Cost Estimation Design & Engineering, Supply, Installation, Testing, and Commissioning of Air-Cooled Screw Chillers with Free Cooling Coil Technology

Cost Estimation for Design & Engineering, Supply, Installation, Testing, and Commissioning of Air-Cooled Screw Chillers with Free Cooling Coil Technology

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In today’s competitive market, achieving accurate cost estimation for projects involving specialized equipment like air-cooled screw chillers with free cooling coil technology is essential. This estimation encompasses each critical step, including design & engineering, supply, installation, testing, and commissioning. Below is a comprehensive breakdown of factors that must be considered to ensure both precision and functionality meet client and operational specifications.

Today, we're exploring the intricate components involved in selecting, engineering, and commissioning air-cooled screw chillers equipped with the latest Free Cooling Coil Technology. With an actual cooling capacity of 220 TR, these units integrate advanced features such as VFD-compatible starters, low-noise condenser fans, and fully-flooded evaporators—all aimed at high performance and sustainability.

###Project Overview

The air-cooled screw chiller system specified is designed for 220 TR capacity with free cooling coil technology. With features such as multiple screw compressors, VFD compatibility, insulated heat exchangers, low RPM condenser fans, and acoustic enclosures, the system demands meticulous planning. Critical requirements include robust BMS integration, spring-type vibration isolators, an IP55-rated control panel, and provisions for a quick restart capability within 240 seconds. Each component must ensure functionality across a range of environmental conditions and duty cycles, requiring a detailed approach to cost assessment.

### Specifications for Optimal Chiller Selection

1. Dual Compressor Systems with Enhanced Free Cooling:

The proposed chillers must include at least two screw compressors, equipped with VFD-compatible starters, optimizing load distribution and energy use. The Free Cooling Coil Technology enables chiller operation to leverage outdoor air for cooling when temperatures fall below the return chilled water temperature. As a result, free cooling capacity increases with further temperature drops, reducing the energy required for mechanical cooling.

2. High-Efficiency Heat Exchangers with Minimum Pressure Drops:

To maintain a smooth and effective cooling process, the heat exchanger is specified to be of a shell and tube type, insulated, with a fully flooded evaporator configuration. The design must account for minimal pressure drops while achieving efficient heat transfer, ensuring optimal cooling even at reduced energy costs.

3. Advanced Acoustic and Vibration Isolation Measures:

Equipped with low RPM, low-noise condenser fans, and factory-fitted acoustic enclosures, the units must restrict sound pressure levels to 75 dBA at 1 meter. Additionally, spring-type vibration isolators with a minimum 90% isolation efficiency at 30 Hz provide a quieter, more stable operational environment, reducing potential disturbances in facility operations.

4. Quick Restart Capability for Uninterrupted Performance:

A notable specification is the requirement for a quick restart feature, enabling full capacity restoration within 240 seconds after a power changeover, minimizing downtime. OEMs are requested to provide a detailed quick start methodology to ensure smooth transitions without latch faults during power fluctuations.

5. Robust Control Panel and BMS Compatibility:

The chiller's control panel, which must meet an IP55 rating, will operate on UPS power provided by the contractor to guarantee continuous functionality. An integrated Building Management System (BMS) interface, with open protocol adaptability, will facilitate real-time monitoring, data integration, and seamless control.

6. Enhanced Durability with Corrosion-Resistant Coils:

Given the stringent requirements for longevity, condenser coils should be factory-coated with anti-corrosive material, verified by a 5000-hour salt spray test in accordance with ASTM B117 standards. This coating, alongside a coil guard and mesh enclosure, extends durability, making the chillers suitable for harsh environments and reducing long-term maintenance.

7. Compliance with Global Standards for Performance and Sustainability:

The performance criteria include COP ≥ 3.0 and IPLV ≥ 4.6 under AHRI standards or Eurovent certification, ensuring high efficiency and sustainability. OEMs must also confirm the use of HFC-134a refrigerant, aligning with ozone-friendly requirements for eco-conscious operations.

