Mahatma Gandhi Mission’sCollege of Engineering and Technology.

Noida, U.P., India

Under the guidance of Prepared by MR. ABHIJIT KULKARNI Krishan Kumar

Technical seminar on

HEATING VENTILATION AND AIR CONDTIONING

CONTENT

• Introduction to HVAC• History of HVAC• Need of HVAC• Heating• Ventilation• Air conditioning process• Types of installation• Recent Development in HVAC• Advantages & Disadvantages• Applications of HVAC• Conclusion

WHAT IS HVAC?• Heating, Ventilation, and Air Conditioning

WHAT DOES IT DO?

• HVAC is a basic requirement for your indoor air quality, what you breathe, temperature, humidity -- in your house.

• So when you hear the term "HVAC" it means the entire air system of your home.

HISTORY OF HVAC

• IN 1851 Dr John Gorrie was granted U.S. Patent for refrigeration machine.

• In 1880 refrigeration became available for industrial purpose. Initially two major uses –freezing meat for transport and making ice.

• Early 1990-new initiative to keep building cool for comfort.

• 1902 cooling the New York stock exchange-one of the first comfort cooling system.

NEED OF HVAC SYSTEM

• Improvement of the air quality

• Moisture regulation

• Depression

• Maintenance of the constant temperature throughout the year

• Energy conservation

HVAC COMPONENTS

• Furnace• Heat exchanger• Ducts• Vents• Air Conditioning Unit• Evaporator Coils• Condensing Unit

FURNACE

• As part of the HVAC, the furnace heats the air that circulates in the home.

• The quality of air in the home can be influenced by how often you change the air filter on your unit.

• Usually the Air Conditioner is outside, and the furnace is inside the house.

• The HVAC uses the same venting system for both.

WHAT ARE BTU’S AND EER’S

• BTU or British Thermal Units, are the amount of heat required to raise the temp. of one pound of water, 1 degree Fahrenheit. 1 ton= 12,000BTU.

• EER is Energy Efficiency Rating and tells you the BTU rating over the wattage. The higher the EER, the better the energy efficiency, but it will probably cost more.

HEATING

CONVECTION-Collective movement of groups of molecules within fluids , through diffusion 

CONDUCTION -Transfer of internal energy by microscopic diffusion and collisions of particles within a body due to a temperature gradient.

RADIATION- Electromagnetic waves (EMR) travel through a vacuum or through matter-containing media.

GENERATION OF HEAT• Heaters exist for various types of fuel, including solid

fuels, liquids, and gases.

• Another type of heat source is electricity, typically heating ribbons made of high resistance wire.

• This principle is also used for baseboard heaters and portable heaters.

• Electrical heaters are often used as backup or supplemental heat for heat pump systems.

DISTRIBUTION OF HEAT

• WATER/STEAM -• Piping is used to transport the heat to the rooms. • Modern hot water boiler heating systems have a

circulator, which is a pump, to move hot water through the distribution system .

• AIR-• Warm air systems distribute heated air through duct

work systems of supply and return air through metal or fiberglass ducts.

• Many systems use the same ducts to distribute air cooled by an evaporator coil for air conditioning.

VENTILATIONMECHANICAL OR FORCED- Provided by an air handler and used to control indoor air quality. • Excess humidity, odours, and contaminants can often be

controlled via dilution or replacement with outside air. • Kitchens and bathrooms

NATURAL- ventilation of a building with outside air without using fans or other mechanical systems.-reduces spread of diseases- tuberculosis, common cold.

IMPROVED VENTILATION EFFECTIVENESS

• Effective mixing of ventilation air within space• Net positive pressure in the southeast; exhaust from

appropriate spaces• Provide clean outdoor air, avoid:

– loading docks – exhaust vents– plumbing stacks– waste collection– stagnant water

AIR CONDITIONING UNITAn air conditioner is like a refrigerator without the insulated box. It evaporates a refrigerant, like Freon, to provide cooling.

Most Air Conditioners Have:– A compressor – An expansion valve – A hot coil (on the outside) – A chilled coil (on the inside) – Two fans – A control unit

• Heart of the system, belt driven pump that fastened to engine.• Responsible for compressing and transferring refrigerant.

Advantages:• Very high volumetric efficiency (almost 98%)

• Lesser Noise and lighter compared to rotary compressor.

COMPRESSOR

CONDENSER• Responsible for heat dissipation. The condenser is designed to

radiate heat. • Located in front of the radiator. Require good air flow when

system is in operation • Plate fin type heat exchanger with micro channels used.Very

compact and better heat transfer capability.• Hot compressed refrigerant vapour cools at constant pressure to

liquid.

