An Air System defines how air is delivered to a building's spaces. The system covers how the air is treated from outside conditions, how the air is controlled and what local room units are utilized. Following is a full list of the current systems options in cove.tool which cover all code baselines and more energy efficiency solutions. To see how each of these systems interact with specific heating and cooling systems refer to the System Types article.

CAV with Reheat

Constant Air Volume (CAV) systems deliver a constant amount of air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local reheat coils. CAV with Reheat systems can operate with a variety of heating and cooling systems, a matrix of those supported by cove.tool follows.

Gas Boiler

Electric Boiler

Electric Resistance

Ground Source Heat Pump

Air Source Heat Pump

Water Cooled Chiller

X

X

X

X

Air Cooled Chiller

X

X

X

X

Ground Source Heat Pump

X

Packaged DX

X

X

X

X

CAV with Radiant

Constant Air Volume (CAV) systems deliver a constant amount of air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local radiant units, typically radiant panels or baseboard heaters. CAV with Radiant systems in cove.tool are formatted to match Canadian National Energy Code for Buildings (NECB) baseline system types. The supported options are

Gas Boiler

Electric Resistance

Packaged DX

X

X

VAV with Reheat

Variable Air Volume (VAV) systems deliver a variable amount of air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local reheat coils. Air flows are turned down to minimum settings when zones do not require additional conditioning reducing energy use. VAV with Reheat systems can operate with a variety of heating and cooling systems, a matrix of those supported by cove.tool follows.

Gas Boiler

Electric Boiler

Electric Resistance

Ground Source Heat Pump

Air Source Heat Pump

Water Cooled Chiller

X

X

X

X

Air Cooled Chiller

X

X

X

X

Ground Source Heat Pump

X

Packaged DX

X

X

X

X

VAV with Radiant

Variable Air Volume (VAV) systems deliver a variable amount of air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local radiant units, typically radiant panels or baseboard heaters. Air flows are turned down to minimum settings when zones do not require additional conditioning reducing energy use. VAV with Radiant systems in cove.tool are formatted to match Canadian National Energy Code for Buildings (NECB) baseline system types. The supported options are

Gas Boiler

Electric Resistance

Water Cooled Chiller

X

X

DOAS with FCU

Dedicated Outdoor Air Systems (DOAS) deliver the minimum required ventilation air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local units, in this case Fan Coil Units (FCU) that handle all heating and cooling loads. DOAS with FCU systems can operate with a variety of heating and cooling systems, a matrix of those supported by cove.tool follows.

Gas Boiler

Electric Boiler

Electric Resistance

Ground Source Heat Pump

Air Source Heat Pump

Water Cooled Chiller

X

X

X

X

Air Cooled Chiller

X

X

X

X

Ground Source Heat Pump

X

DOAS with VRF

Dedicated Outdoor Air Systems (DOAS) deliver the minimum required ventilation air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local units, in this case Variable Refrigerant Flow Units (VRF) that handle all heating and cooling loads. DOAS with VRF systems can operate as air source or water source systems, the following options are supported by cove.tool, a matrix of those supported by cove.tool follows.

Gas Boiler

Electric Boiler

Air Source VRF

Air Source VRF

X

Cooling Tower

X

X

DOAS with Induction

Dedicated Outdoor Air Systems (DOAS) deliver the minimum required ventilation air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local units, in this case an Induction System that handle all heating and cooling loads. Typical Induction Systems include Active Chilled Beams and induction units. DOAS with Induction systems can operate with a variety of heating and cooling systems, a matrix of those supported by cove.tool follows.

Gas Boiler

Electric Boiler

Electric Resistance

Ground Source Heat Pump

Air Source Heat Pump

Water Cooled Chiller

X

X

X

X

Air Cooled Chiller

X

X

X

X

Ground Source Heat Pump

X

DOAS with Radiant

Dedicated Outdoor Air Systems (DOAS) deliver the minimum required ventilation air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local units, in this case radiant panels. Radiant cooling panels have low capacities limiting their application. DOAS with Radiant systems can operate with a variety of heating and cooling systems, a matrix of those supported by cove.tool follows.

Gas Boiler

Electric Boiler

Electric Resistance

Ground Source Heat Pump

Air Source Heat Pump

Water Cooled Chiller

X

X

X

X

Air Cooled Chiller

X

X

X

X

Ground Source Heat Pump

X

DOAS with WSHP

Dedicated Outdoor Air Systems (DOAS) deliver the minimum required ventilation air to all zones of a building during occupied hours from central air handling units (AHU). Temperature of each zone is controlled through local units, in this case Water Source Heat Pumps (WSHP). The WSHP use a condenser water loop as the source for heating and cooling to each zone. DOAS with WSHP systems operate with a few of heat generation and heat rejection options, a matrix of those supported by cove.tool follows.

Gas Boiler

Electric Boiler

Cooling Tower

X

X

Single Zone

A Single Zone system delivers air a building as a whole entity. Temperature is controlled for the whole building only and there are no local zone units. Single Zone systems are typically found in residential, industry and retail buildings. Single Zone systems can utilize a wide array of heating and cooling systems, a matrix of those supported by cove.tool follows.

Gas Boiler

Furnace

Electric Boiler

Electric Resistance

Water Cooled Chiller

X

X

X

X

Air Cooled Chiller

X

X

X

X

Packaged DX

X

X

X

X

Direct Expansion

X

Natural Ventilation

Natural Ventilation systems do not deliver any forced ventilation air to the building, instead the ventilation is achieved passively through openings. Temperature of each zone is controlled through local units, often some form of radiant heating and direct expansion cooling . The natural ventilation systems supported by cove.tool follows.

Gas Boiler

Electric Boiler

Electric Resistance

Air Source Heat Pump

Direct Expansion

X

X

X

X

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