Archive for the ‘energy efficiency’ Category

Plasma Lighting update

Wednesday, May 6th, 2009

A couple of months ago Barney wrote a post on this blog about plasma lighting - a form of cold cathode fluorescent lighting. They aren’t yet on the market, but I’ve managed to get hold of a couple. I’ve just installed these lights in my house, next to a window, above each end of a sofa often used for reading at night. So how have the plasma lights performed?

Considering that they only use 8 watts of power - as compared to the 55 to 65 watts used by a 50 watt halogen downlight - they have performed well. They are cheaper than the very high performance LEDs, but produce around the same amount of light. They start up quickly - unlike many CFLs. And if I wanted, I could have put them on a dimming circuit - unlike LEDs which generally aren’t designed for dimming. They are fully sealed, so there is no air movement through the fitting into the ceiling cavity. The light colour is acceptable, although it’s perhaps slightly too blue for my liking (I’ve installed cool white lamps). But the light colour is still much more comfortable than the harsh light of a 5000K daylight compact fluoro.

There is still a significant disadvantage, as compared with a 50 watt halogen though, which is the light output. When the white curtains in the window next to the lights are closed there is just enough light to read comfortably for long periods. But when the curtains are open at night the loss of reflection from the curtains is just enough to make the light not quite bright enough for me personally. I’d like it if they were a bit brighter. The lights are mounted roughly 2.2m above the floor, directly above each end of the sofa.

I reckon that the plasma downlight is better than an LED downlight for general lighting. Certainly we haven’t had the reliability problems or failures with the few that we have tested in the office and now at my home that we have had with LEDs. We’ve spent a small fortune buying expensive LED downlights only to see them fail shortly after install. For rooms such as toilets and bathrooms, where you want full brightness within a few seconds, the plasma lights are probably a better option to a compact fluoro, and may better handle frequent switching. I look forward to plasma lights coming onto the market, as they can make a valuable contribution to reducing energy consumption and greenhouse gaas emissions.

Action gets results

Sunday, April 26th, 2009

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 ( 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.

Overnight energy audit saves $50,000

Wednesday, March 4th, 2009

We assume so much in life, both personally and at work. Our assumptions and reality aren’t always the same. An occasional “reality check” can be very valuable. I wonder what expensive assumptions our organisations might harbour?

One of our clients, a medium size organisation somewhere in Australia, discovered in a very easy way that they were unnecessarily using $50,000 extra electricity each year.

It only took an overnight audit to discover this fantastic wastage. It was done by their staff as participants in our Greenhouse Gossip program

Most staff would shut down their computers when leaving work. No one was there to see that many of the computers were turning themselves back on around 8pm! Really, who would expect that?

After their audit, the staff came back the next day, to speak to the staff members whose computers were on. They discussed this and discovered the problem. By speaking to staff in other buildings in their organisation, and the ICT people, they discovered it was across the organisation.

The problem is now solved and they have an additional $50,000 to use each year from that one building (plus other savings identified and implemented in the program).

This is the kind of benefit that a structured, inquiring program can deliver.

Sunlight in a Cable

Wednesday, February 25th, 2009

We are all familiar with the concept of the traditional skylight or solar tube that directs sunshine through a duct or a flexible tube from the roof to a ceiling. This is an easy way to get natural daylight into a room but it is dependent on tube length and on a direct route between the roof top and the ceiling. There is another way known as ‘fiber optic solar lighting technology’.

Parans , the Swedish company behind the ‘sunlight in a cable’ concept, believes that it is possible to have sunlight in every single room of an indoor environment - even underground. The principle of the Parans’ system is simple; first the sunlight is collected by panels outdoors then it is transported through fiber optic cables into carefully designed luminaires located anywhere within a building including between floors.


The system consists of a light-collecting panel called a SkyPort that’s made up of a layer of movable and a fixed layer of lenses that track the movement of the sun through stepping motors controlled via a microcomputer. These can be mounted on a roof, facade or the ground just like other solar collecting devices; however glare shields may be used to throw direct sunlight onto its surface if the orientation is not quite perfect. The SunWire, consisting of a bunch of optical cables, then guides the sunlight indoors with minimum light loss. Very high quality light can be transported for up to 15-20 metres without major losses since the decrease of intensity for visible light is only 4.6% per metre.

