Why do we prefer VCB over ACB in high-power transmission lines?

Why do we prefer VCB over ACB in high-power transmission lines?

1. High arc quenching capabilities

2. High insulation strength

3. Compact design

4. Less maintenance

5. Reliability and longevity

6. High interrupting capacity

Please comment if anything else needs to be considered.

Datacenter Key Metrics

The following are considered key metrics for any type of data center. Please comment if you think anything else needs to be considered:

1. Power Usage Effectiveness (PUE)

2. Water Usage Effectiveness (WUE)

3. Carbon Usage Effectiveness (CUE)

4. Uptime

5. Cooling Efficiency

6. Network Latency

7. Data Center Power Density

8. Data Center Infrastructure Effectiveness (DCiE)

#Datacenter #Infrastructure #Management #AshokrajS #EngineersView #Ameee #HappyLearning"

7 thing's To Known To Calculate the Heat Load

To calculate head load, there are seven things you need to know:

1. Solar heat gain for  floor, wall & Roof

2. Solar heat gain for glass & Window 

3.Effective room sensible heat load 

4.Effective room  Latent Heat Load

5.Effective room total heat load 

6. Effective room sensible heat factor

7. Dehumidified air flow

Thanks for your time.

Ashokraj S

What are the factors to be considered while choosing UPS batteries ( LIB , Lead Acid etc.. ) ?

 

What are the factors to be considered while choosing UPS batteries  ( LIB , Lead Acid etc.. ) ?

1. Footprint

2. Temperature Requirements

3. Charging time

4. Charging & Discharging Cycle

5. TCO

6. BMS

7. Battery Protection & Alerts

8. Environmental Impact

9. Design Life 

Pls do comment if anything is to be considered.

Thanks for reading. 

Er. Ashokraj S

Energy Performance Index Of The Building

What is EPI ? What is the national bench mark of the EPI ?...

EPI Stands for energy performance index of commercial building.
It is one of the key metric used for benchmarking the energy usage of the commercial building.

EPI is nothing but the ratio of energy consumption and build up areas in a year. The unit of the EPI is Kwh/m2 /year.

The ideal bench mark of the EPI between 100 to 150 KWh/m2/year.

The national bench mark of the EPI is 180Kwh/m2/Year.

The EPI of the commercial building will change based on the five climatic zone of the India  as specified in BEE.

Thanks for reading...

Er. Ashokraj S

IGBC AP Exam Model Question Paper -2

 IGBC AP Exam Model Question Paper -2

 

 

Question 1:

 

What is IGBC’s annual flagship event ?

 

1. Green Building Congress
2. Green Building forum
3. Green Building Conference

 

Question 2:

 

ECBC is Applicable for ?

 

1. 1000Sq.m and More
2. Connected load of 100KW
3. Both A & B

 

Question 3:

 

NBC Part 9 deals with ?

 

     A) Plumbing Service

     B) Building Material

     C) Building Service

 

Question 4:

 

MERV Related to ?

 

1. Ventilation
2. Light Pollution
3. Rain Water Harvesting

 

Question 5:

 

Hazardous waste management guidelines is provided by ?

 

A) ECBC

B) NBC

C) CPCB

 

Question 6:

 

Which standard is used for basic facilities for construction workers?

 

1. BOCW
2. ECBC
3. ASHRAE

 

Question 7:

 

NBC Parking Area Guidelines are based on ?

 

1. Building Area
2. Location
3. No of Occupants & function

 

Question 8:

 

Which of the following is not rapidly renewable material ?

 

1. Sunflowers
2. Bamboo
3. Sawdust

 

Question 9:

 

What is the pressure to be maintained in the smoking room ?

 

1. -5Pa
2. +5Pa
3. 10+Pa

 

Question 10:

 

Which of the following is the least detrimental to the ozone layer ?

 

A) CFC

B) HCFC

C) HFC

 

IGBC AP Exam Model Question Papaer -1

 IGBC AP Exam Model Question Paper – 1

 

 

Question 1:

 

If a project is achieving 65 credits and missing one mandatory requirement , can it still apply for certification?