###Key Components for Cost Estimation

1. Design & Engineering

• Detailed Engineering and Design Calculations: Evaluate capacity, pressure drops, heat exchange efficiency, and free-cooling features. Ensure compatibility with Eurovent or AHRI standards, particularly EN14511-3:2013.
• Compliance with Specification Requirements: Each component, from electronic expansion valves to spring isolators, must adhere to the project’s technical specifications.
• Integration with BMS: Costs for developing an open protocol-based integration for seamless monitoring and control through BMS.

2. Equipment Supply

• Chiller Unit: Base cost for air-cooled screw chillers with HFC-134a refrigerant. Additional cost for anti-corrosive coating, factory-fitted acoustic enclosures, and coil guard for enhanced durability.
• Compressors and Variable Frequency Drives (VFDs): Selection of VFD-compatible screw compressors, sized and rated as per load variations to maintain COP ≥ 3.0 and IPLV ≥ 4.6.
• Acoustic Enclosures & Anti-Vibration Components: Factory-fitted acoustic enclosures and high-efficiency vibration isolators to meet noise specifications and protect components.

3. Installation and Site Preparation

• Structural Setup: Ensure a stable frame with provisions for 3M face-to-face spacing to prevent short cycling.
• Power & Cabling: Considerations for 415V power requirements, UPS-backed control panel, ATS for power module, and Form-3B construction with RAL 7032 coating on the chiller junction box.
• Automatic Transfer Switch (ATS) Integration: Additional safety and reliability in power transitions, minimizing potential downtimes.

4. Testing and Commissioning

• Load Testing at Design Conditions: Verify chiller performance at varied loads (100%, 75%, 50%, and 25%) as per AHRI 551/591 standards, ensuring optimal functionality across operational ranges.
• Salt Spray Testing for Anti-Corrosive Coating: 5000 Hr Salt Spray ASTM B117 test certification on condenser coils.
• Joint Testing and Commissioning: Coordinate with low-side contractor to verify all functional parameters and ensure seamless handover.

5. Logistics and Import Duties

• Port and Customs Charges: Include port handling, transportation, and insurance up to the site. Custom duties, local taxes, and incidentals are also integral to the total cost.
• Receiving and On-Site Handling: Consider costs for equipment handling upon arrival and handover to the low-side contractor.

Additional Considerations

• Quick Start Methodology: Include cost for technical support from the OEM to confirm chiller restart capabilities under 240 seconds without fault latching.
• Maintenance and Warranty: Extended warranties for condenser coils to cover up to five years on anti-corrosion coating, vital for long-term cost savings.
• Environmental Compliance: The use of eco-friendly HFC-134a refrigerant aligns with sustainability objectives and may impact project funding eligibility or tax incentives.

###Additional Considerations

• Quick Start Methodology: Include cost for technical support from the OEM to confirm chiller restart capabilities under 240 seconds without fault latching.
• Maintenance and Warranty: Extended warranties for condenser coils to cover up to five years on anti-corrosion coating, vital for long-term cost savings.
• Environmental Compliance: The use of eco-friendly HFC-134a refrigerant aligns with sustainability objectives and may impact project funding eligibility or tax incentives.

### Ensuring Seamless Supply Chain and On-Site Installation

To provide a comprehensive solution, all logistics from port handling to on-site delivery are to be detailed, ensuring seamless transition and minimal downtime. Additionally, OEMs are to collaborate in joint testing and commissioning, ensuring all indigenous accessories are in place and operational at handover.

The RFQ specifies that the chiller junction box be built for outdoor duty, compliant with Form-3B 14G construction, and suitable for aluminum cable termination. This durable infrastructure ensures the chillers are installation-ready, simplifying integration with existing setups and providing a hassle-free experience for facility teams.

Conclusion

This comprehensive approach to cost estimation not only addresses initial procurement and setup but also encompasses long-term performance reliability and compliance with environmental and noise regulations. By focusing on precise engineering, robust testing, and seamless integration, projects can achieve cost-effective solutions that maintain high efficiency and dependability over time.

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