Repeat delivery for the ice arena: ~1 MW chiller with screw compressors

TOV AIS LAB is an engineering and installation company, which has been designing and building ice arenas in Ukraine and abroad for more than 10 years.

Its portfolio includes permanent and seasonal ice rinks from 400 to 2500 m², mobile arenas, cooling stations, cooling systems for ice fields, pumping units and boards. In sports facility engineering, where temperature tolerances of ±0.3 °C or less are required, errors in all calculations are unacceptable – and this is where AIS LAB has developed a reputation for keeping ice surfaces perfectly flat.

With EVROPROM, they have a practical partnership that has been tested in dozens of facilities – arenas in Ukraine, ice rinks in Bulgaria by the sea, and mobile ice rinks in Kazakhstan. The joint work is based on clear technical scenarios: screw systems with Bitzer compressors, hydromodules with automation, water tests before commissioning.

Coherence of co-operation allows facilities to be commissioned within 10-14 days after installation, which is a high-end indicator in the refrigeration industry, where the average time is 2 months.

A new stage is the city ice arena in Lviv, where the project required a capacity of about 1 MW and stable operation at constant fluctuations in street temperature. The challenge is to ensure stable temperature conditions and minimum energy consumption during intensive operation.

Requirements for EVROPROM and parameters of the ice arena

The engineering concept of the Lviv ice rink was initially formed as a project of high thermal stress: ice area – 1 750 m², calculated heat supply – 870 kW at 5 °C air temperature and up to 1 MW in the peak of the off-season. The objective is to keep the ice surface temperature within -5 ± 0.3 °C during intensive operation for up to 16 hours per day. The client requested a cooling capacity reserve of at least 15 per cent, so that the rink would remain in operation even during partial shutdowns. In other words, the system had to provide double fault tolerance atwhile maintaining accurate temperature and pressure control at the same level.

The system was based on 2 Bitzer CSH9583-21Y-40D screw compressors, each with a nominal cooling capacity of about 480 kW under standard conditions and a potential of up to 520 kW with setpoint adjustment for low-temperature operation. The 2×100 % architecture is implemented with a priority of even life distribution and automatic motor hour equalisation. Each refrigeration circuit is controlled by an independent automation system with 18 monitoring points.

Start-up is realised by soft-start and frequency control, which reduces start-up currents by 40-45 % and prolongs the life of standby electric turbines. Dynamic power modulation is realised in the range of 25-100 %, which allows a flexible response to heat load fluctuations from daytime peaks to night energy dips, keeping the ice surface temperature within the nominal and low setpoints at ±0.3 °C.

The hydraulic unit is a modular system with redundant pumps (2×11 kW) designed to operate with 35 % ethylene glycol or 20 %– CaCl₂ solution. The brine flow rate is 62 m³/h and the temperature difference across the system is 3.8 K. To eliminate pulsations, balancing valves with an adjustment step of 1 % are installed, and an electronic pressure compensator with precise adjustment to 0.05 Bar is installed in the collector itself. Prior to start-up, the system underwent a three-stage preparation: flushing, deaeration and hydraulic equalisation; the exact test results are recorded in a video protocol with real-time recording of all parameters. Thanks to the supply of equipment from EVROPROM’s stock, installation and commissioning took less than 10 days – a result that can be considered a benchmark in the HVAC engineering environment.

Refrigeration equipment for the longevity of an ice arena

A RHOSS TCAVSZ21040 unit with a rated output of 1037.3 kW at 12/7 °C and 35 °C outside air was integrated into the project. For the ice, the unit was converted to -10/-5 °C setpoints with a cooling capacity of approx. 850 kW. It includes 2 Bitzer screw compressors, 2 independent circuits, a shell-and-tube evaporator for salt brine as cooling medium and a copper-aluminium condenser unit designed for pressures up to 13 Bar. R134a refrigerant provides stable operation at low evaporation and stable oil return, which is critical for systems with lower boiling points.

