Instruments for Energy Audits

1
Instruments for Energy Audits

• Solar Energy Society of Canada
• April 2007

2
The Numbers Game

• When you look at alternative energy, the numbers
  to be considered break down to the following
• How much energy do you consume?
• How much energy can you produce?
• How much energy can you conserve?
• How much does it cost you to purchase
  conventional energy?
• How much will it cost you to purchase alternative
  energy?

3
Energy Use - The Energy Audit

• An energy audit will answer two questions.
• How much energy do you consume?
• Very few of us actually know how much energy we
  use as we tend to view it in terms of how much we
  spend each month. This allows us to ignore some
  of the ugly facts.
• How much energy can you conserve?
• Actually once you get a handle on your energy
  consumption it will become quite obvious where
  you can conserve energy.

4
Energy Audit

• What do we measure?
• Look at your utility bills.
• If you are paying for it, you probably want to
  audit your actual consumption.

5
Energy Audit - Records

• Start keeping records.
• All of this testing and checking will do you no
  good at all until you can compare numbers.
• Open a notebook or use your computer to record
  all of your figures and information in one place.
  This will help you compare notes during and after
  the energy audit.

6
Energy Audit - Sample Home

• Start with a conventional urban house.
• 1100 square foot bungalow, built in 1960.
• 4 walls with fiberglass insulation.
• Gas furnace and hot water heater.
• Electric stove and dryer.
• Two adults and one pre-school child.
• What do we measure?
• How do we measure it?

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Energy Audit - Utility Bills

• The example house consumes
• Electricity.
• 400 kWh per month
• Natural Gas.
• 8.00 GJ per month
• Water.
• 12 m3 per month
• Other fuels (I.e. propane, wood, etc).
• 20 gallons of propane per month.

8
Energy Audit - Utility Bills

• From your utility bills record the following
• Electricity.
• Natural Gas.
• Water.
• Other fuels (I.e. propane, wood, etc).
• Break it out month by month for actual
  consumption (even if you are on a budget plan)

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Energy Audit - Appliances

• Start with a list of every appliance
• Electrical.
• Electric stove, electric dryer, entertainment
  equipment, lighting, furnace, computer equipment,
  automotive heaters, etc.
• Natural Gas.
• Gas furnace, hot water heater, etc.
• Other fuels (I.e. propane, wood, etc).
• Garage heater, barbecue, etc.

10
Energy Audit - Appliances

• For every appliance list the following
• Fuel or resource consumed (gas, electric,
  propane, water, etc)
• Number of hours used in a day.
• Standby power requirements.
• Running power requirements.
• Nameplate power ratings.

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Electricity

• For most of us, electrical power offers
  convenient and relatively inexpensive heating,
  cooling, lighting and entertainment.
• Because of its convenience we tend to use it
  (and waste it) more than any other resource.

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Electricity - Measurement

• Electricity use can be measured in several
  different ways.
• Volts - electrical potential - volt-meters.
• Amps - electrical flow - amp-meters.
• Watts - electrical power - watt-meters.
• Watt-hours - cumulative electrical power -
  watt-hour meters.

13
Electricity - Kilowatt-hours

• While electricity use can be measured in several
  different ways, we will work in Watts and
  Kilowatt-hours
• Equipment nameplates are labeled in Watts.
• We purchase power in units of Kilowatt-hours.
• It makes sense to record all of our electricity
  use in terms of kilowatt-hours and there are many
  tools designed for that exact purpose.

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Electricity - Utility Meters

• The kilowatt-hour meter most of us are familiar
  with is the standard utility meter mounted on the
  power pole.
• These units are quite accurate, but normally
  monitor the whole house. This is inconvenient
  when doing energy audits.

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Electricity - Connections

• To measure electricity use in a house, we are
  faced with four common types of equipment.
• 120 volt devices that plug into an outlet.
• 120 volt devices that are directly wired into the
  house electrical panel.
• 240 volt devices that plug into an outlet.
• 240 volt devices that are directly wired into the
  house electrical panel.

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Electricity - 120 volt plug-in

• 120 volt devices that plug into an outlet.
• These are the most common items in a normal
  household and are the easiest to monitor.
• Purchase a standard power monitor device
  (Kill-a-watt, EM100, Watts-up, etc.) plug it in
  and read off the power consumption.
• There are a few caveats but it is that simple.

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Electricity - 120 volt plug-in

• Recommended approach.
• P3 - Kill-a-watt.
• ULM - EM100
• EED - Watts Up

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Electricity - 120 volt direct wire

• 120 volt devices that are directly wired into the
  house electrical panel.
• These are quite common items in a normal home
  (lights, fans, etc).
• Without having to bring in an electrician, the
  most practical approach is to estimate their
  power consumption using nameplate data and the
  operating time.

