Research on the Economic Analysis of HVAC System Life Cycle for Public Office Building –Case Studies on a City Hall Chiller Plant Retrofit

• Main Authors: Pan-Chen Chan, 詹邦鎮
• Other Authors: 楊詩弘
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/sbtu93

碩士 === 國立臺北科技大學 === 建築與都市設計研究所 === 96 === The space purpose of the building might be different from original when facility meets retrofit needs. It is necessary to anticipate energy consumption for making a retrofit decision. So that, to use a computer base building energy simulation system to anticipate post-retrofit energy consumption. In the operation stage, we can easily represent the building energy scenario by calibrated simulation with the simultaneous electrical data record from the Building Energy Management System. Thus, the individual alternative’s post-retrofit energy scenario can be simulated to assess the life-cycle cost during retrofit planning stage. The research study pre-retrofit and post-retrofit stage from the public building chiller plant retrofit project and shows the conclusions as below: 1. Re-Model Existing Building With Computer Base Building Energy Simulation The research performs whole building calibrated simulation to represent the building energy behavior. The mean bias error (MBE) is range from -9.5% to 3.4% by comparison from utility bill and simulated data. It is acceptable from ASHRAE Guideline 14-2002, for using the building energy characteristic to simulate the post-retrofit scenario to estimate the future energy consumption. Furthermore, the MBE is range from –5.94% to 11.35% after the comparison of anticipation and the reality data from EMS. That shows the decision making process is feasible for life-cycle management. 2. Engineering Economic Analysis With Life-Cycle Cost Concept The research studies five alternatives based on the biding scope from the building owner. Option 1 is to re-model chiller plant. Option 2 is also re-model chiller plant with variable speed centrifugal chiller. The option 3 is simply replace old equipment without system re-model. Option 4 is simply replace old equipment with variable speed cooling tower and secondary chilled water pump. Option 5 is simply replace old equipment with secondary chilled water pump. The research input the system characteristics into the building model simulation software for post-retrofit energy consumption and further economic analysis. From the post-retrofit energy consumption that shows the most efficient system is option 2 which is saving 40.8%. The worse one is simply equipment replace case - option 3, whose efficiency is 18%. The research also shows option 2 is the lowest life-cycle cost and the valuable design. However, option 1 has been chosen because of the initial cost of the option 2 is higher than budget. After comparing from option 1 and option 3, the SIR is 5.836 and payback period is shorter than 3.8 years during 15 years life-cycle. 3. Optimize the Life-Cycle Management During the series assessment, shows the process can account the life-cycle cost to look for the optimum design option with representing building model. And, the model has been simulated from simultaneous energy behavior by collecting utility bill and electrical data record. In post-retrofit stage, the chiller plant running over 6 months and collects data from EMS for the post-retrofit system commissioning. The result shows the optimum energy-saving system is now running and under a predicted efficiency. Thus, the research proof the procedure is feasible to life-cycle management for existing office buildings in Taiwan.