Water-Cooled Screw Chiller | Central HVAC Cooling Solution – FAQ

Yes, water quality is critically important for the performance, efficiency, reliability, and service life of a water-cooled screw chiller system.In water-cooled HVAC systems—especially high-capacity, long-running equipment such as Aurashu water-cooled screw chillers—water quality directly affects heat transfer efficiency, operating stability, maintenance frequency, and overall lifecycle cost.1. Why water quality matters in water-cooled chillersA water-cooled screw chiller relies on two major water circuits:Chilled water loop (supplying cooling to terminals or processes)Condenser water loop (rejecting heat via cooling tower)In both circuits, water flows continuously through heat exchangers, pipes, valves, and pumps. Poor water quality can lead to scaling, corrosion, fouling, and biological growth, all of which reduce system performance and may cause serious equipment damage over time.Aurashu designs its water-cooled screw chillers for high-efficiency and long-term industrial operation, but even the most robust equipment requires properly managed water conditions to perform at its full potential.2. Impact of poor water quality on system performance(1) Reduced heat transfer efficiencyScale deposits (calcium carbonate, magnesium salts) form insulating layers on heat exchanger tubesEven a thin layer of scale can significantly reduce heat transferChiller must run longer or at higher load → increased energy consumptionIn Aurashu chillers, precision-machined shell-and-tube heat exchangers are designed for optimal thermal performance, but scale buildup directly offsets these advantages.(2) Increased energy consumptionFouled heat exchangers raise condensing temperatureCompressor power increases to maintain cooling capacitySystem COP (Coefficient of Performance) declinesOver long operating periods, poor water quality can increase annual energy costs by 10–30% or more.(3) Corrosion and equipment damageImproper pH, high dissolved oxygen, or aggressive ions (chlorides, sulfates) accelerate corrosionCorrosion can cause:Tube leakageReduced pressure resistanceRefrigerant contaminationPremature heat exchanger failureAurashu offers optional anti-corrosion materials, tube coatings, and water-side protection designs, but correct water treatment remains essential.(4) Biological fouling and blockageAlgae, bacteria, and biofilm can form in untreated water systemsBiofouling reduces flow area and heat exchange efficiencyCan cause unpleasant odors, hygiene issues, and system instabilityThis is especially critical in cooling tower condenser water systems.3. Key water quality parameters to controlAurashu recommends managing water quality according to industry standards and project-specific requirements, typically including:pH value (usually 6.5–8.5)Hardness (calcium & magnesium content)Total dissolved solids (TDS)Chloride and sulfate concentrationDissolved oxygenMicrobial contentSuspended solidsMaintaining these parameters within acceptable limits ensures stable chiller operation and extends service life.4. Aurashu design features supporting water quality managementAurashu water-cooled screw chillers are engineered with water quality considerations in mind:High-quality shell-and-tube heat exchangersOptimized tube velocity to reduce fouling riskOptional cupronickel, stainless steel, or enhanced copper tubesIntelligent control system with temperature and pressure monitoringCompatibility with standard water treatment and filtration systemsHowever, equipment design alone cannot replace proper water treatment.5. Recommended water treatment solutionsFor optimal long-term performance, Aurashu strongly recommends the following measures:Water softening (to reduce scale formation)Chemical water treatment (corrosion inhibitors, biocides)Side-stream filtration (to remove suspended solids)Automatic blowdown systems (for cooling towers)Regular water quality testing and reportingThese measures significantly reduce maintenance costs and unplanned downtime.6. Impact on maintenance and lifecycle costGood water quality results in:Longer heat exchanger lifeFewer tube cleaningsReduced compressor stressStable capacity outputLower total cost of ownership (TCO)Poor water quality, by contrast, often leads to:Frequent shutdownsEmergency repairsReduced system reliabilityShortened equipment lifespanFor large commercial buildings, industrial plants, data centers, and hospitals using Aurashu chillers, water quality management is a critical operational strategy, not an optional extra.7. Aurashu service support and guidanceAurashu provides:Water quality guidelines during project designCoordination with EPC contractors and water treatment suppliersCustom material selection for special water conditionsOperation & maintenance recommendations tailored to local water qualityThis ensures that each chiller system delivers stable, efficient, and reliable performance throughout its lifecycle.

