Title: Instruments for Energy Audits
1Instruments for Energy Audits
- Solar Energy Society of Canada
- April 2007
2The 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?
3Energy 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.
4Energy Audit
- What do we measure?
- Look at your utility bills.
- If you are paying for it, you probably want to
audit your actual consumption.
5Energy 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.
6Energy 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?
7Energy 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.
8Energy 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)
9Energy 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.
10Energy 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.
11Electricity
- 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.
12Electricity - 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.
13Electricity - 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.
14Electricity - 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.
15Electricity - 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.
16Electricity - 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.
17Electricity - 120 volt plug-in
- Recommended approach.
- P3 - Kill-a-watt.
- ULM - EM100
- EED - Watts Up
18Electricity - 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.
19Electricity - 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.
20Electricity - 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.
21Electricity - 240 volt plug-in
- Recommended approach.
- Estimate power use.
- Surplus utility meter.
- Dent Instruments - ElitePro Logger
22Electricity - 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.
23Electricity - 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.
24Electricity - 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.
25Electricity - 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.
26Electricity - 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.
27Electricity - 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.
28Natural 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.
29Natural 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.
30Natural 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.
31Heat 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.
32Heat 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.
33Heat 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.
34Heat 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
35Heat 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.
36Heat Loss - Thermography
- Typical 1960 era bungalow.
- Note the heat loss at the windows and basement
walls. - 13 C difference between ambient and window
temperature.
37Heat 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.
38Heat 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.
39Heat 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.
40Heat 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.
41Heat 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.
42Heat 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
43Heat 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.
44Temperature
- 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)
45Temperature - 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)
46Temperature - 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.
47Temperature - 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.
48Temperature - 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.
49Temperature - 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.
50Water 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.
51Water 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.
52Water 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.
53Water 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.
54Data 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.
55Data 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.
56Data 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.
57Data Acquisition - PC Based
- Manufacturers
- Dataq
- Omega
- Weedtech
- Cyber Research
58Data 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.
59Data Acquisition - PLC units
- Manufacturers
- Alan Bradley
- Opto 22
60Data 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.
61Data Acquisition - Standalone units
- Manufacturers
- Dataq
- Omega
- Campbell Scientific
- Cyber Research
- Yokogawa
62Data 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
63Data 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.
64Other 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.
65KISS - 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.
66Applause 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.