Hvac System Components

Refrigeration and HVAC Systems and Equipment components help system designers and operators to select and use equipment that is the best fit for a particular application or controlling scenario.

Duct Static Pressure Control

Duct Static Pressure Control

Direct Expansion—Two-Position Control

Direct Expansion—Two-Position Control

Duct Static Control of Return Fan

Duct Static Control of Return Fan

Modulating Direct-Expansion Cooling

Modulating Direct-Expansion Cooling

Airflow Tracking Control

Airflow Tracking Control

Cooling Tower

Cooling Tower

Economizer Cycle Control

Economizer Cycle Control

Preheat with Secondary Pump and Two-Way Valve

Preheat with Secondary Pump and Two-Way Valve

Warm-Up Control

Warm-Up Control

Cooling and Dehumidifying with Reheat

Cooling and Dehumidifying with Reheat

Night Cooldown Control

Night Cooldown Control

Sprayed Coil Dehumidifier

Sprayed Coil Dehumidifier

Preheat with Face and Bypass Dampers

Preheat with Face and Bypass Dampers

Chemical Dehumidifier

Chemical Dehumidifier

Steam Jet Humidifier

Steam Jet Humidifier

Condenser Water Temperature Control

Condenser Water Temperature Control

Throttling VAV Terminal Unit

Throttling VAV Terminal Unit

Load and Zone Control in Simple Hydronic System

Load and Zone Control in Simple Hydronic System

Fan-Powered VAV Terminal Unit

Fan-Powered VAV Terminal Unit

Duct Heater Control

Duct Heater Control

Pressure-Independent Dual-Duct VAV Terminal Unit

Pressure-Independent Dual-Duct VAV Terminal Unit

Zone Mixing Dampers—Three-Deck Multizone System

Zone Mixing Dampers—Three-Deck Multizone System

Variable-Flow Chilled-Water System (Primary Only)

Variable-Flow Chilled-Water System (Primary Only)

Multizone Single-Duct System

Multizone Single-Duct System

Dual-Duct Single Supply Fan System

Dual-Duct Single Supply Fan System

Constant-Flow Chilled-Water System (Primary/Only)

Constant-Flow Chilled-Water System (Primary/Only)

FREQUENTLY ASKED QUESTIONS

What are the key components of a refrigeration system?
The key components of a refrigeration system include the compressor, condenser, expansion valve, and evaporator. These components work together to transfer heat from one location to another, allowing for cooling or heating of a space. The compressor compresses refrigerant, which then flows to the condenser where heat is rejected. The expansion valve reduces the pressure of the refrigerant, allowing it to expand and cool, and the evaporator is where the heat is absorbed from the surrounding environment.
How does duct static pressure control work in HVAC systems?

Duct static pressure control is a method of controlling the airflow in an HVAC system by regulating the static pressure in the ductwork. This is typically achieved through the use of sensors, actuators, and control algorithms. The sensors measure the static pressure in the ductwork, and the actuators adjust the fan speed or damper position to maintain a setpoint pressure. This helps to ensure that the airflow is evenly distributed throughout the system and that the desired indoor air quality is maintained.

What is the purpose of a direct expansion valve in an HVAC system?

A direct expansion valve is a type of valve used in HVAC systems to control the flow of refrigerant into the evaporator coil. Its purpose is to meter the correct amount of refrigerant into the coil, allowing for efficient heat transfer and preventing flooding or starving of the coil. The valve is typically controlled by a thermostat or other temperature-sensing device, which opens or closes the valve to maintain the desired temperature.

How do two-position control systems differ from modulating control systems?

Two-position control systems, such as those used in direct expansion systems, have two discrete states: on or off. This means that the system is either fully operational or fully shut down. Modulating control systems, on the other hand, can operate at varying levels of capacity, allowing for more precise control of the system. Modulating systems are often used in larger, more complex HVAC systems where precise temperature control is critical.

What are some common applications for direct expansion HVAC systems?

Direct expansion HVAC systems are commonly used in small to medium-sized commercial and residential applications, such as rooftop units, split systems, and packaged terminal air conditioners (PTACs). They are often used in situations where a simple, cost-effective cooling solution is required, and the cooling load is relatively small.

How do HVAC system designers select the appropriate components for a particular application?

HVAC system designers select the appropriate components for a particular application by considering factors such as the cooling or heating load, airflow requirements, and system operating conditions. They must also consider the physical constraints of the installation, such as available space and accessibility. By evaluating these factors, designers can select components that are optimized for the specific application, ensuring efficient and effective system operation.