HVAC basics

 Compressor. Compressor is a device which is used to compress refrigerant and make flow of refrigerant in whole air conditioning system. This is the heart of air conditioning system. Classification of compressor according to method of compression. There are two different types of compressor used in Air conditioning system. 1. Positive displacement compressor 2. Dynamic compressor 1. Positive displacement compressor In this compressor pressure of refrigerant increased by compress refrigerant (to reduce volume). We know that pressure is inversely proportional to volume.  There are following types of positive displacement compressor. A. Reciprocating compressors 1. Single acting  2. Double acting  3. Diaphragm   B. Rotary compressors  1. Lobe compressor 2. Screw compressor 3. Scroll compressor 4. Liquid ring compressor 5. Vane compressor 2.Non positive displacement compressors or dynamic compressor. In this type of compressor increase the velocity of refrigera...

 There are two types of reactor. 1. AC Reactor -AC Reactor is basically an inductor used in series of AC supply. -Transients and harmonics are generated from inverter due to high current switching in Inverter Circuit. Also Inverter Drive circuit is sensitive to external surges and spikes Function of ac reactor 1 Reduce Harmonics 2 Restrict Transients 3 Suppress external surges 4 Improve input Power factor -AC Reactors are generally required where very high VA Inverter drive is used. -Also if our Drive circuit needs to comply to some Statuatory standards then AC reactors helps in achieving required specifications DC reactor -DC Reactor is also basically an inductor connected in the DC bus between the Rectifier bridge and the capacitor bank. Function of DC REACTOR 1. Reduce Harmonics 2. Restrict Transients 3. Improve Input Powerfactor -DC reactors donot protect Rectifiers from possible voltage transients in mains Advantage of DC Reactor. -Less expensive compared to AC reactor -Less l...

 Inverter air conditioner. Inverter air conditioner is an intelligence system which can modulates (varying)  it's cooling capacity according to indoor heat load requirements. Many people think that inverter AC works on inverter But it's not true. Inverter ac consume less power than non inverter AC. Now we will know about inverter circuit. Inverter basics.  Inverter is an device which converts direct current (DC) in to AC. We know that we use rectifiers to convert AC in DC . Inverter system circuit. There are two circuit in inverter AC. 1. Converter circuit. 2. Inverter circuit 1. Converter.   AC- DC In this circuit there is a diode bridge which converts AC to DC. After than there is a resistance and capacitor,which creates smooth voltage. 2. Inverter circuit. DC - AC In this circuit there are four switches 1, 2,3 and 4. There are two circuit when switch 1&4 on and when switch 2 and 3 on.

 Vapour compression refrigeration system. There are four fundamental process in vapour compression refrigeration system. We represent these processes on temperature entropy diagram and pressure enthalpy diagram. 1. Compression Process 1-2   Isentropic compression process In this process low pressure and low temperature vapour refrigerant enter in compressor and convert in to high pressure and high temperature vapour refrigerant. In figure compression process represented by line 1-2. In this process entropy remains constant. 2. Condensation. Process 2-3  constant pressure (isobaric) pressure process In this process high pressure and superheated vapour refrigerant enter in Condenser and convert in to high pressure liquid refrigerant by removing latent heat. Condensation process is represented by line 2-3 in TS and PH diagram. In this process pressure remains constant. 3. Expansion. Process 3-4 Isenthalpic  process In this process high pressure and high temperature...

 Vapour compression refrigeration system. In this cycle low pressure vapour refrigerant convert in to high pressure vapour refrigerant, so it's called vapour compression refrigeration cycle. In vapour compression refrigeration cycle there are four fundamental process. 1. Compression 2. Condensation 3. Expansion 4. Evaporation 1. Compression. In this process low pressure and low temperature vapour refrigerant enter in compressor and convert in high pressure and high temperature vapour refrigerant . In compression process - State of refrigerant- Gas Pressure - Low pressure to high pressure Temperature - Low temperature to high temperature Function - increase refrigerant pressure. 2. Condensation. In this process high pressure superheated vapour refrigerant convert in to high pressure and high temperature liquid refrigerant. In condensation process -  State of refrigerant. - gas to liquid Pressure - high pressure Temperature - high temperature Function - discharge heat of condens...

Micro chanel Heat exchanger (M C H X) Micro channel is a coil type used in many evaporator (indoor unit heat exchanger) and condenser (outdoor heat exchanger) coils. You can easily identify it by its flat tubes, and its fins look like waves between the tubes. Technology was developed to use in the automobile industry and is used in radiators and automobile A/C condenser coils. These coils are made of aluminum, and we use them because of the superior heat transfer; aluminium coils have greater surface contact between the refrigerant and the metal. They also have a low  weight and smaller refrigerant charge. Aluminium coils have come under a lot of problems from technicians due to  high failure (leak rate of the condenser coils) in some systems. Some have felt these failures occur due to inherent issues with the design, while others have stated that the leaks were due to specific manufacturing issues on a few coils and that these issues are largely in the past. No matter how you...

Quality month Quality month is of the worlds annual celebration commitment to continuous improvement systems. In Quality month organization select yearly target as suppose the target is   "To Reduce defect ratio 1.7% to 0.8%. It is celebrated every year around the world in November. world wide that The day was designed to increase awareness of the important contribution. quality makes towards and national and organisational growth.  World's quality day celebrated every year in second Thursday of November. Why we celebrate quality month in November  This month is selected by Japanese in 1960-1970. American society also celebrating quality month in November month. Quality month November 2022.

