Indoor Design Parameters and Thermal Comfort Standards
Article 3.0.2 of GB 50736 specifies the design parameters for hotel guest rooms at Grade I thermal comfort level: summer air-conditioning temperature 24-26°C, relative humidity 40%-60%, air velocity not exceeding 0.25 m/s; winter heating temperature 22-24°C, relative humidity 30%-50%, air velocity not exceeding 0.15 m/s. Public areas: summer temperature 25-27°C, winter temperature 20-22°C. Regarding outdoor air volume, Article 3.0.6 requires guest room outdoor air volume not less than 30 m³/(h·person), and ballroom not less than 20 m³/(h·person). Marriott MIDS requires guest room outdoor air volume of 50 m³/(h·room), Hilton HDDG requires 60 m³/(h·room). Regarding CO2 concentration, indoor CO2 concentration shall not exceed 1000 ppm. Article 3.0.7 requires that for five-star hotel guest rooms, daytime noise shall not exceed 35 dB(A) and nighttime noise shall not exceed 30 dB(A).
Cooling and Heating Load Calculation Methods and Software Application
Article 7.2.1 of GB 50736 mandatorily requires that air-conditioning load calculation shall adopt the hourly load calculation method, and the unit area index method is strictly prohibited. Hourly load calculation shall consider eight factors: envelope heat transfer, solar radiation heat gain, occupant heat gain, lighting heat gain, equipment heat gain, outdoor air load, infiltration air load, and internal heat gain. Dynamic energy simulation software such as EnergyPlus, DeST, DesignBuilder, or HAP is recommended. Taking a five-star hotel in Shanghai (building area 52,000 m²) as an example, the DeST hourly simulation design cooling load was 5,600 kW, while the traditional index estimation method gave 6,500 kW (estimated at 125 W/m²), a difference of 16%. Article 7.2.2 stipulates that the load calculation results of each air-conditioning zone shall be aggregated and the system total load determined after considering the diversity factor. Recommended diversity factors for hotel functional areas: guest room area 0.7-0.8, restaurant area 0.8-0.9, ballroom 1.0.
Air-Conditioning System Type Selection and Zoning Principles
Section 8.1 of GB 50736 specifies the basic principles for air-conditioning system type selection. For hotel guest room areas, fan coil unit + fresh air system (FCU+FAU) or variable air volume system (VAV) is recommended. For public areas, all-air constant air volume (CAV) or variable air volume (VAV) system is recommended. The kitchen area shall be provided with an independent once-through air-conditioning system (no return air) per Article 8.1.7. Regarding system zoning, Article 8.1.5 stipulates that air-conditioning air systems shall be zoned by orientation, usage function, and usage time. Water system zoning shall consider building height; Article 8.5.5 requires that the vertical zoning height of chilled water systems should not exceed 100 m, and when exceeded, intermediate heat exchangers or two-stage pump systems shall be provided. Marriott MIDS requires zoning height not exceeding 80 m.
Energy-Efficient Design and Energy Efficiency Index Requirements
Article 5.2.1 of GB 50189 requires that when the rated cooling capacity is greater than 1163 kW, the COP of water-cooled centrifugal chillers shall not be lower than 5.6, and Grade 1 energy efficiency products (COP not lower than 6.0) are recommended. Marriott MIDS requires COP not lower than 6.3, Hilton HDDG requires COP not lower than 6.0. Article 8.5.12 requires variable frequency control for chilled water and cooling water systems. Article 7.3.2 requires the provision of exhaust air heat recovery devices, with sensible heat recovery efficiency not lower than 60% and total heat recovery efficiency not lower than 50%. Marriott MIDS requires heat recovery efficiency not lower than 65%. Regarding insulation thickness, Article 11.1.4 requires calculation based on condensation prevention requirements and compliance with the minimum insulation thickness requirements of GB 50189. Taking the Shanghai region as an example, the insulation layer thickness for DN50 chilled water pipes shall not be less than 40 mm (closed-cell elastomeric material).