Whatsapp Will offer Group Video Calling Feature

Facebook has made an announcements, WhatsApp group video calling feature along with stickers feature at its F8 Developer conference in San Jose, California.

WhatsApp is wolrd most popular messaging service, now owned by Facebook.
Whats app already support video and voice calling which already very popular in india.

WhatsApp will also support third-party stickers created by developers.

Group Video calling will likely make it more appealing to users but facebbok has not given release date.

History of Air Conditioning

Isn’t AC’s doing enough to cool down your summer? Here are few fun facts and history about our beloved air conditioner

Surviving the heat has always been a tough challenge throughout the history, from cavemen to the modern civilization. Unlike cavemen who relied on age-old natural techniques to sustain the heat, we the modern millennials, thanks to the advancement in technology, we make use of many efficient and effective ways of staying cool. Throughout the history men were always in search of a better way to beat the heat, not only their motive for cooling was intended towards comfort and luxury but at a certain point this was inevitable and had become the question of survival. Especially in the countries in the middle east where the average temperature ranges north of 45-degree Celsius.

Thanks to the advancements in the field of heating, ventilation and air conditioning (HVAC), we are today possessing few of the remarkable ways of retaining body temperature and preserve food for the longer durations.

The evolution of cooling systems throughout the ages

The Cavemen

The stones have proven to be natural insulators and hence our cavemen used to rely on finding refuge in old stone caves for shelter and to prevent heat. Also whenever cave wasn’t an option, the dug burrows in the ground. Even today, the stone buildings are more efficient in regulating temperature.


One of the notable civilizations of man king had a unique solution to beat the heat. The started with hanging the wet reeds on their open windows so that the crosswinds blowing into their houses would be cool.


Who isn’t familiar with the iconic hand fans from the land of China? The invention of those stylish fans was purely out of necessity and dates back to the second century BC.

Middle East

We all are familiar with the Disney’s game called Aladdin, the standout feature in this game was the famous Aladdin’s castle. Ever wondered the importance of those tall towers? In fact, it is a structural marvel, where the tall towers and the underground channels acted as the temperature regulator, to bring in cool air from beneath and drive off warm air out of the tower.


Greeks followed a simple technique which allowed them to continuously flow water through the aqua-ducts. This enabled them to monitor temperature at public baths and maintain heat or cool down the area as per their requirements.


They added to the structural aspects of the building like the people from the Middle East. The common architectural design included high ceilings, deep porches and large windows, which provided enough cross ventilation to keep the room cool. These techniques are still in practice even today in many countries.

Modern times

Willis Haviland Carrier is a well-renowned name in the HVAC world and often known as the father of Air Conditioning. In the year 1902, he discovered the relationship between temperature, humidity, pressure and dew point which led him to the invention of “the apparatus for treating air” which he then on patented in the year 1906. These developments inspired him to form his own company, Carrier corporation in 1915. He also made a revolutionary contribution by replacing the bulky rotary compressor with centrifugal compressors.

Through the history- evolution of AC’s

1813: The very first ever steam-powered refrigerator was built by Jacob Perkins

The 1830’s: To cool the patients suffering from yellow fever and Malaria, Dr John Gorrie invents the ice making machine

1899: Concept of comfort cooling gained popularity

1904: St. Louis had a fully air-conditioned Missouri state building was featured in the world fair.

1914: Charles Gates became the owner of the very first domestic AC system installed.

1917: Cinema got its very first AC

1928: The first practical household AC unit was demonstrated by the Carrier Corporation. Also, DuPont introduced its Freon.

1930: The first air-conditioned car was introduced in the rail route of Baltimore and Ohio

1936: The first air-conditioned passenger plane was introduced by United Airlines

1939: First AC car was made by Packard

1953: The sales of AC units crossed the milestone of 1 million, in total sales

1987: Important and much needed Montreal Protocol was signed to regulate the usage of CFC’s in the HVAC systems which was the primary reason for depleting the ozone layer.

