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HVAC (heating, ventilation, and air conditioning) is a major subdiscipline of mechanical engineering. The goal of HVAC design is to balance indoor environmental comfort with other factors such as installation cost, ease of maintenance, and energy efficiency. The discipline of HVAC includes a large number of specialized terms and acronyms, many of which are summarized in this glossary. :(詳細はAir conditionerを参照) An appliance, system, or mechanism designed to dehumidify and extract heat from an area. Usually this term is reserved for smaller self contained units such as a residential system. :(詳細はBritish thermal unitを参照) Any of several units of energy (heat) in the HVAC industry, each slightly more than 1 kJ. One BTU is the energy required to raise one pound of water one degree Fahrenheit, but the many different types of BTU are based on different interpretations of this “definition”. In the United States the power of HVAC systems (the rate of cooling and dehumidifying or heating) is sometimes expressed in BTU/hour instead of watts. Abbreviated BTU or Btu. ::(詳細はChillerを参照) A device that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. This cooled liquid flows through pipes in a building and passes through coils in air handlers, fan-coil units, or other systems, cooling and usually dehumidifying the air in the building. Chillers are of two types; air-cooled or water-cooled. Air-cooled chillers are usually outside and consist of condenser coils cooled by fan-driven air. Water-cooled chillers are usually inside a building, and heat from these chillers is carried by recirculating water to a heat sink such as an outdoor cooling tower. :Equipment that performs heat transfer to air when mounted inside an air handling unit or ductwork. It is heated or cooled by electrical means or by circulating liquid or steam within it. :(詳細はrefrigeration cycle that ejects or removes heat from the system. The condenser is the hot side of an air conditioner or heat pump. Condensers are heat exchangers, and can transfer heat to air or to an intermediate fluid (such as water or an aqueous solution of ethylene glycol) to carry heat to a distant sink, such as ground (earth sink), a body of water, or air (as with cooling towers). :(詳細はController (control theory)を参照) A device that controls the operation of part or all of a system. It may simply turn a device on and off, or it may more subtly modulate the set point of components. Most controllers are automatic but have user input such as temperature set points, e.g. a thermostat. Controls may be analog or digital. :(詳細はDeep lake water coolingを参照) The heat is rejected to deep lake regions to cool homes and offices, reducing the energy costs. :''(Also delta T)'' a reference to a temperature difference. It is used to describe the difference in temperature of a heating or cooling medium as it enters and as it leaves a system. :(詳細はEconomizerを参照) An HVAC component that uses outside air, under suitable climate conditions, to reduce required mechanical cooling. When the outside air’s enthalpy is less than the required supply air during a call for cooling, an economizer allows a building’s mechanical ventilation system to use up to the maximum amount of outside air. :(詳細はEvaporatorを参照) A component in the basic refrigeration cycle that absorbs or adds heat to the system. Evaporators can be used to absorb heat from air or from a liquid. The evaporator is the cold side of an air conditioner or heat pump. :(詳細はFurnaceを参照) A component of an HVAC system that adds heat to air or an intermediate fluid by burning fuel (natural gas, oil, propane, butane, or other flammable substances) in a heat exchanger. :A gas furnace heat exchanger is responsible for the transfer of heat from inside the furnace into the air outside the furnace. The duct system then transfers this exchanged air to different rooms in the building or space. :A facing across a duct opening, often rectangular in shape, containing multiple parallel slots through which air may be delivered or withdrawn from a ventilated space. The grille directs the air flow in a particular direction and prevents the passage of large items. :A heating coil is the part of the system that conducts heat. It allows electricity to act as fire. :A heat exchanger is the part of the system that transfers heat from the hot parts of the machine or a system to the cold parts of the machine or system. :Terms for the amount of cooling (heat gain) or heating (heat loss) needed to maintain desired temperatures and humidities in controlled air. Regardless of how well-insulated and sealed a building is, buildings gain heat from sunlight, conduction through the walls, and internal heat sources such as people and electrical equipment. Buildings lose heat through conduction during cold weather. Engineers use heat load calculations to determine the HVAC needs of the space being cooled or heated. :A heat pump is a compressor that cycles hot or cold air. It is a device that is designed to move thermal energy in the opposite direction of heat flow by absorbing heat from a cold space which is released to a warmer space. :Heat transfer happens when heat moves from one area to another. It is an important and vital step in the process of cooling a space. :Heating Seasonal Performance Factor is the measurement of heat