The fan group consists of 18 axial fans with continuously variable speed control. This configuration keeps condensing pressure at 11-13 Bar, reduces noise and saves up to 15% energy in the off-season. The hydraulic module is based on two Lowara FCT4150-250 pumps – 2×11 kW with redundancy and the possibility of replacing one unit without stopping the system. Motor hours are confirmed by water test and full pre-sale diagnostics. The compressors undergo filter changes and oil checks at every inspection, and the machines are designed to last up to 80,000 operating hours, ensuring many years of operation without a single major intervention in the future.

High-tech approach to HVAC systemisation calculation

The power calculation for the ice field takes into account brine viscosity and density at negative setpoints: ethylene glycol density 1.11 kg/l at -8 °C, viscosity 4.2 mPa/s. To maintain a stable flow rate of 220-230 m³/h, balancing valves with ±2 % setting are installed on each circuit. Pulsation control across the manifolds keeps ΔP ≤0.15 Bar, minimising flow fluctuations and preventing overheating.

The shell-and-tube evaporator is designed for differential pressures up to 14 Bar and brine temperatures of -8 °C, ensuring cavitation-free and stable operation at low temperatures. The copper and aluminium condenser unit uses 25 mm and 24 mm diameter finned tubes for optimum heat transfer at high temperatures.

The automation is integrated with pump and fan speed sensors, allowing fine modulation of the flow within a range of ±5 % of the set flow rate. At the same time, the system monitors overpressure and temperature on each circuit, preventing peak loads and overheating of the oil. Energy efficiency is further improved by optimising ΔT at the manifold – up to 3 K, providing an even ice mirror over an area of 1.5-1.8K m² without potential energy overrun.

The control system provides 4 levels of automatic protection: pressure, temperature, current and compressor vibration, with automatic system thresholds ranging from ±0.2 to ±0.5 Bar.

The electrical part operates on a supply voltage of 400 V ± 10 %, the starting current is limited to 420 A by soft start and frequency control. The speed of the fans varies from 450 to 950 rpm and of the pumps from 980 to 1450 rpm, which allows to maintain the brine flow rate in the range of 85-120 m³/h and the temperature difference not exceeding 0.3 K. All parameters are monitored. All parameters are monitored via 32 telemetry points integrated into the new generation BMS system of the roller.

Reasons for selecting a cooling unit and process synergies

– Two Bitzer screw compressors – for rollers with volatile loads – maintain efficiency at 30-40% of the total capacityand a service life of up to 80,000 engine hours, taking into account evaporations down to -10 °C;

– Shell and tube evaporator – resistant to fouling, designed for brine operation at ∆T ≈ 3 K, allows flushing without disassembly and maintains heat transfer even when particles are fully crystallised;

– Hydromodule – two Lowara pumps with deaeration and changeover under load, integrated flow and pressure sensors, system balancing is ensured in 100% efficiency;

– Two independent circuits – full redundancy; when one circuit is out of service, the other takes over the load without changing the setpoints.

– Fans 18 pcs. – smooth speed control, noise reduction of up to 6 dB(A), adaptation to outdoor temperatures from 5 to 35 °C;

– R134a refrigerant – reliable for screw chillers with low risk of cavitation, stable at minus evaporations providing EER up to 3.3.

Hydraulic-pumping and source flow control

The hydraulic module is based on two Lowara FCT4150-250 pumps, each with a capacity of 45 m³/h at 18 m head. Total flow rate in the circuit is 90 m³/h, temperature delta 4 K, working pressure 4,2 Bar. Both pumps are equipped with frequency converters and operate according to a 12-hour alternation algorithm with automatic switching on of the standby unit when the pressure drops below the nominal 3.8 Bar

The system has 9 sensors: flow, pressure, vibration, supply/return temperature and cavitation. The controller records all parameters in 5-second increments, maintaining a flow rate deviation of no more than ±2.5 %. Pump switching takes place without the presence of water hammer.

The fans are controlled in 1 % speed increments. At an outside temperature of 10 °C the speed drops to 38-40 %, which reduces the energy consumption by up to 14 % and reduces the noise level from 71 dB(A) to 63 dB(A). In night mode, a condensing pressure of 1.25 MPa is maintained with minimal acoustics, which is fully compliant with city regulations.

