Urban Heat Island

infra red Hong Kong Island by John A. Herbert

Here is an interesting image, the infrared of Hong Kong Island promenade, the sum has been shining all day and the path is absorbing the sun’s energy, the walkway is warmer than its surroundings. At night, that stored energy keeps the area warm, warmer than the air temperature, a good example of the urban heat island effect.

Infra-red is accurate and very sensitive, the image even shows the edges of the manhole covers!

It is not too difficult to avoid this problem (remember white reflective roof post) choose a material with a high solar reflectance index (SRI) say 80 or above, that will reduce the energy absorbed.

last large coal-fired power plant in Beijing closed by John A. Herbert

by John A. Herbert

Great news from Beijing, mark your diary, on 20 March 2017, RTHK (www.rthk.org.hk) reported that “….the last large coal-fired power plant in Beijing has suspended operations, with the city’s electricity now generated by natural gas” LINK: http://news.rthk.hk/rthk/en/component/k2/1320043-20170319.htm Meanwhile here in Asia’s World city, burning coal for power generation continues.

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E-Bus for Hong Kong? Not soon Enough

Hong Kong may have a new electric bus, sooner than you think. The new vehicle was spotted around town last week, outside HKPC in Kowloon Tong, and at the Eco Asia Expo 2015 exhibition.

Left to Right: Simon Cheung (China Dynamics), Lyndia Hui (Green Council) and John A. Herbert (HAESCO)

Left to Right: Mr Simon Cheung (China Dynamics), Ms Linda Ho (Green Council CEO) and John A. Herbert

Considering Hong Kong’s small area, this E-Bus must be killer app for Hong Kong’s urban pollution problems. I understand that many argue against EV’s because the rational is that EV’s merely move the pollution problem from our lungs to the distant electricity generating stations, and they claim that is a problem?

Repeated studies have shown the pollution at street level is often intolerable with excess PM2.5 PM10 and NOX. (nitrogen oxides). However, these power generating stations already have pollution control measures in place, and are discharged far from the lungs of busy pedestrians presently dodging the fumes in Central.

Burning diesel at street level should be a crime nowadays! Now we know, the diesel combustion (petroleum diesel not bio diesel) process the combustion is incomplete, and creates tiny microscopic soot particles, they are so small they are easily inhaled, hence the grave concern over particulates in the PM2.5-10 range. Hong Kong’s EPD in fact publish the monitoring data:
http://www.epd.gov.hk/epd/english/environmentinhk/air/data/air_data.html

Screenshot - EPD Pollution Monitoring Data

Screenshot – EPD Pollution Monitoring Data

And the source of those PM2.5 and PM10 particulates? the overwhelming majority are created by diesel engine discharged at lung (street) level. Furthermore, I understand that the E-Bus creators (designed in Hong Kong!) have useful applications in mind for the ‘used’ batteries, to avoid creating another waste problem dealing with spent batteries. I had a tour, inside it looks like every other Hong Kong bus, in fact you would find it hard to distinguish between the diesel  version, except for the tailpipe.

Another sustainability perspective to consider, beside being conceived and designed in Hong Kong, it is manufactured close to home, avoiding the related emissions caused from importing buses from Europe which I understand is the usual practice.

Let us hope it is on the road, here in Hong Kong, sooner rather than later. One of Hong Kong’s key selling points must be the fantastic low cost, public transport system, but can it be improved? Of course, there is always room for improvement, as Paul Zimmerman points out, there are water taxi’s and ferries that would improve connectivity across the harbour, however the Hong Kong public transport system is one that many cities envy.