 

1. Yes, after paying some fees
2. Yes, if applying for the first time
3. No

 

Question 2:

 

Which of below topic is covered in ASHRAE 90.1?

 

A) Water

B) Energy

C) Green Building

 

Question 3:

 

Statement A: Use of turf on the site should be minimized to conserve water.

Statement B: Treated wastewater can be reused for landscaping, flushing and cooling tower make-up water

1. A is True, B is False          
2.  A is False, B is True

      C)   Both are True                   

      

 

Question 4:

 

Which of the following is the objective of exterior light pollution reduction?

 

1. Reduce impact on nocturnal environment
2. Reduce lighting energy consumption
3. To turn off non-emergency lighting

 

Question 5:

 

Which of the following is the most efficient irrigation system?

1. Drip irrigation
2. Sprinkler
3. Crown flood

 

 

Question 6:

 

The strategy of using high solar reflective index to cover exposed roof area is used for what purpose?

 

1. Outdoor Light Pollution Reduction
2. To minimise heat island effect
3. Minimising negative impact on the ozone layer

 

Question 7:

 

How many CIRs are answered without levying any fee?

1. 2
2. 4
3. 1

 

 

Question 8:

 

The Precertification is valid for how long from the date of award?

 

1. 2 years
2. 5 Years
3. 3 Years

 

 

Question 9:

 

Which credit and how many points are awarded to a project with IGBC AP as a principal design team member?

 

1. Innovation, Three point
2. Innovation, Two point
3. Innovation, One point

 

 

Question 10:

 

How long does IGBC take to perform preliminary review?

 

1. 20 working days
2. 30 working days
3. 15 working days

UPS Design Configuration

There are many types of UPS design configuration available in today market. They are,

1. Capacity UPS Configuration 

2. Isolated redundant UPS Configuration 

3. Parallel redundant UPS configuration 

4. Distributed redundant UPS configuration 

5. System plus system UPS configuration 

To know about more details, please follow up in youtube and subscribe it today without fail.

For Tamil & Hindi :

Engineers View 

For English :

Mep Engineers 

Thanks.

Ashokraj S

Calculation of Chiller Volume Flow Rate

Calculation of chiller volume rate : 

Since the water is standard fluid, mass flow rate of water and volume flow rate are both equal. 

Hence we can use the below formula to find out the mass/volume flow rate of water.

Q =m ×Cp ×Delta T 

Where

Q is chiller coil load in KW 

m is  Mass flow rate of water 

Cp  is Specific heat of water 

Delta T is difference between chiller entering water temperature and leaving water temperature.

Thanks for visiting our blogger. 

For more information, please link the below link and see our videos 

https://youtu.be/rN4a0rqlXyg

Battery Charging Current Calculation

How to calculate battery Charging Current ?

Battery Charging Current should be 10% of its battery AH rating .

Example 2: 

If you have 200AH SMF lead acid battery, then what will be the Charging Current ? 

10 % of Battery AH rating

10% of 200AH 

= 200×10/100

= 20 A.

The charging Current of 200AH battery should be 20A as per the thumb rule.

Example 1: 

If you have 100AH SMF lead acid battery, then what will be the Charging Current ? 

10 % of Battery AH rating

10% of 100AH 

= 100×10/100

= 10 A.

The charging Current of 100AH battery should be 10A as per the thumb rule.

Thanks for reading this. 

Requesting you to follow me on blogger and YouTube. 

Ashokraj S 

YouTube Link :

https://youtu.be/w_CzSOk7ilY

Harmonic Allowable limit as per CEA Guidelines

As per the CEA Guidelines, those who  maintaining the Substation in the voltage level of 11KV,22KV,33KV, they should maintain the total Harmonic distortion as per the below allowable limit.

