This glossary provides a list of key terms in the HVAC (Heating, Ventilation, and Air Conditioning) industry. We will continue to update this list to ensure its relevance.
- Air Handling Unit (AHU): A device used to regulate and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system.
- Chiller: A machine that removes heat from a liquid coolant via a vapor-compression or absorption refrigeration cycle.
- Chilled Water System: An HVAC system where a central chiller cools water, which is then distributed through pipes to air handlers in various zones for cooling.
- Compressor: A mechanical device that increases the pressure of a gas by reducing its volume. Compressor is the “heart” of the refrigeration cycle.
- Condenser: A component in the refrigeration cycle that facilitates the transfer of heat from the hot, high-pressure refrigerant to a cooler medium (e.g., ambient air), causing the refrigerant to condense from a gas to a liquid.
- Corrosion-Resistant Materials: Materials specifically chosen for marine HVAC components (e.g., titanium, copper-nickel) to withstand the corrosive effects of saltwater and high humidity.
- Dehumidifier: A device that reduces the level of humidity in the air.
- Discharge Line: The pipe carrying hot, high-pressure refrigerant vapor from the compressor to the condenser. It is typically the hottest line in the refrigeration cycle.
- Energy Efficiency Design Index (EEDI): a mandatory International Maritime Organization (IMO) measure for new ships to promote energy efficiency and reduce CO2 emissions by setting minimum efficiency levels based on technical design parameters like capacity, speed, and engine type..
- Evaporator: A component in the refrigeration cycle where the cold, low-pressure liquid refrigerant absorbs heat from the surrounding air, causing it to evaporate into a gas and cool the space.
- Fan Coil Unit (FCU): A simple device consisting of a heating or cooling coil and a fan, part of an HVAC system, often used in chilled water systems.
- Gay-Lussac’s Law: A gas law stating that the pressure of a fixed amount of gas at fixed volume is directly proportional to its temperature. In HVAC, it implies that increasing pressure increases temperature.
- Global Warming Potential (GWP): A measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period, relative to carbon dioxide. Low-GWP refrigerants are environmentally preferred.
- Heat Exchanger: A device that transfers heat from one medium to another without the two media directly mixing.
- Humidity Regulation: The process of controlling the amount of moisture in the air, vital in marine environments to prevent condensation, mold, and corrosion.
- International Maritime Organization (IMO): A specialized agency of the United Nations responsible for measures to improve the safety and security of international shipping and to prevent marine pollution from ships. Sets compliance standards for marine HVAC.
- Internet of Things (IoT): A network of physical objects embedded with sensors, software, and other technologies for the purpose of connecting and exchanging data with other devices and systems over the internet. Used in smart HVAC systems for remote monitoring.
- Latent Heat: The heat absorbed or released during a phase change (e.g., melting, freezing, boiling, condensing) of a substance, without a change in temperature. It is critical for the cooling and heating processes in refrigeration.
- Low Global Warming Potential (Low GWP) Refrigerants: Refrigerants that have a reduced impact on global warming.
- MARPOL Annex VI: International Maritime Organization (IMO) regulations aimed at preventing air pollution from ships. Promotes the adoption of low-emission technologies, including energy-efficient HVAC.
- Metering Device (Expansion Valve): A component in the refrigeration cycle that drops the pressure of the liquid refrigerant, causing it to cool rapidly before entering the evaporator. Examples include TXVs, pistons, and capillary tubes.
- Predictive Maintenance: A maintenance strategy that uses data analytics and sensors to predict when equipment failure is likely to occur, allowing for proactive maintenance to prevent breakdowns. A key benefit of AI-driven HVAC.
- Pressure Temperature Chart: A reference tool used in HVAC to determine the saturation temperature of a refrigerant at a given pressure, or vice versa. Essential for diagnosing system performance.
- Refrigerant: A substance used in a heat pump or refrigeration cycle that undergoes phase changes (liquid to gas and back) to absorb and release heat.
- Retrofitting: The process of adding new technology or features to older systems or vessels, often done to upgrade HVAC systems to be more energy-efficient or compliant with new regulations.
- Saturated: A state where refrigerant exists as a mixture of both liquid and vapor at a specific temperature and pressure, remaining at a constant temperature during phase change.
- SCADA (Supervisory Control and Data Acquisition): A control system architecture that uses computers, networked data communications, and graphical user interfaces for high-level process supervisory management. Used for integrating and monitoring marine HVAC systems.
- Self-Contained Unit: A compact, all-in-one HVAC system where all major components are housed within a single cabinet.
- Sensible Heat: Heat that causes a change in the temperature of a substance without changing its physical state.
- Smart HVAC Systems: HVAC systems that use advanced sensors, data analytics, and automation (often with AI) to optimize operation, predict maintenance needs, and integrate with overall vessel management.
- Split System: An HVAC system composed of an indoor unit (evaporator, fan) and an outdoor unit (compressor, condenser) connected by refrigerant lines.
- Subcooled Liquid: Liquid refrigerant that has been cooled below its condensing temperature at a given pressure, ensuring that only liquid enters the metering device.
- Suction Line: The pipe carrying low-pressure, low-temperature refrigerant vapor from the evaporator back to the compressor.
- Superheated Vapor: Refrigerant vapor that has been heated above its boiling point (saturation temperature), ensuring it is 100% vapor before entering the compressor.
- Ventilation Fans: Fans used to circulate air and remove pollutants, especially critical in areas like engine rooms to expel toxic fumes.
- VRV (Variable Refrigerant Volume) or VRF (Variable Refrigerant Flow) system: An advanced air conditioning system that uses a variable refrigerant flow to provide precise temperature control in multiple zones or rooms from a single outdoor unit.
- Variable Speed Drive (VSD): A device that controls the speed of an electric motor, allowing HVAC components like fans and compressors to adjust their output based on demand, thereby improving energy efficiency.