The ice rink chiller is the most expensive piece of equipment in the entire refrigeration system, and the one most often specified incorrectly. Oversize it and the upfront investment rises noticeably, with frequent start-stop cycling at low load; undersize it and it cannot hold the ice temperature during peak traffic, so the ice turns soft, fogs over and puddles.
This article does not cover brands. It covers three things only: how to determine the cooling capacity, how to choose between screw and scroll compressors, and what to watch for under -15℃ conditions.
The ice rink cooling load is made up of four parts; omit any one and you will underestimate it:
| Load item | Description | Reference share |
|---|---|---|
| Ice sheet load | Heat exchange between the ice sheet and the air + lighting radiation | 35–45% |
| Resurfacing and melt | Hot water and latent heat introduced by each resurfacing | 10–15% |
| Occupants and outdoor air | Number of skaters on the ice, heat introduced by outdoor-air dehumidification | 20–30% |
| Building envelope | Heat transfer through walls, roof and floor slab, plus infiltration at door openings | 15–25% |
Common engineering estimates: a standard indoor ice rink has a cooling load of approximately 350–450 W/㎡ (based on ice surface area). A 1,200 ㎡ ice surface corresponds to roughly 420–540 kW of cooling capacity.
Why is this range so wide? The difference comes down to four things:
Ice thickness: 30 mm and 40 mm have different cooling storage capacity and different defrost recovery times (40 mm is recommended for figure skating)
Ceiling height and suspended ceiling: for every 1 m increase in ceiling height, the cooling load increases by about 3–5%
Dehumidification method: desiccant wheel dehumidification versus chilled-water dehumidification directly affects the unit’s evaporating temperature
Door openings: in rinks with doors that open directly to the outdoors, infiltration load can account for more than 10%
Estimates are only for preliminary scheme screening. Formal calculations should also include indoor design temperature and humidity, ice surface set temperature, ice resurfacing frequency, operating hours, and local summer outdoor parameters, and should distinguish between initial freeze and normal operation: the former focuses on pull-down time, while the latter focuses on ice surface maintenance and resurfacing recovery. Peak values should not be used directly as the year-round operating point.
Conclusion: Do not work backward from “cost per square meter” to select the unit. First produce a load calculation report, then have the manufacturer select the model based on the calculated cooling capacity. If you do it the other way around, the extra cost will definitely land on you.
II. Screw vs. Scroll: Divide by Cooling Capacity, Not Price
Comparison item Scroll chiller Screw chiller Typical single-unit cooling capacity 30–300 kW 150–1,500 kW Part-load efficiency Medium (can be improved with multiple compressors) High (stepless slide valve control) Upfront investment Low 20–40% higher Failure rate and maintenance Simple structure, low repair cost Complex structure, high overhaul cost Suitable applications Small rinks, mobile rinks, snow rooms Standard rinks of 1,000 ㎡ and above Decision guideline:
Ice surface ≤ 600 ㎡, single-unit cooling capacity ≤ 300 kW → scroll (multiple compressors in parallel, staged on demand)
Ice surface ≥ 800 ㎡ → screw, and it is recommended to use two compressor heads or dual chillers in parallel, operating only one at low load
Between 600–800 ㎡ → check the load profile: choose scroll for year-round full load, screw for large load fluctuations
What a rink fears most is not insufficient cooling capacity, but efficiency collapsing at part load. Nighttime load at a rink is only 25–30% of daytime load (even lower after insulation covers are installed). If only one large chiller is installed, at night it is like using a cannon to shoot mosquitoes—frequent start-stop cycles drive up both energy consumption and wear.
The selection table must also verify the minimum stable load, turndown range, starting current, and allowable number of starts/stops. Multiple units in parallel are not simply a matter of adding cooling capacities; you should confirm the hydraulic balance on the secondary coolant side, isolation for servicing a single unit, control rotation, and the operating strategy after a fault. For a 1,200 m² indoor ice rink, you can first calculate the total cooling capacity at 420–540 kW, then split the number of units according to the hourly load profile.
This point is worth more than choosing between screw and scroll: the number of units must match the load profile—do not rely on one unit to handle everything.