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Electricity - 120 volt direct wire

• Recommended approach.
• Actually, as monitoring these loads requires
  altering your electrical wiring, the estimate
  approach is probably the most efficient.
• If you are an electrician you can make the
  necessary changes to monitor these loads.

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Electricity - 240 volt plug-in

• 240 volt devices that plug into an outlet.
• These are larger loads, generally used in heating
  applications (electric stoves, electric dryers,
  etc) and they are a challenge to monitor
  effectively.
• The estimate approach is reasonably accurate, but
  a surplus 240 volt utility meter can be used for
  more accurate monitoring. Another solution is an
  industrial power meter which can be rented.

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Electricity - 240 volt plug-in

• Recommended approach.
• Estimate power use.
• Surplus utility meter.
• Dent Instruments - ElitePro Logger

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Electricity - 240 volt direct wire

• 240 volt devices that are directly wired into the
  house electrical panel.
• These are not common in a normal urban home, but
  may be encountered in some applications (electric
  heaters, well pumps, etc).
• Bring in an electrician to set up monitoring
  these items or estimate their power consumption
  using nameplate data and the operating time.

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Electricity - 240 volt direct wire

• Recommended approach.
• Estimate their power consumption using nameplate
  data and the operating time.
• Bring in an electrician to set up monitoring of
  these items using equipment designed for this
  purpose.

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Electricity - Estimated Power

• While it seems somewhat unscientific, an estimate
  of power consumption is sometimes quite a
  practical approach.
• Most electrical equipment has a nameplate which
  gives power requirements and consumption data
  which are provided by the manufacturer.
• Combine the nameplate data with the operating
  hours and you can have a reasonable estimate.

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Electricity - The Meter is Lying!

• It seems fairly simple, plug in your meter, plug
  in your equipment, read the power consumption and
  write it down. Easy right?
• Many modern appliances consume power when they
  appear to be turned off! This is called a
  phantom load.
• Appliances with motors or transformers will
  consume larger amounts of power when starting up,
  than when they are running.

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Electricity - The Meter is Lying!

• The power meter may consume some power itself and
  combine that with your appliances power
  consumption.
• Carefully read the manual of any equipment to
  find out if it may lie to you under particular
  conditions.
• Actually, if the meter lies consistently, you can
  account for this and adjust your totals
  accordingly.

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Electricity - Other Options

• There are many companies manufacturing smart
  sensors which will read voltage and current
  from your electrical system and convert it to a
  standard DC signal which can be then connected to
  a chart recorder, hour meter, computer or data
  logger.
• For long term monitoring of some equipment,
  these devices (although somewhat expensive) are
  probably your best choice.

28
Natural Gas

• Gone are the days when many of us split wood or
  shoveled coal. Most of our heating in Alberta is
  done with natural gas.
• It is less labor intensive than other fuels and
  only requires that your house be connected to the
  gas main. All in all quite simple.

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Natural Gas - Measurement

• Actually the natural gas meters are reasonably
  accurate and there are few after-market
  solutions for measuring natural gas consumption.
• I do not recommend altering your gas line in any
  way to monitor gas flow.
• What I do recommend is having your furnace tested
  for combustion efficiency and replacing any
  furnace that does not test at least 70.

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Natural Gas - Furnace Testing

• There are several after-market solutions for
  testing furnaces. Most of them measure the
  mixture of gases within the furnace flue for the
  following
• Flue gas and inlet air temperature
• Oxygen levels
• Carbon dioxide and monoxide levels
• Nitrogen oxide and dioxide levels
• With these numbers, the combustion efficiency of
  the furnace can be calculated.

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Heat Loss

• All of the fuel you expend to heat your household
  does little to no good if your house loses heat
  to the outside environment.
• While nobody wants to live in the perfect
  insulated building (small footprint, thick walls,
  one door, no windows, etc), it is worth reducing
  your heat losses to the outside as much as
  possible.

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Heat Loss - Measurement

• Measuring heat loss is a bit of a challenge for
  the average home owner as most techniques are
  either very time consuming or very expensive.
• Initially there are two basic methods for heat
  loss measurement, point by point measurement or
  estimate from calculations based on wall
  structure. Both of these are time consuming and
  not necessarily accurate.

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Heat Loss - Measurements

• Fortunately there is another approach available
  to the average householder.
• Thermal imaging used to be limited to large
  corporations and governments as the equipment
  required was usually in the 30,000 to 50,000
  range and it was not commonly available.