RHOSS chiller test runs and pre-sales preparation

Before shipment, the chiller was tested on water at the EVROPROM test station with 8 parameters: temperature, pressure, flow rate, compressor speed, current, vibration, noise and EER. The test was carried out at loads of 50 % | 75 % | 100 %. The circuits were tested with nitrogen at 26 Bar, vacuumised and refilled with high quality desiccant.

Results: cooling capacity 912kW, power consumption 282 kW, current 485 A, noise 71 dB(A). The pre-sale report includes replacement of filter-drier, oil test with moisture < 30 ppm and motor insulation test > 1.5 megohms. The test report and video of the test were handed over to the customer together with all certification documentation.

Quick commissioning of the roller with reference quality in mind

Unloading and installation took less than 4 hours, after which the chiller was moved to the site by forklift and secured to the vibration supports. The connection was made to a DN100 brine manifold, the system was flushed with a corrosion inhibitor solution and the flow rate was balanced – 90 m³/h ±2 % at a nominal pressure drop of 4.1 atmospheres.

Pre-commissioning work included calibration of 18 sensors, adjustment of the Siemens RLU220 controller, testing of the high and low pressure setpoint protections at 2.65/0.25 MPa and testing of the automation. The installation was carried out with the use of a 40 T low-loader platform.

After commissioning, optimisation of pump and fan speeds was carried out: 100% | 85% in day mode and 65% | 40% in night mode, which provided up to 12% reduction of energy consumption without loss of stability in ΔT.

Repeat deliveries and continuity in engineering

The Lviv ice rink project is the fourth successful case of EVROPROM and AIS LAB working together after the projects in Kiev, Varna and Alma-Ata.

Over the years of co-operation, a stable engineering bundle has been formed: equipment selection, tests, commissioning and operational control are carried out according to a well-established algorithm within 10-14 days without any downtime.

Each new facility is optimised for local parameters – brine type, climate and skating load. This reduces commissioning by 30 %, minimises the risks of installation errors and reduces energy losses.

EVROPROM is the best choice for an engineering partnership: the company has been on the market for almost 12 years, has customers in 60 countries and a stock of more than 300 HVA equipment units. This scale and technical expertise allow us to guarantee the result – perfectly flat ice with full insurance of the result and savings of up to 14,000 euros per year.

Why choose EVROPROM? HVAC engineering cycle from selection to commissioning with guarantees and energy optimisation

The project demonstrates that EVROPROM is a contractor for companies with their own generation and high requirements for reliability and economics in the industrial operation of high-end projects.

– HVAC engineering cycle – selection, calculation, installation, commissioning and support with 6-36 months warranty including Bitzer compressors, heat exchangers and condensers;

– Testing of 8 parameters – temperature, pressure, flow, cooling capacity, energy consumption, noise, vibrations, Freon refuelling; test station with water and electrical connection, EURO-1 certificate;

– Pre-sale service – flushing, tightness, filters and oil, insulation control; balancing of the hydromodule, check of pump switching under load;

– Documentation – PFI, packing list, test report, protocols and calculations, full transparency for the customer;

– Warehouse and logistics – 250 pieces of equipment, delivery 5-10 days, discounts up to -50%, taxes and customs included;

– Energy saving – Lviv arena: Bitzer & Lowara tuning reduced energy consumption by 18%, savings ~14,000 € for first season, 10 years >140,000 €;

– Reliability – 60 countries, 12 years on the market, two circuits, pump redundancy, service without stopping the rink, power reserve for peak loads;

– Technical transparency – ∆T ≈ 3 K control, brine consumption <3 %, remote support, adaptation to roller schedules, night and day modes.

This project of Lviv ice arena became an example of equipment re-delivery: chiller and hydromodule were selected and adjusted on the basis of previous successful projects, which allowed to reduce installation time, speed up commissioning and immediately ensure stable operation of HVAC-system for uninterrupted rinks operation period of 3-4 months.

Author of the article:

Svyatoslav Ovcharenko, Sales Manager

3.11.2025