3. -15℃ Operating Conditions: Three Questions You Must Clarify
The secondary coolant outlet temperature in an ice rink is typically -12 ~ -18℃, more than 10℃ lower than that of a conventional air-conditioning chiller, which makes it a low-temperature application. Ask the following questions one by one during procurement:
1. Is the secondary coolant ethylene glycol or brine?
Ethylene glycol solution Calcium chloride brine Corrosiveness Low (corrosion inhibitor required) High; concentration and pH must be strictly controlled Specific heat Approx. 3.9 kJ/(kg·K) (30%) Approx. 2.8 kJ/(kg·K) Flow requirement Lower Higher (approx. 30–40% more) Consequences of leakage Contaminates the floor; does not corrode structures Corrodes rebar and equipment foundations Most new projects now use ethylene glycol because it has lower pump power consumption and is simpler to maintain. Brine should be considered only when the retrofit budget for an existing rink is limited.
Glycol concentration is not better the higher it is; changes in concentration affect the freezing point, specific heat, viscosity, and pump power at the same time. The procurement list should specify the design concentration, corresponding freezing point, liquid supply/return temperature difference, solution-side pressure drop, and heat exchanger correction factor, and verify corrosion inhibitor, make-up, and concentration testing requirements. Cooling capacity and flow rate from air-conditioning condition samples cannot be applied directly.
2. Which conditions are the evaporating temperature and COP reported for?
COP in manufacturer catalogs is often based on air-conditioning conditions (7°C leaving water). At -15°C secondary refrigerant conditions, COP typically drops by 35–45%. Require the manufacturer to provide performance curves for actual operating conditions, not catalog peak values.
Rough check: under -15°C ethylene glycol conditions, a unit COP of 2.0–2.6 is normal; if it is below 1.8, ask whether the heat exchanger is undersized.
Performance curves should at minimum specify the evaporation and condensation conditions, secondary refrigerant concentration, liquid inlet/outlet temperatures, and input power basis; when comparing different options, also align the condensing method and outdoor or cooling water conditions, and avoid comparing only a single COP number.
3. Freeze protection and defrost logic
Under low-temperature conditions, frost formation on the evaporator is unavoidable. Confirm: whether there is a freeze protection switch, how the defrost cycle is set, and how much the ice temperature fluctuates during defrost. Ice temperature fluctuation exceeding 1.5°C will affect ice surface quality, and figure skating venues are especially sensitive.
Also confirm whether other units can maintain cooling during defrost, and whether temperature sensor placement, alarms, and operating records are easy for operators to view.
IV. Price range (reference, not a quotation)
Cooling capacity range Scroll units Screw units 100–200 kW Typical range: 8-15 × RMB 10k — 200–400 kW Typical range: 15-30 × RMB 10k Typical range: 30-50 × RMB 10k 400–700 kW — Typical range: 50-90 × RMB 10k Above 700 kW — 90 × RMB 10k class The ranges in the table are typical industry ranges and vary with configuration; final pricing is calculated per project. The above covers the main unit price only and excludes the evaporator, condenser, water pumps, piping, electrical controls, and installation. A complete refrigeration system typically costs 2–2.5 times the main unit price (also an estimated range).
When comparing prices, align the number of compressors, heat exchanger configuration, condensing method, electrical control communications, transportation and rigging, and commissioning scope; otherwise, the main unit prices may look close but will not be comparable after site add-ons.
V. Five Questions to Check Before Purchase
What are your ice surface area and design ice thickness? (Determines thermal storage capacity and load)
Will insulation covers be used at night? (Determines the number of units and modulation capability)
Should the secondary refrigerant be ethylene glycol or brine? (Determines pump and piping cost)
Can the manufacturer provide a performance curve at -15℃? (Determines actual energy consumption)
How much will the ice temperature fluctuate during defrost? (Determines ice quality and operating reputation)
If you cannot answer three of these five questions, the solution is not yet ready for contract signing.
Contract technical annexes should specify fixed design conditions, rated and part-load performance, noise, power supply and maximum operating current, connection dimensions, control protocol, spare parts list, and acceptance methods. Performance acceptance should correspond to the same secondary refrigerant conditions; do not accept delivery based solely on air-conditioning condition parameters.
VI. Summary in One Sentence
Calculate the load first, then determine the number of units, and finally select the model. Screw and scroll are not a matter of high vs. low; they are divided by cooling capacity range. Under -15°C conditions, what truly determines success is secondary refrigerant selection, performance curves, and defrost logic.
*Beijing Yangsheng Ice & Snow Technology — indoor ice rinks / ski resorts / ice and snow parks / snow house engineering. For ice rink refrigeration system selection and retrofit, please call: 13691511384.*
