PDX_17_Hvac Building Systems Vocab Flashcards
Delivers heated or cooled air or water to necessary zones
Distribution system
Equipment that creates warm or cool air, typically in mech room
Plant
Vary depending type / use of bldg
Example: each story, offices versus apartments, commercial versus recreational spaces
Zones
Heating device, arranged to deliver heat through the air
Convector
Space above suspended ceiling used to convey return air
Plenum
Alternative to chilled water systems in HVAC, used to cool air containing water vapor. A refrigerant is used to remove sensible/latent heat from the air
DX (direct expansion)
Transfer heat from one flew to another,
fluids physically separated
Heat exchanger
Treating of air it an occupied space to control its temperature, humidity, and cleanliness
Air-conditioning
Cooling system provides refrigerated air using solar radiation as prime source of energy
Solar air-conditioning
Substance used in the heat cycle usually including a reversible phase transition from a liquid to a gas
Refrigerant
A family of several CFC gases used in the refrigeration cycle
Freon
The part of a refrigeration system in which the refrigerant evaporates and absorbs heat from the medium to be cooled
Evaporator
Movement of a fluid by a fan or punk in order to force heat exchange
Forced convection
A heat exchanger in which refrigerant vapor is condensed, or liquefied, releasing heat to external medium
Condenser
The velocity of air in an enclosed space measured in feet per minute
Air movement
The heat rejection device which extract waste heat to the atmosphere through the cooling of a water stream to a lower temperature. Often found on the roof.
Cooling tower
Used in a hot climate with high cooling demands
Chiller
Floor of air through a flue or chimney
draft
A duct for smoke and waste gases produced by a fire, gas heater, power station or other fuel burning installation
Flue
A balanced air valve positions to admit air to the flu or stack of a furnace in order to maintain a constant amount of draft
Barometric damper
Or draft regulator
Valve which permits passage of air or water, but not steam, often used with steam radiators
Steam trap
Adding of sensible heat to a supply air stream which has been previously cooled
Reheat
A ventilation system that consists of air intakes, filters, fans, electric heating coils, connected ductwork/components, fire/control dampers, electric reheat boxes, airports, and control systems. Can also include DX or chilled water cooling coil, refrigerant storage, and pump systems.
Air handling unit (AHU)
A unitless number that is a rating of the efficiency of heating or cooling equipment
Coefficient of performance (COP)
Ratio of net cooling capacity in BTU H to the total rate of electrical and put in Watts, under designated operating conditions
Energy efficiency ratio (EER)
Standardized system for rating the energy efficiency of residential buildings. Scores between 0-100 and indicates the relative energy efficiency compared to a HERS efficient home.
Home energy rating system (HERS)
Single number figure of merit based on part load EER or COP expressing part load efficiency for air conditioning and heat pump equipment
Integrated part load value (IPLV)
Computer-based integrated system used to monitor and control building systems
Building automation system (BAS)
This fuel type is easy to install and control, simple operation, flexible zoning, little space required but most expensive type, especially high for heating loads.
Electricity
95–100% efficiency
3, 413 BTU/kWh
This fuel type is 95–100% efficient, and has a heating value of 3413 BTU/kWh
Electricity
This fuel type is portable, good for remote areas. It’s not as clean burning natural gas.
Propane
This fuel type is 70–90% efficient, and produces a heating value of 2500 BTU/ft³:
Propane
This fuel type is the most efficient fossil fuel and clean burning but can’t be used in remote areas.
Natural gas
This fuel type is 70–80% efficient and produces a heating value of 1050 BTU/ft.³
Natural gas
This fuel type is portable and storable but has a wide price fluctuation and burning equipment needs lots of maintenance. It must also be stored securely.
No.2 Oil
This fuel type is 65-85% efficient and produces a heating value of 137,000-141,000 BTU/gallon
No. 2 Oil
This fuel type is 65 - 75% efficient and has a heating value of 12,910 BTU/lb
Anthracite coal
Furnace and boiler both have typical efficiency of
80%
Water paternally fills a barrel with the small volume left above to commentate steam, used in early all steam locomotives, Laredo steam production but high steam storage capacity. Mostly burns solid fuels but can burn liquid or gas
Fire tube boilers
Water tubes are arranged inside a furnace. Gives heisting production rates but less storage capacity. Generally preferred in high-pressure application since I pressure water/team is contained within small diameter pipes
Water tube boiler
Packaged boiler system that operate in parallel or series to provide varying amounts of steam. Typically most efficient when run at full capacity.
