The magazine "SBC. Sport Business Consulting” (issue №35) published an article by Sergey Bryuzgin, Head of the Heating, Ventilation and Air Conditioning department of the Metropolis company, entitled “Microclimate of ice arenas” about the design features of engineering systems of indoor ice complexes.
The main requirement for the design and further operation of ice sports facilities is the quality of the ice and, as a result, the maintenance of the temperature and humidity conditions required for the normal functioning of the ice field. At the same time, the required characteristics of ice rinks for arenas and skating venues may differ from each other in microclimate parameters depending on the functional purpose and mode of operation of the facility. Despite the general principles, it is necessary to apply a differentiated approach to heating, ventilation and air conditioning (HVAC) systems for indoor rinks and ice arenas.
The main function of HVAC systems is to maintain the temperature and humidity conditions:
- to ensure the required parameters of the ice field;
- for the normal work of athletes;
- for a comfortable stay of spectators in the stands.
HVAC systems must provide the required microclimate parameters in different functional areas of the ice arena. The temperature of ice in the ice rink during sports events is limited by technological requirements and is -7°С, -5°С, -4°С for short track, hockey and figure skating, respectively. At the same time, the required air temperature at a level of 1.5 m from the ice surface should be provided in the ranges of +6°С….+12°С, and in the stands +10°С…+15°C. The design conditions in different functional areas are significantly affected by heat and moisture release, which directly depend on the number of spectators during mass events.
The main problems that arise in the premises of ice arenas and indoor rinks
When designing air conditioning systems for ice arenas, one of the main problems that designers have to face is the need to prevent the creation of conditions for the formation of excess air humidity in the room. As a result of the interaction between the ice surface and the surrounding air with excess moisture, fog can form over the surface of the ice rink, which in turn affects the energy consumption of refrigeration systems and the physical characteristics of the ice cover. It is worth paying special attention to the characteristics of the enclosing structures of the ice arenas and especially the enclosing structures of the premises adjacent to the ice arena. Structures under the influence of radiant (radiative) heat transfer can be cooled to temperatures below the dew point temperature of the air surrounding them, and conditions for condensation can form on the surface of the fences. In order to reduce this effect, the surfaces of enclosing structures should be provided with a minimum absorption coefficient.
Radiant heat transfer for closed systems in a simplified form can be described by the formula q = eпС0[(T1/100)4 - (T2/100)4], in which one of the significant factors that can be influenced is the reduced coefficient eп, characterizing the emissivity of a system of bodies. The reduction of this coefficient can be ensured by the appropriate selection of finishing materials. This aspect, which significantly affects the energy efficiency of ice field cooling systems, is an integral part of architectural planning and interior solutions, and an incorrect choice of finishing materials can increase the energy consumption of cooling systems from 30 to 150 kW, which can be a significant value throughout the entire life cycle of a sports facility.
The most effective material for finishing the roof of an ice arena in terms of thermophysical processes is an insulating material with a foil surface with an absorption coefficient of 0.1. Galvanized steel is also effective and has an absorption coefficient of 0.3. The use of dark colors for finishing the internal enclosing structures of indoor ice structures should be carried out carefully, since this solution increases the radiant heat transfer from the heated internal surfaces to the ice surface and, as a result, the cooling power spent on its freezing. During breaks in the use of ice rinks and arenas, it is advisable to increase the temperature of the ice field. This possibility should be provided at the design stage of engineering systems and their automation. Each degree of increase in the temperature of the ice surface contributes to a reduction in energy consumption for the refrigeration system by 2-3%, which is primarily associated with a decrease in radiation and convective heat transfer from surrounding structures, air and the ice surface.
Solution methods for obtaining optimal microclimate parameters and the use of numerical methods for calculating the thermodynamic state of the air environment
When designing air conditioning systems, many factors that affect the microclimate of the room and the energy efficiency of the complex cannot be described by simple numerical methods. Therefore, when designing sports facilities, and especially ice arenas, it is advisable to use numerical methods for modeling hydrodynamic processes (CFD modeling) with subsequent analysis of the results obtained.
In their practice, the specialists of the Metropolis company used this approach for a wide range of facilities and, in particular, for the Dynamo ice arena with a seating capacity of up to 12,000 spectators.
At the Project stage, Metropolis specialists performed the development of engineering systems for the entire complex, as well as CFD modeling of the ice arena.
In rooms with a mass stay of people, air convective flows are formed due to heat and moisture emissions from the audience. These flows, in turn, can create microclimate parameters that are uncomfortable for the spectators and athletes themselves. In particular, the non-isothermal nature of air jets and the effect of carbon dioxide released during respiration, as a substance with a higher molar mass, can form zones on the lower tiers of stands with an excessive level of CO2 concentrations, as well as with increased mobility of air masses. Determination of critical conditions for the microclimate at the design stage based on the analysis of the CFD model allows timely decisions to be made both in terms of engineering systems and architectural and planning solutions, providing for additional shafts and air distributors in the lower part of the stands. To achieve the required microclimate parameters in the premises, both in the volume of the ice rink and in the volume of the stands, as a rule, separate climatic installations are provided, the main task of which is to assimilate excess moisture from the air and maintain the required temperature.
But only by the result of the analysis of the CFD model it is possible to determine the most optimal ratios of temperatures and air flow rates for arenas with a mass stay of people. Such modeling sometimes makes it possible to solve questions that seem at first glance indefinable. And the design solutions chosen on its basis successfully increase the energy efficiency of systems. Classic bottom-up or top-up air distribution schemes can have significant differences in supply and exhaust air flow rates for the considered room at the same target values of the required temperature, relative humidity and carbon dioxide concentration. The choice of air distribution scheme directly affects the air exchange costs in rooms with a massive stay of people, often exceeding sanitary standards.
The accumulated experience in working with technically complex sports facilities, combined with the use of CFD modeling, made it possible to apply the existing knowledge in the integrated work for the project of the training skating rink of the "Sports complex Olympic Village-80" of the Moskomsport at the address: Moscow, Michurinsky Prospekt, Olympic Village, d. 2. Acting as the General Designer at the facility, the Metropolis company acted as the author of technological, architectural, structural and engineering solutions. In the hall of the ice arena of the sports facility, measures were taken to maintain the microclimate, which were reflected in:
- thermal engineering solutions associated with architectural solutions in terms of thermal insulation;
- interior solutions in terms of materials used;
- engineering solutions in terms of organizing air exchange and air distribution.
The complex was developed by the Metropolis company at the Design and Working Documentation stages using BIM and in 2017 entered the final of the BIM technology competition organized by the Ministry of Construction of Russia.
Architectural solutions for ice arenas should combine a modern form, a bright personality and progressive energy-efficient engineering systems. Only in this combination will the building meet the high requirements of the end user and owner throughout the entire life cycle of the facility. For complex sports facilities, the use of CFD modeling is necessary and economically justified, as it leads to the optimization of financial costs both at the construction stage and during the operation of the facility. In addition, this work allows you to timely evaluate the correctness of the decisions made and, if necessary, make the required changes to the project.
Read the full material on the Sport Business Consulting website.