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Instruments for Energy Audits

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Title: 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?

7
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)

9
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.

11
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.

12
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.

14
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.

15
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.

16
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.

17
Electricity - 120 volt plug-in
  • Recommended approach.
  • P3 - Kill-a-watt.
  • ULM - EM100
  • EED - Watts Up

18
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.

19
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.

20
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.

21
Electricity - 240 volt plug-in
  • Recommended approach.
  • Estimate power use.
  • Surplus utility meter.
  • Dent Instruments - ElitePro Logger

22
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.

23
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.

24
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.

25
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.

26
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.

27
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.

29
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.

30
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.

31
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.

32
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.

33
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.

34
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

35
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.

36
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.

37
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.

38
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.

39
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.

40
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.

41
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.

42
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

43
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)

45
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.

47
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.

48
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.

49
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.

50
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.

51
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.

54
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.

55
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.

56
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.

57
Data Acquisition - PC Based
  • Manufacturers
  • Dataq
  • Omega
  • Weedtech
  • Cyber Research

58
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.

59
Data Acquisition - PLC units
  • Manufacturers
  • Alan Bradley
  • Opto 22

60
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.

61
Data Acquisition - Standalone units
  • Manufacturers
  • Dataq
  • Omega
  • Campbell Scientific
  • Cyber Research
  • Yokogawa

62
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

63
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.

64
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.

65
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.

66
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.
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