Modular boiler
Comes in a complete package, requires only the steam, water, paperwork, fuel supply and electrical connection.
Packaged type boiler
Steam is generated using electricity rather than the combustion of a fuel. More expensive than gas run boilers are simple and easy to use
Electric boiler
Cooling systems can be operated by child air or water produced by:
Compressive refrigeration,
Absorption,
Or evaporative cooling
Refrigerant types:
These are being phased out because they deplete the ozone layer
Fluorocarbons,
especially chlorofluorocarbons.
Refrigerant types:
Fluorocarbons.
Ammonia.
Sulfur dioxide.
Non-halogenated hydrocarbons.
Refrigerant types:
Non–CFC refrigerants may be
Less effective and involve a higher energy cost
This cooling system is based on the transfer of heat during the liquefication and evaporation of a refrigerant. Latent heat is released as refrigerant changes form.
Compressive refrigeration
In the compressive refrigeration process the evaporator serves this role
Expanse refrigerant, vaporizes back to gas absorbing surrounding heat
This refrigeration type is produced in a closed loop system by a salt solution that draws vapor from the evaporator. It’s less efficient than compressive systems and needs about two times the heat rejection capacity of the compressive cycle.
Refrigeration by absorption
This refrigeration tight uses water dropped over pads or tubes that circulate outdoor air or water. works well in hot air and climates with low humidity. Simple to construct, requires no refrigerant line.
Evaporative cooling (swamp cooler)
Most simple type of system, is self-contained unit that passes non-ducted air to be cooled over the evaporator and back into the room. Uses outdoor air directly and typically placed on exterior walls or roof mounted.
Direct expansion (DX) system
The most simple forced air system. Only works when loads are similar to a building, and bad for perimeter zones in cold climates.
Single duct
This forced air system is good for perimeter zones and can heat and cool at the same time. It needs twice as much ductwork and the boiler in chiller have to run all the time,equaling the most consuming system. Common in hospitals. Mixing box located at each room with thermostat.
Double duct or
Dual duct or
High velocity
This forced air system is not as efficient with many zones or non-square buildings. Mixing box is located in the mechanical room.
Multizone forced air system
This forced hot air system can heat and cool different zones at the same time and is the most common inefficient system. Saves energy because it doesn’t have to run at peak all the time. Thermostat controls a damper in each zone to adjust the volume of conditioned air entering that space. Requires a lot of interstitial space. cannot heat and cool different rooms in the same zone at the same time.
Variable air volume system
This forced hot air system is self-contained, used one ducks are impractical to run, and each unit can have its own utility bill. The units you see in big box stores.
Unitary forced hot air system
In this forced hot air system return air and fresh outside air are combined and cooled and dehumidified. Ducts are smaller and fan horsepower is lower. Inefficient because first cools and then heats air, but can have an economizer cycle where outside air is used directly when temps are low enough.
Reheat (constant volume)
In this forced hot air system, high pressure and velocity to each induction unit. Ducts are smaller, works best in perimeter rooms of multi story buildings.
Induction unit
Most simple hydronic system, has low initial cost and is simple. Can’t go very far because water temperatures drop and can only heat/cool at one time. Can be combined with a forced air system.
Hydronic single pipe
This hydronic system separates the supply and return, so that the radiators are running in series and not parallel.
Hydronic two pipe
This hydronic system incorporates a separated hot and cold pipe, so can cool and heat at the same time. More piping is required.
Hydronic three pipe
Hydronic system has a separated hot and cold, and separated returns, giving it the most expensive typing but efficient performance and can heat and cool at the same time.
Hydronic four pipe
This combined system is one of the most efficient, provides heating and cooling simultaneously. High initial cost because plumbing and ductwork. Can just be used for ventilation without heating and cooling.
Fan coil system
This combined system has good efficiency, reduces ductwork, and returns over 200% it’s electrical input when outdoor temperatures above freezing. Each zone has its own heat pump and fan. Pump either lose heat some water and blows it into a room, or removes heat from room and into the water.
Heat pump system
