The Process Of Accessing Energy

Published Date: 02 Nov 2017

Abstract:

The process of accessing energy usage by individual energy consuming devices on a residential or commercial scale is called energy auditing. A diagram can be created using energy audit details and it shows the energy consumption by individual energy consuming devices, e.g. refrigerator, washer, dryer, television, heating system, hot water heater, etc.

Introduction:

As population increases, the electricity requirement continues to rise day by day. Even though electricity seems to be a clear and easy to use energy source for consumers, producing process of electricity affects the environment badly. There are many things to do protect environment while using electricity as an environmental friendly consumer; such as, determine amount of electricity usage in home, identify higher energy usage appliances, design a plan to reduce overall electricity consumption. Now a day’s media is also given much attention regarding energy issues. Therefore individual awareness of this matter is critical. Many people take for granted how much our society depends on electricity, only realizing its importance when we experience a power outage. Environmental literacy between electricity usage and production will increase by this investigation.

Objectives:

Main aspect of the home energy audit is to calculate the amount of energy usage in house and improvements needed to minimize the usage and save money as well.

Home energy audits can be:

Conducted by an energy audit/survey of electrical appliances in home, in terms of the amount of energy used and the costs involved.

Determine the amount of energy used by different appliances.

Interpret a monthly electric bill.

Make calculations and conversions related to energy usage.

Increase of understanding of energy units such as watts, volts, amps, and kilowatt-hours.

Evaluate the relationship between electricity generation and usage for environmental consequences.

Design and implement a specific strategy or conservation plan that will lead not only to a reduction in the amount of electricity that use, but also to a lower monthly cost.

Audit planOverview:

Checklists preparation

Energy Audit Preparation

Initial walk-through

Collecting energy bills & available data

Preliminary analysis

Data Inventory & Measurements

Analysing energy use patterns

Energy Audit Execution

Benchmarking & Comparative analysis

Identifying energy efficiency Potential s

Cost- Benefits analysis

Writing audit report with Recommendations

Energy Audit Reporting & Post Audit Activities

Preparing the action plan for implementation

Implementing the Action Plan

Fig1: Overview of the Energy Audit

Basic electrical units:

Electrical current (I) is the flow of electrons through a wire and is measured in amperes (or amp). The voltage (V) is a measure of the electric force required to keep the electricity flowing through a wire. Electric power, the rate at which electricity does work or provide energy, is measured in watts (W). The current and voltage are related to electric power by the following equation;

Power=Voltage X Current

Watts= Volt X amp

Table-1:

Energy Usage of All Current in Using Electrical Appliances:

Device

Energy Usage/Hour (kWh)

(1)

Daily Usage Hours

(2)

Energy Consumption of Current Appliances (kWh)

(3) = (1)×(2) ×30

Lights

2

6.0

360

Refrigerator

.17

23.9

122

Microwave

1

0.4

12

Laptop

.05

12.0

18

Toaster

.9

0.1

3.5

Dryer

3

1.0

90

Electric Water Heater

5

2.7

400

Small Appliances

(Iron, toaster oven, etc.)

.5

0.7

10

Total Energy Usage/Month (kWh):1015.5

The energy usage per hour was measured by using a power monitor. The exception was lights, water heater, and electric dryer because those devices are wired directly. The hourly power consumption for those three devices was calculated based on the power capacity which is printed on the device’s identification plate.

Investigating a laptop by undertaking a thermodynamic energy analysis:

The technique which is used by infrared imaging and measurement camera to "measure" invisible infrared energy (heat) being emitted from an object is called infrared thermography. Using very sophisticated technology, infrared cameras process the image (what it sees) and displays it on a video screen on the camera. Before and after the capture of images it goes through series of measurements and steps of thermography to ensure quality of image. Those images can be used for immediate diagnosis and also processed through specialized computer for further evaluation, accuracy and to take output report.

Thermal imager for home Inspection and Energy Audits:

Thermal image reveals hot spots on the Acer laptop. Below thermal images (figure 2 and 3) shows heat generation of Acer laptop at the various performance levels such as idiling, watching video etc.. According to the figure 2 it shows maximum temperature of 26.50C during the idiling. After 15 minutes watching of video the temperature rose to 30.50C. It shows that that laptops generate considerable heat while its in high performance levels.seems it's not unusual for many laptops to feel warm during heavy use.