Hong Kong’s E-Bus was also featured by RTHK 

e-bus hong kong hkpc by RTHK

credit: RTHK

short link: bit.ly/hongkong-ebus

by John A. Herbert

unintended consequences

We are all hindered by unintended consequences, Sweden one might argue a global leader for harvesting leftover heat was hamstrung by the law which prevented other suppliers accessing the district heating grid, but that changed when a law was passed last year that allows outside suppliers to deliver heat through the district heating grid. Now the town of Kiruna in northern Sweden can use waste heat from their local industry to cheaply heat homes, a neat solution when the mercury hits -30 Deg C in winter. Details are scarce in the Guardian article [1] however using waste heat whether from industry or power generation is cost-effective when the distance (where increasing distance equates causing increasing heat loss) between the source and end-user is not great.

Less commonly known is that waste heat can be used in the tropics to drive air conditioning, necessary in large parts of Asia. Low grade heat energy is often dumped into rivers or the sea, instead it can be used to change the concentration of liquid salt, e.g. lithium bromide, creating cold water for comfort cooling.

[1] http://www.theguardian.com/sustainable-business/2015/may/01/leftover-industrial-heat-to-warm-swedens-chilly-northern-city

Air Conditioning Leakage

by John A. Herbert
condensate

Spring has arrived, the humidity is increasing and air conditioning and their power consumption start in earnest.

Air conditioning systems rely upon converting electrical energy at the central chiller to chilled water, yet these veins, the chilled pipes are often hidden from view, deep inside the building behind locked plant room doors. The chilled water piping should deliver cold water from the chiller at approximately 7 deg. C to the AHU’s.

However, the photo above is a big problem, the chilled water piping is insulated, covered with vapour barrier, and finished with aluminium cladding. However, condensation is clearly visual and that equates to lost energy. If it not repaired the water wicks along the piping and thermal insulation, causing more condensation, increasingly wasting more energy.

To rectify the wet and damaged thermal insulation needs to be cut back and removed, piping cleaned and insulation replaced, and wrapped with a new vapour barrier, and re-clad. the new vapour barrier is key!! to prevent moist air contacting any surface, including the insulation, having a lower dew point temperature.

BEAM for Offices Training

BEAM for offices training

There is about 40 Million sqm of office space in Hong Kong, with renovation and fitting out projects representing the bulk of active projects each and every day. Because of their number and repetitive nature these projects have a significant impact on the environment and our quality of life. Responding to market demand and recognising those who choose to do this work in an environmentally friendly fashion and offer users a healthier workspace, a new green building rating tool was created locally by BEAM Society Limited: BEAM Plus BEAM for green officesInteriors. The new addition to the suite of BEAM green rating tools covers fitting out works for commercial premises, offices, hotels, and retail spaces. This two (2) hour training course is specially designed solely for BEAM Professionals. It will introduce the new framework, grading, credits and features of the new rating tool. Undertaking this training course is a prerequisite for all BEAM Professionals to submit Interiors projects for assessment and certification using the BEAM Plus Interiors rating tool.

Speaker: Mr John A. Herbert REA, FCIPHE, MASHARE, BEAM Pro
John has worked across Asia for 20 years, he is an authority on sustainable building development, GB rating tools, and energy efficiency. He is the Managing Director and Head of Sustainable Building at Kelcroft E&M Limited, and he was one of the first BEAM Professionals in Hong Kong. John led the team developing BEAM Plus Interiors in 2013, is chairman of the BEAM Technical Review Panel, and a member of the BEAM Technical Review Committee.

 

Article: Technical Due Dilgence

An interesting English language website, which seems to be focused on the China market (http://www.rightsite.asia) has published my Technical Due Diligence article, here is the link

– John Herbert, Consultant, Kelcroft E&M Limited
helping lower the cost and impact of doing business in Asia

A Systems Approach for Total Cooling Design

I have long advocated for the “Whole Building Design” approach, it has been an uphill struggle without a doubt. The renewed interest in green building has certainly increased awareness of this important skill. Now more help is at hand the Whole Building Design Guide (http://www.wbdg.org). It is published by the National Institute of Building Sciences (USA) so is naturally it is biased towards the USA market, however it will save us acolytes tremendous effort in the longer term.