A water-cooled screw chiller is widely recognized as one of the most reliable cooling solutions for large-scale commercial and industrial HVAC systems. Its high reliability comes from a combination of robust mechanical design, stable operating conditions, mature control technology, and long-term engineering validation. Aurashu water-cooled screw chillers are engineered specifically to deliver continuous, stable performance under demanding operating environments where downtime is unacceptable.First, the screw compressor itself is designed for durability and long service life. Compared with reciprocating or small-capacity compressors, screw compressors operate with fewer moving parts, lower vibration levels, and continuous rotary motion. This significantly reduces mechanical wear and stress. Aurashu selects internationally proven screw compressor platforms with optimized rotor profiles, high-precision machining, and advanced bearing systems, ensuring stable operation even under high load or long operating hours.Second, water-cooled heat rejection provides inherently stable operating conditions. Unlike air-cooled chillers that are directly affected by outdoor ambient temperature fluctuations, water-cooled screw chillers use cooling water with relatively stable temperatures. This allows the compressor to operate at lower condensing pressures, reducing thermal stress and improving reliability. Aurashu designs condenser systems with optimized water flow paths, high-efficiency heat transfer surfaces, and corrosion-resistant materials to ensure consistent heat rejection over many years of operation.Third, advanced control and protection systems play a key role in reliability. Aurashu water-cooled screw chillers are equipped with intelligent microprocessor-based controllers that continuously monitor critical parameters such as suction and discharge pressure, motor current, oil temperature, water flow, and refrigerant status. Multiple layers of protection—including overload protection, phase loss protection, high/low pressure protection, and oil system monitoring—help prevent abnormal operation and automatically shut down the unit before damage occurs.Fourth, partial-load stability and smooth capacity control enhance long-term reliability. Screw chillers are particularly suitable for variable building loads. Through slide valve control or optional variable frequency drive (VFD) solutions, Aurashu units can precisely match cooling output to actual demand. This avoids frequent start-stop cycles, reduces electrical and mechanical stress, and significantly extends component lifespan.Fifth, system-level reliability is strengthened through engineering customization and redundancy options. Aurashu provides project-specific design services, including multiple-chiller configurations, standby unit planning, and optimized hydraulic system design. In mission-critical applications such as data centers, hospitals, pharmaceutical plants, and industrial production lines, this modular or multi-unit approach ensures that cooling can be maintained even if one unit is temporarily offline for maintenance.Finally, ease of maintenance and service accessibility contribute to operational reliability. Aurashu water-cooled screw chillers are designed with clear internal layouts, accessible components, and standardized parts. This simplifies routine inspection, oil replacement, tube cleaning, and performance checks. Combined with detailed documentation and technical support, this reduces maintenance errors and unplanned downtime.In summary, a water-cooled screw chiller offers exceptional reliability due to its robust compressor design, stable water-cooled operation, intelligent controls, smooth capacity regulation, and proven engineering practices. With Aurashu’s focus on quality manufacturing, strict testing standards, and customized system solutions, these chillers are well suited for long-term, high-demand HVAC applications where reliability and continuity are critical.

A Water-Cooled Screw Chiller or Heat Pump Unit does not operate as a standalone device. To ensure stable, efficient, and long-term performance, it must work together with a series of auxiliary equipment that forms a complete central HVAC system. The required auxiliary components depend on system configuration, cooling/heating capacity, climate conditions, and project requirements.At Aurashu, we provide not only the core chiller unit but also integrated system design, ensuring that all auxiliary equipment is properly selected, matched, and optimized for maximum efficiency and reliability.1. Cooling Tower (Cooling Mode Required)For cooling applications, a cooling tower is essential to reject heat absorbed by the chiller into the atmosphere. Warm condenser water from the chiller flows to the cooling tower, where heat is dissipated through evaporation before the cooled water returns to the condenser.Aurashu engineers select cooling towers based on:Heat rejection capacityAmbient wet-bulb temperatureNoise requirementsWater-saving and anti-scaling designOptional closed-circuit or low-noise cooling towers can be configured for sensitive environments.2. Chilled Water & Condenser Water PumpsA complete water-cooled system requires circulation pumps to move water through the system:Chilled water pumps deliver cooling or heating energy to terminals (AHUs, FCUs).Condenser water pumps circulate water between the chiller and cooling tower.Aurashu systems often adopt variable frequency drives (VFDs) for pumps, allowing flow to adjust dynamically with load demand, significantly reducing energy consumption.3. Heat Exchangers (Optional / System Dependent)In certain projects, plate or shell-and-tube heat exchangers are used for:Hydraulic separationEnergy recoveryProcess cooling isolationRedundancy and system protectionAurashu provides heat exchanger selection based on pressure drop, fouling factor, and temperature approach requirements.4. Expansion Tank & Water Makeup SystemTo maintain system pressure stability and compensate for thermal expansion:Expansion tanks absorb volume changes in water circuitsAutomatic makeup units ensure correct water levels and prevent air ingressThese components improve operational safety and reduce long-term maintenance risks.5. Water Treatment EquipmentProper water treatment is critical for water-cooled systems:Prevents scale, corrosion, and biological growthProtects heat exchangers and condenser tubesExtends service life and maintains efficiencyAurashu recommends filtration units, softeners, and chemical dosing systems customized to local water quality.6. Terminal Units (AHU / FCU / Process Loads)The chilled or heated water produced by the chiller must be distributed to:Air Handling Units (AHUs)Fan Coil Units (FCUs)Radiant systemsIndustrial process equipmentAurashu ensures hydraulic balancing and proper control integration across all terminals.7. Control & Automation SystemAn advanced control system integrates:Chiller controlPump and cooling tower coordinationTemperature, pressure, and flow sensorsBMS / Modbus / BACnet communicationAurashu provides intelligent control strategies for energy optimization, fault diagnosis, and remote monitoring.Aurashu System AdvantageRather than supplying isolated equipment, Aurashu delivers complete water-cooled HVAC solutions, including:Auxiliary equipment selectionSystem simulation and load matchingEnergy-saving optimizationCustom engineering for commercial and industrial projectsThis integrated approach ensures lower operating costs, higher reliability, and simplified installation.

