22 | HVAC
To align expectation and reality, a formal risk assessment is undertaken to identify all the variables that place your energy targets at risk. The outcome of which is an accurate baseline to predict, track and optimise energy performance for the life of the building.
opposite: AE Smith’s David Odd (right) with a client on site at a Sydney office tower.
Simulate building energy performance Returning to the racing car analogy, every driver would benefit from a course simulation to know what’s coming before the real race begins. A tool that allows you to do just that for a building, and thereby accurately assess risk, is Dynamic Thermal Modelling. A 3D model of the facility is built and meta-data is loaded such as the thermal properties of every element and every room, internal heat loads such as occupants and lighting, load reactions of HVAC equipment and any known equipment inefficiencies. The model is then subjected to a year’s worth of dynamic weather data including ambient temperatures, cloud cover and wind speed. This technology is often used for new construction projects to predict energy performance, but has only recently been applied by AE Smith to building retrofits and refurbishments,
How to save energy
using existing performance data. Done correctly, this delivers a very accurate energy profile for the life of the building for each piece of HVAC equipment, creating a baseline for any HVAC upgrade you can imagine. It
without capex
also allows a NABERS rating to be predicted far more accurately.
Turn your BMS into an HVAC watchdog Once there is a reliable baseline, alarms can be added into a BMS to alert a facility manager to energy wastage. Typically, though,
Energy savings and NABERS rating maintenance without dipping into capital expenditure is possible when you use your Building Management System (BMS) to its full potential, writes DAVID ODD, National Sustainability Engineer, AE Smith.
a BMS only provides alarms for system faults – for example, when a piece of equipment fails to start when scheduled. However, it won’t set off an alarm if that same piece of equipment is running when it shouldn’t be. While the existing sensors in the building are already connected, the energybased alarms that use these sensors are, surprisingly, not
I
programmed as standard practice. There are myriad energy focused alarms that can be magine you’re sitting in a racing car. You’re in the
in existing facilities. The value of removing the blindfold is
added in to any BMS. These provide alerts long before energy
driver’s seat on the starting grid. You feel the engine
undeniable, particularly when it promises energy savings
reports reveal a problem. Consider installing alarms to check
throbbing. It’s hot and it’s noisy. The start flag goes
and maintenance of a building’s hard-earned NABERS
for leaking valves, correct economy cycle operation and
down and your pit crew’s screaming at you over
rating. All without spending any of your capex (capital
equipment running out of schedule.
the radio, “Go, go, go!” It’s then you realise you’re
expenditure) budget.
In one building in Sydney, AE Smith identified 1200 individual alarms that could be added to the BMS with no
blindfolded! You take off down the straight. You hit the wall
Understand what puts your energy targets at risk
additional sensors.
right now. It can’t see the corners in the road ahead, such as
The first step to reduce risk is to understand the difference between expectation and reality. Expectation is based on an understanding of how a
to optimise your systems to reduce energy use.
changes to the weather throughout the day. In effect, your BMS
building HVAC system operates using historical data, energy
Thermal comfort is complex because it’s related to air
is blindfolded as well, bouncing from one set point to another.
consumption models and future vacancy rates, whereas
temperature, humidity, air movement, radiant heat sources,
on the right, so you turn left. You hit the wall on the left, so you turn right. It’s scary how little control you actually have. Now, replace the car with the Building Management System (BMS) in your facility. This is exactly how it’s ‘driving’
With HVAC systems typically accounting for 60 to 70
right: It’s possible to build a very accurate energy profile for the life of the building for each piece of HVAC equipment, creating a baseline for any HVAC upgrade you can imagine.
Once energy wastage is under control, you can look at ways
Measuring the temperature of comfort
reality is driven by other, less predictable factors such as the
clothing levels and the metabolism of every individual
percent of Base Building Energy consumption, arguably
weather, the behaviour of occupants, the placement of the
occupying the space. But for the facility manager, only one of
your BMS poses the single greatest risk to controlling energy
thermostat, the efficiency of equipment.
these variables is controllable – air temperature.
FM JUNE | JULY 2014
above right: Thermal comfort is complex because it’s related to air temperature, humidity, air movement, radiant heat sources, clothing levels and the metabolism of every individual occupying the space.
www.fmmagazine.com.au
www.fmmagazine.com.au
JUNE | JULY 2014 FM
22 | HVAC
To align expectation and reality, a formal risk assessment is undertaken to identify all the variables that place your energy targets at risk. The outcome of which is an accurate baseline to predict, track and optimise energy performance for the life of the building.
opposite: AE Smith’s David Odd (right) with a client on site at a Sydney office tower.
