Case Study: Changsha IFS — 22-Chiller Condenser Online Cleaning Retrofit

Changsha International Finance Center (Changsha IFS) is a landmark super high-rise complex in Changsha, Hunan, China — combining a large shopping and entertainment mall, Grade-A offices, serviced apartments and a platinum five-star hotel. To keep its central chiller plant at design efficiency, the facility retrofitted all 22 chillers in the main plant with the HyApexFlow automatic condenser tube cleaning system (ATCS) — sponge-ball type, running on site as the HCTCS unit.

Changsha IFS central chiller plant — 22 chillers across three plant rooms, all covered by the ATCS retrofit.

Project Background

The retrofit was executed in two phases: five chillers ordered in August 2019 were installed by the end of that year, and seventeen more ordered in March 2020 were completed by June 2020. Unit 5# — a 950 RT centrifugal chiller with a 600 kW motor and roughly 3,000 operating hours per year — was the first unit to run continuously, so the site’s verification report tracks this machine in detail. The findings below come from the on-site user report compiled after one full year of ATCS operation.

The Challenge

Before the retrofit, fouling inside the condenser tubes held unit 5#’s approach temperature (the gap between refrigerant condensing temperature and leaving condenser-water temperature) at about 3.0°C. Both the ARI guideline and China’s GB 50736-2012 HVAC design code put the penalty at roughly 3–4% more compressor power for every 1°C of additional condensing temperature — so a 3°C gap was a permanent, material energy loss on every running hour.

The Solution

Each chiller was fitted with an ATCS sponge-ball online cleaning unit. Cleaning balls circulate continuously through the condenser water circuit, wiping the tube inner walls on every pass and returning through a separator — keeping the bundle near design cleanliness without shutting the chiller down. With a pre-season mechanical brush pass as the starting baseline, the system holds the approach-temperature rise at 100% load to no more than 0.3°C ± 0.1°C.

ATCS ball cleaning unit installed on the chiller condenser water line.

Measured Results After One Year (August 2020)

During a two-week August 2020 sampling window (compressor load 65–80%), unit 5#’s approach temperature read 0.7–1.1°C as run, averaging about 0.9°C — roughly 1.2°C normalized to 100% load, versus 3.0°C before the retrofit:

At the site’s CNY 0.80/kWh industrial tariff, that single chiller alone returns a six-figure RMB saving every year — and the report notes the remaining 21 chillers deliver the same benefit as their runtime accumulates.

Applicability

This project is a reference model for large mixed-use complexes: shopping malls, offices and hotels stacked in one footprint means long chiller hours and high peak demand. Continuous online condenser cleaning protects exactly the hours where those loads concentrate — with no shutdown and no extra operating staff.