Individual Voltage Harmonic Distortion :

Maximum acceptable limit is 3% 

Total Voltage Harmonic Distortion :

Maximum acceptable limit is 5% 

Total Current Harmonic Distortion :

Maximum acceptable limit is 8% 

This limit has mentioned by institute of electrical and electronic engineer (IEEE 519 2014)

If THD is breaching the acceptable limit, then you have to install harmonic filter to maintain the level as stated by above standards, otherwise government authority will impose the penalty.

The Harmonic filter may be active harmonic filter or passive harmoic filter or hybrid harmoic filter.However, the selection of filter is based on your site load requirement. 

If you want to know about Harmonics and its type and its control method, then please follow me at blogger and also subscribe our YouTube channel without fail.

Thanks for reading this small information!...

Stay Home, Stay Safe.

Ashokraj  S

How to calculate efficiency of air cooled chiller ?

Chiller efficiency is generally expressed interms  of iKW/TR. 

Where,

i stands for indicated 

KW stands for kilo watt 

TR stands for ton of refrigeration 

iKW/TR is nothing but the ratio of electrical power input to the compressors to ton of cooling produced by the equipment.

Less value of iKW/TR indicates high efficiency of chiller

Higher value of iKW/TR indicates low efficiency of chiller.

The chiller performance test is usually carried out once in year by the chiller OEM

During the performance test, OEM will bring power quality analyser and ultrasonic clamp on flow meter to the site .

Ultrasonic clamp on flow meter will be installed at return chilled water pipeline of chiller.This flow meter will sense the flow rate of fuild flowing through the chiller. The flow rate can be expressed in gpm or m3/hr.

The power quality analyser will be installed at input power supply consumed by chiller/compressor. 

To calculate the TR of chiller, we have to use the below formula 

TR =(gpm x delta T)/24

Where 

Gpm is gallon per minute 

Delta T is temperature difference between entering and leaving chilled water temperature 

Once you find out the TR of chiller by using the above formula,then you can find out iKW/TR. 

For example:

Kw of chiller at 100% load is 2

Ton of refrigeration of chiller is 2

Formula to find out chiller efficiency is 

iKW/TR =2/2=1 

Thanks for reading this topics.

If you have any doubt on this,please write your queries in the comment box and also you can write your comment in our YouTube channel.

Ashokraj S

TDS level in drinking water

TDS stands for total dissolved solids.TDS represents total concentration of disolved solids in the water.

TDS is made of up inorganic substances and small amount of organic substances.

The inorganic substances refers to the  salts and heavy metals.

How to measure the TDS ?

TDS in water can be measured using portabal conductivity meter. The another name of this meter is TDS meter.

How to control the TDS level in water ?

TDS can be controlled using reserve osmosis process.but the main drawback of this process is more wastage of water I.e. reject water.

Unit of TDS :

TDS will be showcased in the term of ppm (Parts per million) or mg/l (milligrams per litre)

 TDS level :

EPA (Environmental Protection Agency)

As per the EPA, 500 ppm is maximum acceptable limit

WHO(World health organization)

As per the WHO, 300 to 600 ppm is  considered as good and the level more than 1200 ppm is considered as unacceptable 

BIS(Bureau of indian standards)

As per the BIS, 500ppm is maximum acceptable limit.

ICMR(Indian Council of medical research)

As per the ICMR, the value between 500 ppm to 1500 ppm considered as good.

Hope the above information is much useful to you.

Thanks for reading this topic.

If you want to read more information on water quality and its treatment methods, please follow me and subscribe this blog spot. 

Ashokraj S

KVAR rating calculation to design the APFC Panel

How to calculate KVAR rating for APFC Panel ?

APFC Stands for automatic power factor correction/controller 

KVAR stands for kilo volt ampere reactive 

Assume that your electrical  distribution system have the value of 100KVA,415V,240.96 Amps and PF is 0.8.

If we want to improve the power factor from 0.8 to 0.99, you need to install the static capacitor in the existing  system. 

There is a standard formula to calculate the required KVAR i.e. 

