commercial central air-conditioning systems
The design of commercial central air-conditioning systems requires comprehensive consideration of multiple dimensions such as building characteristics, usage requirements, energy efficiency, etc., and the corresponding equipment must be matched to achieve stable, efficient and energy-saving operation.
Load calculation: "basic parameters" of system design
- Accurate calculation of cold/heat load: The hourly cold/heat load needs to be calculated using professional software based on the building area, building envelope, fresh air load, etc.
- Dynamic load characteristics: Load fluctuations in different time periods and seasons need to be considered to ensure that the system can be flexibly adjusted.
Architectural and spatial characteristics
- Building structure: floor height, ceiling space, machine room location, load bearing.
- Enclosure structure: exterior wall insulation, glass curtain wall ratio, door and window sealing.
- Functional zoning: Different areas in the same building have different requirements and require zoning design.
Usage requirements
- Temperature and humidity requirements:
- Different scenarios require different temperature and humidity requirements.
- Fresh air and cleanliness: places with dense crowds need to ensure fresh air volume; hospitals and laboratories need to filter PM2.5 and sterilize; chemical workshops need explosion-proof and anti-corrosion designs.
Energy and Environmental Protection
- Energy type: Select according to local resources; give priority to the use of renewable energy.
- Environmental protection requirements: refrigerants must comply with local regulations; noise control.
- Energy-saving design: use frequency conversion technology, waste heat recovery, and heat recovery fresh air unit.
System type
- Centralized system: large shopping malls, gymnasiums, hospital outpatient buildings
- Semi-centralized system: office buildings, hotel rooms
- Decentralized system: small and medium-sized office buildings, restaurants, exhibition halls
- Radiated system: high-end office buildings, hotels (requires low wind speed).
Installation and maintenance
- Space restrictions: Space should be reserved for air ducts and water pipes to avoid conflicts with fire pipes and cable trays; maintenance channels should be reserved in the machine room.
- Maintenance convenience: Filters should be easy to replace; equipment should have maintenance doors; pipes should be equipped with drain valves and pressure gauges.
Control and intelligence
- Zoning control: Independent control by floor and functional area to avoid energy waste.
- Intelligent linkage: integrated with BA (building automation) system, real-time adjustment through sensors.
- Emergency guarantee: key areas require dual power supply or backup cold and heat sources to avoid downtime risks.
Cost and cycle
- Initial investment: equipment purchase (accounting for 60%-70%), installation engineering (pipes, air ducts, civil engineering), design fees; performance and cost need to be balanced.
- Operation cost: energy consumption (accounting for more than 70% of the full cycle cost), maintenance costs (filter replacement, equipment maintenance); equipment with high energy efficiency ratio (COP) (such as first-class energy efficiency chillers) is preferred.
Regulations and standards
- Must comply with the "Design Code for Heating, Ventilation and Air Conditioning of Civil Buildings" (GB50736), "Design Standard for Energy Saving in Public Buildings" (GB50189), etc. In terms of fire protection, air ducts must be made of non-combustible materials (such as galvanized steel plates), and fire dampers (70°C fuse) must be installed at places where they pass through fire partitions.