System Controls

Table 17. VFDs and centrifugal chillers performance at 90% load

ECWT

2 Chillers*

1 Chiller

Difference

 

 

 

 

85°F

306.4

268.0

-38.4

 

 

 

 

80°F

268.0

238.0

-30.0

 

 

 

 

75°F

230.8

210.6

-20.2

 

 

 

 

70°F

195.2

185.7

-9.5

 

 

 

 

65°F

160.3

164.3

+4.3

Note: Data shows only chiller power. * Load equally divided.

If the chiller and tower capabilities are conducive to this strategy, the location and load profile determine if, when, and for how long the right conditions might occur. Determine the optimum control sequence for the entire plant by performing a detailed energy analysis of each component. Base the analysis on realistic load profiles and ambient conditions, and account for the energy used by all ancillary equipment.

For VPF systems, there will likely not be enough system flow to allow more chillers than necessary to operate without requiring bypass to stay above the chillers’ minimum flows.

Condenser-Water System Control

Minimum refrigerant pressure differential

Every chiller requires a certain refrigerant pressure differential between the evaporator and condenser in order to operate. The chiller must develop its pressure differential within a manufacturer-specified time or its controls will shut it off. During some start-up conditions, this pressure differential may be hard to produce within the time limitation.

An example of such a condition is an office building that has been unoccupied during a cool, clear, fall weekend. The tower sump water is at 40°F [4.4°C]. Monday is sunny and warm, which requires a chiller to be turned on. Since the chiller is lightly loaded and the tower sump is large, the pressure differential cannot be reached before the chiller turns off. If the condenser flow rate for a given chiller can be reduced, this scenario is less likely to occur. The lower flow rate increases the leaving condenser-water temperature, which increases the condenser-refrigerant temperature and refrigerant pressure.

SYS-APM001-EN

Chiller System Design and Control

89

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Trane SYS-APM001-EN manual Condenser-Water System Control, Minimum refrigerant pressure differential, Chillers Difference
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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.

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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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