In a complex and logistically challenging retrofit project, Chilled System Solutions was appointed to carry out a full HVAC system upgrade in Bristol within a busy city centre commercial building. The objective was to replace ageing, inefficient cooling infrastructure with a high-performance, future-ready solution. This included the decommissioning of three existing Geoclima chillers, removal of four outdated dry air coolers, full replacement of corroded condenser pipework, and conversion of the condenser system from an open to a closed loop. The project aimed to enhance energy efficiency, improve system reliability, and ensure long-term operational resilience while meeting the cooling demands of a high-occupancy, mixed-use environment.

Project Overview

Client: Confidential
Location: Bristol City Centre
Sector: Commercial Property (mixed-use – data centres, gyms)
Service Provided: Full HVAC Retrofit – Chiller Replacement, Pipework Upgrade, System Modernisation
Completion Date: Not specified
Contractor: Chilled System Solutions

Background & System History

This city-centre property was built in the 1980s with HVAC infrastructure tailored to high-cooling-demand environments such as data centres and gyms. The original system featured:

3 chillers (model unknown)
3 cooling towers
2 buffer vessels (40,000 litres each)
Approx. 60,000 litres total circuit volume (chilled & condenser loops)

Previous Retrofit Highlights:

Cooling towers replaced with 4 dry air coolers
Chillers upgraded to 3 Geoclima water-cooled units
However, original condenser pipework remained in service—only modified, not replaced

Due to performance and reliability issues linked to this ageing infrastructure, a new retrofit was commissioned to modernise the system and increase efficiency.

Project Objectives

Replace ageing equipment with high-efficiency modern systems

Improve hydraulic performance
Ensure long-term system reliability
Reduce operational costs and environmental impact
Address legacy pipework issues

Scope of Works

Equipment Replacement:

Removed:

3 existing Geoclima chillers
4 dry air coolers

Installed:

2 new Geoclima chillers featuring Turbocor oil-free compressors with variable speed drives
4 new dry air coolers with EC fans, capable of ambient conditions >35°C (previous units were rated only up to 28°C)

Pipework Upgrade:

Fully replaced legacy condenser pipework under dry air cooler compound
New pipework:

Fabricated in mild steel
Fitted with antivibration bellows, isolation valves
Uninsulated to allow passive heat rejection—an energy-saving feature

Water Quality & System Protection:

Installed 2 filter skids (one per circuit) to protect against debris and contamination
Converted condenser loop from open to closed system, with:

Pressurisation unit
Expansion vessels

Antifreeze and chemical inhibitors added to both loops to prevent corrosion and fouling

Contractor Coordination & QA

Contractor Management:

Managed multiple specialist subcontractors (mechanical, electrical, insulation, crane ops, water treatment)
Conducted comprehensive RAMS (Risk Assessments & Method Statements)
Enforced on-site health & safety compliance throughout

Crane Operations:

Two crane lifts (equipment removal & installation)
Detailed planning included:

Lift diagrams
Risk & method statements
Ground pressure calculations
Plate load testing

Spotters and banksmen ensured on-site lift safety

Quality Assurance:

Issued Quality Plan outlining inspection criteria and commissioning process
Daily/weekly site logs maintained with photos and activity notes
Final as-fitted mechanical drawings provided for future reference

Execution Challenges

No direct craning access to chillers in basement plantroom
➜ Chillers were disassembled and transported through the basement

Legacy isolation valve failures required freeze isolation and localised drain-downs
Old pipework was found to contain significant debris, reinforcing the value of pipe replacement and filtration

Work in Progress Highlights (Visual)

Take a look at the PDF HERE

📸 Page 7–10: Equipment cleared from lower compound; significant corrosion and debris in pipework

📸 Page 11–16:

Crane lifts completed
New steel frames installed for dry air coolers
Pipework installation penetrated to upper level
New filter skids and chillers placed
Final pipework fabricated on-site

Project Outcomes

Significantly enhanced energy efficiency with advanced compressor and fan technology

Improved resilience and reliability
Closed, filtered circuits protect against corrosion and extend equipment lifespan
60,000-litre system volumes now under better control with improved cleanliness and hydraulic performance

Concluding Our Full HVAC System Upgrade Project in Bristol

This retrofit showcases best practice in transforming legacy HVAC systems. Through a holistic upgrade—including modern equipment, smart hydraulic redesign, and robust water treatment—Chilled System Solutions delivered a future-ready system that meets today’s performance and environmental standards.

The project also demonstrates Chilled System Solutions’ ability to:

Coordinate multi-disciplinary contractors
Deliver projects in logistically complex, urban sites
Execute projects safely, transparently, and to the highest technical standards

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