Ashrae Guideline | Trane TRG-TRC016-EN guide

period four

Chiller-Plant Control

notes

chiller operating log

ASHRAE Guideline 3

▲	Chilled-water inlet and outlet	▲ Compressor-refrigerant suction
	temperatures and pressures	and discharge temperatures
▲	Chilled water flow	▲ Oil pressures, temperature, and
▲	Evaporator-refrigerant	levels
	temperature and pressures	▲ Refrigerant level
▲	Evaporator approach	▲ Vibration levels
	temperature	▲ Vibration levels
	temperature	▲ Addition of refrigerant or oil
▲	Condenser-water inlet and	▲ Addition of refrigerant or oil
	outlet temperatures and
	pressures
▲	Condenser water flow
▲	Condenser-refrigerant
	temperature and pressures
▲	Condenser approach
	temperature	Figure 110

ASHRAE Guideline 3, Reducing Emission of Halogenated Refrigerants in Refrigeration and Air Conditioning Equipment and Systems, includes a list of recommended data points to be logged daily for each chiller. Much of this data may be available from the display on the chiller control panel. It is also helpful to the operator if this information is available at the chiller-plant control system and presented in a clear format.

In addition to current status, historical operating information is valuable for keeping the equipment operating at peak efficiency and for identifying operating trends that signal either impending problems or a drop in system performance. For example, the condenser approach temperature is the temperature difference between the water leaving the condenser and the refrigerant inside the condenser. If there has been a problem with water treatment in the cooling tower, fouling may build up inside the tubes in the chiller condenser. This will cause the difference between the condenser water and refrigerant temperatures to increase, reducing chiller efficiency. By noting an increase in this approach temperature, the operator can schedule cleaning of the condenser tubes. By monitoring system and equipment trends, the operator has a chance to fix minor issues before they cause operational problems.

102	TRG-TRC016-EN

Image 109

Trane TRG-TRC016-EN manual Ashrae Guideline

Contents

Air Conditioning Clinic Chilled-Water Systems Business Reply Mail One of the Systems Series Comment Card One of the Systems Series Publication Trane Company Preface Contents Iii Water systems Types of Water Chillers Compressor-driven heat-driven Driving Sources Vapor-Compression Water Chillers Vapor-Compression Cycle Scroll Reciprocating Helical-rotarycentrifugal Compressor Types Variable-Speed Drives Air-Cooled or Water-Cooled Condenser TypesAir-Cooled or Water-Cooled Condensing Maintenance Low Ambient Operation Efficiency Comparison Packaged or Split Components Packaged Air-Cooled Chiller Remote Evaporator Barrel Remote Air-Cooled Condenser Indoor Air-Cooled Condenser Absorption Water Chillers Absorption Refrigeration Cycle Absorption Chillers Offer Choice Single-effectdouble-effect Direct-fired Absorption Chiller Types Equipment Rating Standards Equipment Rating StandardsAir-Conditioning & Refrigeration Institute ARI Integrated Part-Load Value Iplv Part-Load Efficiency RatingNon-Standard Part-Load Value Nplv Evaporator Condenser Rating Chiller type Flow rate Standard Rating Conditions QBtu/hr = 500 ⋅ flow rate ⋅ ∆T Flow Rates and Temperatures ARI conditions Low-flow conditions Electric Vapor-Compression Chillers ASHRAE/IESNA StandardEnergy Standard Chiller type Capacity Water-Cooled Absorption Chillers Ashrae Standard Chilled-Water System Components Chilled-Water System Design Chilled-Water System Load-Terminal Control Load-Terminal Control Options Three-Way Valve Control Two-Way Valve Control Face-and-Bypass Damper Control Three-way modulating valve Chiller Evaporator FlowConstant flow is most common Variable flow is possible Single-Chiller System Redundancy Part-load efficiency Multiple-Chiller Systems Single Pump Parallel Configuration Dedicated Pumps Percent flow Chillers Piped in Series Series Configuration Equal Set Points Staggered Set Points Primary-Secondary Decoupled Configuration Primary-Secondary Configuration Bypass pipe should be free of restrictions Primary-Secondary System Rules Production Loop Manifolded Production Pumps Distribution Loop Load terminals should use two-way modulating control valves Bypass pipe should be free of restrictions Variable-speed control riding the pump curve Varying Distribution Flow Multiple Distribution Pumps Distribution Tertiary Pumping Distribution Loop Characteristics Primary-Secondary System Rules Primary-Secondary System Operation System Operation Deficit Flow Excess Flow Control of Primary-Secondary System Pressure-based Types of Fluid Flow MetersTurbine and impeller Vortex Magnetic Ultrasonic Temperature-Based Calculations Alternate Fuel Choice Electric Utility Deregulation Indirectly-coupled, gas-engine chillers Fuel Choice Options Low-Flow Systems Chiller Efficiency Improvements Trend Toward Lower Flow Rates Greater Focus on System Efficiency Low-Flow Systems Variable-Primary-Flow Systems Variable-Primary-Flow Systems Critical VPF System Requirements Preferential Loading Preferential Chiller Loading Sidestream Configuration Heat Recovery Heat-Recovery Chiller Heat-recovery Auxiliary Dual condenser Condenser Heat pump Heat-Recovery Chiller Options Mode Heat-Recovery Chiller Efficiency Unloadingwith Control of a Heat-Recovery Chiller Asymmetric Design Asymmetric DesignDifferent chiller Capacities Different chiller Swing Chiller Chiller Free Cooling Free CoolingAirside economizer Waterside economizer Plate-and-Frame Heat Exchanger Refrigerant Migration Application Outside the Operating Range of the Chiller Application Outside Range of Chiller Chiller-Plant Control Chiller Controls What Is Important? Chiller Sequencing Chiller Sequencing Temperature Flow Capacity Chiller Rotation Small electric Chiller largeelectric chiller Heat Recovery Variable-Primary-Flow Systems Failure Recovery and Contingency Planning System Failure RecoveryMaintain flow of chilled water Keep it simple Notify the operator Allow the operator to intervene Contingency Planning System Tuning System TimersLoad-confirmation timer Staging-interval timer Unload Before Start Soft Loading Chilled-Water Set Point Control System Optimization System Optimization Pros Chilled Water ResetCons Tower Condenser-Water Temperature Control of Condensing Pressure Operator Interface Operator Training and Support Operator Interface Ashrae Guideline Vapor-compression water chillers Review-Period One Load-terminal control Review-Period Two Review-Period Three Review-Period Four For more information, refer to the following references Quiz 109 Answers 111 Glossary 113 114 115 Trane Company