H:\PRASHAN\IR_0885.jpgH:\PRASHAN\IR_0887.jpg

Fig2: Thermal image view of laptop in front Fig3: Thermal image view of laptop in

back

Use of Sankey Diagram:

Sankey diagrams give the clear picture of energy flow in a building/unit, from its internal distribution to its final consumption per use and per energy system.In these diagrams, the energy losses-outflows, the energy gains-inflows, as well as the useful energy in every energy system, are represented quantitatively and in proportion to the total energy inflow, according to existing data from energy bills and invoices, from calculations and in-site measurements of the building/unit. Representing energy flows visually with the aid of the Sankey diagrams helps to locate the more critical energy consuming areas of the building, unit or building block, and, at the same time, to identify the sources that lead to energy losses. This ascertainment leads to a sound evaluation of each system’s behaviour, as well as to a better scheduling of the proposed energy saving measures.

Implementation:

Displays - LCD screen of laptops large arrays of information (pixels) according to per watt of power consumed. Those attributable are differing from each other machines due to differences in screen brightness, size, and performance, whilst the rest is due to various in the technologies employed. Some displays shows more advance features such as, better off-angle viewing or more accurate rendering of colours and moving images than others by using more power than others.

Battery Charging Systems- even though battery capacity and run time were significantly related, our measurements do not reveal any major efficiency differences in battery charging systems across the various laptop models. It seems that most of such battery components are fairly similar for the need of portability. By using smart charging technology, batteries automatically inform fairly similar the charger, according to their temperature and state of charge. Computers consumed 20% of more AC energy to operate a computer in battery mode and then recharge it, compared to plug in mode. Therefore, it can conclude that the battery charging systems used in other consumer products to be much less efficient.

Obviously, laptops save more energy than desktops. At least 5 times, laptops are more energy efficient than worst desktop systems (computer and CRT monitor). However, highly efficient laptop components could be readily incorporated into desktop designs, preserving the basic form factor and functionality of a desktop while saving energy and space and reducing noise from cooling fans. However, the present trend is the reverse, with each new desktop computer model incorporating faster, higher power CPUs and video cards.

The laptops can be operating in either battery state or AC state. Any of these two states does not show the amount of energy consumption or speed of machine, it tells where laptop gets its power source. If the Laptop gets the household alternative current by plugging in is called AC state. If the laptop is working without plug in and using battery power called battery state.

While laptop is in an either of above power states, its power consumption is vary. Below shows the decreasing order of typical power consumption;

Max on – The laptop is on with full brightness of screen. The computer is performing some intensive computing operation, such as opening a program, downloading e-mail, finding a web-site, saving a file, or searching a directory. This state happens only over interval of a few seconds or less, so it shows a less total time that a laptop is used.

On – The laptop is on and the screen is set to full brightness.

The computer is performing only lower computing activities, with or without user input such as; running a word processing or spread sheet program or playing solitaire game. During this period, the computer’s power usage does not change condiderably whether the user is entering data or not, so both situations are included in this mode.

Monitor sleep – The laptop is on and the screen is powered down. This low power option is available through the power management (PM) software and is automatically enabled after a certain time period of user inactivity (ranging from minutes to hours). The circumstances which computer can be entered to this mode are; the user is attending to other non-computer work and is not typing or otherwise not using the computer, so the screen on the computer automatically turns off, which sends the laptop into monitor sleep mode. The laptop quickly returns back to on mode when the computer detects a key press or a mouse movement.

Hardware sleep – This power mode is achieved by either choosing the "Standby" option from the Windows Start menu, or by enabling an automatic timer in the PM software that sends the laptop into hardware sleep mode after the user has not been typing or otherwise using the computer for some period of time. This period of time selected by the user is usually longer than the time period designated by the user for transition into monitor sleep mode. In order to get the computer to return to on mode from hardware sleep, a particular button (usually the power button) must be pressed. The computer returns to on mode more slowly than monitor sleep, but more quickly than starting up from the off mode.

Different PM software has different names for this mode and in all cases the monitor is off in this mode.

Off – The laptop is switched off by manually pushing the power switch or by choosing "Shut Down" from the Windows start menu. In order to get the computer to on mode from this mode, the user must start up the computer using the power button. If the computer is in AC state in this mode, a small amount of power continues to be consumed even if the laptop battery is fully charged.

Total power consumption of each mode listed above can be influenced by the battery charging conditions that occur in the AC state. Power draw for battery charging varies widely depending on the state of charge, so is not amenable to categorization in the same way as operating mode. To keep the complexity of measurement and discussion manageable, we made all power measurements in each mode with either no battery installed or a fully charged battery, effectively removing battery charging as a variable in determining the power consumption of the operational modes.