1997: Restrictions were imposed on environmentally harmful refrigerants through the Kyoto Protocol

2002: As per estimation the AC production crossed over 6.7 million units

Interesting facts about your Air Conditioner

The most common terminology used to measure the cooling capacity of any Ac is represented by the term “tonnage”. One ton simply means the amount of heat absorbed by melting ice weighing one ton!

The employers were convinced that AC promoted laziness in their employees work environment and hence were against the idea of installation of air conditioning systems in 1940 till late 1950. But soon they showed interest towards an air-conditioned environment upon noting a significant increase in the productivity of their workforce under AC installed environment.

Ever wondered what are these terms like R-22, R-12, R-134, it emphasizes the chemical structure of the molecules in an alkaline refrigerant. Upon adding 90 to this number, using the resulting three-digit number, we can derive the number of carbon, hydrogen and fluorine atoms present in the molecule.

The common misconception among room AC users is that the air is cooled by passing through a system of coils but in fact, the air is never passed through the coils but passes over the coils. The cooling is achieved by refrigerant which draws the heat from the air as it passes over the evaporator coils.

Hopefully, we were able to ignite a spark and get you curious about your everyday used AC’s. This information is brought to you by Repairkidukan, where we try to resolve your any electronic issues in minimal time. We are operational in parts of Mumbai, Thane and Navi Mumbai.
To know more about our services and avail our help, do visit Faq. For more fun facts stay tuned to us, and in case of your AC failure feel free to reach us out on repairkidukan@gmail.com or simply call us on +91 7666744447. With Repair Ki Dukan, getting an expert technician is an easy and hassle-free task.

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Tel: +91 7666744447

Email: repairkidukan@gmail.com

Samsung announced the launch of Wind-Free Air Conditioner(AC) in India

Samsung the most trusted electronics brand in India has announced the launch of Wind-Free Air Conditioner(AC) in India on Tuesday(21-02-2018).This new air conditioner (AC) has integrated Wind-Free Cooling technology into its design. This AC provides cooler climate with better energy efficiency than normal Air Conditioners.
In standards Air Conditioner system customer face major two problems. One is “direct cold air dispersion” and second is “high electricity bills”. Samsung new Wind-Free Air Conditioner address both of these issues together by providing cooling comfort along with guaranteed optimum energy efficiency by up to 72% compared to fast Cooling mode. Samsung Wind Free AC is price start from Rs. 50,950 to Rs. 74,260.

samsung wind-free air conditioner Kandivali
samsung wind-free air conditioner Kandivali
samsung wind-free air conditioner Thane
samsung wind-free air conditioner Thane
samsung wind-free air conditioner Mumbai
samsung wind-free air conditioner Mumbai

Online IRCTC Tatkal Tickets Booking Tips and Tricks – Repair Ki Dukan

Tips To Book Confirm Tatkal Ticket via official website www.irctc.co.in

  • Keep your Id card, Internet Bank Details ready, keep phone along with you for OTP and make sure Internet is up. You must decide you source and destination station,train number and class in advance.
  • Tatkal ticket booking starts at 10:00 am, so login in Irctc website before 5 mins around 9:55 am (You can see time in Irctc website) and keep your session active. Do click on plan my Travel or train availability multiple time otherwise you may logout.
  • In Plan My Journey Select From Station , To Station, Journey Date and Journey Class and Finally Click on Find Train.
  • Right side you can see the list of the train for next day. select quota as TATKAL and click on class you want to travel.
  • Above you can see the train availability then click on BOOK NOW.
  • No you can see the page where you need to enter passenger details. click on ‘Select Passenger From Your Master List‘ to get saved passenger details. it will save your 1-2 min.
  • Fill the CAPTCHA carefully. if you don’t get CAPTCHA, you must reload captcha. In TATKAL IRCTC send difficult CAPTCHA then click next.
  • Now you need to make payment Select Payment Mode  internet banking then select your preferred bank (HDFC,AXIS and ICICI is fast).
  • Fill the bank details to make payment.
  • Your ticket is booked Successfully.

