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Central heating heating network circulating pump energy saving 70% technical methods
**Abstract:** This article explores the operation mode of "quality and quantity adjustment" in central heating systems, aiming to achieve a 70% energy-saving effect by optimizing the water pump's performance. It introduces the self-operated resistance balancing valve as an essential tool for achieving this mode of operation. The paper explains the principle of this type of balancing valve and outlines the basic process of adjusting heat networks using self-balancing resistance valves.
**Keywords:** Quality adjustment, mass adjustment, balance valve, self-regulating flow control valve, self-regulating differential pressure control valve, self-regulating resistance balancing valve, initial adjustment, operational adjustment.
Heating systems are inherently complex, and ensuring optimal heating quality—where indoor temperatures remain comfortable without being too high or too low—requires careful management. For any given system, the best operating conditions depend on outdoor temperature, with corresponding ideal circulation flow and temperature differences. Therefore, the most effective way to regulate heating is through a comprehensive approach known as "quality and quantity adjustment." This involves modifying both the flow rate and the water temperature based on changes in external conditions. Such an approach not only enhances heating efficiency but also significantly reduces energy consumption.
However, implementing the "quality and quantity" adjustment method poses challenges, particularly in maintaining hydraulic balance across the network. Despite efforts by many heating companies to adopt variable-speed pumps and frequency control in recent years, the results have often been unsatisfactory. One major issue is that the flow rates rarely decrease sufficiently, remaining higher than the design values, which prevents the system from reaching its optimal energy-saving state. As a result, the potential for energy savings remains largely untapped.
The core problem lies in the lack of an efficient and practical tool for balancing the heat network. This paper discusses the theoretical basis for the energy-saving benefits of the "quality and quantity" mode and introduces the self-regulating resistance balancing valve as a solution. This device helps achieve balanced flow distribution, making it possible to implement the "quality and quantity" mode effectively.
**1. Energy-Saving Effect of the "Quality and Quantity" Operation Mode**
Taking Changchun City, Jilin Province, as an example, where the heating season lasts 165 days (3,960 hours), the average heat consumption at the design outdoor temperature is approximately 52 kcal/m².
- **1.1** In a constant flow operation mode, the circulation pump consumes 100% of its power.
- **1.2** When using a quality-adjustment mode with phased flow reduction, the flow rate is adjusted over three stages: 80% for the first 50 days, 80% again for the next 50 days, and 100% for the remaining 65 days. The average flow rate is 87.9%, resulting in a power consumption of 70.4% compared to the constant flow mode.
- **1.3** With the "quality and quantity" mode, the flow rate is dynamically adjusted based on outdoor temperature. The calculated flow consumption is 65.81% of the maximum, leading to a power consumption of 28.5%. This represents a 71.5% reduction in energy use compared to the traditional method.
Although actual results may vary slightly, these calculations clearly demonstrate the significant energy-saving potential of the "quality and quantity" operation mode. Beyond cost savings for heating companies, this approach contributes to national energy conservation goals and environmental protection, benefiting future generations.
**2. Self-Regulating Resistance Balancing Valve**
Currently, several types of valves are used for hydraulic regulation in heating systems, including balance valves, self-regulating flow control valves, and self-regulating differential pressure control valves. Each has its own advantages and limitations. For instance, self-regulating flow control valves maintain constant flow but are not suitable for "quality and quantity" operations. Differential pressure control valves are better suited for metered heating systems but face challenges in widespread adoption.
To address these issues, a new type of valve has been developed: the self-regulating resistance balancing valve. It combines the features of both flow control and balancing valves, offering flexibility and effectiveness in both constant and variable flow scenarios. This device enables precise control of flow distribution, making it ideal for the "quality and quantity" operation mode.
**2.1 Hydraulic Characteristics of the Heating Network**
In a parallel piping system, the relationship between pressure drop and flow rate can be expressed as:
$$
\Delta P = S \cdot V^2
$$
Where:
- $ \Delta P $ is the pressure drop,
- $ S $ is the resistance coefficient,
- $ V $ is the flow rate.
This equation shows that when resistance is constant, the flow rate is proportional to the square root of the pressure difference. Adjusting the total resistance of the network affects the flow distribution across all branches.
**2.2 Working Principle of the Self-Regulating Resistance Balancing Valve**
The self-regulating resistance balancing valve includes a self-regulating orifice plate, a differential pressure balancing mechanism, and a locking device. During initial setup, the valve functions as a constant-flow device, allowing rapid balancing of the network. Once the system is balanced, the locking mechanism engages, transforming the valve into a resistance-balancing device. This ensures that even when the circulation flow changes, the flow distribution remains stable, maintaining hydraulic balance.
**2.3 Application in Heat Metering Systems**
In heat metering systems, differential pressure control valves are often installed at building entrances to stabilize pressure and prevent interference between different units. However, their effectiveness is limited in practice due to low pressure drops and the automatic adjustment capabilities of thermostatic valves. In such cases, replacing differential pressure control valves with self-regulating resistance balancing valves can simplify the system and improve overall efficiency.
**3. Conclusion**
The self-regulating resistance balancing valve overcomes the limitations of traditional balancing and flow control valves. It enables accurate hydraulic balance and supports both qualitative and quantitative adjustments, making it an ideal tool for modern heating systems. Whether in non-metered or metered environments, this technology has the potential to significantly enhance energy efficiency and reduce operational costs. Its implementation promises a more sustainable and effective approach to heating system management.