System Configurations

System ΔT greater than 14°F

One reason series chilled-water systems should be designed using at least a 14 degree ΔT is because a lower ΔT ignores the opportunity for lower flow rates and reduced pump energy. For small, packaged chillers, a reason to have at least a 14 degree ΔT is to avoid exceeding the chiller’s maximum flow rate. The system will more likely experience evaporator flow limit maximums if the ΔT is too low.

Series Chillers

If chillers are piped in series, as in Figure 27, the mixing problem disappears and the starving coils problem (when one of the pumps in a parallel arrangement is not running) is resolved. Series flow presents a new set of temperature and flow control challenges.

Figure 27. Series chillers

 

 

56°F [13.3°C]

49°F [9.4°C]

 

42°F [5.5°C]

 

 

 

Chiller 2

Chiller 1

 

 

setpoint = 42°F [5.5°C]

 

 

setpoint = 42°F [5.5°C]

 

Loads

The flow rate through each chiller is the entire system flow, that is, double the individual flow rate of two parallel chillers. This means that the chiller evaporator must accommodate the doubled water quantity. This may be accommodated by using fewer water passes in the evaporator, which may result in decreased chiller efficiency.

However, this efficiency loss due to fewer passes is more than offset by the increased efficiency of the upstream chiller, now operating at a warmer temperature.

Pressure losses are additive when the chillers are piped in series. This increases total system pressure drop, thereby using more pump energy. On the other hand, series chillers work particularly well in low-flow systems, where the system temperature difference is greater than 14°F [7.8°C], resulting in less pressure drop.

Low-flow systems were discussed in detail in “Selecting flow rates” on page 30. Series chillers are also suited to variable flow systems, where the operating pressure drop is reduced. Variable flow is discussed beginning on page 55.

Temperature control can be executed in several ways. Figure 27 shows a strategy where the controller on each chiller is set at the system design setpoint. Either chiller can be used to meet the system demand for up to 50

44

Chiller System Design and Control

SYS-APM001-EN

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Trane SYS-APM001-EN manual Series Chillers, Series chillers
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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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