Trane Explore the Chiller Working Principle for Efficient Cooling Solutions
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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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Contents May Page Chiller System Design and Control Preface Contents 100 Chiller Primary System ComponentsChiller evaporator Primary System ComponentsEffect of chilled-water flow rate and variation Effect of chilled-water temperatureEffect of condenser-water flow rate Effect of condenser-water temperatureWater-cooled condenser Air-cooled condenser MaintenanceAir-cooled versus water-cooled condensers Packaged or Split System?Energy efficiency Low-ambient operationAir-cooled or water-cooled efficiency LoadsTwo-way valve load control Three-way valve load controlFace-and-bypass dampers Variable-speed pump load controlChilled-water pump Chilled-Water Distribution SystemManifolded pumps Distribution pipingPump per chiller Constant flow system Pumping arrangementsCooling tower Condenser-Water SystemPrimary-secondary system Variable-primary systemEffect of load on cooling tower performance Condenser-water pumping arrangementsEffect of ambient conditions on cooling tower performance Single tower per chillerRecommended chiller-monitoring points per Ashrae Standard Unit-Level ControlsChiller control Centrifugal chiller with AFD Centrifugal chiller capacity controlAFD on both chillers Small Chilled-Water Systems 1-2 chillers Application ConsiderationsCondensing method Application Considerations Constant flowVariable flow Number of chillers Application ConsiderationsParallel or series Part load system operationPreferential vs. equalized loading and run-time Mid-Sized Chilled-Water Systems ChillersManaging control complexity Large Chilled-Water Systems + Chillers, District Cooling Large chilled-water system schematicWater PowerPipe size Limitations of field performance testing Chiller performance testingChiller Plant System Performance ControlsSYS-APM001-EN SYS-APM001-EN Guidance for Chilled- and Condenser-Water Flow Rates System Design OptionsSystem Design Options Chilled-Water TemperaturesStandard rating temperatures Standard rating flow conditions Condenser-Water TemperaturesChilled- and Condenser-Water Flow Rates System Design Options Selecting flow rates Low-flow conditions for cooling tower Base Case Low Flow DP2/DP1 = Flow2/Flow11.85System summary at full load Total system power Component Power kW Base Case Low FlowChilled water system performance at part load Coil response to decreased entering water temperatureCooling-tower options with low flow Entering fluid temperature, F CSmaller tower System designSame tower, smaller approach ΔT2 = 99.1 78 = 21.1F or 37.3 25.6 = 11.7CSame tower, smaller approach Present Smaller Approach Same tower, larger chillerRetrofit capacity changes Larger Present Chiller Same tower Retrofit opportunitiesCost Implications Misconception 1-Low flow is only good for long piping runs Misconceptions about Low-Flow RatesKWh SYS-APM001-EN Parallel Chillers System ConfigurationsParallel chillers with separate, dedicated chiller pumps System ConfigurationsSeries chillers Series ChillersHydraulic decoupling Primary-Secondary Decoupled SystemsCheck valves Production loop System Configurations ProductionDistribution-loop benefits of decoupled system arrangement System Configurations DistributionTertiary or distributed CommonCampus Tertiary pumping arrangement Decoupled system-principle of operationFlow-sensing Temperature-sensingFlow-based control Subtracting a chiller Multiple chilled-water plants on a distribution loopAdding a chiller Double-ended decoupled system Pump control in a double-ended decoupled systemChiller sequencing in a double-ended decoupled system Other plant designs Variable-Primary-Flow SystemsOperational savings of VPF designs Advantages of variable primary flowDispelling a common misconception Chiller selection requirementsFlow, ft.water Flow rate Flow-rate changes that result from isolation-valve operation Managing transient water flowsSystem Configurations Effect of dissimilar evaporator pressure drops System design and control requirementsAccurate flow measurement Bypass flow control Chiller sequencing in VPF systemsFlow-rate-fluctuation examples Adding a chiller in a VPF systemSequencing based on load Subtracting a chiller in a VPF systemSelect slow-acting valves to control the airside coils Other VPF control considerationsConsider a series arrangement for small VPF applications Plant configurationChiller selection Guidelines for a successful VPF systemBypass flow Plant configurationChiller sequencing Airside controlChilled-Water System Variations Heat RecoveryCondenser Free Cooling or Water Economizer Plate-and-frame heat exchangerRefrigerant migration Chilled-Water System VariationsWell, river, or lake water Refrigerant migration chiller in free-cooling modePreferential loading parallel arrangement Preferential LoadingSidestream plate-and-frame heat exchanger Preferential loading sidestream arrangementChilled-Water System Variations Sidestream with alternative fuels or absorptionSidestream system control Preferential loading series arrangementSeries-series counterflow Series-Counterflow ApplicationCondensers Unequal Chiller SizingEvaporators Amount of Fluid in the Loop System Issues and ChallengesLow ΔT Syndrome Chiller response to changing conditions System Issues and ChallengesSystem response to changing conditions ExampleType and size of chiller ContingencyMinimum capacity required Alternative Energy Sources System Issues and Challenges Location of equipmentWater and electrical connections Ancillary equipmentThermal storage Plant ExpansionAlternative fuel Flow rate out of range Retrofit OpportunitiesApplications Outside the Chiller’s Range Precise temperature control System Issues and Challenges Temperatures out of rangePrecise temperature control, multiple chillers System Controls Chilled water reset-raising and loweringChilled-Water System Control Chilled-water pump controlNumber of chillers to operate Critical valve reset pump pressure optimizationSystem Controls Minimum refrigerant pressure differential Condenser-Water System ControlVFDs and centrifugal chillers performance at 90% load Chillers DifferenceCooling-tower-fan control Condenser-water temperature controlChiller-tower energy consumption Chiller-tower energy balanceChiller-tower-pump balance System Controls Variable condenser water flowEffect of chiller load on water pumps and cooling tower fans Decoupled condenser-water systemCDWP-2 Failure recovery Failure RecoveryConclusion Glossary Pumps system GlossaryGlossary Plant. Idea 88th Annual Conference Proceedings 1997 ReferencesEngineering July References102 Ashrae IndexIndex 105 106 Page Trane

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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