The Björk luminaires are designed to give a spectacular sunlight experience both as strong light beams and as ambient light. The luminaires are made from thin sheets of semi-transparent acrylic. The feeling of natural light is immediate. The light intensity under one of these luminaires can be as high as 4000 lux when 100 000 lux outdoors (based on seven metres of fiber optic cable). UV and IR radiation are naturally blocked out by the Parans system making it the perfect solution for environments where these must be avoided. It is possible to ‘switch off‘ the system in case the darkening of a room is necessary for presentations etc.

While the Parans system works perfectly well in reasonable daylight conditions it is necessary to use artificial lighting during overcast days or when the hours of daylight diminish in winter. To counteract this there is a hybrid luminaire that incorporates T5 lighting technology, which dims automatically according to how much natural light is emitted.

However, the main focus of the system is to harness as much sunlight as possible before needing any artificial lighting thus reducing energy costs and most importantly greenhouse emissions. The only power the Parans system uses is 0.9W for the motorised panels and the microprocessor. Using the Parans lighting system can lower energy costs by 20-25% annually and probably around the same percentage of GHG emissions (based on brown coal emissions).

(Ref: and

HVAC Controls to save the Poles!

Wednesday, February 11th, 2009

In almost all commercial buildings, the Heating Ventilation & Air Conditioning (HVAC) system uses the largest percentage of power. Like lighting, the HVAC operates throughout business hours but its plant consumes much larger amounts of energy. Traditionally HVAC systems source heating from gas (oil in some cases) fired boilers, and cooling from electric chilled water or refrigerant plants. Reverse cycle package air conditioners produce heating and cooling via compressors within the unit. Most large HVAC systems are centrally controlled via a Building Management System (BMS), which activates the heating or cooling relative to the demand within the serviced area. This is controlled via a temperature set point, proportional bands and dead bands.

Shown below is a simple temperature control proportional–integral–derivative (PID) controller diagram. It shows a temperature set point and heating cooling proportional bands (PB) or percentage heating/cooling.

When the thermostat within the room reads a temperature below 21 degrees the percentage heating (PB) will begin to rise. When the proportional band reaches 35% the boiler is activated and will continue to heat until 0% PB (set point) is reached. This is unnecessary because as you can see, the temperature has only dropped 1°C from 21°C to 20°C, which is still comfortable for occupants. Also, heating should not continue until 0% PB as this will cause the room to overheat and subsequently call for cooling.

This type of control configuration creates a plant room scenario similar to that in the engine room of the Titanic! The boiler and chiller are constantly in operation in order to maintain the tightly controlled set point. Comfort levels within the serviced area are also compromised as occupants constantly feel surges of warm air followed by surges of cool air.

This problem can be easily averted by changing the control settings. Within the BMS, the boiler and chiller settings can be manipulated. If the heating percentage PB is brought out to 65% for instance, the boiler will not be activated until the room temperature reaches 19.3°C, which is still not cold for occupants. Also the boiler should be programmed to cut out at 25% PB as there will be a delay on the heated air getting to the thermostat. The room will still reach set point even though heating stops at 20.3°C. This will avoid the set point being unnecessarily exceeded and the cooling being activated. The same control fundamentals apply for packaged air conditioners.

The potential savings from the alteration of simple control bands are huge. The run times of both the boiler and chiller are significantly reduced, which shows up on your energy bills. At first occupants may complain that it is too hot or too cold. If this arises, have a thermostat close at hand to check that temperatures are within standard office comfort conditions (see “What is a comfortable office temperature” Bruce Rowse Dec ’09). Advise them on appropriate dress if they are experiencing discomfort. It may also help if they are advised as to why these modifications have been made and what has been achieved.

I have been involved in a lot of these control system alterations and I can safely say that it is the cheapest, easiest and fastest way to achieve significant electricity, gas, money and greenhouse gas savings from the your largest energy consumer, the HVAC system.