EVAPORATOR• Heat absorption component.• Used remove heat from the inside of vehicle. • Secondary benefit - dehumidification. • Unconditioned air passes through a filter before entering the

evaporator.• Plate-fin evaporator with micro channels used.

BASIC REFRIGERATION CYCLE

HEAT PUMP (HP)• A machine or device that moves heat from one location (the

source) to another location (the mechanical work)• Can produce heating or cooling by reversing the direction of heat

flow

• Can be used in:– Forced Air System– Hot Water System– Radiant Heat System

TYPES OF INSTALLATION• Window unit and packaged terminal

• Split system

• Mini Split System -typically produce 9,000–36,000 BTU(9,500–38,000 KJ) per hour of cooling.

• Central air conditioning• Portable units-easily transported inside a home or

office ,capacities of about 5,000–60,000 BTU/h (1,800–18,000 W output)

USES OF AIR CONDITIONING

• Comfort application

• Domestic use

• Process application

HVAC SYSTEMS

Central Forced air system

Air handling system

• Hot water system

• Zone control system

• Radiant heat

CENTRAL FORCED AIR SYSTEM

• Most common HVAC system circulates air through or around heating and cooling devices.

• A fan forces air into ducts • Supply ducts transport conditioned air into building

through diffusers or supply registers• Air is routed back to heating/cooling device through

return ducts

AIR HANDLING UNIT(AHU)

• Device used to condition and circulate air as part of an HVAC system

• Large metal box containing a blower, heating or cooling elements, filter, and sound attenuators.

• Connects to ductwork that distributes the conditioned air through the building and returns it to the AHU

AIR HANDLING UNIT (AHU)

• May need to supply heating, cooling, or both• A furnace generates heat– Fuel oil or natural gas– Electric heating elements

• A refrigeration system absorbs heat– Air conditioner– Heat pump

AIR HANDLING UNIT (AHU)• Smaller air handlers may contain a fuel-burning heater or a

refrigeration evaporator placed directly in the air stream• Large commercial air handling units contain coils that

circulate water– Boiler provides hot water or steam– Chiller provides chilled water

AIR HANDLING UNIT (AHU)

Typical AHU components:

1. Supply duct2. Fan compartment3. Flexible connection4. Heating and/or cooling coil5. Filter compartment6. Return and fresh air duct

HOT WATER SYSTEM• Water heated in boiler and circulated through pipes to

radiators• Requires plumbing rather than ductwork

ZONE CONTROL SYSTEM

• One heater and one thermostat per room

• No ductwork

• Often used in hotel rooms

RADIANT HEAT• Supply heat directly to the floor, wall, or ceiling• Hot water pipes or electric heating element runs through

building component• Dependent on radiant heat– Heat transferred from hot surface to people and objects

RECENT DEVELOPMENT IN HVAC

Emerson Climate Technologies Launches E360

E360 provide a 360-degree view of commercial refrigeration issues and advancements by addressing energy efficiency, equipment reliability and safety, environmental protection, and economic considerations.

Serves as a means of centralizing all of this information and providing us with the tools to interact with industry experts and ultimately improve their operations.

RECENT DEVELOPMENT IN HVAC

DuPont Introduces New HFO Refrigerants for Commercial Refrigeration

Opteon XP40, Opteon XP44, and Opteon XP10.

Opteon XP40 is designed to effectively replace the refrigerant R-404A.

Opteon XP10 is a lower GWP replacement for R-134a for refrigeration

• Replacements for R-22 are HFC-134a, R-410a, R-410b

ADVANTAGES OF HVAC

1. Conserves Energy

2. Regulates Moisture

3. Air Quality Improvement.

DISADVANTAGES OF HVAC

• Initial installation cost is high.

• Primary disadvantage of ductless air conditioners is their cost.

APPLICATIONS OF HVAC

• “Free cooling” during moderate temperatures (chiller

bypass).

• Thermal storage—isolation of storage tank

• Water source heat pump pre cooler with isolation

• Heating potable hot water (instantaneous heater)

• Waste heat recovery from condenser water

CONCLUSION

• Proper system design accounts for building type and size, layout, surrounding area, the nature of activities taking place, the number of occupants, climate and other factors, making each situation distinct.

• Optimizing system operation.

• Making and analysing certain key measurements is essential for optimizing the HVAC system performance.

REFERENCES

1. http://en.wikipedia.org/wiki/HVAC

2. www.saminfratech .com

3.http://www.fsec.ucf.edu/en/consumer/buildings/

commercial/hvac.htm

4. Ventilation and Infiltration chapter, Fundamentals volume

of the ASHRAE Handbook, ASHRAE, Inc., Atlanta, GA, 2005

THANK YOU