During energy audits, our team often finds situations where walls or partitions have been moved or an extension has been added to a building and the electrical and mechanical services have not been considered. This leads to reduced occupancy comfort and energy wastage. The major energy saving opportunities lie in the duct design and the lighting layout. The following case study examines the opportunities brought about by re-examining duct design.

(part 1) HVAC opportunities

The following diagrams show a case study of an existing duct layout where an extension has been added on the west facing windows of the office. Measuring the flow rates of the packaged units servicing the area alerted us to the fact that air velocities were excessive and fresh air rates were greater than 10 litres per second per person.

Figure 1 – Mechanical service duct layout with measured diffuser air velocities

What is the affect of high air velocities and what energy saving options does this present?

High air velocities cause wind chill. Wind chill is a convection process which increases the transfer of heat from surfaces such as skin and clothes.

Figure 2 – Wind chill cartoon from
www.r-p-r.co.uk/wind_chill_table.htm

In figure 1, occupants were complaining of feeling cold even though the temperature in the area was measured at a comfortable 23 degrees Celsius.

Rule of thumb

At 25 degrees C, an air speed of 1m/sec will be felt by the body as 2 degrees cooler.

If air velocities are too high there may exist an opportunity to slow the air handling fan down. This can be done via the installation of a Variable speed drive (VSD) or in belt driven fans, by changing the pulley size. Both of these methods result in fan energy savings.

Note: care must be taken not to reduce the air speed excessively in refrigerant systems as this could lead to malfunction or excessive wear and tear on the unit.

It is also important to consider what happens to the fresh air volume when slowing down air handling systems. If the fresh air intake is set to 10% which provided the occupants with precisely 10 litres per second per occupant and then adjustments are made to reduce the air flow rate by 25%, this would result in new fresh air volumes of 7.5 litres which may be too low. In a fixed fresh air system this may mean opening the fresh air damper (if it is adjustable) and in a modulating system, this will require adjustments at the controller or in the Building Management System (BMS).

An alternative to increasing the fresh air rate may exist in installing CO2 monitoring. The opportunities of which will be the subject of a later blog.

In our case study we have identified that there is an abundance of air volume and higher than required fresh air volumes. The small west positioned packaged unit was installed initially to service a different heat load presented by the west facing glass. Since then the building has been extended and the glass is now internal. This has the effect of reducing the heat load on this part of the office.

By simply reviewing duct design, a complete packaged unit has been removed from service!

By measuring the air volumes at each diffuser we can determine the quantity of excess air and how we can balance the system to improve occupancy comfort. Auditing the diffusers also highlighted some areas that did not require air conditioning such a store room, and a copy room that has been retrofitted with its own split system and extraction system (see diagram above). The following diagram shows the new layout of the HVAC ducts. Note that AC unit 3, and 4, have been extended to allow the removal of AC unit 5. By simply reviewing duct design, a complete packaged unit has been removed from service.

Figure 3 – Mechanical services duct layout after changes

It should be noted that this analysis has been made significantly easier because of the access to up to date mechanical services drawings and accurate floor plans. As any alterations are made to buildings it is important to update the floor layouts, mechanical, and electrical services drawings. If your facility does not have up to date drawings, it may be worth while seeking the services of a drafting company to develop a Computer Aid Design (CAD) set. This will allow the facilities department to track any changes as they occur and allow more efficient analysis of problems for contractors which ultimately will result in faster and more comprehensive analysis of problems.

If you know much about climate change you’ll know that cows and sheep produce a lot of greenhouse gas. In fact a cow can produce around 200 litres of methane a day, and methane has global warming potential 23 times greater than carbon dioxide. To put that into context thats 1.2 tonnes of greenhouse gas a year per cow, a bit over one quarter of the greenhouse gas produced by a car over a year. I once did an audit of a large business that grazed cattle basically to keep grass under control (it was by no means their core business), and the cattle accounted for 10% of their carbon emissions. Needless to say I recommended they switch to grazing kangaroos, which don’t produce methane.

As reported by MX The town of Ghent in Belgium has now declared Thursday a vegetarian day to help reduce carbon emissions. All government departments and schools are banning the consumption of meat on Thursdays.