WhatsApp tips and tricks – How to Format Text Bold, Italics, and Strikethrough in WhatsApp


Open Chat box and Follow below steps to format the Whatsapp text.

  • Bold: just add (asterisk) “*” before and after the text Eg: *Repair Ki Dukan*
  • Italics: If you want to type in Italics add (underscore) “_” before and after the text. Eg: _Repair Ki Dukan_
  • Strikethrough: In order to use Strikethrough, you need to add (tilde) “~” before and after the text. E.g: ~Repair Ki Dukan~

Apache Server Setup with system user

Apache Server Setup with system user

In this article we are going to learn how to configure and install Apache from source code.

We divide the setup in below steps.

1. Installing missing dependencies

1.1 Install gcc compiler

$ sudo apt-get update

$ sudo apt-get upgrade

$ sudo apt-get install build-essential

Above command will install list of packages which are considered essential for building Ubuntu packages including gcc compiler, make and other required tools.

Verify installation

Type the following command:

$ whereis gcc make
$ gcc –version
$ make -v

1.2 Install PCRE

Download PCRE from PCRE.org

Compile and install it:

cd pcre-8.30/

make install

1.3 Install APR & APR-UTIL

Download the latest versions of both APR and APR-Util from Apache APR,

Assuming download folder is srccode

wget http://mirror.fibergrid.in/apache//apr/apr-1.5.2.tar.gz

wget http://mirror.fibergrid.in/apache//apr/apr-util-1.5.4.tar.gz

extract tarfile in srccode folder only

tar -xvf apr-1.5.2.tar.gz

tar -xvf apr-util-1.5.4.tar.gz

2. Downloading the source code

Download the latest release from http://httpd.apache.org/download.cgi say httpd-2.4.25.tar.gz

wget http://mirror.fibergrid.in/apache//httpd/httpd-2.4.25.tar.gz

extract tarfile in srccode folder only

tar -xvf httpd-2.4.25.tar.gz

Apache HTTP Server needs APR or Apache Portable Runtime for functioning and use -–with-included-apr option to the apache configure script.

copy apr-1.5.2 and apr-util-1.5.4 in httpd-2.4.25/srclib with anme without version apr and apr0util respectivily.

3. Compiling and installing apache

Type below command

Cd srccode/ httpd-2.4.25

./configure –prefix=/home/agni/httpd –with-included-apr


make install

4. Post Installation Process

4.1 Apache by default runs as root users. Running the apache as rootuser is insecure and so not advisable.

It is better to run the apache under a system account with limited privileges. So we will create a User and Group for Apache. In the terminal, execute the following command.

$ groupadd apachegrp

$ useradd -M -g apachegrp -d /home apacheusr

set password for apacheursr user

$passwd apacheusr

Go to httpd.cofg file and finf User daemon and Group daemon change this.

User apacheusr

Group apachegrp

4.2 Setting proper permissions for DocumentRoot directory

Apache to access file in htdocs need permissions for user apacheusr and group apachegrp.

Change the Owner and Group of htdocs directory t  apacheusr and apachegrp.

chown -R apacheusr:apachegrp /home/agni/httpd/htdocs

Note: /home/agni/httpd/htdocs is the system DocumentRoot directory.The contents of this directory are usually modified by the standard user from a local machine and no the user have access to this directory.So everytime we have to modify the contents of this directory, we will have to do it as root user and set proper permissions afterwards. This is an inconvenience. Performing the following steps will solve this issue.

Add the standard user’s group as a supplementary group, to the group apachegrp.

Replace GROUPNAME with the name of your primary group.

usermod -G apache GROUPNAME

You must have logged out and logged in again.

