The first application of refrigeration CO2 in ski facility cooling system.

Indoor skiing is on the rise. Indoor ski resorts have been used all over the world. There are hundreds of millions of Dubai ski resorts in the distance, and the Qiaobo ski resort in the Royal Park. Recently, with the completion of the Wenzhou County Swan Castle Ski Hall, Wenzhou people are also at their doorstep.

You can experience the world of ice and snow.
Located in Shijie Forest Park, Wencheng County, which is known as the “Healthy Preserve and Summer Survival Paradise”, the Swan Castle Indoor Ski Resort in Wenzhou City of Zhejiang Province is one of the top supporting projects in the super large-scale tourism complex of the Swanburg Township. Advanced system

Cold, snow-making technology, 205 meters long slide, sliding hall can accommodate 600 people skiing. The altitude of the ski stadium is 800m, the building area is about 8000m2, the width of the ski trail is 36m, the bottom width is 45m, the top building height is 10m, the bottom building height is 12m, and the ski trail is long

The degree is 200m, the slope is 14°, 10°, and 8°; the design venue can accommodate 300 people at the same time, the ski venue is open every day from 10:00 to 0:00, and the snow making time is from 0:00 to 8: 00. Maximum heat transfer load inside the ski area: 860 kW; fresh air volume:


System Overview

For the consideration of system safety and environmental protection, the Swan Township Ski Resort adopted R507 and CO2 cooling system technology. The high-temperature side refrigerant is R507, whose ODP value (destruction ozone potential value) = 0, GWP value (global warming coefficient value) = 3985, at this stage

Environmental protection refrigerants; in the dense areas of the ski resort, where personnel are active, use safe and environmentally friendly CO2 as a refrigerant and use CO2 to evaporate directly to cool the air. In this project, the evaporating temperature of high temperature grade R507 is used to condense the low temperature grade CO2 gas and condense into a liquid and then use the pump

Send to the end heat exchanger evaporation heat transfer.

case analysis

Refrigeration system is safe and environment-friendly, economical and energy-saving, and advanced in technology level.

High-temperature refrigeration working fluid selection: As the refrigerating engine room of the project belongs to civilian buildings in the ski resorts, the traditional R22 refrigerant will not pass the EIA approval, and the use of ammonia (R717) as the refrigerant will not be approved by the safety assessment. High temperature system

The choice of azeotropic refrigerant R507 is environmentally friendly, economical and easy to purchase.

The selection of cryogenic refrigerants: The investment and operating costs of ski resorts has always been the focus of ski resort investors. The energy conservation and insulation of ski resorts is also the focus of refrigeration and architectural design. The project fully considered the refrigeration system at the beginning of the project design

The energy-saving operation.

The traditional ski resort uses ethylene glycol aqueous solution as a refrigerant, and it needs to transport ethylene glycol aqueous solution through a brine pump to the chiller coils in the ski resort. The sensible value of the temperature rise of the brine will be used in the ski resort. Heat load away.

In this project, CO2 is selected as a cryogenic grade refrigerant. The CO2 pump conveys the CO2 liquid and evaporates within the chiller coil to remove the heat load in the ski resort. CO2 as a refrigerant is phase-change heat, compared with the traditional ski resorts using ethylene glycol aqueous solution, single

The large capacity for bit volume refrigeration, the small size of the coolant system piping, valves and CO2 pump, the small CO2 pump power, and the advantages of energy saving and environmental protection.

Energy efficiency analysis

The use of CO2 for evaporative cooling can save users a considerable (about 350,000) operating costs per year compared to glycol-based refrigerant systems.
Major equipment selection

1. Refrigeration Compressor Unit: The compressor of this project selects “semi-closed open type screw refrigeration compressor unit” and closes the compressor and the motor with a shell, which solves the problem that the shaft seal of the screw compressor is easily leaked and the shaft seal is vulnerable. Pieces of the problem. In order to improve the system

The cooling efficiency of the compressor motor is cooled with cooling water.

2. Design of air coolers in the pavilion: Taking into account the uniformity of cooling in large spaces in ski resorts, the use of 18 stainless steel tubes in the form of ceilings for CO2 coolers are all on the side of a ski run of about 200m in length, requiring a high range of chillers. low noise.

The chiller adopts the CO2 pump to supply liquid, and at the same time, the ICS liquid level control valve is installed at the inlet of the chiller to ensure that the liquid supply for multiple different level elevation chillers is even.

3, the cream flushing method: Due to the relatively high relative humidity in the stadium, taking into account the chiller frost and cream, the project uses the water flush cream method, safe and reliable, economical and energy saving.

The flushing water tank is set at the lowest point of the ski resort building. The water tank does not need to be insulated. Considering that the flushing water in the water tank may have freezing water freezing for many cycles, a condensing condenser is installed on the intake pipe. Taiwan heat recovery, utilization

Waste heat from the compressor’s exhaust is counteracted by frost water heat treatment.

After calculation and selection, the power and head of the submersible pump for the red water submersible pump and the regenerator are the same. In the optimized design of the plan, the two submersible pumps are used for each other.

4, the design of the new air system

1) Energy-saving design of ventilation

The design of ski resorts is different from that of cold storage design. It is necessary to consider the air quality requirements of the occupants of the stadium. It is necessary to replenish the venue with a certain amount of fresh air. This is similar to air-conditioning design. Taking into account the energy efficiency of the cooling system program, ventilation through fresh air

The machine exchanges heat between the discharged waste air and fresh air. According to the characteristics of the building space, 3 new air ventilators are selected, which are respectively arranged in the middle and both ends of the ski field. A single fresh air ventilator can be exchanged for 5000m3/h.

2) The function design of fresh air dehumidification

After calculation, after the heat exchange between waste air and fresh air, the fresh air is cooled to 21°C. In order to prevent the fresh air from entering the ski hall (maintaining temperature at -3°C), fogging occurs, and the fresh air after heat exchange needs to be dehumidified. In the plan, a dehumidification and cooling device is added to the fresh air ventilator.

The dehumidifying cold source is provided by the siphon evaporator ZFH56 of the refrigeration system.

5, other

1) The project plans to use water-saving and energy-saving evaporative condensers to further improve the operating efficiency of the refrigeration system;

2) The project plans to use a vertical siphon reservoir, the reservoir also serves as a siphon tank, reducing the refrigerant system refrigerant R507 charge.

The design of the ski resort cooling system has many similarities with traditional air conditioning design and cold storage design, but it has its own particularities. If the refrigerating machine room is included in a civil building, the temperature in the stadium is between the air-conditioned room temperature and the cold room storage temperature, and the choice of refrigerant and refrigerant

Large-space cooling temperature field uniformity; fresh air system energy-saving and comfortable appearance. There is a limited number of examples of projects that can be referenced in the country. In particular, ski resorts with CO2 as a refrigerant are unprecedented. Wencheng County Swan Castle Skiing project successfully signed a make up

The gap in the domestic market laid the foundation for the development of CO2 as a refrigerant-based refrigeration system for domestic all-weather indoor ski resorts.