Simulate building energy performance Returning to the racing car analogy, every driver would benefit from a course simulation to know what’s coming before the real race begins. A tool that allows you to do just that for a building, and thereby accurately assess risk, is Dynamic Thermal Modelling. A 3D model of the facility is built and meta-data is loaded such as the thermal properties of every element and every room, internal heat loads such as occupants and lighting, load reactions of HVAC equipment and any known equipment inefficiencies. The model is then subjected to a year’s worth of dynamic weather data including ambient temperatures, cloud cover and wind speed. This technology is often used for new construction projects to predict energy performance, but has only recently been applied by AE Smith to building retrofits and refurbishments,
How to save energy
using existing performance data. Done correctly, this delivers a very accurate energy profile for the life of the building for each piece of HVAC equipment, creating a baseline for any HVAC upgrade you can imagine. It
without capex
also allows a NABERS rating to be predicted far more accurately.
Turn your BMS into an HVAC watchdog Once there is a reliable baseline, alarms can be added into a BMS to alert a facility manager to energy wastage. Typically, though,
Energy savings and NABERS rating maintenance without dipping into capital expenditure is possible when you use your Building Management System (BMS) to its full potential, writes DAVID ODD, National Sustainability Engineer, AE Smith.
a BMS only provides alarms for system faults – for example, when a piece of equipment fails to start when scheduled. However, it won’t set off an alarm if that same piece of equipment is running when it shouldn’t be. While the existing sensors in the building are already connected, the energybased alarms that use these sensors are, surprisingly, not
I
programmed as standard practice. There are myriad energy focused alarms that can be magine you’re sitting in a racing car. You’re in the
in existing facilities. The value of removing the blindfold is
added in to any BMS. These provide alerts long before energy
driver’s seat on the starting grid. You feel the engine
undeniable, particularly when it promises energy savings
reports reveal a problem. Consider installing alarms to check
throbbing. It’s hot and it’s noisy. The start flag goes
and maintenance of a building’s hard-earned NABERS
for leaking valves, correct economy cycle operation and
down and your pit crew’s screaming at you over
rating. All without spending any of your capex (capital
equipment running out of schedule.
the radio, “Go, go, go!” It’s then you realise you’re
expenditure) budget.
In one building in Sydney, AE Smith identified 1200 individual alarms that could be added to the BMS with no
blindfolded! You take off down the straight. You hit the wall
Understand what puts your energy targets at risk
additional sensors.
right now. It can’t see the corners in the road ahead, such as
The first step to reduce risk is to understand the difference between expectation and reality. Expectation is based on an understanding of how a
to optimise your systems to reduce energy use.
changes to the weather throughout the day. In effect, your BMS
building HVAC system operates using historical data, energy
Thermal comfort is complex because it’s related to air
is blindfolded as well, bouncing from one set point to another.
consumption models and future vacancy rates, whereas
temperature, humidity, air movement, radiant heat sources,
on the right, so you turn left. You hit the wall on the left, so you turn right. It’s scary how little control you actually have. Now, replace the car with the Building Management System (BMS) in your facility. This is exactly how it’s ‘driving’
With HVAC systems typically accounting for 60 to 70
right: It’s possible to build a very accurate energy profile for the life of the building for each piece of HVAC equipment, creating a baseline for any HVAC upgrade you can imagine.
Once energy wastage is under control, you can look at ways
Measuring the temperature of comfort
reality is driven by other, less predictable factors such as the
clothing levels and the metabolism of every individual
percent of Base Building Energy consumption, arguably
weather, the behaviour of occupants, the placement of the
occupying the space. But for the facility manager, only one of
your BMS poses the single greatest risk to controlling energy
thermostat, the efficiency of equipment.
these variables is controllable – air temperature.
FM JUNE | JULY 2014
above right: Thermal comfort is complex because it’s related to air temperature, humidity, air movement, radiant heat sources, clothing levels and the metabolism of every individual occupying the space.
www.fmmagazine.com.au
www.fmmagazine.com.au
JUNE | JULY 2014 FM
24 | HVAC
Research shows that the ideal temperature for the majority of occupants will still cause discomfort to five percent of building occupants. Any adjustment to the ‘ideal’ temperature to appease the unhappy occupant is likely to cause even more people to be dissatisfied. So, how can you keep the most people comfortable, whatever the weather, and still save energy?
