DESIGN AND ENERGY ANALYSIS OF AIR CONDITIONING SYSTEM OF X MALL BUILDING IN SEMARANG

• Main Author: Muhammad Irfan, Abiyyu
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/64914
• Institution: Institut Teknologi Bandung

The design of air conditioning system of mall buildings must consider air conditioning design options that have efficient energy consumption to achieve energy conservation. Energy consumption for mall buildings is 62.9% of all the building’s electrical energy needs. In designing process of air conditioning systems in X Mall building in Semarang, comparison of two systems was done: air conditioning system with constant flow chiller and air conditioning system with variable flow with combination of thermal energy storage (TES) in aspects of electrical energy consumption and energy efficiency of air conditioning systems. Air conditioning system with variable flow chiller with combination of TES has the potential to be more energy efficient and consume less electrical energy. X Mall building has a maximum cooling load of 5,024.2 kW according to the Trace 700 software output; thus, it is designed to use four chillers with each capacity of 1,303.7 kW (370 TR). The total cooling energy which is the total of cooling load throughout the year, is 18,344,812 kWh/year, this amount of energy is fully charged to the chiller in constant flow chiller system, whereas for the variable flow chiller system with combination of TES, 69.19% of total cooling energy is charged to chiller and 30.81% is charged to TES filled with chilled water. In the constant flow chiller system, chillers operate as the X Mall opens, whereas in the variable flow chiller system with combination of TES, chillers operate as two functions, firstly, chillers charge TES tank for six hours until 9:00 AM, then secondly, chillers operate as the X Mall opens at off-peak load time (ID: LWBP) from 9:00 AM until 5:00 PM, then TES tank filled with chilled water operates at peak load time (ID: WBP) from 6:00 PM until 10:00 PM as the chillers deactivate. Chilled water inside the TES tank received 3.97% of the TES energy as its heat gain because of the nine-hour storage time in the TES tank. Energy consumption for constant flow chiller system, is 4,934,238 kWh per year, whereas for variable flow chiller system with combination of TES is 4,144,172 kWh per year. The cooling energy consumption intensity (ID: IKE pendinginan) of the two systems are 168 kWh/m2.year and 141 kWh/m2.year respectively, with maximum standard of 180 kWh/m2.year. Electrical energy cost for constant flow chiller system is IDR 5,741,312,831 per year, whereas electrical energy cost for variable flow chiller system with combination of TES is IDR 4,404,186,567 per year, the latter system saves up to 23.30% of energy cost. Air conditioning system with variable flow chiller with combination of TES has the potential to lower the energy consumption and energy cost, compared to air conditioning systems with constant flow, with also the system’s higher energy efficiency.