INTRODUCTION

With the advent of technology buildings have shifted from traditional to modern architecture. As of 2010 buildings have a 32% share in the total energy demand and generate around 30 % of CO2 emissions . This sector consumes around 30 % of the world’s electricity produced. Developed countries have seen a more tectonic shift from traditional to modern architecture and the use of modern material. For example like in India the building sector is more energy intensive and constitutes around 40% of the national energy consumption. Around 60% of the building load was for space cooling and heating. Similarly in European nations 40% of the energy was consumed by the building sector .

METHODOLOGY

A building interacts with both the internal and external environment. The parameters mentioned above contribute to the load of the building. Load calculation is a lengthy and complex process and involves many calculations and iterations. The complexity is increased as the size of the building increases. The major loads contributing to energy consumption are :

1. Lighting Load

2. Cooling load

3. Equipment Load

4. Heating load Over the years and with the advancement of computer softwares various tools have come up which can help the designers to predict and analyze the load calculations and building energy performance with good accuracy and with a substantial decrease in effort.These simulation programmes model the thermal, visual ,ventilation and other energy consuming processes to measure the building energy performance. The calculations are done on the basis of input data of parameters like HVAC,lighting,occupancy,equipments and building form and orientation.

BUILDING ENERGY SIMULATION

Building energy simulation is the process of calculating building load and energy performance using softwares with a good accuracy and substantial decrease in effort.The calculations are done on the basis of input data of parameters like HVAC,lighting,occupancy,equipments and building form and orientation. A simulation software uses a simulation engine which calculates energy flows on a hourly basis for 8760 hours of the year.

The tool used for the purpose is e-QUEST. This is a widely used ,time proven whole building performance design tool .It is highly user friendly and its graphical interface helps users to visualize their model .Besides it also has parametric runs which can compare the results of various varying inputs for the same project .It can also compute financial analysis and cost of energy consumption .It uses simulation engine of DOE 2.2.

DESCRIPTION OF CASE STUDY

The project here, AI REALBUILD is a 14 floor office space in the heart of bustling metropolis of Gurgaon. The facility includes two basements, five floors of multilevel parking and nine floors of office space. The total conditioned area is 83, 260 sqft and the site area is 33,153 sqft. The project is seeking for certification under IGBC new building ratings system.

The project is simulated for both base-case and proposed design case and the input parameters for both have been discussed below.

BASE- CASE DESIGN

For designing base case the project follows ASHRAE 90.1.2010 appendix G methodology using whole building performance method. The input parameters are discussed in the table below.

DESCRIPTION	SPECIFICATION	UNITS
LOCATION	GURUGRAM
WEATHER FILE	NEW DELHI_BIN
CLIMATE ZONE AS PER ASHRAE	1A
MODELLING SOFTWARE	E QUEST 3.65
BUILDING AREA	83260	Ft2
HOURS OF OPERATION	15	HOURS
WALL U-VALUE	0.124	BTU/h-ft2–0F
ROOF U-VALUE	0.063	BTU/h-ft2–0F
WINDOW GLASS U-VALUE	1.2
WINDOW GLASS SHGC	0.25
INTERIOR LIGHTING LPD	AS PER ASHRAE 90.1 Space by Space method
EQUIPMENT POWER DENSITY	2.5 for office areas	W/ ft2
HVAC SYSTEM	Variable air Volume
CHILLER	Water cooled screw chiller type
NO. OF CHILLERS	2
CAPACITY OF EACH CHILLER	9.6	Mbtu/hr
CHW Supply TEMP	55	0F
COP	4.8
FAN POWER	0.9	Kw/cfm
FRESH/OUTDOOR AIR	AS PER ASHRAE 62.1

PROPOSED CASE

DESCRIPTION	SPECIFICATION	UNITS
LOCATION	GURUGRAM
WEATHER FILE	NEW DELHI_BIN
CLIMATE ZONE AS PER ASHRAE	1A
MODELLING SOFTWARE	E QUEST 3.65
BUILDING AREA	83260	Ft2
HOURS OF OPERATION	15	HOURS
WALL U-VALUE	0.37	BTU/h-ft2–0F
ROOF U-VALUE	0.087	BTU/h-ft2–0F
WINDOW GLASS U-VALUE	0.47
WINDOW GLASS SHGC	0.39
INTERIOR LIGHTING LPD	AS PER LIGHTING DRAWINGS
EQUIPMENT POWER DENSITY	2.5 for office areas	W/ ft2
HVAC SYSTEM	Variable Refrigerant flow
COP	4.41
FAN POWER	0.3	Kw/cfm
FRESH/OUTDOOR AIR	AS PER DBR
CONTROLS	DAYLIGHT AND OCCUPANCY

RESULTS

Results of the analysis are summarized in the Table below. The building has the potential to achieve approximately 3509940 INR (20%) in annual utility savings per year compared to a minimally compliant ASHRAE 90.1-2010 building. Calculations are shown in the following table.

LIGHTS(kWh)	MISC EQUIP. (kWh)	SPACE HEATING(kWh)	SPACE COOLING(kWh)	PUMPS & AUX(kWh)	VENT FANS(kWh)	TOTAL(kWh)
398564	428573	192136	517630	301230	290274	2163557

LIGHTS(kWh)	MISC EQUIP. (kWh)	SPACE HEATING(kWh)	SPACE COOLING(kWh)	PUMPS & AUX(kWh)	VENT FANS(kWh)	TOTAL(kWh)
398564	428573	261694	514240	300741	291375	2230150

LIGHTS(kWh)	MISC EQUIP. (kWh)	SPACE HEATING(kWh)	SPACE COOLING(kWh)	PUMPS & AUX(kWh)	VENT FANS(kWh)	TOTAL(kWh)
398564	428573	260132	516565	301646	292707	2233288

LIGHTS(kWh)	MISC EQUIP. (kWh)	SPACE HEATING(kWh)	SPACE COOLING(kWh)	PUMPS & AUX(kWh)	VENT FANS(kWh)	TOTAL(kWh)
398564	428573	170847	520748	301943	291408	2147430

LIGHTS(kWh)	MISC EQUIP.(kWh)	SPACE HEATING(kWh)	SPACE COOLING(kWh)	PUMPS & AUX(kWh)	VENT FANS(kWh)	TOTAL(kWh)
201014	428573	2019	494879	3445	624990	1754920

Base-case	Energy Consumption(kWh)	Savings(%)	Savings(INR)
0⁰	2163557	19.99840445	3509490
90⁰	2230150
180⁰	2233288
270⁰	2147430
Average	2193606.25
Proposed case	1754920