Influence of initial systems on the renewal planning of energy supply systems for a hospital

Shu Yoshida, Akira Yoshida, Koichi Ito, Yoshiharu Amano

Research output: Contribution to journalArticlepeer-review


In this study, a renewal planning problem of energy supply system is formulated as a large scale mixed-integer linear programming problem, in which the objective function to the minimized is the average value of annual total cost during system's evaluation period. By adopting the programming language AMPL and CPLEX solver, a numerical study is carried out for a hospital, where electrical(e.g., heat pump) and gas(e.g., gas engine cogeneration) systems are compared together with arbitrary combination one, which is composed of electrical and gas driven pieces of equipment, by focusing particularly on the influence of initial system's difference. The main results obtained are as follows: (a) If the initial system is gas one, it is better to renew it to the electrical one as soon as possible due to relatively low energy efficiency of gas utilizing pieces of equipment, the high price of gas input energy and so on. (b) If the initial system is electrical one, the optimal renewal year becomes relatively later year, because it is economically better to use the initially installed high efficiency system as long as possible. (c) Theoretically, the arbitrary combination system is of course the best renewal one. However, there is no economic difference between the arbitrary combination system and the electrical one.

Original languageEnglish
Pages (from-to)2312-2323
Number of pages12
JournalNihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
Issue number806
Publication statusPublished - 2013
Externally publishedYes


  • Energy management
  • Energy supply systems
  • Engineering optimization
  • Hospital
  • Renewal planning
  • Systems engineering

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering


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