efficiency over the period of a heating season. :A liquid or gas used to transfer heat between two heat exchangers. An intermediate fluid is used when the hot and cold fluids are too bulky (such as air) or difficult to handle (such as halocarbon refrigerant) to directly transfer the heat. :1. Components made of multiple smaller blades, sometimes adjustable, placed in ducts or duct entries to control the volume of air flow. When used inside of ducts, their function is similar to that of a damper, but they can be manufactured to fit larger openings than a single-piece damper. :2. Blades in a rectangular frame placed in doors or walls to permit the movement of air. :An air handler that conditions 100% outside air. Typically used in industrial or commercial settings, or in "once-through" (blower sections that only blow air one-way into the building), "low flow" (air handling systems that blow air at a low flow rate), or "primary-secondary" (air handling systems that have an air handler or rooftop unit connected to an add-on makeup unit or hood) commercial HVAC systems. Abbreviated MAU. :The lowest amount of fresh air flow that can be allowed into a recirculating system. This limit is sent to ensure that the interior air remains safe and comfortable to breathe. :An automatic louver or damper that controls the fresh air flow into an air handler and modulates to the most energy efficient setting. :A measure of the air temperature outside a building. The temperature and humidity of air inside and outside the building are used in enthalpy calculations to determine when outside air can be used for free heating or cooling. Abbreviated OAT. :An air conditioner and heater combined into a single, electrically powered unit, typically installed through a wall and often found in hotels. Abbreviated PTAC. :(詳細はrooftop unit (RTU) :(詳細はdropped ceiling and the structural ceiling, or a raised floor and the hard floor. Distinct from ductwork as a plenum is part of the structure itself. Cable and piping within a plenum must be properly rated for its fire and smoke indices. See also: plenum chamber :(詳細はAir handler.'' :Usually metal panels suspended under the ceiling, insulated from the building structure. The primary cooling/heating agent temperature is close to the room's temperature. :A type of radiant heating system where the building floor contains channels or tubes through which hot fluids such as air or water are circulated. The whole floor is evenly heated. Thus, the room is heated from the bottom up. Radiant floor heating eliminates the draft and dust problems associated with forced air heating systems. :The transfer of heat directly from one surface to another (without heating the intermediate air acting as a transfer mechanism). :A damper or adjustable louver designed to augment the ventilation of a space during a fire. :A split system is the combination of an outdoor unit and an indoor unit. This is the most common type of system. :A The number of degrees a vapor is above its boiling point at a specific pressure. :A The condition where liquid refrigerant is colder than the minimum temperature required to keep it from boiling which would change it from a liquid to a gas phase. Subcooling is the difference between its saturation temperature and the actual liquid refrigerant temperature. :General term used to refer to the set or a subset of components that perform a specific HVAC function within a building. :A small component that contains a heating coil, cooling coil, automatic damper, or some combination of the three. Used to control the temperature of a single room. Abbreviated TU. :An individual space or group of neighboring indoor spaces that the HVAC designer expects will have similar thermal loads. Building codes may require zoning to save energy in commercial buildings. Zones are defined in the building to reduce the number of HVAC subsystems, and thus initial cost. For example, for perimeter offices, rather than one zone for each office, all offices facing west can be combined into one zone. Small residences typically have only one conditioned thermal zone, plus unconditioned spaces such as garages, attics, and crawlspaces, and basements. :A thermostat is a system that monitors and regulates a heating or cooling system. It can be used to set the desired temperature at which it keeps the environment either heated or cooled. :A two-stage air conditioner is designed to operate on high and low settings during different weather conditions and seasons. The high setting is used during extreme weather, and the low setting is used during moderate weather. This type of air conditioner produces a balanced temperature and is in use for a longer period of time. :A thermostatic expansion valve is a piece of equipment that meters the flow of liquid refrigerant into the evaporator while measuring the vapor refrigerant leaving the evaporator. It thereby controls the superheating at the outlet of the evaporator. :(詳細はair plenum below a raised floor to distribute conditioned air through diffusers directly to the occupied zone. Abbreviated UFAD. :(詳細はGreen Building and Controls Glossary )'', by KMC Controls, New Paris, IN, 2015. *ASHRAE Terminology www.ashrae.org/ASHRAEterms () 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Glossary of HVAC terms」の詳細全文を読む スポンサード リンク
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