Yes. Aurashu screw-type chiller and heat pump units fully support advanced variable capacity control solutions, including stepped capacity regulation and optional inverter (VFD) control, designed to meet the dynamic load demands of modern commercial and industrial HVAC systems.1. Variable Capacity Control for Real Operating ConditionsAurashu screw chillers are engineered to operate efficiently across a wide load range. Unlike fixed-capacity systems that frequently start and stop, Aurashu units regulate cooling or heating output to closely match real-time building demand. This significantly improves part-load efficiency, reduces energy waste, and enhances system stability.Capacity modulation is achieved through:Slide valve or volume ratio (Vi) control within the screw compressorMulti-step unloading (e.g., 25% / 50% / 75% / 100%)Smart PLC logic that continuously adjusts capacity based on water temperature, pressure, and system loadThis approach ensures smooth transitions during load changes and prevents temperature fluctuations in critical environments such as data centers, hospitals, and industrial processes.2. Optional Inverter (VFD) Control for Maximum Energy SavingsFor projects with highly variable loads or strict energy-efficiency targets, Aurashu offers inverter-driven screw chiller solutions. By integrating a Variable Frequency Drive (VFD), the compressor motor speed is continuously adjusted rather than operating at a fixed speed.Key advantages of inverter control include:Precise output matching to actual cooling/heating demandLower starting current, reducing electrical stress on the power gridSignificantly improved IPLV and seasonal efficiencyReduced mechanical wear, extending compressor service lifeAt partial loads—where most HVAC systems operate for the majority of the year—inverter-controlled units can achieve substantial energy savings compared to conventional on/off or stepped systems.3. Intelligent System Integration and Control FlexibilityAurashu variable-capacity and inverter chillers are equipped with intelligent control platforms that support:Real-time load monitoringAutomatic capacity optimizationRemote monitoring and fault diagnosticsIntegration with BMS protocols such as Modbus, BACnet, or LonWorksThis allows facility managers to fine-tune performance, reduce operational costs, and maintain optimal comfort or process conditions with minimal manual intervention.4. Custom Control Strategies for Different ApplicationsAurashu understands that different projects require different control philosophies. Variable capacity and inverter solutions can be customized based on:Building type and usage patternClimate conditionsElectrical infrastructureRedundancy and reliability requirementsWhether the application is a large commercial complex, industrial plant, pharmaceutical facility, or data center, Aurashu engineers tailor the control strategy to ensure efficiency, reliability, and long-term performance.5. Long-Term Operational BenefitsBy supporting variable capacity and inverter control, Aurashu screw chillers deliver:Lower annual energy consumptionReduced operating noiseImproved temperature stabilityExtended equipment lifespanFaster return on investment (ROI)These advantages make Aurashu solutions particularly suitable for projects pursuing green building certifications, energy cost optimization, or high-performance HVAC system design.

