Trane SYS-APM001-EN Air-cooled condenser, Air-cooled versus water-cooled condensers, Maintenance

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Primary System Components

Packaged or Split System?

A number of different options are available for packaging and splitting the components of an air-cooled chiller. There is an excellent discussion in Chilled-Water Systems, part of the Air Conditioning Clinic Systems Series (TRG-TRC016-EN).

While they found that some of the internally-enhanced tubes fouled in the long term, they concluded:

Because of the high hardness and low water velocity used in these tests, we do not believe that the fouling experienced is typical of that expected in commercial installations. With use of good maintenance practices and water quality control, all of the tubes tested are probably suitable for long-term-fouling applications.

It is important to remember that a chiller selected for low flow does not necessarily have low velocity through its tubes, as discussed in the chapter “System Design Options” on page 27. If tube fouling is a major concern, consider the use of smooth, rather than internally-enhanced, tubes in the condenser for ease of cleaning.

Air-cooled condenser

Air-cooled chillers do not use condenser-water, since they reject their heat by passing ambient air across refrigerant-to-air heat exchangers. In packaged air-cooled chillers, the manufacturers improve performance by staging fans in response to chiller load and ambient, dry-bulb temperature. Air-cooled chillers can also be split apart. One technique is to use an indoor remote evaporator with a packaged air-cooled condensing unit outdoors. Another technique is to locate the compressor(s) and the evaporator indoors (also known as a condenserless chiller) with an air-cooled condenser outdoors. It is also possible to have an indoor air-cooled condenser.

Air-cooled versus water-cooled condensers

One of the most distinctive differences in chiller heat exchangers continues to be the type of condenser selected—air-cooled versus water-cooled. When comparing air-cooled and water-cooled chillers, available capacity is the first distinguishing characteristic. Air-cooled condensers are typically available in packaged chillers ranging from 7.5 to 500 tons [25 to 1,580 kW]. Packaged water-cooled chillers are typically available from 10 to nearly 4,000 tons [35 to 14,000 kW].

Maintenance

A major advantage of using an air-cooled chiller is the elimination of the cooling tower. This eliminates the concerns and maintenance requirements associated with water treatment, chiller condenser-tube cleaning, tower mechanical maintenance, freeze protection, and the availability and quality of makeup water. This reduced maintenance requirement is particularly attractive to building owners because it can substantially reduce operating costs. However, see “Energy efficiency” below.

Systems that use an open cooling tower must have a water treatment program. Lack of tower-water treatment results in contaminants such as bacteria and algae. Fouled or corroded tubes can reduce chiller efficiency and lead to premature equipment failure.

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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