Terminologies of Terminologies of HVACHVAC

► Air ConditioningAir Conditioning- Air conditioning is defined as the simultaneous control of air - Air conditioning is defined as the simultaneous control of air

temperature, humidity, motion and purity of air in a confined temperature, humidity, motion and purity of air in a confined space.space.

► Air ConditionerAir Conditioner- A device provides air conditioning.- A device provides air conditioning.

► HeatHeat- A form of energy that is transformed by temperature difference.A form of energy that is transformed by temperature difference.

► EnthalpyEnthalpy- The quantity of heat in BTU/ min. in a fluid or gas.- The quantity of heat in BTU/ min. in a fluid or gas.

► CondenserCondenser- A heat-exchange device in a refrigeration system; it consists of a A heat-exchange device in a refrigeration system; it consists of a

vessel or arrangement of pipes or tubing in which refrigerant vessel or arrangement of pipes or tubing in which refrigerant vapor is liquefied by the removal of heat.vapor is liquefied by the removal of heat.

► CompressorCompressor- A machine for drawing refrigerant from the evaporator at a - A machine for drawing refrigerant from the evaporator at a

relatively low pressure, compresses it and then discharges it to relatively low pressure, compresses it and then discharges it to the condenser.the condenser.

► EvaporatorEvaporator- That part of the refrigeration system in which refrigerant is - That part of the refrigeration system in which refrigerant is

vaporized, thereby taking up external heat and producing cooling.vaporized, thereby taking up external heat and producing cooling.

► ConvectionConvection- Heat transmission, either natural or forced, by currents resulting - Heat transmission, either natural or forced, by currents resulting

from difference in density due to temperature difference in the from difference in density due to temperature difference in the heated space.heated space.

► HumidityHumidity- Water vapor within a confined space or environment.- Water vapor within a confined space or environment.

► Relative HumidityRelative Humidity- The ration of the weight of water vapor actually in humid air to the The ration of the weight of water vapor actually in humid air to the

maximum possible weight of water vapor that the air could contain maximum possible weight of water vapor that the air could contain at the same temperatureat the same temperature

► Humidity RatioHumidity Ratio- Weight of water vapor in a mixture per pound of dry air.- Weight of water vapor in a mixture per pound of dry air.

► Humidistat, HygrostatHumidistat, Hygrostat- A device actuated by changes in humidity- A device actuated by changes in humidity

► ThermostatThermostat- Device which responds to changes in temperature, directly or - Device which responds to changes in temperature, directly or

indirectly.indirectly.► Adiabatic SaturationAdiabatic Saturation

- The introduction of water into an un saturated air to increase - The introduction of water into an un saturated air to increase humidity ratio but w/o transfer of heat to or from outside humidity ratio but w/o transfer of heat to or from outside source.source.

► Dew PointDew Point- the temperature at which air-water vapor mixture will become saturated and - the temperature at which air-water vapor mixture will become saturated and begins to yield drops of condensed water.begins to yield drops of condensed water.

► Latent HeatLatent Heat- The amount of heat which is absorbed or evolved in changing the state of the The amount of heat which is absorbed or evolved in changing the state of the

substance w/o changing its temperaturesubstance w/o changing its temperature Latent Heat of FusionLatent Heat of Fusion- One where change is from liquid to solid state.- One where change is from liquid to solid state. Latent Heat of VaporizationLatent Heat of Vaporization- One where change is from liquid to gas.- One where change is from liquid to gas.

► Sensible HeatSensible Heat- Heat in BTU absorbed by a substance in changing its temperature without changing its - Heat in BTU absorbed by a substance in changing its temperature without changing its

state.state.► Wet Bulb TemperatureWet Bulb Temperature

- Temperature of air-water vapor mixture as measured in the normal way with - Temperature of air-water vapor mixture as measured in the normal way with o o F F thermometerthermometer

► DesiccantDesiccant- An absorber which could be liquid or solid that can remove water vapor from a - An absorber which could be liquid or solid that can remove water vapor from a

material.material.► DamperDamper

- A device used to vary the volume of air passing through an air outlet, inlet, or duct.- A device used to vary the volume of air passing through an air outlet, inlet, or duct.► Duct, Air Conditioning Duct, Air DuctDuct, Air Conditioning Duct, Air Duct

- A passageway usually fabricated of metal, fiberglass, concrete or cement and - A passageway usually fabricated of metal, fiberglass, concrete or cement and asbestos fibers; used to transfer air from one location to otherasbestos fibers; used to transfer air from one location to other

► RefrigerantRefrigerant- Substance which produces refrigerating effect by absorbing heat while - Substance which produces refrigerating effect by absorbing heat while

expanding or evaporating.expanding or evaporating.► Condensing UnitCondensing Unit

- Specific refrigerating machine combination for a given refrigerant.- Specific refrigerating machine combination for a given refrigerant.► Air Conditioning MachineryAir Conditioning Machinery

- Equipment including any or all of the following: compressor, condenser, - Equipment including any or all of the following: compressor, condenser, generator, evaporator, absorber, receiver, connection pipe, air handling generator, evaporator, absorber, receiver, connection pipe, air handling units, dehumidifier and heat exchanger.units, dehumidifier and heat exchanger.

