Trane TRG-TRC014-EN manual Single Duct, Cooling Only, Primary air ir

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period two

Components of a VAV System

notes

Single Duct, Cooling Only

primary air

supply air

Figure 22

The simplest of all VAV terminal units is the single-duct,cooling-onlyterminal unit. It consists of an airflow modulation device with controls packaged in a sheet-metal enclosure. The unit can only modulate the primary airflow to the space. The primary air is supplied by a single, central air handler.

This VAV terminal unit is typically used for those zones that require year-round cooling, like the interior zones of a building. It is the most common and basic type of single-duct VAV terminal unit.

Single Duct, Cooling Only

100%

remote source of heat

 

maximum

 

 

 

primary

 

 

heating

tempering

airflow

to space

 

 

 

 

 

 

airflow

 

 

 

minimum

 

 

 

primary

%

 

 

 

 

 

primary airir

airflow

 

 

 

 

 

 

 

0%

 

 

 

 

design

 

space load

design

heating load

cooling load

 

 

Figure 23

This graph indicates how the air supplied to the space by the terminal unit varies as the space loads change. The vertical axis indicates the total airflow supplied to the space. The horizontal axis indicates the space load.

The supply airflow to the space is reduced as the cooling load in the space decreases. Responding to the space thermostat, the primary airflow is modulated between maximum and minimum settings. The maximum setting is

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TRG-TRC014-EN

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Contents Air Conditioning Clinic VAV Systems One of the Systems Series Publication of The Trane Company VAV Systems PrefaceContents TRG-TRC014-EN Constant-Volume Variable-Temperature System What Is Variable Air Volume?Constant Volume-Full Load Constant × Supply Airflow Constant Volume-Part LoadFine Constant Volume-Multiple SpacesTerminal Reheat System VAV-Full Load Variable-Air-Volume VAV SystemVAV-Part Load Why VAV? Energy SavingsReduced fan energy Reduced refrigeration energy Dedicated terminal units Dedicated thermostats Why VAV? ComfortVAV System ComparisonVariable Thermal Load Profiles VAV Building CharacteristicsCommon Return Air Path Independent Space ControlComponents of a VAV System Components of a VAV SystemAir Heating coil Filter Mixing fan VAV Terminal UnitsVAV Terminal Units Primary air ir Single Duct, Cooling OnlySpace Heating with a VAV System Primary air VAV ReheatSeries Fan-Powered Terminal UnitsParallel, Fan-Powered Series, Fan-Powered Parallel Versus Series Fan-Powered Single-Duct VAV Systems Dual-Duct Cool Primary air Variable Air Volume to the SpaceSingle-Fan, Dual-Duct VAV System Constant Air Volume to the SpaceTwo-Fan, Dual-Duct VAV System Upstream Pressure Affects Airflow VAV Terminal Unit ControlsVAV Terminal Unit Controls Pressure-Independent Control Pressure-Dependent ControlTerminal-Unit Control Technologies Primary Airflow MeasurementPneumatic Control Electronic Control Direct Digital Control DDC Components of a VAV System Diffusers DiffusersEffect Linear Slot DiffuserCeiling-Diffuser Compatibility Components of a VAV System Supply Duct System Supply Duct SystemEqual friction method Duct DesignStatic regain method Duct Design Recommendations Perimeter P Versus Interior System ConfigurationsPerimeter Spaces Perimeter SpacesBaseboard Perimeter Heating Overhead Supply Perimeter Heating Heat loss 250 Btu/hr/ft Dual-Duct VAV Fan-Powered VAVInterior Spaces, Reheat Required Interior SpacesChangeover/Bypass VAV System Small BuildingsSystem-Level Control Modes Occupied mode Unoccupied mode Morning warm-up/cool-down modeOccupied Mode Unoccupied Mode Morning Warm-up/Cool-down Mode Fan Performance Curve Fan ModulationFan Performance Curve System Resistance Curve System Resistance CurveRiding the Fan Curve Operating PointForward-Curved Centrifugal Fan Fan Modulation Curve Fan Modulation CurveVAV Fan Modulation Fan Control LoopDischarge Dampers Fan Modulation MethodsStatic pressure Discharge damper SP loss Inlet Vanes 0 r p m Fan-Speed ControlVariable-Pitch Blade Control BI fan with Discharge Dampers Fan Modulation ComparisonsFan Outlet Static-Pressure Control Controlling System Static PressureSensor located Down supply duct Supply Duct Static-Pressure ControlAt fan outlet Optimized Static-Pressure ControlPart-Load Comparison Period five Application ConsiderationsSystem-Level Ventilation System-Level VentilationVentilation Reset Measures to Prevent Coil Freeze-Up Freeze Protection for CoilsFreeze Protection for Coils Part-Load Space Humidity Control Part-Load Space Humidity ControlPart-Load Supply Air Tempering Direct Pressurization Control Building Pressure ControlBuilding Pressure Control Application Considerations Review-Period One ReviewReview-Period Two Review-Period Four Review-Period ThreeTrane Air Conditioning Manual Review-Period FiveReview Questions for Period QuizQuiz TRG-TRC014-EN Answers Glossary Glossary Glossary Trane Company

TRG-TRC014-EN specifications

The Trane TRG-TRC014-EN is a comprehensive technical resource guide that serves as an essential tool for HVAC professionals and engineers looking to enhance their understanding of Trane's commercial HVAC systems. This guide provides an in-depth examination of Trane’s advanced technologies, key features, and design characteristics that position their products as industry leaders in heating, ventilation, and air conditioning.

One of the standout features of the TRG-TRC014-EN is its focus on energy efficiency. Trane continuously works on incorporating cutting-edge technologies that minimize energy consumption while maximizing performance. This includes the use of variable speed compressors and advanced control systems that adapt the HVAC operation according to real-time demand, significantly reducing energy costs for end users.

The guide also highlights Trane’s commitment to sustainable practices. The incorporation of environmentally friendly refrigerants and compliance with regulatory standards ensures that Trane units not only deliver comfort but also contribute to lower environmental impact. The guide provides detailed specifications on these refrigerants, allowing engineers to make informed decisions in line with environmental policies.

Another important aspect of the TRG-TRC014-EN is its technical information regarding system design and application. With comprehensive data on airflow, capacity calculations, and installation techniques, the guide serves as a valuable resource in the design phase of HVAC projects. This ensures that systems are optimized for performance and meet the specific needs of any given commercial space.

Additionally, the TRG-TRC014-EN addresses integration with smart building technologies. Trane units are designed to easily integrate with building management systems (BMS), enabling better monitoring and control of HVAC operations. This compatibility enhances operational efficiency and supports predictive maintenance, reducing downtime and servicing costs.

Moreover, the guide emphasizes Trane’s extensive warranty and service support. Understanding that customer satisfaction extends beyond the sale, Trane provides comprehensive service options that assure users of reliable and prompt support throughout the lifecycle of their HVAC systems.

In conclusion, the Trane TRG-TRC014-EN stands as an essential guide for HVAC professionals seeking to leverage Trane’s innovative technologies and design features. With a strong emphasis on energy efficiency, sustainability, technical accuracy, smart integration, and robust support, this guide underscores Trane's position as a leader in the HVAC industry.
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