Trane SYS-APM001-EN Condenser-Water System Control, Minimum refrigerant pressure differential

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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

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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 Packaged or Split System? MaintenanceAir-cooled condenser Air-cooled versus water-cooled condensersEnergy 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 arrangementsVariable-primary system Condenser-Water SystemCooling tower Primary-secondary systemSingle tower per chiller Condenser-water pumping arrangementsEffect of load on cooling tower performance Effect of ambient conditions on cooling tower performanceRecommended 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 Part load system operation Application ConsiderationsNumber of chillers Parallel or seriesPreferential 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 Controls Chiller performance testingLimitations of field performance testing Chiller Plant System PerformanceSYS-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 temperatureSystem design Entering fluid temperature, F CCooling-tower options with low flow Smaller towerSame 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 systemAirside control Plant configurationBypass flow Chiller sequencingPlate-and-frame heat exchanger Heat RecoveryChilled-Water System Variations Condenser Free Cooling or Water EconomizerRefrigerant 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 Example System Issues and ChallengesChiller response to changing conditions System response to changing conditionsType and size of chiller ContingencyMinimum capacity required Ancillary equipment System Issues and Challenges Location of equipmentAlternative Energy Sources Water and electrical connectionsThermal 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 Chilled-water pump control Chilled water reset-raising and loweringSystem Controls Chilled-Water System ControlNumber of chillers to operate Critical valve reset pump pressure optimizationSystem Controls Chillers Difference Condenser-Water System ControlMinimum refrigerant pressure differential VFDs and centrifugal chillers performance at 90% loadCooling-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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