KVAR =P(Tan pi 1 - Tan pi 2) 

Let us assume Cos Pi 1 = 0.8 

                                  Pi 1 = cos inverse of 0.8

                                  Pi 1 = 36.869 

Also let us assume Cos Pi 2 =0.99

                                       Pi 2=Cos inverse of 0.99

                                       Pi 2= 8.109 

Now apply all the known values into the KVAR standard formula.

KVAR= 100( Tan 36.869 - Tan 8.109)

          =100(0.749-0.142)

          =100(0.607)

          =60.7

So, to improve the power factor from 0.8 to 0.99, we need to install at least 60KVAR capacity of APFC panel in the electrical system.

Thanks for reading this topics.

If you like to read our blogs, please follow me and also please follow me at YouTube and subscribe the "Engineers View" channel.

Ashokraj S 

APFC in Electrical Systems

APFC panel in Electrical System

 APFC stands for Automatic Power factor correction/Controller.

APFC Panel used in electrical power distribution system to improve the power factor from lagging PF to near to unity PF.

Power factor is the ratio of active power to the apparent power .It is denoted by cos Pi

Cos Pi = KW/KVA

Where

 KW is equals to 1.732 x V x I x Cos pi (or) V x  I x Cos pi

KVA is equals to V x I 

Thanks for reading this topic.

1 TR = 400CFM ?

Hi All,

Generally we are using 1TR =400CFM in most of our HVAC system design. But which is wrong and there is no theoretical calculations on this too.

Before discussing further, I just want to describe what is TR and what is CFM.

TR is called as ton of refrigeration TR or refrigeration ton RT. TR means amount of heat extracted to produce one ton of ice.

CFM is the unit of measure of air flow, CFM stands for cubic feet per minute. CFM means volume of air entering the room in a minute. 

Coming back to the topic, 1 TR may be equal to 400 CFM or 300 CFM or 450 CFM or some other value . It will differ one manufacture to another manufacture .

However, there is a standard equation available to relate the BTU/HR and CFM .

BTU/HR=1.08×density correction factor ×CFM×Delta T 

Where,

1.08 is constant for air at standard condition 

Delta T is difference between inlet and outlet air 

CFM is cubic feet per minute 

By using the above formula, we can calculate the CFM for any TR cooling equipment. 

I would like to add another point that as per the ASHRAE,we don't have any formula to relate the TR and CFM.

As per the human comfort standard, 1TR of air conditioned should have a discharge of air 400 CFM .If we discharge below 400CFM,the people who using the equipment will feel suffocated even though we maintained low temperature. 

The conclusion  of this topic that if we want to calculate the CFM of equipment roughly, please use the below thumb rules or otherwise you want to calculate the CFM exactly ,please use the equation 1 .

For centralized air conditioning system 

1TR =400CFM 

For non centralized air conditioning system 

1TR=300CFM 

Thanks for reading our blog post. Please post your doubts in the comment box if any.

By

Ashokraj S

Why night lamps called as zero watts bulb, even though it consumes some amount of power ?

There are four different types of lamps available in the market .

1.Incandescent lamp

2. Fluorescent lamp

3.Compact fluorescent lamp

4.LED lamp 

Among these types, we are mostly used incandescent lamp as a night lamp.

Actually low intensity incandescent bulb are called as Zero watt bulbs and there is no lamp with zero watt consumption.

Even a small LED indicator consume power,though it is a fraction of a watt.

The zero watt lamp actually consume 15-20W.

In earlier days, we were using only zero watt lamp at night and other loads were kept off at home .In such case, the conventional type electromagnetic energy meter could not record the energy consumption because the disk inside meter did not move when the load was only with 15 Watt.

But in our modern life, we are using the digital energy meter and it is  capable of capturing in fraction of watt.

My recommendation is to procure the LED type zero watt bulb for your home instead of incandescent lamp . LED type night lamp will consume less power i.e 0.5 W or 1 W and you can save the electricity here and there by we can save your money too.

Thanks for the reading!..

By

Ashokraj S 

BE EEE

What is star rating in electrical appliances and what is EER and its calculation

Buying a new air conditioner and electrical appliances is really a big task for all.Because if we procure bad product then it will hit our electrical bill more high than usual.

