An air conditioning system includes a first unit and a second unit. The space above the ceiling of each of a plurality of clean rooms is included in the chamber as a single space common to a plurality of the clean rooms. The first clean room is higher than the second clean room in air cleanliness.

Provided is an air conditioning system that maintains a room pressure in a clean room at high accuracy while having a simple configuration. An air conditioning system includes: a fan filter unit including a supply air fan to supply air to a preparation room from a chamber including space above a ceiling of the preparation room; a fan filter unit including a supply air fan to supply the air to the preparation room from the chamber; and a fan filter unit including a return air fan to return the air from the preparation room through the chamber and to exhaust the air from the preparation room, and further includes: a pressure sensor provided in the preparation room; and a control unit to control a return air fan based on a value detected by the pressure sensor.

An air conditioning system suppresses energy consumption by efficient shared use of air in a common space that is not subjected to air conditioning in an indoor area, among a plurality of air conditioners for the purpose of heat exchange. A plurality of air conditioners each include: a usage-side heat exchanger configured to carry out heat exchange with air in an air-conditioning target space; a heat source-side heat exchanger configured to carry out heat transfer to and from the usage-side heat exchanger; and a heat source-side fan configured to feed air from a common space to the heat source-side heat exchanger and to blow the air into the common space. The heat source-side heat exchangers of the air conditioners are disposed in the common space. A first ventilation fan whose airflow volume is changeable is disposed near an exhaust port through which air is discharged from the common space toward an outdoor area. A controller changes the airflow volume of the ventilation fan, based on information on an air temperature of the common space.

An HVAC system is described having components of a variable refrigerant flow (VRF) outdoor compressor unit connected to an indoor fan coil unit. The indoor fan coil unit supplies air to ducts that condition a plurality of zones. Each zone has a volume modulating air damper that can maintain a predetermined volume of air flowing through it. As the dampers for some zones vary between open and close positions, the air pressure in the ducts changes. The volume modulating dampers compensate for these pressure changes, ensuring that only the predetermine volume of air is passing into the zones. By regulating the volume of into each zone, the volume modulating air dampers can restrict the air volume through the fan coil causing the outdoor unit to reduce compressor speed, thereby saving energy.

Provided is an air conditioning system that maintains a room pressure in a clean room at high accuracy while having a simple configuration. An air conditioning system includes: a fan filter unit including a supply air fan to supply air to a preparation room from a chamber including space above a ceiling of the preparation room; a fan filter unit including a supply air fan to supply the air to the preparation room from the chamber; and a fan filter unit including a return air fan to return the air from the preparation room through the chamber and to exhaust the air from the preparation room, and further includes: a pressure sensor provided in the preparation room; and a control unit to control a return air fan based on a value detected by the pressure sensor.

An HVAC system is described having components of a variable refrigerant flow (VRF) outdoor compressor unit connected to an indoor fan coil unit. The indoor fan coil unit supplies air to ducts that condition a plurality of zones. Each zone has a volume modulating air damper that can maintain a predetermined volume of air flowing through it. As the dampers for some zones vary between open and close positions, the air pressure in the ducts changes. The volume modulating dampers compensate for these pressure changes, ensuring that only the predetermine volume of air is passing into the zones. By regulating the volume of into each zone, the volume modulating air dampers can restrict the air volume through the fan coil causing the outdoor unit to reduce compressor speed, thereby saving energy.

Methods for providing heating or cooling to a plurality of zones in a conditioned space, include adjusting a temperature of a primary airflow using a heating, ventilation, air conditioning, and refrigeration (HVACR) system including a heat pump circuit and distributing the primary airflow to a plurality of terminals in the zones. The methods further include directing heat from the heat pump circuit to at least one of the plurality of terminals and heating air at the at least one of the plurality of terminals using the heat directed from the heat pump circuit. The methods can further include utilizing sources and sinks of the heat pump circuit to efficiently provide the heating or cooling. Systems include the heat pump circuit, terminals, heat distribution, and can include a controller to operate those components.

An HVAC system is described having components of a variable refrigerant flow (VRF) outdoor compressor unit connected to an indoor fan coil unit. The indoor fan coil unit supplies air to ducts that condition a plurality of zones. Each zone has a volume modulating air damper that can maintain a predetermined volume of air flowing through it. As the dampers for some zones vary between open and close positions, the air pressure in the ducts changes. The volume modulating dampers compensate for these pressure changes, ensuring that only the predetermine volume of air is passing into the zones. By regulating the volume of into each zone, the volume modulating air dampers can restrict the air volume through the fan coil causing the outdoor unit to reduce compressor speed, thereby saving energy.

A terminal unit is provided for cooling a conditioned space. The terminal unit is provided conditioned air and augments cooling with a local heat exchanger. The terminal unit controls the flow of coolant through the heat exchanger. Latent cooling provided by the conditioned air is augmented by allowing moisture accumulation on the heat exchanger. The terminal unit lacks a drainage system so deleterious moisture accumulation (e.g., dripping) is avoided by monitoring moisture accumulation and controlling the terminal unit accordingly. If the moisture accumulation is below a threshold, the terminal unit is permitted to provide latent cooling locally. If the moisture accumulation is above a threshold, the terminal unit prevents further local latent cooling. Some sensor configurations allow for calculation of air flow rates, the latent cooling rate, and moisture accumulation. This information is used to achieve the desired room conditions more rapidly and precisely.

An airflow sterilizing unit configured to airflow in a heating, ventilation, and air conditioning (HVAC) system is disclosed. The airflow sterilizing unit includes a portion of a duct at least partially lined with an ultraviolet (UV) reflective material, a plurality of hollow structures positioned within the portion of the duct, each comprising an external UV reflective surface, and at least one array of UV light emitting diodes (LEDs) mounted on a surface of at least one of the plurality of hollow structures. The sterilizing unit is configured to replace a section of an existing duct in the HVAC system such that air within the HVAC system passes through the sterilizing unit before exiting from one or more vent.