerators, heat pumps, gas engine cogeneration unit, steam boiler, thermal storage tank, and other similar things and 25 structures of alternative energy supply systems are composed by combining these kinds of equipment. By the mathematical optimization method, the following results have been obtained; that is, the optimal system is the hybrid-system that consists of electricity-driven and natural gas-fired equipment together with cogeneration equipment, which is difficult to get by intuition and experience of the designer. Sensitivity analysis is also carried out by changing parametric values related to initial capital cost and upgrading performance of each equipment in addition to energy charges, and as the obtained result the optimal energy supply system for the hospital is proposed from comprehensive viewpoints.

For the purpose of saving cost, distributed energy supply systems have been installed in commercial and public buildings. In general, the distributed energy supply system is composed of many kinds of equipment, for example, cogeneration units, refrigerators, heat pumps, thermal storage tanks, boilers and so on. In order to realize the high economical system, it is necessary to determine its structure rationally by selecting some kinds of equipment from many alternative ones so that they match energy demand requirements for an objective building. It is also important rationally to determine the number and capacities of each kind of equipment selected, and maximum contract demands of utilities such as electricity and natural gas in consideration of the system’s annual operational strategies corresponding to seasonal and hourly variations in energy demands [1], [2] and [3]. The purpose of this paper is to investigate what system structure is suitable for a hospital by taking account of the aforementioned design and operation items based on an optimization method. First, the mathematical formulation of the optimal planning problem is presented. Then, the numerical study is carried out for a hospital building, which has 10 floors with 2500 m2 per floor. The optimal system structure is affected by the performance characteristics and capital costs of equipment as well as the rates of utilities. Therefore, the optimal system structure is investigated under standard values of these conditions. In addition, the sensitivity analysis is carried out to investigate the influence of these conditions on the optimal system structure.

In this paper, the method of rationally determining the system structure and operational strategies based on the optimization approach has been proposed for the energy supply system for the hospital with total floor area of 25,000 m2 in the typical condition. There exist many kinds of energy demands for hospital generally, the kinds of equipment that should be considered are miscellaneous, and the obtained optimal system is the complicate hybrid-system, which consist of electricity-driven and natural gas-fired equipment together with cogeneration equipment. This result shows that by using optimization method, we can obtain the system structure rationally, that is, difficult to get by intuition and experience of the designer. Sensitivity analysis has been carried out by changing parametric values from typical condition to have the knowledge about the difference of system structure under the different conditions, that is useful to make a proper system planning considering the trend of future improvement of technology and cost.