Chilled-Water System Variations

load. The details of operation are discussed in “Sidestream plate-and-frame heat exchanger” on page 74.

Plate-and-frame heat exchangers isolate the building loop from the water in the open cooling tower loop, but they must be cleaned, typically annually. The labor and parts for cleaning and reassembly (e.g., gasketing) is an expense that should be factored into the life-cycle cost of this option.

Refrigerant migration

Another method of “free” cooling is to transfer heat between the cooling tower water and the chilled water inside a centrifugal chiller through the use of refrigerant migration, also known as a thermosiphon. Figure 41 shows a centrifugal chiller equipped for refrigerant migration free cooling. When the temperature of the water from the cooling tower is colder than the desired chilled-water temperature, the compressor is turned off and automatic shut- off valves inside the chiller refrigerant circuit are opened, as shown in Figure 42. Because refrigerant vapor migrates to the area with the lowest temperature (and pressure), refrigerant boils in the evaporator and the vapor migrates to the cooler condenser. After the refrigerant condenses, it flows by gravity back through a shutoff valve to the evaporator. This allows refrigerant to circulate between the evaporator and condenser without the need to operate the compressor.

Depending on the application, it is possible for refrigerant migration in a centrifugal chiller to satisfy many hours of cooling load without operating the compressor. Free cooling chillers serving systems that can tolerate warmer chilled-water temperatures at part-load conditions can produce more than 60 percent of the rated capacity without compressor operation. There are no cooling coil fouling concerns because the cooling-tower water flows through the chiller condenser and is separate from the chilled-water loop. There is no additional expense for cleaning, as the condenser tubes are the same as those used for normal cooling mode and should already be on a maintenance schedule. In addition, fewer pipes, pumps, and fittings are required, and no additional heat exchanger is required.

Figure 41. Refrigerant migration chiller in compression cooling mode

Conditioner

Refrigerant Storage Tank

Economizers

Compressor

Evaporator

SYS-APM001-EN

Chiller System Design and Control

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Trane SYS-APM001-EN manual Chilled-Water System Variations, Refrigerant migration
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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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