System Configurations

• Locate a bypass line and valve near the end of the piping run. The bypass control valve sees a lower operating pressure and may provide more stable control. Some operating cost savings may be sacrificed to maintain the pump-operating pressure at a higher level with the bypass located away from the chillers. The line sizes must be large enough to allow the minimum flow rate.

One final method to ensure minimum evaporator flow is to have a constant load and flow somewhere in the system. However, if in the future the system changes and this constant flow no longer occurs, the system is likely to have operating issues when its flow approaches the chiller’s minimum.

Delivering the appropriate bypass flow requires attention to line sizing, control-valve selection, and the response time of the system.

Bypass flow control

In a VPF system, the sole purpose of the bypass line with modulating control valve is to assure that the rate of chilled water flow through each operating chiller never falls below the minimum limit required by the manufacturer.

Select a suitable control valve of high quality. When the bypass line is positioned near the chiller plant (A in Figure 37), as it is in many VPF installations, the control valve is exposed to comparatively high operating pressures. Selecting an appropriate valve actuator is critical because the valve must close against this pressure. As for the valve itself, choose one that maintains a linear relationship between valve position and flow rate; otherwise, the valve may permit too much water flow when it begins to open.

Note: A common butterfly valve won’t provide the necessary flow characteristics. Some have found that pressure-independent valves work well as a bypass valve. Verify the suitability of a particular valve by requesting flow-versus-position data from the supplier.

Locating the bypass line far from the chiller plant (B in Figure 37) lowers the operating pressure for the control valve.

Minimize control lag. Regardless of where the bypass line is situated (at A or B in Figure 37), the control valve must react quickly to changes in system flow. You can improve control response either by hard-wiring the flow- sensing device, valve controller, and valve actuator; or by selecting devices that communicate directly with each other. Avoid relaying input/output signals through multiple system controllers.

Chiller sequencing in VPF systems

The success of a VPF application depends on more than the chilled-water system. It requires careful orchestration of the entire HVAC system, which means air handlers and coil-control valves as well as chillers and pumps.

Proper sequencing helps to maintain the flow rate through each evaporator within the range recommended by the chiller manufacturer. As the system

SYS-APM001-EN

Chiller System Design and Control

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Trane SYS-APM001-EN manual Chiller sequencing in VPF systems, Bypass flow control
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SYS-APM001-EN specifications

The Trane SYS-APM001-EN is an advanced control system designed for HVAC (Heating, Ventilation, and Air Conditioning) applications, specifically tailored to enhance energy efficiency and system performance. This comprehensive solution integrates cutting-edge technologies to optimize climate control in commercial and industrial environments.

One of the main features of the SYS-APM001-EN is its intuitive user interface. The system is equipped with a large, easy-to-read display that provides real-time data on system performance, energy usage, and environmental conditions. This user-friendly interface makes it simple for operators to monitor and adjust settings, ensuring optimal comfort levels and efficient energy consumption.

Another key characteristic of the SYS-APM001-EN is its advanced data analytics capabilities. The system collects and analyzes data from various sensors throughout the building, providing insights into occupancy patterns, equipment performance, and energy consumption trends. This data-driven approach allows facility managers to make informed decisions about system adjustments, predictive maintenance, and energy savings.

The SYS-APM001-EN also boasts robust integration capabilities. It can seamlessly connect with a variety of building management systems (BMS) and other third-party devices. This interoperability enables a cohesive operational ecosystem where HVAC systems can communicate and cooperate with lighting, security, and fire safety systems, enhancing overall building efficiency.

Energy efficiency is a hallmark of the SYS-APM001-EN, as it implements sophisticated algorithms to optimize system operation. These algorithms adjust equipment performance in real-time based on current conditions, thereby reducing energy waste and lowering operational costs. The system is designed to support multiple energy-saving strategies, including demand-controlled ventilation and optimal start/stop scheduling.

Additionally, the SYS-APM001-EN is built with scalability in mind, accommodating facilities of various sizes and configurations. Whether it’s a small office building or a large industrial complex, the system can be tailored to meet specific needs, ensuring that HVAC performance aligns with operational goals.

In conclusion, the Trane SYS-APM001-EN is an innovative HVAC control solution that emphasizes user experience, data-driven decision-making, and energy efficiency. With its advanced features and technologies, it is an essential tool for optimizing building performance and enhancing occupant comfort while reducing environmental impact.
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