Provide write permission to members of apachegrp group, so that the standard user will have write access to the DocumentRoot directory.

chmod -R g+w /usr/local/apache2/htdocs

Still, there is a problem. If the standard user creates a file/directory inside the htdocs directory, the owner will be set to standard user and group will be set to primary group of standard user. As a result, Apache HTTP Server will not have write access to those files/directories unless we set proper permissions as root.

This can be overcome by setting SGID bit on the htdocs directory. This makes the created file/directory to retain the group ownership of directory with SGID under which it was created. Thus Apache HTTP Server will have read&write access to these file/directories. For this, execute the below command in terminal.

find /usr/local/apache2/htdocs -type d -exec chmod g+s {} ;

4.4 Adding the DirectoryIndex type index.htm

DirectoryIndex index.html index.htm

4.5 Enabling htaccess directives

AllowOverride All

4.6 Enabling module mod_rewrite.so

Uncomment the line, so that it looks as shown below.

LoadModule rewrite_module modules/mod_rewrite.so

Source http://howtolamp.com/lamp/httpd/2.4/installing#accounts

That’s all for now. I will be here soon with another intersting topic. Till then stay tuned and connected to Repair Ki Dukan.

Browsing the internet from the Terminal (command line) in Linux

Browsing the internet from the Terminal (command line) in Linux

There are actually a number of text-mode web-browsers, We are going to see few of them.


Links is a text based web browser written in C language. You may install it from repo.

$ apt-get install links

After installing links you can browse any website within terminal as mentioned below.

Links google.com

To navigate use UP and DOWN arrow keys. RIGHT keys to go links and Left arrow keys to go back to page. Q key for quits.

2. Links2

Links2 is graphical web browser. To install

$ apt-get install links2


to install Lynx

$ apt-get install lynx

To Use

$ lynx www.google.com

4. w3m

to install

$ apt_get install w3m

to use

w3m www.google.com

That’s all for now. I will be here soon with another interesting topic. Till then stay tuned and connected to Repair Ki Dukan.

We provide doorstep home appliance repair and service.
Ac Repair | Ac Services | Ac maintenance
Call us at 76667 44447 or visit: repairkidukan.com


Air Conditioner (AC) Ratings

Air Conditioner Ratings

How do you interpret the air conditioner ratings provided by the manufacturers of the equipment that you are comparing? If you are looking for a heat pump or air conditioner unit for your house or office, you may want to do a little bit of homework before going to the shops and purchase the unit.

Getting a suitable equipment that will usually last you for many years is essential as there is a trade off between the initial price and the operating cost over the years.


A good unit that comes with energy saving feature such as inverter control of the compressor is higher cost compared to the normal ON/OFF compressor. This is because the electronic control is very much more complicated and contributes substantially to the cost of the unit. However, the energy efficient unit will save you energy hence your utility bill.

If you add up the savings over the years, you will in fact gain more savings even though your initial investment is higher. Therefore, house owners will usually be willing to pay more for better and efficient unit. Look out for Energy Star or equivalent logo on the equipment.

Air Conditioner Ratings & Typical Specifications

Here are some of the air conditioner ratings you may encounter in the brochures or specifications of the air conditioner or heat pump unit.

1. Capacity

This is the most basic specifications that you should look out for. In ductless split, the range of cooling capacity can go from 9,000 Btu/h to over 30,000 Btu/h. The amount of cooling needed by the space will be used to determine the capacity of the air conditioner needed.

2. COP(Coefficient of Performance)

This coefficient is the ratio of the cooling capacity(W) versus power consumption(W).

COP= Cooling Capacity(W)/Power Consumption(W)

The higher the COP, the higher the efficiency of the air conditioner. Usually the value range from 2-4 but in recent years, the use of inverter compressors have enabled this coefficient to go higher than 4. This formula is also applicable for the heat pump system. See the explanation on heat pump COP.

If the cooling capacity is given in Btu/h, you can convert it to Watt by dividing it with 3.412.