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Heat Loss - Thermography

• With the introduction of small, inexpensive
  thermal imaging cameras like the Fluke Ti30 and
  the FLIR Systems ThermaCAM, it is possible to
  rent a thermal imaging system for as little as
  150 per day.
• These cameras allow you to point and shoot and
  see your infrared image directly on the screen,
  then save the image and download it to your
  computer for future reference

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Heat Loss - Thermography

• This allows you to look at your house and
  actually see hot spots caused by faulty
  insulation, poor quality windows, air leaks and
  other issues with the building envelope.
• While this technique is best used when it is cold
  outside, to allow for the most contrast between
  the inside and outside temperatures, it is not
  necessary to wait until winter to do your
  analysis as any difference it temperature can be
  monitored. This feature allows you to check for
  cold spots on interior walls as well.

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Heat Loss - Thermography

• Typical 1960 era bungalow.
• Note the heat loss at the windows and basement
  walls.
• 13 C difference between ambient and window
  temperature.

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Heat Loss - Thermography

• Typical 1960 era bungalow that has been upgraded
  with insulation and new windows.
• Note the heat loss at the basement walls.
• 8 C difference between ambient and window
  temperature.

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Heat Loss - Thermography

• Typical 1960 era bungalow.
• Living room - East wall
• Note the effects of thermal bridging in the
  walls. Each 2 x 4 shows quite clearly.

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Heat Loss - Thermography

• Typical 1960 era bungalow.
• Rear door - South wall.
• Single pane window and no caulking or weather
  stripping at door frame show up as localized cold
  spots.

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Heat Loss - Thermography

• One of the major advantages of this approach is
  the ability to keep an on-going record of the
  changes to the heat loss picture within your
  home.

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Heat Loss - Calculated Estimate

• There are several ready made programs and
  mathematical techniques for calculating heat
  loss. HOT 2000 is one of the more popular
  packages in use.
• Most of the simple packages allow you to input
  ceiling height, floor space, wall openings and
  coverings and estimated R value of the insulation
  and will provide an estimated heat loss value.
• While these are useful for estimating how big
  your conventional furnace needs to be, they will
  not allow for the real world issues (air leaks,
  wet insulation, mouse holes, etc) which will
  determine your actual heat loss.

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Heat Loss - Calculated Estimate

• HOT 2000 is probably the software tool of choice
  for many designers and builders.
• It allows you to define your wall structures,
  window types and materials, expected weather
  conditions and heating systems.It then
  automatically calculates the expected energy use.
• Natural Resources Canada

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Heat Loss - Point Measurement

• The point measurement technique for analyzing
  heat loss is very time consuming and tends to
  miss a lot of small air leaks and insulation
  issues.
• Basically, you lay out a grid of points to be
  measured on your walls, roof and floor. Now you
  take a thermocouple and measure the surface
  temperature of the first point. Record the
  temperature at that point. Repeat until you have
  completed your grid of points. Now you see why
  few if any people will do it this way.

44
Temperature

• Often you are monitoring temperature in relation
  to some other issue ( heat loss, hot water
  systems, electrical efficiency, etc.) and you
  need to know an exact value.
• There are a variety of different temperature
  measurement technologies.
• Thermocouples
• Solid state sensors (thermistors, controller
  chips)
• RTD (Resistance Temperature Devices)

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Temperature - Thermocouple wire

• The most common approach for measuring
  temperature is the thermocouple. It is merely two
  pieces of wire of different metals that are
  twisted together at the end. The milli-volt level
  signal is measured and converted into a
  temperature reading.
• These are simple, robust and quite accurate, but
  they are difficult to directly interface to a
  computer (for automatic recording)

46
Temperature - Thermistors

• These are common in inexpensive monitoring
  system, but suffer from non-linear measurements
  over a wider temperature range. This means that
  each thermistor must be calibrated individually.
• These are simple to interface to a computer or
  meter as they can be configured as a voltage
  divider which allows their to be measured
  directly.

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Temperature - Controller chips

• These are specialty integrated circuits which
  are designed to directly interface with a
  computer or data logger.
• While they are much more expensive than
  thermistors or thermocouples, they are preferred
  for industrial applications as all of the
  interface circuitry is built into one package.
  Many of them can be configured to control heaters
  and other industrial devices directly.

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Temperature - RTD Probes

• These are specialty resistors with 2, 3 or 4
  wires.
• They are extremely accurate, but are also
  expensive and require a special meter to
  interface to them.
• Generally these are only used in laboratory
  applications.