Now this may seem radical to some, but I believe this is a fantastic “climate positive” initiative. In fact its something we may start in our office – a vegetarian Thursday. Its easy to do, it will save you money, and its good for the environment, and if you eat a lot of meat its good for your health too. A triple win!

And if you do enjoy meat the other days of the week consider kangaroo. Its lean. Its inexpensive. You can buy it in the supermarket, and it tastes delicious. YOu can buy it as a roast, plain, marinated and you can even get kangaroo sausages. My favourite is roast skippy.

Direct quote from the government’s 2009 budget web site:

“Households and small businesses will be able to calculate the potential dollar savings from their energy efficiency actions and make tax deductible donations to the Energy Efficiency Savings Pledge Fund. The Australian Carbon Trust will use these donations to purchase and retire Australian emissions units or purchase carbon offsets.”

What this means:

• If you voluntarily cut your household energy consumption to save greenhouse gas – sorry the greenhouse savings don’t count! If you want to reduce greenhouse gas emissions, you have to actually now go and pay to “retire” the carbon you’ve saved – and pay the government to do so. See my earlier blog posting rantings about the disincentives in the CPRS (Carbon Pollution Reduction Scheme) for more detail. Basically if you don’t pay to retire the greenhouse gas you’ve saved, the entity generating the energy (say an electricity generator) can claim it. And trade it. And you have contributed no additional greenhouse savings beyond that which the emissions trading scheme would achieve anyway.
• If you are a small business…. hang on… what is a “small business”? As only Australia’s top emitters get to participate in the CPRS doesn’t the definition of a “small business” in this context mean anyone who can’t participate in the CPRS? To participate in the CPRS you either have to directly generate over 25,000 tonnes of carbon a year, or consume more than 100 Terajoules of energy. In other words you are a small business if your annual energy consumption is less than 100 TeraJoules of energy or you directly produce less than 25,000 tonnes of carbon. What is a tera joule? You are probably familiar with kilojoules (1,000 joules), a tera joule is actually 1,000,0000,000,000 Joules. 100 TJ equates to an annual energy expense of about $2 million (as does the production of 25,000 tonnes). So, if you spend less than around $2 million a year on energy you are a “small business”!

So let me rewrite what budget actually means in plain English. “If you spend less than around $2,000,000 a year on energy, and you cut your energy use, in order to be able to also say that you’ve cut Australia’s greenhouse gas emissions you need to pay the government for it to recognise that what you’ve saved is an actual saving.”

Or, lets do a hypothetical here. Lets assume that you are a “small business” – ie your energy expense is less than $2 million a year. (What a tiny, wee business you’ve got if you’re not spending $2 million a year on energy!) You invest $10,000 in upgrading your lighting (using Mirrorlux Reflectors say). This saves you  $5000 a year on your electricity bills and about 25 tonnes of carbon annually. But if you want to say that your investment has reduced Australia’s emissions you actually have to pay. Lets say the carbon price settles at $50 a tonne. You’ll have to spend $1,250 a year to be able to genuinely say that your investment in your lighting upgrade is saving greenhouse gas. Because if you don’t, under the CPRS, the electricity generator supplying you the power that energises your lights has the right to the carbon you’ve saved.

Another hypothetical. This time you invest in a new gas heating system in your school. You spend $300,000 to put in gas space heaters and eliminate the old central heating system. It saves you approximately $20,000 a year in gas costs, and about 160 tonnes of greenhouse gas emissions a year. At $50 a tonne you have to pay the government $8,000 to “retire” the carbon you’ve saved. 40% of the financial savings you’ve realised goes to the government if you want to be able to say that your investment is actually reducing greenhouse gas emissions.

Are, you, like me, someone who believes that personal or “small business” action can do something to avert dangerous climate change? Do you, like me, spend less than TWO MILLION DOLLARS a year on energy? Well the government is clearly telling you and me that if we want to make a difference we have to pay twice. Pay for the investment to cut your emissions. And then pay the government to retire those emissions.

Isn’t there something really really wrong if we have to spend twice to cut our greenhouse gas emissions?

Its been a while since our last blog post. Which of course means we have been busy helping our customers save lots of carbon!

Its always tremendously satisfying to see customers act on our advice and thus cut their energy costs and carbon emissions. We recently helped one of our oldest customers identify savings in a building they have recently occupied, before I knew it our advice had been acted on and the next bill that comes in will be lower. As a consultant its pretty hard to beat the sense of fulfilment that comes from results such as this.