The whole building design approach is really simple. If designers conceptualise buildings without considering energy costs from day one, that building will surely become an energy hog. The WBD (Whole Building Design) approach means thinking about the whole building impacts simultaneously.  A simple example, if a west facing glazing is shaded, reduce or eliminated, both the initial capital cost, and operating cost for the cooling plant will be reduced.  Since 63% of Hong Kong’s carbon footprint, and 90% of all the electricity generated is attributed to buildings, the opportunities for improvement are obvious.

The hidden beauty is that the principle is equally applicable to other sectors, including process, industry, and even cooling systems. And the latter is one area where the WBDG has overlooked an opportunity to apply whole system design approach for cooling systems.

Too often, building codes and energy codes only specify COP (coefficient of performance) for chiller plant, yet it is one part of the cooling system cycle. In the diagram below, each circle represents a heat exchange process.

kelcroft designConsider all the electrical power consumed for every heat exchange process, and divide by the total cooling capacity gives us a common metric kilowatts per ton (Kw/Ton) defining the whole cooling system efficiency.

The whole system includes all the electrical power used by:

  1. motors driving fans in the AHU (Air Handling Units) and other air moving equipment
  2. motors driving the chilled water pumps
  3. motors powering the chiller compressor
  4. motors driving the condenser water pumps
  5. motors driving fans in the cooling tower

With the focus elsewhere many cooling systems operate inefficiency in a range between 1.0-1.2 Kw/TR, whereas an efficient system would operate nearer 0.6-0.70 Kw/TR.

energyLAB limited Hong Kong

The question is where is your system operating?  If your cooling system is operating in the red, the good news is you have opportunities for improvement.

John A. Herbert
Consultant
Kelcroft E&M Limited

helping lower the cost of doing business in Asia

Saving Energy in Steam Systems

Opportunities to lower operating costs for Steam systems using energy efficiency improvements – there are plenty opportunities to improve industrial energy efficiency for steam systems in China, and elsewhere in Asia. And some projects may also qualify to earn extra income from a carbon credit (officially known as CER – Certified Emission Reduction) under the Clean Development Mechanism (CDM).

I see the potential for the wider application  of CDM AM0017, which is the official CDM methodology for calculating the Steam system efficiency improvements by replacing steam traps and returning condensate.

System Systems
Steam is still a marvellous high density medium for transporting heat energy, and an essential part of industrial process needs, however a high pressure fluid, at temperatures up to 500 Deg C needs to be respected.  Twenty years ago I cut my teeth on steam projects in the United Kingdom, a typical hospital project demonstrates the utility of steam, where it is used for autoclaves, sterilising, catering, cleaning, domestic hot water, humidification, and also heating systems.

A steam system, consists of four main elements:

  1. Steam Generation
  2. Steam Distribution
  3. Steam Traps
  4. Condensate Return

energy efficient steam and condensate systems

Energy Audit Opportunities
An energy audit should examine the whole steam system, from generation through to point of use to identify wasted energy, and identify any cost effective improvements. You’ll notice immediately that unlike other piped systems, the steam flow and condensate return have to be handled separately.

Steam Generation
Steam generation means creating steam using fuel typically coal, oil, or gas, although electricity is sometimes used also.  Water is heated from atmospheric pressure to the designed steam pressure for use in the facility.  Operating boilers at maximum efficiently, including monitoring air flow, improved firing controls optimise the use of fuel and can yield good results. Power stations often use coal fired boilers, and naturally have a low thermal efficiency thirty percent is common, so there are opportunities to utilise that wasted heat energy for an local industrial process.  Opportunities for energy savings would include recovering any waste heat energy for example from flue gases, or blowdown to pre-heat the any fresh (raw) water. For large industrial plants it could be possible to use higher pressure steam to drive electricity generating turbine, and use that lower pressure exhaust for process purposes.

