Hybrid Cooling System and New Mechanical Ductwork Layout
Original:Apr 3rd, 2012
After analyzing the mechanical system of American Art Museum (AAM), two proposed ideas are conducted a further and detail analyses. The overall report is focused on the cost effectiveness of mechanical system.
Mechanical Depth – Hybrid Cooling System
Today, the price of No.2 oil is increasing. And, the utility company, ConEd, which is contracted with AAM, generates electricity by fueling oil. As other fuels, the applications provide either attractive incentive and/or rebate programs or relatively lower price. Therefore, a hybrid cooling system is suggested to seek for further saving with the highly energy efficient mechanical system. After conducting an exhaust search of the best hybrid system, it found that the best system is two natural gas-fired single stage absorption chillers and one electric centrifugal chiller with 5 year payback period.
Structural and Acoustical Breadths – New Ductwork layouts
AAM will consist of 3 mechanical floors. Two out of three floors will hold ventilation systems, which will serve different floor levels. The ventilation system on cellar level will serve conditioned air from cellar level to 7th floor, and the ventilation system on 9th floor will deliver air to 8th floor only. So, the proposed idea is to bring more AHU closer to the load with the consideration of minimizing the structural impact and acoustical impact. Overall, the result shows that the proposed duct work layout will save about $36,000 by reducing the amount of ducts.
After conducting the studies of two ideas, it shows that there are more potential savings of AAM mechanical system. For example, the fuel type of AAM should be more toward natural gas. And, the area of 9th floor would be increased and more AHUs can be put on 9th floor to be closer to the load, if the aesthetics of AAM is not affected.
MAE Course Relation
The MAE courses related to this project are:
AE 557 Centralized Cooling System:
The ideas of absorption refrigeration in this course help to understand the impact to other mechanical components and the installation requirement of absorption chillers. Also, the lecture of AHRI Standard 550/590 and ASHRAE Standard 90.1 explains the potential energy saving of operating with multiple chillers instead of one. Third, this course mentions the requirements and needs of mechanical room layout.
AE 555 Building Control System:
This course provides different search methods that can be applied on HVAC operation, such as increasing the efficiency of HVAC system by changing the combination of mass flow rates, temperature setpoints, and part load ratios. This concept helps to find the cost effective combination of electric and absorption chillers, and also the well balanced layout of the mechanical room on 9th floor.
AE 551 Combined Heat and Power:
This course provides information of today fuel economy and theories of different cogeneration operations. It significantly gives the analysis of this project more alternatives of redesigning the HVAC system.