To align expectation and reality, a formal risk assessment is undertaken to identify all the variables that place your energy targets at risk.
Smart enough to predict the future Australia’s CSIRO developed a system called BuildingIQ, which optimises energy consumption, energy costs and occupant comfort utilising Predictive Energy Optimisation. This technology continuously monitors inputs including hourly weather forecasts, occupancy, demand response events and real-time energy prices.
Using a change of season as an example, research tells
The system begins with a ‘watch and learn’ phase as it
us the majority of people will be more comfortable with a
builds a thermal dynamic model of the facility and learns
higher space temperature in summer than in winter. As
how the building reacts to changes in load such as occupancy
many buildings have a constant annual set point of 22.5
and weather. When the system is fully deployed, usually
degrees Celsius, this in fact means more energy is used
only two to three months after installation, it makes hourly
for cooling throughout summer than is required to keep
adjustments to set points to achieve 10 to 25 percent energy
occupants happy.
savings on the HVAC system overall, while maintaining high
A simplistic solution would be to manually adjust the set point based on the current ambient temperature. However,
levels of occupant comfort. For commercial buildings, these energy savings can result
this doesn’t take into account the fact that people take time to
in a NABERS improvement of 0.5 to 1 Star, with little or no
acclimatise to changes in the weather.
capital investment – and no disruption to building operation
If you have a string of cool days and then a much hotter
and occupants.
day, people will likely still be wearing warmer clothing. But if you have four warmer days in a row, by then people will
Changed HVAC maintenance practice
have changed their dress and will accept a gradual change
Back in the pits your crew is collecting and analysing all sorts
in set point.
of information to inform your next lap, with the aim of taking
A more intuitive solution would be to build in Adaptive
your blindfold off. Once you start collecting and trending
Temperature Control algorithms into your BMS. These
data on your building’s system performance, you can identify
gradually adjust set points, (possibly just 0.1 degree per
energy wastage, faults or imminent failures. With enough
day) based on a weighted rolling mean of previous ambient
data, the way you maintain your facility can be changed for
temperatures.
a better outcome.
Both of these methods will improve occupant comfort
Routine preventative maintenance has been around since
levels and save energy. Neither method will truly remove ‘the
the start of the Industrial Revolution. When you monitor and
blindfold’ because they’re based on the previous days’ and
report on the performance of a system remotely and in real
weeks’ weather. To remove the blindfold entirely, you need
time, you can start to employ condition-based maintenance,
a system that can look into the future.
a much more effective modern practice.
FM JUNE | JULY 2014
www.fmmagazine.com.au
26 | HVAC
Time intervals for maintenance are adjusted, tasks that affect energy consumption are optimised, and faults are identified and rectified faster. These measures will reduce overall operating and servicing costs to your facility.
Energy saved, capex budget intact Imagine how much easier your life would be if you woke up tomorrow and your facility was consuming less energy, with less comfort complaints, and you still had your capex budget intact. There are many ways to save energy even if you’ve already completed an upgrade and your BMS is optimised. You can use Adaptive Temperature Control, add energy-based alarms to your BMS, install Predictive Energy Optimisation with BuildingIQ and switch to condition-based maintenance with remote monitoring. All of these measures add up to taking the blindfold off and taking complete control of your facility. l David Odd is the national sustainability engineer at
Research shows that the ideal temperature for the majority of occupants will still cause discomfort to five percent of building occupants. Any adjustment to the ‘ideal’ temperature to appease the unhappy occupant is likely to cause even more people to be dissatisfied.
AE Smith, Australia’s largest privately owned mechanical services contractor and BRW Top 500 Private Company. David is a degree qualified mechanical engineer, member of AIRAH, AIRAH Accredited Energy Auditor, NABERS Assessor and CBD Assessor. As such he can conduct Energy Audits to AS 3598, certified NABERS Energy, Water, IEQ and Waste Ratings for Offices, Hotels and Shopping Centres, certified CBD Lighting Assessments and can subsequently issue Building Energy Efficiency Certificates (BEEC). He can be contacted on 1300 313 313, davidodd@aesmith.com.au, or
Australia’s CSIRO has developed a system called BuildingIQ, which optimises energy consumption, energy costs and occupant comfort utilising Predictive Energy Optimisation.
www.aesmith.com.au
FM JUNE | JULY 2014
www.fmmagazine.com.au