So we need to check few parameters before buying the product. The parameter such as star rating, energy efficiency ratio, seasonal energy efficiency ratio,indian seasonal energy efficiency ratio etc..

 Star Rating:

The government of india was launched the BEE bureau of energy efficiency in the year 2002 under energy conservation act 2001.

The main moto of BEE is to reduce the power intensity with indian economics and to promote the use of energy efficiency equipments. 

To promote the equipments,they introduced star rating system. The star values from 1 to 5.

The highest star rating represents the maximum efficiency of the equipment. 

After introducing this, many manufacturers were voluntary involved in the star labeling programme to get the more customers. 

All the electrical appliances ( TV, AC, LED lamps, heater, refrigerators etc.) would have this star rating.

EER:

Energy Efficiency ratio is defined as ratio of output cooling energy to the input electrical energy at given operating points.

EER is generally calculated with 95 degree F out side temperature and inlet temperature of 80 degree F and 50% relative humidity.

If you see the home air conditioners, there would be lable on it and it contains  the value of star rating and values of EER.

But after Jan 2018, the BEE was also introduced ISEER (indian seasonal energy efficiency ratio) because AC willbe operated maximum at summer season and  operated less at rainy seasons. 

We willbe discussing later about SEER and ISEER..

Let us see how to calculate the EER if you know value of TR and KW.

Example 1:

If 24000BTU capacity of AC  is operated under 1200W power,then what would be the EER? 

EER =(Cooling energy in BTU)/(Electrical energy in watt)

= 24000/1200

EER =20 

Example 2:

If 24000BTU capacity of AC  is operated under 2400W power,then what would be the EER? 

EER =(Cooling energy in BTU)/(Electrical energy in watt)

= 24000/2400

EER =10

From the above examples,  we need to understand that we need to checkup the EER and star rating while we purchasing the new AC for your home.

Thanks for reading !...

By 

Er. Ashokraj S 

Difference between MCB & Isolator

MCB:

MCB is Miniature circuit breaker,which used to  protect the electrical equipment from over load and short circuit conditions.

There are 5 type of MCB in the market based on the magnetic trip current,

1.Type B

2.Type C 

3.Type D 

4.Type K 

5.Type Z 

Based on the applications and demand, we are using the MCB's in domestic & industrial area.

There are two trip unit available in MCB, there are thermal trip unit and magnetic trip unit.

When over current is drawn by the electrical equipment, thermal trip unit trip the MCB,whereas magnetic trip unit will trip the MCB when the short circuit occurs .

Isolator :

Isolator used to isolate the electrical equipment from power supply or electric current for servicing and maintaining the equipments.

There is no protection system available

If over load occurs, the isolator will burns out.

Difference between MCB and Isolator:

        MCB                                   Isolator 

1. Automatice device        1.Manually operated 2.Protection available      2.Not available 

3.High Cost                           3.Low cost

4.Electronic circuit            4.Mechancial device 

made by transistors             act as switch

5.Arc suppression              5. Not available 

mechanism available 

6.High current                    6. Low current 

withstand                                  withstand 

capacity                                     capacity 

7.ON load device                  7.OFF load device

Please comment if you may have any doubts. 

How to calculate GPM of AHU/CSU/FCU/VAHU/PAHU

GPM stands for gallon per minute.

It is one of the unit  used to measure the water volumetric flow rate. 

The stand formula for calculating the TR as follow,

TR = (GPM × Delta T)/24 

For this,we can find out the GPM 

GPM =( TR×24)/Delta T 

Where GPM is flow rate 

              TR is ton of Refrigeration 

              Delta T is temperature difference between supply and return chilled water

Let us consider AHU and its  inlet and outlet water temperature is 30 degrees fahrenheit and 38 degrees fahrenheit and TR is 10.

Apply all these values in the GPM formula

GPM = (10×24)/(38-30)

          = 240/8

  GPM=30 

Here the GPM depends only on temperatures, as the TR is constant throughout the process.