**Abstract:** This paper presents the application of the ABB ACS-510 frequency converter in a thermal network, focusing on its role in optimizing energy efficiency through Modbus communication. The study demonstrates how the use of variable frequency drives (VFDs) can significantly improve the performance and reduce energy consumption in heating systems.
**Keywords:** Inverter, load control, Modbus, thermal station, energy saving
**1. Introduction**
Heating networks play a crucial role in providing warmth to residential and industrial areas. As a key component of these systems, the thermal station directly impacts user comfort and system efficiency. Ensuring energy savings and safe operation within the thermal station is essential for both economic and environmental reasons. This paper explores how modern control technologies, such as the ABB ACS-510 frequency converter, can enhance the performance of thermal stations.
**2. Project Overview**
The Harbin Airport Development Zone includes 120 central heating stations covering an area of approximately 5.7 million square meters. With a total heat load of 10,000 J/H, the system operates with a primary water temperature range of 130°C to 70°C. The heating mode is based on hot water circulation, with the thermal station responsible for heat exchange between the primary and secondary networks. Two circulating pumps and one makeup pump are controlled using VFDs, specifically the ABB ACS-510 series, which improves automation and energy efficiency.
**3. System Composition**
A typical thermal station consists of several components: a heat exchanger, a control panel, circulating and makeup pumps, and communication lines. The control system is primarily managed by a Schneider PLC, which collects data from the field and transmits it to the dispatch center via ADSL. Based on the indoor temperature of end users and outdoor weather conditions, the system automatically adjusts the secondary water supply temperature and flow rate to maintain comfort while minimizing energy use.
**4. Thermal Station Functionality**
The thermal station's main functions include maintaining indoor temperatures at city-approved levels and reducing operational costs. Two approaches are used for regulation: quality control, which adjusts the flow of primary water to regulate secondary water temperature, and quantity control, which uses variable frequency drives to adjust the flow rate. Combining both methods results in significant energy savings—up to 30% annually—and helps achieve a balance between comfort and efficiency.
**5. Circulating Pump Control Mode**
The ABB ACS-510 is well-suited for square load applications due to its low cost and built-in Modbus communication capabilities. It is used to control the speed of the circulating pumps through Modbus, allowing for precise and efficient operation. By adjusting the pump speed based on the pressure difference between the secondary water supply and return, the system ensures stable flow and optimal energy use. The setup involves two 37 kW pumps, with one serving as a backup. Parameters are configured to ensure smooth operation and reliable communication with the PLC.
**6. Makeup Pump Control**
The makeup pump also utilizes the ABB ACS-510 frequency converter, though it is set to address "3" on the Modbus bus. The PLC sends control signals to the pump via register 4003, ensuring constant pressure in the secondary network. This method helps maintain system stability and prevents overpressure or underpressure issues that could affect performance.
**7. Conclusion**
The integration of ABB ACS-510 frequency converters in thermal stations has proven to be highly effective in reducing energy consumption and improving system reliability. By using Modbus communication, the system minimizes the need for additional hardware, reduces failure rates, and enhances overall efficiency. The results demonstrate that VFDs are a valuable tool for achieving energy savings and improving the performance of heating systems, making them a promising solution for future implementations.
Al-ti Alloy
Hudeng Metal Materials Co., Ltd , https://www.hudengmetal.com