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Temperature - Measurement Tools

• Start with a good digital multi meter which will
  accept type K thermocouple wire as a input.
• Fluke 87 V
• Beckman 321
• Fluke 80TK Thermocouple module (converts any
  meter to a thermocouple meter)
• Purchase a small amount (10 - 20) of type K
  wire and about 6 modular plugs and build your own
  thermocouples.

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Water Use

• Domestic water isnt often considered as an
  energy issue, but in many cases the heating of
  domestic water is a sizeable part of a households
  heating costs.
• The other energy issue with water use is the
  energy used to pump it from the well or cistern
  to the household plumbing. While not an issue in
  urban environments it is an issue in some
  suburban and rural environments.

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Water Use - Domestic Hot Water

• One of the largest consumers of heating fuel
  over the course of the year is the hot water
  heater.
• While it is possible to monitor the fuel
  consumption of the natural gas hot water heater
  by monitoring the natural gas flow, this is an
  approach best left to professionals.
• It is simpler to monitor how much water flows
  through the hot water heater.

52
Water Use - Domestic Hot Water

• By inserting an ordinary water turbine meter in
  the cold water inlet line of the heater, you can
  accurately monitor how much hot water you use.
• By placing it into the cold water line you dont
  require a high temperature rated turbine.

53
Water Use - Domestic Hot Water

• This particular unit can be read directly from
  the mechanical counter display or can be
  connected to the pulse input of a data logger and
  the amount of water used can be recorded
  electronically.

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Data Acquisition

• Many of these measurement applications benefit
  from automation of the recording procedure.
• Power consumption, temperature monitoring, water
  consumption all have sensors that can be
  interfaced to data logging systems.
• This allows the user to record all of these
  readings without running around with notepad in
  hand.

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Data Acquisition - Types

• Data loggers break down into three major types
• PC based units which use a computer to provide
  the control intelligence and data storage.
• Programmable Logic Controller type units which
  will acquire data and upload it through a network
  to a computer.
• Standalone data loggers which acquire the data,
  store the data and may even do some processing of
  the data without any outside hardware.

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Data Acquisition - PC Based

• PC based units which use a computer to provide
  the control intelligence and data storage.
• This is often the least expensive approach and
  works well for the householder, but does require
  that you dedicate a computer to the application.
• Some of the PC based units come with software
  designed for acquisition, but some units will
  require you to build your own program.

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Data Acquisition - PC Based

• Manufacturers
• Dataq
• Omega
• Weedtech
• Cyber Research

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Data Acquisition - PLC Units

• Programmable Logic Controller type units which
  will acquire data and upload it through a network
  to a computer.
• These are mostly used in industrial control
  systems, but often have sophisticated data inputs
  to accommodate the wide array of industrial
  sensors.

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Data Acquisition - PLC units

• Manufacturers
• Alan Bradley
• Opto 22

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Data Acquisition - Standalone

• Standalone data loggers which acquire the data,
  store the data and may even do some processing of
  the data without any outside hardware.
• These are often the most flexible units, but also
  quite expensive. It is possible to rent or lease
  these units from industrial suppliers.

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Data Acquisition - Standalone units

• Manufacturers
• Dataq
• Omega
• Campbell Scientific
• Cyber Research
• Yokogawa

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Data Acquisition - Inputs

• Data loggers can be configured to accept a very
  wide variety of input signals.
• Line level AC signals
• Low level voltage signals
• Low level current signals
• Thermocouple type signals
• Low level pulse signals
• TTL or CMOS digital signals
• Switch or relay contact signals
• Industrial communications protocols

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Data Acquisition - Our Approach

• The solution I recommend for serious monitoring
  of a variety of inputs is the Yokogawa DX-100
  series of paperless chart recorders.
• These units will accept a wide variety of inputs
  and will save the data to a floppy disk.
• They can also be configured to send your data via
  the internet to a standard web / ftp server.

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Other Tools and Solutions

• Every time you look at measuring anything energy
  related in the household, stop and look at how
  the local industrial instrument companies do that
  measurement.
• In a large industrial application there may be
  thousands of sensors and measurements. In order
  to have these economically viable, most
  manufacturers have come up with robust,
  relatively inexpensive instruments to do what you
  want.

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KISS - Keep It Simple Sir!

• Before you step out and start designing a tool
  or application to monitor your energy use, look
  at commercial-off-the-shelf equipment.
• Let someone else pay for the research and
  development costs to monitor energy.
• How do the utilities do this? They have an
  interest in keeping costs reasonable and
  equipment reliable.

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Applause Please!

• Actually the best approach to monitoring
  anything is to keep up to what the rest of the
  world is doing.
• Dont consider this to be the last word in
  instruments for energy audits.
• Even while creating this presentation, I found
  items that were worth another look once I had
  some more spare time.