Water-cooled chillers are widely recognized as one of the most energy-efficient cooling solutions for large commercial and industrial HVAC systems, and this advantage becomes even more evident in Aurashu’s water-cooled screw chiller solutions. The primary reason lies in the superior heat transfer characteristics of water compared to air. Water has a much higher specific heat capacity and thermal conductivity, allowing it to absorb and release heat more efficiently. As a result, water-cooled chillers can reject heat at lower condensing temperatures, significantly reducing compressor workload and overall power consumption.In Aurashu water-cooled screw chillers, heat generated during the refrigeration process is transferred to cooling water through high-efficiency shell-and-tube or falling-film evaporators and condensers. This cooling water is then circulated to a cooling tower, where heat is dissipated efficiently. Because the cooling water temperature is more stable than outdoor air temperature, the chiller operates under consistent conditions, maintaining high efficiency even during peak summer loads. In contrast, air-cooled chillers must rely on ambient air, which can be extremely hot in summer, forcing compressors to work harder and consume more energy.Another key factor is part-load efficiency. Large buildings such as data centers, hospitals, industrial plants, and commercial complexes rarely operate at full load all the time. Aurashu water-cooled screw chillers are designed with excellent part-load performance, supported by advanced screw compressors, intelligent capacity control, and optimized heat exchanger design. This allows the system to precisely match cooling demand, minimizing energy waste during off-peak operation. When combined with variable frequency drives (VFDs) and smart control algorithms, energy savings can be further enhanced.System integration also plays a crucial role. Water-cooled chillers are typically part of a centralized cooling system that includes cooling towers, chilled water pumps, and building automation systems (BAS). Aurashu designs its water-cooled chiller solutions to seamlessly integrate with intelligent control platforms, enabling real-time monitoring, load optimization, and energy management. By optimizing the operation of the entire system—not just the chiller—Aurashu helps clients achieve lower total energy consumption and reduced operating costs.Additionally, water-cooled chillers generally have a longer service life and more stable performance. Lower operating pressures and temperatures reduce mechanical stress on compressors and key components, maintaining high efficiency over many years of operation. This long-term stability means that efficiency does not degrade as quickly as in air-cooled systems, resulting in better lifecycle energy performance.In summary, water-cooled chillers are more energy-efficient due to superior heat transfer, stable operating conditions, excellent part-load efficiency, and system-level optimization. Aurashu leverages these advantages through advanced engineering, high-quality components, and customized solutions, delivering reliable, energy-saving cooling for demanding commercial and industrial applications.

A Water-Cooled Screw Chiller is a high-capacity central HVAC cooling system that uses water as the heat rejection medium and a screw compressor as its core compression component. It is widely applied in large-scale commercial, industrial, and infrastructure projects where high efficiency, stable operation, and long service life are required.At Aurashu, water-cooled screw chillers are engineered as core cooling sources within complete chilled water systems, typically operating together with cooling towers, condenser water pumps, and chilled water circulation networks. Compared with air-cooled chillers, water-cooled screw chillers achieve superior energy efficiency by utilizing water’s higher heat transfer coefficient, especially under high ambient temperature or heavy-load conditions.Working PrincipleAurashu water-cooled screw chillers operate on a vapor compression refrigeration cycle. The screw compressor compresses low-pressure refrigerant vapor into a high-pressure, high-temperature state. The refrigerant then enters a water-cooled condenser, where heat is transferred to condenser water and discharged through a cooling tower. After condensation, the refrigerant flows through an expansion device and evaporator, absorbing heat from the chilled water loop to provide cooling to air handling units, fan coil units, or process equipment.Aurashu adopts high-efficiency twin-screw compressors, optimized refrigerant flow design, and precision control logic to ensure smooth capacity regulation and stable performance across wide load ranges.Key Advantages of Aurashu Water-Cooled Screw ChillersHigh Energy Efficiency: Optimized heat exchange surfaces and advanced compressor design deliver excellent COP and IPLV performance, significantly reducing operating costs for long-term projects.Stable Large-Capacity Output: Ideal for continuous operation in large buildings, factories, data centers, and district cooling systems.Long Service Life: Designed for 24/7 operation with reinforced components, vibration isolation, and intelligent protection logic.Flexible System Integration: Easily integrated with building automation systems (BAS), BMS platforms, and Aurashu’s intelligent control solutions.Custom Engineering Capability: Aurashu offers tailored designs based on cooling capacity, climate conditions, redundancy requirements, and project standards.Typical ApplicationsAurashu water-cooled screw chillers are widely used in:Large commercial complexes and shopping mallsOffice towers and headquarters buildingsHospitals and medical centersData centers and communication hubsIndustrial plants and process coolingAirports, railway stations, and public infrastructureDistrict cooling and energy stationsThese units are especially suitable for projects requiring high reliability, low noise, stable indoor comfort, and long-term operational efficiency.Aurashu Engineering StrengthAurashu integrates product manufacturing, system design, installation guidance, commissioning support, and lifecycle service. Each water-cooled screw chiller solution is backed by Aurashu’s engineering experience in large-scale HVAC projects and complies with international energy efficiency and quality standards. From feasibility analysis to post-installation optimization, Aurashu ensures that each system delivers maximum value over its entire lifecycle.