By Mr. Sibte Ahmad Jafri, CEO
Jafri and Associates(Pvt)Ltd.
Science, Technology, Engineering, and Mathematics (STEM) are widely regarded as critical to the national economy. Engineers greatly impact our everyday lives, from small nail to designing Multistory Buildings, creating cars and mobile phones prosthetic limbs and the facilities that make them.
Demand-side management and environmental energy goals:
Demand side management (DSM) in electricity markets can improve energy efficiency and achieve environmental targets through controlled consumption. For the past 10 to 15 years or so DSM programs have registered significant results. However, detailed analysis of its real impact as observed by a large number of pilot studies suggests that such programs need to be fine-tuned to suit clearly identified conditions as per today’s technology. The aims are to provide recommendations for the instruments to be used to prompt demand response with a view to maximizing energy and environmental efficiencies of various countries.
I suggest that different DSM models should be deployed depending on the specific generation mix in any given country. Beside the natural benefits from cross-borders infrastructures, DSM improves the flexibility and reliability of the energy system, absorbing some shock on generation mix. We show efficiency increases with demand response but at a decreasing rate. So, according to rebound and effects, simple DSM tools should be preferred.
Highlights:
- Demand side management can improve energy and environmental efficiency.
- Several instruments should be used to achieve significant load-shedding.
- DSM models should be deployed depending on generation mix.
- Efficiency increases with demand response but at a decreasing rate using new technologies.
- Rebound and report effects reduce positive impacts.
We’ve come a long way from Thomas Edison’s light bulb. Today, Electricity Powers our workforce, connecting Electrical, Civil & Mechanical assembly lines and propelling conveyors inside and across the country. Electricity is an integral component of our way of life and global economy, but it’s not without hazards. Electrical hazards can be unpredictable and dangerous, placing engineers, electricians, and other professionals in harm’s way.
Unfortunately there are no codes or standards which mark an upper limit for frequency of overall electrical system assessment but studies have revealed that the buildings which are built on international standards and installed with advanced technology equipment undergo less frequent fire outbreaks as compared to old buildings which are not designed on international standards. As per NFPA 70E 2012, every 5 years or when major changes are made to the electrical system, arc flash assessment should be done and as a matter of fact there have been major electrical load changes in past 25 years due to population increase. Studies reveal that most of the fire outbreaks are a result of short circuit & overload on electrical systems hence the building should undergo electrical system assessment. Thus keeping demand load to a minimum level and keeping track of loads to avoid overload and short circuit is very necessary. Fire outbreaks are frequent but the results are a disaster! “Life is more costly than cost of electrical system assessment”.
There has been gradual change in number of building. As building tenants increased in number; to meet new load demands, tenants started using components in the form of extension boards and increased the load on certain circuit breakers as compared to how much these circuit breakers were designed for; thus exceeding from designed capacity of circuit breaker and the upstream wire. This way unknowingly the building’s loads increase in an unpredictable manner. An electrical socket is designed for a few watts but after plugging an extension board, the load can increase up to 300% of designed wattage. Most people do not notice that while plugging load in an extension board, there is some sparking hence this moves the building towards fire hazards as well. One way to reduce this problem is to avoid extension boards. Other way is that already keep so much future capacity that even after exceeding load to a small amount, the electrical panel can support the additional electrical load and the insulation of wires does not get fatigued.
As more and more buildings are being built, professional consulting engineers come across difficult situations and develop good design practices from their adverse experience applying new codes and standards. Hence it has become necessary to review latest codes and standards while designing a new building.
After every electrical assessment, it is not a matter of surprise that the building will definitely be exceeding from building’s original designed capacity. One way to handle and obviate this problem is to conduct frequent electrical system assessments. Another way is to keep track of all sections of a building that any unnecessary overuse can be readily visualized and proper action can be taken (Sub metering can be a solution). Yet another way is to reduce building electrical load demand to so much minimum level by making use of new technologies that even after increasing load capacity, the increased demand is low in quantity. Some of these are:
- Low voltage lighting controls
- Designing to appropriate light levels to avoid unnecessary lighting loads
- Efficient lighting fixtures
By utilizing these technologies, a building can reduce its load to within or under the originally designed system capacity.
Another aspect which needs to be studied is load pattern change. Even if the population of a building remains same, electrical load per capita is increasing due to continuous advancements in technology. At present the normal trend is that every employee is provided with a desktop or laptop and in some cases a printer as well. Also few years ago, the system usage was also not meant for long hours; people would be using their computers for say 2 – 3 hours; may be 4 hours as required but now its utilization has increased. This changes the load consumption pattern and the amount of reactive load as well and therefore harmonics and power factor of the system. Thus Harmonics, power factor and load flow pattern of the building needs to be studied carefully.
Electrical system components have a certain life expectancy and become unreliable as they exceed their lives. Aging of equipment is a normal process. Equipments are rated for a specific number of operations before they fail but most of the time it is not obvious how much life the equipment has passed and how much is left. There are a number of examples:
- Transformers age as the time passes
- Nuts and screws which are mounted on DBs are also limited to a specific number of operations.
- Every time when breakers trip influence the insulation of downstream wires in negative way and the broken contacts
- Switchgear & LT Panels doors which can be opened and closed several number of times where after they develop fatigue
- Cables are connected to panels through lugs and some wear and tear occurs at the connection points as well because of heating and cooling
This way all equipment are subject to some kind of wear and tear and cannot be determined first by visual examination.
Hence it is highly desirable for the safety of occupants to conduct its overall electrical system study by a consultancy firm registered with PEC. All areas of safety as mentioned above should be considered.
The above notes cover a typical building project. However major Electrical Loads emanate from industrial projects and / or complex multiuse commercial buildings. Since it would not be possible to go into details of such major projects. It is recommended that the basic ideas put forth in this article are applied to all projects that have had a life of more than 5 to 10 years.
It may not be considered that older buildings and projects in a developing country like Pakistan only need proper Technical Audit/ Evaluation. Even in advanced countries major buildings are being subject to typical evaluation to determine whether they meet the current required standards of safety. (A typical example is the major fire in the 24th story building in the Eastern London recently that resulted into extensive loss of life and property).
It may be of surprise and interest to the reader that even in an advanced country like USA there are many established Engineering firms providing Gap-Engineering services to major existing projects. Therefore there should be no shame in undertaking this activity for projects in Pakistan.