1W= 3.4121 Btu/h

3. EER (Energy Efficiency Ratio)

This rating was established by ARI or Air Conditioning and Refrigeration Institute in 1975 for manufacturers to rate their equipment so that consumers or consultants can tell the cooling efficiency of the air conditioner by just looking at the specifications provided.

This rating is obtained by dividing the cooling capacity(Btu/h) with the input power(Watt). The rating points are at 80 °F dry bulb/67 °F wet bulb indoor temperature and 95 °F dry bulb/75 °F wet bulb outdoor temperatures.

For instance, if you look at the brochure and the unit has a Cooling Capacity = 25,000 Btu/h and Input Power = 2,400 W,

EER = (25,000 Btu/h)/2400W

       = 10.42

The larger the value of EER, the more efficient the air conditioner is. Therefore, choose a bigger EER if you are comparing between two equipment.

The EER has a limitation in that it is measured only when the unit is in steady-state condition. The starting up and shutdown cycles are not included in the calculation.

Therefore, this rating does not give a complete picture of the efficiency of the unit. A better efficiency ratio known as Seasonal Energy Efficiency Ratio or SEER is developed.

Choose wisely these air conditioner ratings as the efficiency of the unit will drop as the unit aged over the years.

The Energy Star Logo

4. SEER (Seasonal Energy Efficiency Ratio)

This ratio is rated by AHRI (Air Conditioning, Heating and Refrigeration Institute) and manufacturers’ equipment ratings are published in their catalogs. This ratio is more accurate as it takes into consideration non steady state conditions such as the start-up and shutdown cycles of the air conditioner.

All central split-cooling system produced in the US must have this ratio effective Jan 23, 2006. In order to ensure more efficient units are produced, a minimum SEER of 13 has been stipulated except for window units which has a minimum SEER of 10.

In choosing the SEER, the choice is always to go for a higher SEER as it is a more efficient equipment. The trade-off in choosing a higher SEER is that usually the initial cost of the equipment will be higher.

This ratio is obtained by dividing the total cooling that the equipment is able to provide over the entire season (Btu) over the total energy in Watt-hours it will consume (Wh).

5. HSPF (Heating Seasonal Performance Factor)

This ratio is used to determine the efficiency of air source heat pumps equipment.

It applies to the heating mode by which the total heating used during the entire season is divided by the energy in Watt-hours that it consumed.

A ratio of greater than 8 is considered an efficient equipment. However, the advancement of better control and inverter compressor have enabled units to have HSPF up to 13.

You will see this figure moving upwards as newer design is being developed.

For example, a ductless split unit heat pump delivering 100,000,000 Btu during the entire season and consuming 12,000 kWh will have a HSPF of:

HSPF = 100,000,000 Btu/12,000 kWh

        = 8.33

The higher the HSPF, the better the unit is.

6. Noise or Sound Level

In ductless split unit, there is an indoor and outdoor unit. The specifications will state the noise level of both the indoor (evaporator) and outdoor (condenser). The lower the dBA value, the quieter it is. Hence, if you are installing a unit in the study room, choose a lower dB level.

The evaporator is always quieter than the condenser unit. Depending on the capacity, the indoor noise level can go down to below 21 dBA and the outdoor unit can go higher than 50 dBA. Higher capacity equipment will have higher sound levels compared to a lower capacity equipment.

7. Refrigerant

The refrigerant used will also determine the pricing of the unit. For example, R22 will be phased out soon whereas R410A is the more ozone friendly refrigerant.

The cost of the newer refrigerant is more costly but you will be helping to reduce the amount of gas that is harmful to the ozone from being used. Ask the dealer on the refrigerant used and get their advice on future replacement and service.

8. Energy Star

Look out for Energy Star rating of the equipment. An equipment with this rating shows that the equipment is designed to save energy hence reducing your electricity bills as well as protecting our environment.

Units that are qualified for Energy Star ratings are listed in the official website. See the Energy Star air conditioner ratings here.