Transcript MENG 547 LECTURE 3 - Eastern Mediterranean University (EMU

MENG 547
LECTURE 3
By
Dr. O Phillips Agboola
COMMERCIAL & INDUSTRIAL BUILDING
ENERGY AUDIT
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Why do we audit Commercial/Industrial buildings
Important for successful business performance
 Provide predictable positive cash flow
 Open doors to energy retrofit
 In the long run, reduce CO2 emission
 Reduce over-head cost of a project, thereby increasing the
feasibility of the project
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Types of Commercial/Industrial buildings energy audits
Walk-through Audit
 Utility Cost Analysis Audit
 Standard Energy Audit
 Detailed Energy Audit
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Walk-through Audit
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This audit consists of a short on-site visit of the facility to
identify areas where simple and inexpensive actions can
provide immediate energy use and/or operating cost
saving. Some Engineers refer to these types of actions as
operating and maintenance (O&M) measured.
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Examples
 Replacing broken windows
 Insulating exposed hot water or steam pipe
 Adjusting fuel-air ratio
 Setting back heating set point temperature
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Utility Cost Analysis Audit
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The main purpose of this type of audit is to carefully analyze the
operating costs of the facility. Typically, the utility data over
several years are evaluated to identify the pattern of energy use,
peak demand, weather effects, and potential for energy savings.
To perform this analysis, it is recommended that a walk-through
survey is done first
In performing this type of commercial energy audit the following
are necessary
 Check the utility charges to rule out error in bills
 Determine the most dominant charges in the utility bills
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Peak demand charges and ways to shaves them
Determine whether or not the facility can benefit from using
other utility rate structure to purchase cheaper energy and
reduce its operating costs.
 Determine if the facility is ripe for energy retrofit
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Standard Energy Audit
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The standard audit provides a comprehensive energy analysis
for the energy systems of the facility. In addition to the activities
described for the walk-through audit and for the utility cost
analysis described, the standard energy audit includes the
development of a baseline for energy use of the facility and
evaluation of the energy saving and the cost effectiveness of
appropriate selected energy conservation measures.
Typically, simplified tools are used in the standard energy audit
to develop baseline energy models and predict the energy saving
of energy conservation measures.
Among these tools are degree-day methods, linear regression,
simple payback analysis, net present value etc
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Detailed Energy Audit
It’s the most comprehensive form of energy audit and
very time consuming.
 Specifically, the detailed energy audit includes the use of
instruments to measure energy use for the whole
buildings and/or for some energy systems within the
building.
 For instance, lighting systems, office equipment, fans,
chillers etc
 In addition, sophisticated computer simulation program
are typically considered for detailed energy audit to
evaluate and recommend energy retrofit for the facility
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NOTE
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During auditing , hand held and clamp –on instruments can be
used to determine the variation of some building parameters
such as
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Indoor air temperature
The luminance level
Electrical energy use
Also, the use of sensors are common e.g the use of Non-Intrusive
Load Monitoring techniques (NILM)
General Procedure for a Detailed Energy Audit
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Step 1: Building and Utility Data Analysis
This step evaluate the characteristics of the energy
systems and the pattern of energy use for the building.
 The building characteristics can be collected from the
architectural/mechanical/Electrical drawings
 The energy use pattern can be obtained from a
compilation of utility bills over several years
 Analysis of the historical variation of the utility bills
allows you to determine if there are any seasonal and
weather effects on the building energy use
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Practical steps
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Collect at least three years of utility date
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Identify the fuel types used
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Electricity, natural gas, oil etc
Determine the fuel type that accounts for the largest energy use
Determine the pattern of fuel use by fuel type
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To identify a historical energy use pattern
Identify the peak demand for energy use by fuel type
Understand utility rate structure (energy and demand
rates)
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Peak demands and if cheaper fuel can be purchase
Analyze the effect of weather on fuel consumption
 Perform utility energy use analysis by building type and
size
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To compare against typical indices
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Step 2: Walk-through Survey
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From this step, potential energy measures should be
identified. The results of this step are important since
they determine if the building warrants any further
energy auditing work. Some of the tasks involved in this
step are
Identify the facility concerns and needs
 Check the current operating and maintenance procedures
 Determine the existing operating conditions of major energy
equipment
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• Lighting
• HVAC systems
• Motors etc
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Estimate the occupancy, equipment, and lighting
• Using energy density and hours of operation
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Step 3: Baseline for Building Energy Use
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The main purpose of this step is to develop a base-case
model that represents the existing energy use and
operating condition for the building, This model is to be
used as a reference to estimate the energy saving
incurred from approximately selected energy conservation
measures. The major tasks to be performed during this
steps are:
Obtain and review architectural, mechanical, electrical, and
control drawings
 Inspect, test, and evaluate building equipment for efficiency,
performance, and reliability
 Obtain all occupancy and operating schedules for equipment
 Develop a baseline model for the building use
 Calibrate the baseline model using the utility data and/or
metered data
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Step 4: Evaluation of Energy Saving Measured
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In this step, a list of cost effective energy conservation
measures are determined using both energy savings and
economic analysis. To achieve this goal, the following tasks
are recommended
Prepare a comprehensive list of energy
 Determine the energy savings due to the various energy
conservation measures pertinent to the building using the balance
energy use simulation model developed
 Estimate the initial costs required to implement the energy
conservation measures
 Estimate the cost-effectiveness of each energy conservation
measure using an economic analysis method
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COMMON ENERGY CONSERVATION MEASURES
1. Building Envelops
Walls, roofs, floors, windows and doors
 Insulations of these envelops
 Windows glazing, door fitting allowance
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Recommended energy conservations measures
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Additional Thermal Insulation
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This can be costly
Replacement of Windows
 Reducing od Air Leakage
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2. Electrical Systems
 Electrical energy cost constitute the dominant part of
the utility bill
Lighting
 Office equipment
 Motors
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When luminance levels are above the levels recommended by
the standard
Fastest growing part of electrical load e.g computers etc
The energy cost to produce electric motors can be a significant
part of the operating budget of any commercial and industrial
building
3. HVAC Systems
 The energy use due to HVAC systems can represent
40% of the total energy consumed by a typical
commercial building
Determine condition of the equipment
 Operating schedule
 Quality of maintenance
 Control procedures
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Case Study/Assignment 1
Submission deadline: 19th October 2012
A. Consider an apartment (2-3 bedroom apartment)
and perform an energy audit.
B. After the audit, perform a retrofitting evaluation of
the apartment base on the energy audit of the
apartment