HVAC equipment and industrial machinery are designed to operate at the peak capacity, to handle the worst case scenario.  However, during normal operation periods of partial load occur when the load is less than the design load.

For example, comfort cooling air conditioning systems operate for 99% of the year inside the design condition, particularly the autumn and spring months demand less capacity and injection moulding machines hydraulics cycle through full load to no load, and back to full load.

Control by Obstruction

Motors are dynamic, driving equipment that moves fluids, hydraulic fluid, water, or air, from one place to where it is needed.  Without variable speed motor control we need an additional device to either bypass or create an artificial resistance to flow.  Briefly, there are two primary means of operation:

Relief

In this situation a valve or other device might be used to divert the excess flow under part load conditions.  Commonly used applications include:

1. the differential pressure relief for chilled water systems and injection moulding machines;
2. the hot gas bypass used in refrigeration systems and chillers;

Restriction

In this situation, a device is installed to create an artificial pressure loss, and therefore reducing the flow rate.  Common applications include:

1. Inlet vanes used on centrifugal fans;

1. Regulating valves used on hydraulic systems;

However, both modes waste energy. To capitalise on the potential energy saving, the speed and hence the power consumption of the motor needs to be lowered during part load conditions.

Solutions

One solution is the tried and tested VFD (Variable Frequency Drive) it is an electronic motor speed controller that varies the motor speed to match the required load.  During periods of part load operation,  lower speeds translate into reduced power consumption, and operating cost savings.

Even a relatively small speed reduction provides attractive energy savings.  for example reducing the speed of 1500 rpm motor by 150 RPM (approximately 10%) equates to a power reduction of  27%.

Because a VFD can vary the motor speed from zero thorough to full speed, it reduces the mechanical and electrical shock and stresses during normal operation extending the operating life of your plant and equipment.

– John Herbert, Consultant

Buy the most efficient motor available, and keep it clean.

Electric motors account for nearly sixty percent (60%) of the global electricity consumption!  Comparing the total life operating cost with the first cost is instructive. Typically the CapEx (capital cost) is only 1 % of the total cost of ownership (e.g. 20- 25 years lifespan for HVAC equipment) Additionally, during the first year of operation a motor will consume electricity to cover its CapEx value, considering the life time cost purchasing the most efficient motor is very cost effective investment.

Look after your motors

Thirty years ago I visited facilities with a real boilerman, he did more than just operate the boiler, but that was his title. Perhaps boilerperson would be politicly correct today.  Back then, he was a rare breed,  and fiercely proud of his domain.  Upon entering any plant room you were greeted by gleaming plates,  gauges, copper and brass polished bright,  polished cladding, the room itself fit for dining, but not today cleanliness has gone the way of the dinosaurs.

One popular and possibly most annoying pastime of today’s fitter is over-painting equipment labels,  indeed it’s seems to be compulsory. Yet it still holds true today, a clean facility will have fewer problems.

One obvious and often overlooked matter is electric motors,  simply keeping the cooling fins clean maintains the heat transfer efficiency from the motor fins to the surrounding air. The failure to follow simple maintenance procedures can be costly, allowing motor winding temperature to exceed the manufacturers rating by 5 DegC halves the operating life of the motor! Keep the plant and motors clean.

– John Herbert, consultant, energyLAB

– John Herbert,  consultant

Recently I was talking to a colleague about the pervasive use of the “percentage”.  You will have seen the advertising offering up to 30% energy savings ,  and no doubt you will have seen NGO’s giving awards for 25% percent energy savings!

It’s a great marketing, but not science.

1. When a system or building is performing poorly,  it’s a simple matter to find one time savings, try to find another 30% saving in the second year!
2. Good data is critical, don’t compare apples with pears.  For example, if building operation in year one 24/7, and in year two it is only 9-5. Just comparing the operating annual cost, magically you have made tremendous energy savings. Quoting these raw cost savings, without a good  metric or benchmark is quick, easy and misleading.  For systems influenced by the weather  i.e.  air conditioning and winter heating,  adjusting the data using degree days takes account of weather variations.
3. Benchmark  – comparing your system, or annual operation cost to an industry standard is a meaningful, however finding a benchmark can be difficult indeed.

Some advisers that can’t do the math to quantifying the energy and cost savings,  so revert to percentage generalisations – Don’t try fool your client -  give data not generalisations.

Pitching your cost saving solution is not always easy, simply stating an energy saving is often dry, and frankly difficult for the majority of people to grasp.  Use an illustrative comparison that can be easily visualised.

For example, our proposal will save xxxx $ -  that’s the same as saving as driving 100,000 km per year.  Choose a comparison that can be readily identified, so your manager can see an image and the savings.

- John A. Herbert, consultant

Date:  15-18 September 2010

Location: Guangzhou Exhibition Centre,  Pazhou complex,  Gz.

The event will be held this yea r in conjunction with the 7^th China International SME Fair (CISMEF).

Visit us at the EnergyLAB booth!!

From our earliest days our parents drilled us about the roads, and road safety. Everyday, every opportunity it was hammered home — look left, look right, then look left again was one of the many rules of life pushed upon us.

As with road safety, we need to appreciate that “Energy Efficiency” is more than a one-time event – A wider carbon consciousness is needed.

Its more than a one-time event, its more purchasing a energy efficient  appliance.  Ultimately, energy efficiency must become full-time carbon consciousness that includes everything from turning off unnecessary lighting to replacing light bulbs to turning off appliances such as televisions when not in use.

A study from the United Kingdom [link] importantly highlights that carbon consciousness will save more than thought possible.  The study shows the gross carbon emitted is thirty percent (30%) higher than individually calculated outputs.  Dr Adam Hawkes author of the paper said:

“This means any reduction we make in our electricity use — for example, if everyone switched off lights that they weren’t using, or turned off electric heating earlier in the year — could have a bigger impact on the amount of carbon dioxide emitted by power stations than previously thought.

Because we have only two power generators the outcome of this study will not impact the  carbon emission factors used in Hong Kong.  However, if we consider our neighbours, and S.E. Asia countries, higher emission factors offer the potential for more carbon savings — and carbon consciousness will have a greater impact than previously imagined.

-  John A. Herbert, Consultant

Mr John A. Herbert, director of energyLAB Limited, was pleased to announce that energyLAB will be one of the title sponsors for the HAESCO annual reception in May 2010.  He said “we must try and support this fledgling  industry”.  energyLAB conducts high level energy audits for organisations, including commercial properties and real estate.

energyLAB limited - bronze sponsor

HAESCO 18 May 2010

energyLAB - energy consultant logo

keynote by Ms Anissa Wong, JP HKSAR Permanent Secretary for the Environment / Director of Environmental Protection

He joins the other directors of HAESCO, working together to promote energy services businesses and opportunities in Asia.

The report covers the usual issues, so if you are looking for new content you would be disappointed. Although several industry leaders including US DOE Steven Chu provide some quotes which could be useful to help persuade your own CFO.

Whilst there is a plenty of talk, action needs to follow, Energy Efficiency is not a thing or product that can be bought, it’s  a process and persuading Asian CEO’s, management decision makers, and CFO’s to invest in a process is real the future.  Governments, for example United Kingdom have use the 10% carbon tax as one incentive to drive improvements. Yet whilst other governments still procrastinate, Asia’s would factory will keep producing the products for European and US consumers.

- John Herbert, Director

On the whole, the updated carbon audit standard is largely unchanged the major difference being the changes to the emission factors. However whilst minor, the whole revised standard has been released as one document.

- John Herbert

related: Carbon Auditing standards