Indian Journal of Science and Technology

Abstract

Background/Objectives: Green Telecommunications System aims at reducing CO2 emission and consumption of energy. Free cooling system is one which optimizes the air conditioning load of the Base Transceiver Station (BTS) shelter. Methods/Statistical Analysis: The main contribution of this paper is modeling and simulation of BTS shelter envelope with the Energy Plus for energy efficiency. The Shelter envelope absorb the heat from atmosphere which varies throughout the year. For the given shelter inside temperature, the Energy plus gives out the shelter envelope's sensible cooling load. This sensible cooling load is considered as separate variable. The sensible cooling load of the shelter and the equipment load are computed as thermal current. A fuzzy logic controller has been designed, which switches ON the free cooling fans or air conditioner depending upon atmospheric temperature and room temperature. Findings: Generally environmental influence on the room temperature is considered as atmospheric temperature variations. Instead if we consider the environmental influence as heat absorbed in kilo Watts (kW) and fed to the controller there will be further reduction in the energy consumption and improvements in contribution of free cooling fans. By modeling and simulating the BTS shelter in Energy Plus this findings are realized. On comparison of the energy consumption during simulations the proposed Energy plus model based control has saving of about 2.69% and 1.37% respectively for fixed and variable capacity air conditioner over the model derived from the basic principles which considerer atmospheric influence as temperature variations. The over all energy saving is increased from 12.04% to 14.41% by using the Energy Plus model based control proposed in this paper with free cooling for Chennai region. Analysis made to find priority city for free cooling in selected important cities. Bangalore region gives more free cooling saving and lesser energy consumption among the selected cities. Applications/Improvements: The simulated heat load data of envelope from Energy Plus can be directly used in the controller for real time applications. The other ways is cure fitting heat absorption data over atmospheric temperature for various seasons/periods. Using the equation and atmospheric temperature the heat load of the envelope calculated for control purpose This concept can be applied even for buildings.
Keywords: BTS Shelter, Energy Efficiency, Energy Plus Model, Free Cooling System, Fuzzy Logic