Managing Operational Energy in BuildingsSP3 Module 4

Global Warming

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation.

Buildings’ Contribution to Greenhouse Gas Emissions

• Buildings Account for 40 - 60% of CO2 emissions• Over the next 25 years, CO2 emissions from buildings are

projected to grow faster than any other sector.• Emissions from commercial buildings are projected to grow

the fastest—1.8% a year through 2030 • Buildings consume 70% of the electricity load • Buildings have a lifespan of 50-100 years during which they

continually consume energy and produce CO2 emissions.Source: U.S. Environmental Protection Agency

• In 2005, the overall worldwide energy use was estimated to be at 500 exajoules (5×1020 J)

• 80 to 90 percent derived from the burning of fossil fuels.• World marketed energy consumption is projected to rise

by 44 percent from 2006 to 2030.• Global emissions of the main greenhouse gas carbon

dioxide will jump more than 39 percent by 2030.• Worldwide demand for liquids and other forms of

petroleum could rise from 85 million b/d in 2006 to 91 million b/d in 2015 and to 107 million b/d in 2030.

Energy Consumption and Generation

Source: International Energy Outlook, Energy Information Adminitrstion. US DOE

38%

23%

26%

6% 6% 1%

Oil Gas Coal Hydroelectric Nuclear Geothermal, Solar, Wind etc.

Sources of Energy

Energy Use in BuildingsEnergy Use by Building Type (Commercial)

Service and Retail(Malls, Stores, Gas Stations etc.) 20%

Offices(Private and Public Offices, Banks etc.) 17%

Education(Elementary, High School, College) 13%

Healthcare(Hospitals, Clinics, etc.) 9%

Lodging(Hotels, Dormitories, etc.) 8%

Public Assembly(Libraries, Sports Arenas etc.) 6%

Energy Management

• Energy management is the process of analyzing how efficiently energy is used (Thumann and Younger, 2008).

• It is important to find ways to reduce energy consumption. For this purpose, we need to analyse all aspects of a building’s energy use to find practical ways of reducing consumption (Pank et.al. 2002).

• Because energy is not a fixed cost, energy management is important.

Energy Audit• A process to evaluate where a building or plant uses energy,

and identify opportunities to reduce consumption (Thumann and Younger, 2008).

• An inspection, survey and analysis of energy flows in a building, process or system with the objective of understanding the energy dynamics of the system under study (Graham, 2003).

Types of Energy Audits

Level 1—The Walk-Through Audit• The walk-through audit, as its name implies, is a tour

of the facility to visually inspect each of the energy using systems.

• It will typically include an evaluation of energy consumption data to analyze energy use quantities and patterns as well as provide comparisons to industry averages or benchmarks for similar facilities.

Types of Energy AuditsLevel 1—The Walk-Through Audit• It is the least costly audit but can yield a preliminary

estimate of savings potential and provide a list of low cost savings opportunities through improvements in operational and maintenance practices.

• The level one audit is also an opportunity to collect information for a more detailed audit later on if the preliminary savings potential appears to warrant an expanded scope of auditing activity.

Types of Energy AuditsLevel 2—Standard Audit• The standard audit goes on to quantify energy uses

and losses through a more detailed review and analysis of equipment, systems, and operational characteristics.

• This analysis may also include some on-site measurement and testing to quantify energy use and efficiency of various systems.

Types of Energy Audits

Level 2—Standard Audit• Standard energy engineering

calculations are used to analyze efficiencies and calculate energy and costs savings based on improvements and changes to each system.

• The standard audit will also include an economic analysis of recommended conservation measures.

Types of Energy Audits

Level 3—Computer Simulation• The level three audit will include more detail of

energy use by function and a more comprehensive evaluation of energy use patterns.

• This is accomplished through use of computer simulation software.

Types of Energy Audits

Level 3—Computer Simulation• This method also accounts for interactions

between systems to help prevent overestimation of savings.

• Because of the time involved in collecting detailed equipment information, operational data, and setting up an accurate computer model, this is the most expensive level of energy audit but may be warranted if the facility or systems are more complex in nature.

Energy Accounting

• The first task is to collect and review two years of utility energy data for all fuels. This includes electricity, natural gas, fuel oil and any other delivered fuels.

• This information is used to analyze operational characteristics, calculate energy benchmarks for comparison to industry averages.

• Estimate savings potential, set an energy reduction target, and establish a baseline to monitor the effectiveness of implemented measures.

Energy Accounting

• Make sure you receive copies of all monthly utility bills and delivered fuel invoices.

• Sort utility bills by building or by meter, and organize them into 12- month blocks using the meter-read dates.

• Locate all meters and sub-meters. If numerous meters are used, it is helpful to clearly label them on a site plan for each building being evaluated.

• Determine which building or space is being served by each meter.

• Calculate area (in square meter) for each building.

Energy Use Index (EUI)

• The Energy Use Index (EUI) is the most common means of expressing the total energy consumption for each building.

• The EUI is expressed in Btus/Square Foot/Year or KWH/Square Meter/Year and can be used to compare energy consumption relative to similar building types or to track consumption from year to year in the same building.

KW vs KWH

• kWh is a measure of energy, whilst kW is a measure of power.

• Energy is a measure of how much fuel is contained within something, or used by something over a specific period of time.

• The kWh is a unit of energy.• Power is the rate at which energy is generated

or used.• The kW is a unit of power.

Energy Use Index

Energy Use Index

References