In order to completely describe the status of the laptop, a state and a mode must be specified. For example, if a user is typing in a word processing program and has the laptop plugged into the wall outlet, this laptop would be in AC state, on mode. If only a power source state is referred to, without a mode specification, then it is assumed that the discussion refers to all power modes within that power source state.

Cost Justification:

A personal computer was evaluated for energy consumption and operating cost. The data was then manipulated to reflect several modes of operation, and the amount of electricity consumed from each mode of operation was assessed.

Electrical Appliances KWh used Cost (Pence)

Computer only 0.04 0.4

Computer and screen 0.15 1.5

Computer and screen on all the time

Time period KWh used Cost (Pence)

24 hours 3.6 0.36/day

1 week 25.2 2.52/week

1 year 1,314 1,971

Computer and screen both on 8 hours a days a week

Time period KWh used Cost

1 day 1.2 0.12/day

1 week 6.0 0.60/week

1 year 312.0 31.20/year

Computer on 24hours a day, 7 days a week; screen on 4 hours a day, 7 days a week

Time period KWh used Cost

1 day 1.4 0.14/day

1 week 9.8 0.98/week

1 year 509.6 50.96/year

Conclusion:

From the above calculation it is clear that one should turn off their computer and screens when they were not being used. For example, even if someone kept the computer on all time (24/7) but only used the screen four hours a day, this would save:

1,314KWh-509.6KWh=804.4KWh per year= £80.4

Obviously, if the computer and screen were only switched on when they were needed, then much greater savings economically would be achieved.

PART-B:

Due to number of reasons the energy consumption of laptop computers has been underestimated in previous part of the study.

Most of the energy efficiency analysts assumed that laptop is a not significant and rarely used item at the home and they paid much more attention to personal equipment that is always plugged in and only runs in AC state.

According to literature the power values of the laptop computer that were quoted in the literature are lower than the averages that we obtained through measurement of 2002-2003 models. Previous studies need to be updated to show the increasing capabilities (and power use) of newer machines.

The duty cycle of the laptop computer, which describe the time taken to different power modes on or off, monitor sleep etc.... They are not well established for laptops, so leading researchers to make guesses their use patterns.

According to the analysts’ previous assumptions, laptops have activated their power management (PM) always. Informal survey of laptop users reveals that their laptops spend much of the time in AC state with minimum activated PM functions. When they running in battery states more likely to activated PM functions. There was no any laptop users found in informal survey which allowed their laptop to go into hardware sleep mode whilst some users activated the monitor sleep mode to increase battery life.

Finally, and imperatively, the relationship between battery state of the laptop and the energy penalty with its portability ability has been overlooked. When considering the duty cycle calculation, analysis up to this point has ignored the battery state. This oversight results in an underestimation of the energy consumed because the amount of energy that is put into a battery during the charge cycle is always larger than the amount that can be extracted from it when it is powering the laptop.

Power management software facilitates lower power usage for various components of the computer during the period of inactivity. Majority of power saving comes from dimming or switching off the screen, reducing processor speed, shutting down the hard drive, or putting the entire computer into "sleep" mode after longer periods of time. The sleep capability of computer depends on many factors such as; various operating systems, computer manufacturers, and component types, and is frequently not fully activated by the user. Most of the operating systems show maximum performance with connotation with Ac state and lower performance with battery state, meaning that the large savings opportunities can go untapped when computers are plugged into AC power.

Component

Possible Efficiency Improvement

Display

From 64,000 pixels/watt

to 128,000 pixels/watt

Power supplies

From partial load efficiency of 56% to 85%

From full load efficiency of 80% to 90%

Power Management

From 50%of laptops PM enabled

to 70% laptops PM enabled

Battery System

From 80% to 85% efficiency

Laptops present opportunities for substantial energy savings through integration of:

Highly efficient, compact power supplies

Highly optimized, smart battery chargers

Advanced screen backlighting designs

Mobile computer processors able to drop into low-power states when needed

Efficient support circuitry

Software enabled to manage and control all energy-saving features automatically

Laptops are point forwarding considerably greater opportunities for energy saving in the future by such integration and optimization. The potential for future energy savings in the laptop computer has been largely examined, due to their limited storage capacity for electricity; it seems that all laptops should be inherently energy efficient. Indeed, to maximize battery life while in battery powered state, energy efficiency is essential for computers. But it is certainly not automatically the case that all laptops always operate efficiently during the much longer periods of time when most of them are plugged into the wall and operating off of AC power. The efficiencies of AC/DC power conversion and battery charging, for example, strongly affect the overall computer efficiency without affecting battery life at all. Correspondingly, some laptops have increases in screen brightness, processor speed, and fan operation that occur when laptops are plugged into AC power.