 Piping diagram of split air conditioning. Room ac (IDU) In indoor unit there are following parts . 1. Heat exchanger (Evaporator). 2. Fan motor. 3. Cross flow fan. 4. Thermistor on heat exchanger. Room ac (O.D.U.)  There are following parts in room air conditioner out door unit. 1. Compressor 2. Accumulator 3. Discharge pipe thermistor 4. Heat exchanger (Condenser)  5. Heat exchanger thermistor 6. Muffler with filter 7. Strainer 8. expansion device 9. Liquid stop valve 10 Gas stop valve 11. Service valve 

 Sensors. Sensor is a device which detects  physical property and records, indicates, and otherwise respond to it. "to ensure greater response, the engineers used electronic sensors to monitor each wheel. Types of sensors used in industrial automation. 1. Proximity sensors. Proximity sensors are able to detect the presence of nearby objects without any physical contact. It's often. emits electromagnetic field ash beam of electromagnetic radiation and looks for changes. the field of return signal.  2. Photoelectric sensors.  Photoelectric sensors are also device  that detects difference in light level recieved from the light source. The sensor is made up amplifier signal converter and a light source an output. There are three types of photoelectric sensors. A. Thru-beam sensor Two seperate device are used to make or Break beam seciever.one is emitter and second is receiver. (B) Diffused sensor, The light source and the receiver are housed in the same housing. Whe...

 ODP Ozone Depletion Potential.  – Ozone Depletion Potential is a number that refers to the amount of ozone depletion caused by a substance. The ODP is the ratio of the impact on ozone of a chemical compared to the impact of a similar mass of CFC-11. Thus, the ODP of CFC-11 is defined to be 1.0. Other CFCs and HCFCs have ODPs that range from 0.01 to 1.0. HFCs have zero ODP because they do not contain chlorine. ˃ GWP - Global Warming Potential  GWP is a number that refers to the amount of global warming caused by a substance. The GWP is the ratio of the warming caused by a substance to the warming caused by a similar mass of carbon dioxide. Thus, the GWP of CO2 is defined to be 1.0. CFC-12 has a GWP of 8,500, while CFC-11 has a GWP of 5,000. Various HCFCs and HFCs have GWPs. The GWP for a gas is a measure of the total energy that a gas absorbs over a particular period of time (usually 100 years), compared to carbon dioxide.

1 Ton of refrigeration. Ton of Refrigeration is defined as transfer of heat from melting or freezing of ice at 0 degree Celsius in 24 hours.  It's mean that if 1 Ton of ice melted at same rate in 24 hours and produce cooling effect as like as 1 Ton of air conditioner.  Latent Heat of ice = 80 kcal/kg To melt 1kg of ice we need = 80 KCal Heat To melt 1000 kg of ice in 24 hours = 80X1000 Kcal To melt "1000 kg " of ice in 1 hours = (80X1000)/ 24 To melt 1000 kg of ice in 1 min. = ((80X1000)/(24X60)                                                                                     Kcal  " Heat transfer rate = ((80X1000)/(24X60) Kcal/min                                     ...

 What is vaccum Atmospheric pressure. The atmospheric air exerts a normal pressure upon all surfaces with which it is in contact and it is known as atmospheric pressure. It is also known as barometric pressure. The atmospheric pressure at sea level (above absolute zero) is called standard atmospheric pressure. Value of atmospheric pressure is given below. Standard atmospheric pressure = 101.3 kN/m² or kPa (1kN/m² = 1kPa) = 10.3 m of water  = 760 mm of Hg = 76   cm of Hg Gauge pressure The pressure measured with the help of a pressure gauge is known as gauge pressure, in which atmospheric pressure is taken as datum. Pressure gauge read difference between the actual pressure and atmospheric pressure. Absolute pleasure = Atmospheric pressure + Gauge pressure Absolute pleasure = Atmospheric pressure - Negative gauge pressure (vaccum pressure) Vaccum pressure. The negative gauge pressure is called vaccum pressure. Vaccum pressure is the pressure less than atmospheric pres...

Psychometric process. 1. Sub cooling 2. Sub heating 3. Humidification 4. Dehumidification 5. Cooling and humidification 6. Cooling and dehumidification 7. Heating and humidification 8. Heating and dehumidification Now we will discuss one by one about psychometric process. 1. Sub cooling  When warm wet air is cooled as it passes over a cooling coil, the temperature begins to decrease. If the air leaves the coil at a temperature above its dew point temperature, then no condensation occurs Since the humidity ratio remains unchanged, and so we use a horizontal line on the psychrometric chart to represent this process.  2. Sub heating The process of sensible heating is represented on the psychrometric chart by straight horizontal lines parallel to the abscissa. Since the humidity ratio remains unchanged, and so we use a horizontal line on the psychrometric chart to represent this process. Heating will result in lower relative humidity.

 Psychometric chart. Graphical representation of psychometric properties is called psychometric chart. In this chart dry bulb temperature lies on x-axis (abscissa). And specific humidity lies on y-axis (ordinate). 1. Dry bulb temperature line. In psychometric chart dry bulb temperature lines draws  vertical and parallel to ordinate at definite distance. Each lines draw in periods of 5 degree celcious. Generally dry bulb temperature shows -6 degree celcious to 45 degree celcious. 2. Specific humidity lines. In psychometric chart specific humidity lines draws as horizontal lines and parallel to abscissa at definite distance. Generally in psychometric chart specific humidity lies between 0 to 30 gram per KG. Specific humidity lines are also called moisture content line. 3. Dew point temperature lines. In psychometric chart dew point temperature lines draws as parallel to abscissa distance between two D.P.T. lines are not same. 4. Wet bulb temperature lines. In psychometric chart ...