Hvac fundamentals

 Heating ventilation & Air conditioning

What is 🔥heating.।। 

Increasing the tempreture of the body by adding heat 🔥⚡energy is known as heating

When do we need heating? 

Heating is required when room temperature🌡️ are very low.।। 

What is ventilation? 

Removal of foul air & adding fresh 🍃💦air is known as ventilation

There are two ✌types of ventilation

Natural ventilation

Forced ventilation

Natural ventilation which takes place through 🚪door gaps & window gaps

Forced ventilation is provided by exhaust fans jet fans or by blowers.।।। 

Air conditioning

Air condition❄💨 is nothing but changing properties of air like

Tempreature

Humidity

Purity

Noise

Air flow

Tempreature is defined as Degree of hotness or coldness of a body 

Comfort body temperature🌡️

22° to 26°c

Exact human comfort temperature🌡️ 75°f

Instrument used for measuring temperature🌡️ is 🔥Thermometer

Humidity is defined as amount of water 💦vapor present in the air is known as Humidity

Human comfort humidity levels is 30% to 70%

Instrument used to measure humidity is Hygrometer or sling Pschrometer

Purity is defined as purity of air is control by using filters is known as purity

Types of filters

Prefilters used for rooms upto 75%

Fine filters used for luxuary upto 95%

Hepa filters & Ulpa filters used for operation

Threatre & for medicine factories 

HEPA high effeciency particulate arrestor 99.7%

ULPA Ultra low particulate arrestor 99.9%

Noise is defined as To reduce the noise accousting lining is used

Unit decibels DB

Instrument used is known as DB metre

Last but not the least

Air flow is defined as air velocity & it's directions 

Air Quantity is measured in CFM

Cubic feet per meter

It is measure by Anemometer

 🔥Heat🔥

It is a form of energy⚡ it transfer or flow from high temperature🌡️ to low temperature🌡️ body

Units of 🔥heat🔥

Joules calories B. T. U British 🇬🇧thermal unit

B. T. U is defined as amount of 🔥heat 🔥required to raise the temperature🌡️ of one pound of water 💦by 1°f

Calorie is defined as amount of🔥 heat 🔥required to raise the temperature🌡️ of one gram of water💦 by 1°c

Types of 🔥heat 🔥

Latent heat 🔥

Sensible 🔥heat

Latent heat🔥 change the phase of the object

Where as

Sensible heat 🔥change the temperature🌡️ of the object

Modes of heat 🔥transfer

Conduction

Convection

Radiation

Conduction takes place due to molecular vibrations 

In solids

Where as

Convection takes place due to molecular movement

In fluids

And

Radiation takes place without any molecule

Means no medium

Heat 🔥transfer in the form of EM 🌊waves🌊 means electromagnetic waves 🌊without affecting any medium 

For example

☀️Sun☀️ rays direct coming to earth 🌎without any medium means direct contact to earth 🌎in the form of rays this is the best example of Radiation heat 🔥transfer

TR means Ton of refrigeration

Ton of refrigeration is defined as amount of heat absorbed by one ton of ice 🧊which is at 0°c to melt completely within, 24hours in closed room is known as Ton of refrigeration

Or

Vice versa

The cooling effect produced by one ton of ice 🧊at 0°c by melting completely within 24 hours in a closed room at normal atmospheric pressure

One TR is equal to

12000 BTU/hr

3024 k. Cal/hr

3.517 kw

Ac is sold or buy in terms of tonn

Hence capacity of AC is measured in TR