Steam Distribution
Steam distribution is the transfer of your steam now under high pressure from the boiler to the point of use with minimising losses, Steam is not mechanically pumped, its movement driven from the inherent pressure difference, high to low pressure.

It is important that the steam distribution system does not reduce or lower the quality (dryness) of the steam because that lowers the heat energy. Unlike other piped systems the steam can travel at high velocity, upto 30m/sec, and the self drainage of the steam pipework is critical to effectively deliver dry steam, and is air vented for start up conditions.

Piping configurations that dip under obstacles such as other services and beams would create a natural low point where condensate will accumulate impacting the steam quality, and provide a source for damage by water hammer. Particular care is required for the configuration of expansion joints to ensure they are self draining.

Opportunities for energy efficiency improvements in the steam distribution system include minimising heat losses, reducing piping routes, where possible design out low points, and economic insulation.

Steam Trapping

Although Steam trapping could be considered as part of Steam Distribution, or Condensate Return, the problems are so common and distinct Steam trapping deserves a separate section.

The steam trap is the gateway between the process outlet and the condensate piping system, very often the traps leak due to internal blockage.  Most steam traps have a small orifice that can easily become blocked by debris and fail in the open position. A failed steam trap wastes energy due to causes increased heat-up time, and lengthened the product cycle times because the potential latent energy in steam passes straight though the process and is lost in to the condensate system.

Condensate

Bad design or maintenance panic (just to get production running again) causes another common problem, the wrong type of steam trap, and facility operators are unaware that the wrong type of trap is wasting energy. In some circumstance, poor management can cause injury to operators.

Traditionally,  condensate steams were fitted with a special type of fitting known as a sight glass so operators had the opportunity to visually check that water, and not steam, was flowing in to the condensate line.

However, the sight glass had many disadvantages.  Over time the “glass” viewing port become obscured and unusable. Also some sight glasses were installed in such a location that the operators couldn’t physically access the sight glass to check it.  To overcome these shortfalls a different type of steam trap monitor was invented to provide remote monitoring of condensate or steam flow, for example, the Spira-Tech manufactured by Spriax Sarco, other companies provide similar systems.  This type of trap monitoring system immediately alerts the facility operator that they have a faulty trap, and importantly its exact location.

Condensate Return
After the steam has been used in the facility process to heat a product, what remains is the Condensate (hot water). It must be noted that still many industrial steam plants don’t have any condensate return system! Why is that a problem? because it millions of litres of hot water are wasted, in additional “cold” raw water needs to be purchased to replace it.

Where uncontaminated condensate can be captured, it can be sent through insulated piping back to to the boiler for reuse. In my experience, next comes the most commonly asked question “What percentage of condensate should be returned to the steam boiler plant?” In a perfect world 100%, yes, all the condensate should be returned to the boiler, since the condensate contains up to 20-30% of the heat energy used to create the steam, returning it to the boiler saves both fuel and raw water.

However, there are no targets written in stone, 100% is an ideal goal but it is simply not practical in the field, any system that returns less than 70%-80% condensate warrants investigation.  It is worth noting that condensate flow varies, during start-up approximately twice the flow rate of normal operating conditions is experienced so condensate handling must account for higher loads at start-up. Opportunities for energy efficiency improvements include increasing the quantity of condensate returned to the boiler, eliminating leakage, and economic thermal insulation for the condensate piping.

Carbon Credits
Energy efficiency improvements are driven by the economic imperative, lower facility operating costs. In addition to the lower costs, saving fuel also reduces the demand for finite fuel resources such as oil and gas.  Another potential income stream from energy efficiency improvement projects in developing countries is provided by the Clean Development Mechanism (CDM).  AM0017 is the CDM methodology for calculating the Steam System efficiency improvements from replacing steam traps and returning condensate. That means the saved energy can be translated into a carbon credit which has a real monetary value, and can be sold on the carbon market.

by John A. Herbert, Consultant