المدونة

What does HVAC mean?

HVAC is an abbreviation for "heating, ventilation, and air conditioning." A residential HVAC system is a complete home comfort system that heats and cools your home, improves indoor air quality, and controls humidity. There are many different types of HVAC systems. They can include individual components such as air conditioning units, heat pumps, air handlers, furnaces, air purifiers, humidifiers, and dehumidifiers.

What is HVAC Control?

The definition of an HVAC control system can vary depending on the purpose, whether it is a simple residential system or a very complex large system. But in general, an HVAC controller is defined as a device that regulates the operation of heating, ventilation, and air conditioning equipment.

Typically, a home will have a thermostat connected to a standalone air conditioner. You can manage the operation of that standalone unit by modifying the temperature (or set point). For example, setting the thermostat to 75 degrees Fahrenheit in the summer will cause the air conditioner to run until the room reaches that temperature.

In this simple example, your thermostat is both a sensor and an HVAC controller because it senses the temperature of your home. We will talk more about sensors as we explore more complex systems.

When applied to larger facilities, HVAC control can sometimes become part of a larger system called building automation or energy management system.

How is the HVAC switchboard controlled?

Multi-branch power distribution

The busbar system is used to distribute the input power (usually three-phase 380V/220V) to multiple branches to provide independent power supply circuits for HVAC components such as compressors, fans, pumps, cooling towers, etc. For example, a precision switchboard can support up to 84 feeder circuits to meet the power distribution needs of complex systems.

Branch circuit measurement is achieved through high-precision current transformers (CTs) with an error as low as ±1%, ensuring the accuracy of power distribution.

Four-level circuit protection system

Short circuit/overload protection: built-in circuit breakers (such as frame circuit breakers, molded case circuit breakers) cut off the circuit within 0.1 seconds when the current is abnormal (such as short circuit current reaches more than 10 times the rated value).

Leakage protection: cooperate with the leakage collection unit, trigger alarm and power off when the ground leakage current is ≥30mA.

Phase sequence protection: detect the imbalance of three-phase voltage (act when it exceeds 15%) to prevent the motor from burning.

Overvoltage/undervoltage protection: automatically trip when the voltage fluctuation exceeds ±10% of the rated value to protect sensitive electronic equipment.

Equipment-level control

Contactor matrix: the start and stop control of fans and water pumps is realized through the contactor combination. The contactor coil voltage is usually AC220V, and the contact capacity covers 10A-630A.

Variable frequency drive integration: The built-in variable frequency drive (VFD) adjusts the compressor and fan speed. For example, the vector control technology is used to adjust the fan speed steplessly within the range of 300-1500rpm, reducing energy consumption by 30%-50%.

Environmental parameter linkage control

Temperature and humidity coupling adjustment: Receive the temperature and humidity set values ​​issued by the BAS system (such as 26℃/50%RH in summer and 20℃/40%RH in winter), and dynamically adjust the cold and heat source output through the PID algorithm.

Air quality linkage: According to the CO₂ sensor (range 0-2000ppm) or PM2.5 detection data, the fresh air valve opening (0-100% stepless adjustment) and the filter section operation mode are automatically switched.