Over the last couple of years its been interesting to observe that the propensity for action is increasing. More of our customers are more willing to invest to achieve carbon savings. I think that there are a couple of  reasons for this.

Firstly, the obvious reason is that there is now much more popular support for efforts to reduce carbon emissions than there were three years ago. This has also transformed the mandate of many of the managers we deal with, to move from planning to action. Which is fantastic.

However another reason is also the experience of many of our customers. They have become “true believers” in energy efficiency because they have seen the results for themselves in the past. Two or three years ago they might have felt they were going out on a bit of a limb to put money into energy efficiency. Could our advice be trusted? But they did. And, surprise surprise, their energy consumption dropped. They saved money and carbon. Now they are much more willing to invest.

If you still haven’t seen the results of investing in energy efficiency yourself, do a small trial. Firstly, establish your baseline energy consumption. Pick a small building – for example your home – and go through the bills to establish your annual cost and carbon emissions (www.fossilfueldiet.com.au has a calculator which will help you do this). Then do some things to reduce your electricity use. Change any incandescent bulbs to compact fluorescent. If you have a beer fridge, used only occassionally, turn it off, and only turn on when needed. Rearrange your power boards so its easy to turn off stand by loads. Actively start thinking about light switches and turning off lights in empty rooms. If you can see that bad switch off habits in the household aren’t changing as quickly as you would like, try to do some things that “lock in” energy savings. For example, if your electric hot water unit is set to 70 degrees, lower this to 60 degrees, and start using timers to turn things off automatically.

You’ll learn a lot, and will see savings in your bills (remember to compare with the same time last year, as usage is seasonal). You can then apply these lessons at work to get much larger savings.

Become a “true believer” in energy efficiency and be a person of action. Simple, but something that can have a big impact when it comes to reducing carbon emissions.

This blog aims to show how acting vigorously to reduce carbon emissions is good for the environment and good for business. That it is possible to create a “win-win” with the right approach. The Emissions Trading Scheme – officially known as the Carbon Pollution Reduction Scheme (CPRS) clearly, as explained in earlier blog posts, is climate negative - its not good for the environment.  

Various blogs today responding to the release of the draft CPRS legislation by Climate Change Minister Penny Wong point out that its not just bad for the environment – it goes so far in its compensation to major emittors that its actually good for big business.  

Crikey.com refer to a study commissioned by the Australian Conservation Foundation which shows that many of the major polluters will actually benefit from the CPRS as a result of the free permits handed out. The Crikey post summarises this as follows “So let’s be clear: the the Government’s rationale for amending its already-generous ETS so that it rewarded big polluters was not to prevent the loss of jobs and emissions overseas, but to ensure the profitability of big polluters.”

Paul Gilding in the Business Spectator writes “This is as good a deal as business will get. It is easy to imagine a future government, when the icecaps have melted, the cyclones are hitting and the fires are burning, imposing a much tougher regime than the one currently on the table. The CPRS is a bad deal for the climate but it’s a great deal for business. Take it and run or you’ll rue the day you didn’t.

So lets summarise the above. The CPRS is bad for the climate, but good for big business. Its lose-win legislation – a loss for the environment and a win for those businesses that are major pollutors. In the short term anyway its a win for the major polluters, but in the long run won’t be - big business managers and shareholders won’t be immune to the effects of dangerous climate change.

Which brings me back to the argument that those of us who want to be climate positive need to be coming up with ways of reducing carbon pollution that are also great for the hip-pocket - in the short to medium term and not just in the long term. With products and services that business willingly buy because its good for the bottom line as well as being good for the environment. And that we need to be making the CPRS irrelevant – by making it so easy to be sustainable that its foolish not to. We have clarity now that the CPRS won’t cut emissions, and may actually put a floor on the amount of emissions reduction that can be achieved. Hopefully this flaw will be removed over the next few months as the legislation is debated. But we have a heck of of an innovation and entrepreneurial challenge!

And there is also a tremendous social challenge – the challenge of changing society to the point where carbon pollution becomes abhorrent and morally repugnant – for most of us.

If you care about future climate stability I’d encourage you to act as a carbon-saving innovator or entrepreneur, or to influence to create a society that is carbon-intolerant, and not put too much faith in the CPRS.