► Unit Air ConditionerUnit Air Conditioner- A type of system used for small installation such as residences and small - A type of system used for small installation such as residences and small

offices.offices.► Split Type Air ConditionerSplit Type Air Conditioner

-- Composed of two separate sections, one installed inside the room while Composed of two separate sections, one installed inside the room while the other is mounted outside the building.the other is mounted outside the building.

► Centralized Type Air Conditioning SystemCentralized Type Air Conditioning System- A type of air conditioning system used for large installation with the use of - A type of air conditioning system used for large installation with the use of

ducts.ducts.► Cooling TowerCooling Tower

- A structure, usually on the roof of the building over which water is - A structure, usually on the roof of the building over which water is circulated so as to cool it evaporative in contact with air.circulated so as to cool it evaporative in contact with air.

► AFUE (Annual Fuel Utilization Efficiency)AFUE (Annual Fuel Utilization Efficiency)- The ratio of annual fuel output energy to annual input - The ratio of annual fuel output energy to annual input

energy.energy.► COP (Coefficient of Performance)COP (Coefficient of Performance)

- The ratio of the rate of heat removal/delivered to the rate of - The ratio of the rate of heat removal/delivered to the rate of energy input.energy input.

► EER (Energy Efficiency Ratio)EER (Energy Efficiency Ratio)- The ratio of net equipment cooling capacity in BTU/ hr. to - The ratio of net equipment cooling capacity in BTU/ hr. to

the total rate of electric input in watts.the total rate of electric input in watts.► IPLV (Integrated Part Load Value)IPLV (Integrated Part Load Value)

- Single number figure of merit based on part-loaded EER or - Single number figure of merit based on part-loaded EER or COPCOP

► SEER (Seasonal Energy Efficiency Ratio)SEER (Seasonal Energy Efficiency Ratio)- The total cooling output of an air conditioner during its - The total cooling output of an air conditioner during its

normal annual usage, in BTU/ hr, divided by the total normal annual usage, in BTU/ hr, divided by the total energy input during the same period, in watt-hours.energy input during the same period, in watt-hours.

► Codes of Heat TransmissionCodes of Heat Transmission ConductionConduction ConvectionConvection RadiationRadiation

► The following are considered essential for human comfortThe following are considered essential for human comfort Temperature of the surrounding airTemperature of the surrounding air Temperature of the surrounding surfacesTemperature of the surrounding surfaces Relative humidity of airRelative humidity of air Motion of airMotion of air OdorsOdors DustDust

► Air conditioning StandardAir conditioning Standard Heating and dehumidifyingHeating and dehumidifying Cooling and dehumidifyingCooling and dehumidifying Air motionAir motion Air supplyAir supply

► Refrigeration and Air Conditioning StandardsRefrigeration and Air Conditioning Standards The temperature and humidity of air to be used for comfortable cooling shall be The temperature and humidity of air to be used for comfortable cooling shall be

maintained at 68-74maintained at 68-74oo F , effective temperature at an air movement from 4.57-7.60 F , effective temperature at an air movement from 4.57-7.60 MPM within the living zone.MPM within the living zone.

► Summer, Air Conditioning, Cooling and DehumidifyingSummer, Air Conditioning, Cooling and Dehumidifying Passing air through sprays of cold waterPassing air through sprays of cold water Passing air through a combination of cold water sprays and cooling coilsPassing air through a combination of cold water sprays and cooling coils Passing air through refrigerating coilPassing air through refrigerating coil

► Design ConsiderationDesign Consideration Type, usage and hours of occupancy of building or structure.Type, usage and hours of occupancy of building or structure. Number of occupants and type of activityNumber of occupants and type of activity Area and Volume of materials in conditioned spaceArea and Volume of materials in conditioned space Building orientationBuilding orientation Types of shades and glass exterior claddingTypes of shades and glass exterior cladding Ventilation requirementsVentilation requirements Amount and type of artificial lightning and hours of useAmount and type of artificial lightning and hours of use

► Heat Gain BuildingHeat Gain Building Heat transmitted through walls, roofs, floors, partitions, ceilings and glass, absorbed Heat transmitted through walls, roofs, floors, partitions, ceilings and glass, absorbed

by them and conducted through the interiorby them and conducted through the interior Heat from solar radiation striking upon the exterior surfaces of walls and glass, Heat from solar radiation striking upon the exterior surfaces of walls and glass,

absorbed by them and conducted through the interiorabsorbed by them and conducted through the interior Heat carried in by infiltrating or ventilating outside airHeat carried in by infiltrating or ventilating outside air Heat given off by occupantsHeat given off by occupants Heat given off by lights, cooking devices, motors, fans and industrial processes Heat given off by lights, cooking devices, motors, fans and industrial processes

within the conditioned space.within the conditioned space.

►Cooling Load Calculation FactorsCooling Load Calculation Factors Internal loadsInternal loads Thermal transmission laodThermal transmission laod Infiltration and ventilation loadInfiltration and ventilation load Solar loadSolar load